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  • 1.
    Abbott, Jessica K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Svensson, Erik I.
    Lund University.
    Morph-specific variation in intersexual genetic correlations in an intra-specific mimicry system2010In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 12, no 1, p. 105-118Article in journal (Refereed)
    Abstract [en]

    Background: Positive intersexual genetic correlations are typically viewed as constraining the evolution of sexual dimorphism, when traits are subject to sexually antagonistic selection. Our study species, the damselfly Ischnura elegans, has a female-limited colour polymorphism with three female colour morphs (males are monomorphic), one of which is considered a male mimic.

    Question: Are there morph-specific differences in the magnitude of intersexual genetic correlations in I. elegans? Specifically, do male-mimic (Androchrome) females have higher intersexual genetic correlations for morphological traits than non-mimic (Infuscans) females?

    Methods: We collected copulating pairs in the field and raised offspring from these pairs in the laboratory. We measured five morphological traits in both parent and offspring generations and investigated their heritabilities and genetic correlations.

    Results: We found a negative overall relationship between the degree of sexual dimorphism for a trait and its intersexual genetic correlation. But the magnitude and direction of intersexual genetic correlations depended on the female morph. As expected, male mimic (Androchrome) females had higher intersexual genetic correlations. In addition, the genetic correlations between the morphs were in all cases significantly lower than unity. Male mimic (Androchrome) females had higher mother-son covariances than the non-mimic (Infuscans) morph, and this difference is the proximate explanation for the difference in intersexual genetic correlations between the morphs.

  • 2.
    Abrahamsson, K., Choo, K.-S., Pedersén, M., Johansson, G. and Snoeijs, P.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Plant Ecology. PLANT ECOLGY.
    Effects of temperature on the production of hydrogen peroxide and volatile halocarbons by brackish-water algae2003In: Phytochemistry, Vol. 64, p. 725-734Article in journal (Refereed)
  • 3. Abrahamsson, K.
    et al.
    Pakhomovc,, E.A.
    Loréna, A.
    Fronemanc,, P.W.
    Bertilsson, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Chiericia,, M.
    Franssona, A.
    Variations of biochemical parameters along a transect in the Southern Ocean, with special emphasis on volatile halogenated organic compounds2004In: Deep Sea Research Part II:: Topical Studies in Oceanography, Vol. 51,, no 22-24, p. 2745-2756Article in journal (Refereed)
    Abstract [en]

    A number of parameters of biogeochemical interest were monitored along a north–southerly transect (S 43–S 63°) in the Atlantic Sector of the Southern Ocean from the 8th to the 20th of December 1997. Changes in total dissolved inorganic carbon (CT) and total alkalinity (AT) were mostly dependent on temperature and salinity until the ice edge was reached. After this point only a weak correlation was seen between these. Highest mean values of CT and AT were observed in the Winter Ice Edge (WIE) (2195 and 2319 μmol kg−1, respectively). Lowest mean AT (2277 μmol kg−1) was observed in the Sub-Antarctic Front (SAF), whereas lowest mean CT concentration (2068 μmol kg−1) was associated with the Sub-Tropical Front (STF). The pH in situ varied between 8.060 and 8.156 where the highest values were observed in the southern part of the Antarctic Polar Front (APF) and in the Summer Ice Edge (SIE) Region . These peaks were associated with areas of high chlorophyll a (chl a) and tribromomethane values. In the other areas the pH in situ was mainly dependent on hydrography. Bacterial abundance decreased more than one order of magnitude when going from north to south. The decrease appeared to be strongly related to water temperature and there were no elevated abundances at frontal zones. Microphytoplankton dominated in the SAF and APF, whereas the nano- and picoplankton dominated outside these regions.

    Volatile halogenated compounds were found to vary both with regions, and with daylight. For the iodinated compounds, the highest concentrations were found north of the STF. Brominated hydrocarbons had high concentrations in the STF, but elevated concentrations were also found in the APF and SIE regions. No obvious correlation could be found between the occurrence of individual halocarbons and chl a. On some occasions trichloroethene and tribromomethane related to the presence of nano- and microplankton, respectively.

  • 4.
    Admassu, Demeke
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Limnology.
    Ahlgren, Ingemar
    Department of Ecology and Evolution, Limnology.
    Growth of juvenile tilapia, Oreochromis niloticus L. from Lakes Zwai, Langeno and Chamo (Ethiopian rift valley) based on otolith microincrement analysis2000In: Ecology of Freshwater Fish, Vol. 9, no 3, p. 127-137Article in journal (Refereed)
    Abstract [en]

    Age and growth of juvenile tilapia, Oreochromis niloticus, from Lakes Zwai, Langeno and Chamo (Ethiopia) were studied from microincrements in otoliths. Growth in length was best described by the Gompertz model. Average growth rate of the fish was most rap

  • 5. Adrian, Rita
    et al.
    O`Reilly, Catherine M.
    Zagarese, Horacio
    Baines, Stephen B.
    Hessen, Dag O.
    Keller, Wendel
    Livingstone, David M.
    Sommaruga, Ruben
    Straile, Dietmar
    Van Donk, Ellen
    Weyhenmeyer, Gesa A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Winder, Monika
    Lakes as sentinels of climate change2009In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 54, no 6(2), p. 2283-2297Article in journal (Refereed)
    Abstract [en]

    While there is a general sense that lakes can act as sentinels of climate change, their efficacy has not been thoroughly analyzed. We identified the key response variables within a lake that act as indicators of the effects of climate change on both the lake and the catchment. These variables reflect a wide range of physical, chemical, and biological responses to climate. However, the efficacy of the different indicators is affected by regional response to climate change, characteristics of the catchment, and lake mixing regimes. Thus, particular indicators or combinations of indicators are more effective for different lake types and geographic regions. The extraction of climate signals can be further complicated by the influence of other environmental changes, such as eutrophication or acidification, and the equivalent reverse phenomena, in addition to other land-use influences. In many cases, however, confounding factors can be addressed through analytical tools such as detrending or filtering. Lakes are effective sentinels for climate change because they are sensitive to climate, respond rapidly to change, and integrate information about changes in the catchment.

  • 6. Ah-King, Malin
    et al.
    Elofsson, Helena
    Kvarnemo, Charlotta
    Rosenqvist, Gunilla
    Berglund, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Why is there no sperm competition in a pipefish with externally brooding males? Insights from sperm activitation and morphology2006In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 68, no 3, p. 958-962Article in journal (Refereed)
    Abstract [en]

    Nerophis ophidion sperm activation and morphology were investigated with the aim of explaining the apparent lack of sperm competition in this syngnathid with externally brooding males. Nerophis ophidion sperm were activated by a mixture of ovarian fluid and sea water, but not by sea water alone. This indicated that sperm were not shed into the water but needed to be released near the eggs, which probably restrained sperm competition.

  • 7.
    Ahlgren, G
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Limnology.
    Ahlgren, I
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Limnology.
    Hernández, S
    Mejia, M.
    Fatty acid quality of seston and its effects on small fish in the lakes Xolotlán and Cocibolca, Nicaragua.2002In: Verh. Internat. Verein. Limnol., Vol. 28, p. 786-791Article in journal (Refereed)
  • 8.
    Ahlgren, G.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Limnologi.
    Van Niewerburgh, L
    Wänstrand, I.
    Pedersén, M.
    Boberg, M.
    Medicinska vetenskapsområdet, Faculty of Medicine, Department of Public Health and Caring Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Imbalance of fatty acids in the base of the Baltic sea food web - a mesocosm study.2005In: Canadian Journal of Fisheries and Aquatic Sciences ., Vol. 62:, p. 2240-2253Article in journal (Refereed)
    Abstract [en]

    A reproductive disturbance in Baltic Sea Atlantic salmon (Salmo salar), the M74 syndrome, has been reported since early 1970s and has occasionally caused up to 90% mortality for newborn fry. Previous research has revealed that the M74 syndrome may be due to reduced levels of the vitamin thiamin, the carotenoid astaxanthin, and elevated ratios of 3/ 6 fatty acids in salmon eggs. Using mesocosm experiments, we compared the quantity (µg•L–1) and quality (mg•g–1 C) of fatty acids in microalgae and copepods in the southern Baltic Sea where the M74 syndrome is common with those in a habitat in the Norwegian Sea where the syndrome has not been observed. Daily additions were made of the nutrients N and P or N, P, and Si, copepods were added after 6–7 days, and nutrient additions were stopped after 9–10 days. Flagellates dominated completely in the Baltic Sea, whereas higher phytoplankton diversity was found in the Norwegian Sea. We found elevated 3/ 6 ratios in phytoplankton and abnormally high docosahexaenoic acid/arachidonic acid ratios (22:6 3/20:4 6) in copepods in the Baltic Sea mesocosms compared with those in the Norwegian Sea. Our results suggest that imbalance in fatty acid composition may prevail in the basic food web of the Baltic Sea.

    On a signalé depuis le début des années 1970 une perturbation de la reproduction, le syndrome M74, chez le saumon atlantique (Salmo salar) de la Baltique qui, à l’occasion, cause une mortalité pouvant atteindre 90 % chez les alevins néonates. Les études antérieures ont montré que le syndrome M74 peut être dû à des concentrations faibles de la vitamine thiamine et du caroténoïde l’astaxanthine et à des rapports élevés des acides gras 3/ 6 dans les oeufs de saumons. Dans des expériences de mésocosmes, nous avons comparé la quantité (µg•L–1) et la qualité (mg•g–1 C) des acides gras dans les microalgues et les copépodes dans le sud de la Baltique où le syndrome M74 est répandu à celles d’un habitat de la mer de Norvège où le syndrome n’a pas été observé. Nous avons ajouté quotidiennement les nutriments N et P ou alors N, P et Si, introduit des copépodes au bout de 6–7 jours et arrêté les additions de nutriments après 9–10 jours. Dans la Baltique, les flagellés sont dominants, alors que, dans la mer de Norvège, le phytoplancton est plus diversifié. Dans les mésocosmes de la Baltique, les rapports 3/ 6 du phytoplancton sont élevés et les rapports acide docosahexanoïque/acide arachidonique (22:6 3/20:4 6) anormalement grands chez les copépodes, par comparaison aux mésocosmes de la mer de Norvège. Nos résultats laissent croire qu’il peut y avoir un déséquilibre dans la composition en acides gras dans le réseau alimentaire de base de la Baltique.

  • 9.
    Ahlgren, Gunnel
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Limnology. Limnologi.
    Goedkoop, Willem
    Markensten, Hampus
    Department of Ecology and Evolution, Limnology. Limnologi.
    Sonesten, Lars
    Boberg, Mats
    Seasonal variations in food quality for pelagic and benthic invertebrates in Lake Erken - the role of fatty acids1997In: FRESHWATER BIOLOGY, ISSN 0046-5070, Vol. 38, no 3, p. 555-570Article in journal (Refereed)
    Abstract [en]

    1. Plankton net samples and sedimenting matter in traps from mesotrophic Lake Erken, Sweden, were analysed for carbon (C), nitrogen (N) phosphorus (P), total lipids and fatty acid (FA) content to determine what differences and seasonal changes might exist

  • 10.
    Ahlgren, Gunnel
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Limnologi.
    Hyenstrand, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Limnologi.
    Nitrogen limitation effects of different nitrogen sources on nutritional quality of two freshwater organisms, Scenedesmus Quadricauda (Clorophyceae) and Synechococcus sp. (Cyanophyceae)2003In: J. Phycol., Vol. 39, p. 906-917Article in journal (Refereed)
  • 11.
    Ahlgren, Gunnel
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Limnology.
    Hyenstrand, Per
    Vrede, Tobias
    Department of Ecology and Evolution, Limnology.
    Karlsson, E
    Zetterberg, S.
    Nutritional quality of Scenedesmus quadricauda (Chlorophyceae) grown in different nitrogen regimes and tested on Daphnia2001In: International Association of Theoretical and Applied Limnology, Vol. 27, no 3, p. 1234-1238Article in journal (Refereed)
  • 12.
    Ahlgren, Gunnel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Tilahun, Girma
    Fatty acid quality of the basic food web in the Ethiopian lakes Awassa, Chamo, and Ziway2008In: INTERNATIONAL ASSOCIATION OF THEORETICAL AND APPLIED LIMNOLOGY, VOL 30, PT 4, PROCEEDINGS / [ed] Jones J, Faaborg J, 2008, Vol. 30, no 4, p. 581-586Conference paper (Refereed)
  • 13.
    Ahlgren, Gunnel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Vrede, Tobias
    Goedkoop, Willem
    Fatty acid ratios in freshwater fish, zooplankton and zoobenthos - Are there specific optima?2009In: Lipids in aquatic ecosystems / [ed] Michael T. Arts, Michael T. Brett, Martin J. Kainz, London: Springer , 2009, p. 147-178Chapter in book (Other (popular science, discussion, etc.))
  • 14.
    Ahlgren, Ingemar
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Limnologi.
    Drakare, Stina
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Limnologi.
    Factors controlling pelagic and sediment heterotrophic bacterial numbers and production in lakes.2002In: Verh. Internat. Verein. Limnol, Vol. 28, p. 792-797Article in journal (Refereed)
  • 15.
    Ahlgren, Ingemar
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Limnology. Limnologi.
    Eriksson, R
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Limnology. Limnologi.
    Moreno, L
    Pacheco, L
    Montenegro-Guillén, S
    Vammen, K
    Pelagic food web interactions in Lake Cocibolca, Nicaragua2001In: Verh. Internat. Verein. Limnol., Vol. 27, no 4, p. 1740-1746Article in journal (Refereed)
  • 16.
    Ahlgren, Joakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    De Brabandere, Heidi
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Reitzel, Kasper
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Waldebäck, Monica
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Sediment Phosphorus Extractants for Phosphorus-31 Nuclear Magnetic Resonance Analysis: A Quantitative Evaluation2007In: Journal of Environmental Quality, ISSN 0047-2425, E-ISSN 1537-2537, Vol. 36, no 3, p. 892-898Article in journal (Refereed)
    Abstract [en]

    The influence of pre-extractant, extractant, and post-extractant on total extracted amounts of P and organic P compound groups measured with 31P nuclear magnetic resonance (31P-NMR) in lacustrine sediment was examined. The main extractants investigated were sodium hydroxide (NaOH) and sodium hydroxide ethylenediaminetetraacetic acid (NaOH-EDTA) with bicarbonate buffered dithionite (BD) or EDTA as pre-extractants. Post extractions were conducted using either NaOH or NaOH-EDTA, depending on the main extractant. Results showed that the most efficient combination of extractants for total P yield was NaOH with EDTA as pre-extractant, yielding almost 50% more than the second best procedure. The P compound groups varying the most between the different extraction procedures were polyphosphates and pyrophosphates. NaOH with BD as pre-extractant was the most efficient combination for these compound groups.

  • 17.
    Ahlgren, Joakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Reitzel, Kasper
    Danielsson, Rolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Biogenic phosphorus in oligotrophic mountain lake sediments: Differences in composition measured with NMR spectroscopy2006In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 40, no 20, p. 3705-3712Article in journal (Refereed)
    Abstract [en]

    Phosphorus (P) composition in alkaline sediment extracts from three Swedish oligotrophic mountain lakes was investigated using P-31-NMR spectroscopy. Surface sediments from one natural lake and two mature reservoirs, one of which has received nutrient additions over the last 3 years, were compared with respect to biogenic P composition. The results show significant differences in the occurrence of labile and biogenic P species in the sediments of the different systems. The P compound groups that varied most between these three systems were pyrophosphate and polyphosphates, compound groups known to play an important role in sediment P recycling. The content of these compound groups was lowest in the reservoirs and may indicate a coupling between anthropogenic disturbances (i.e., impoundment) to a water system and the availability of labile P species in the sediment. A statistical study was also conducted to determine the accuracy and reliability of using P-31-NMR spectroscopy for quantification of sediment P forms.

  • 18.
    Ahlgren, Joakim
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry.
    Reitzel, Kasper
    Danielsson, Rolf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry.
    Gogoll, Adolf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Rydin, Emil
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Biogenic phosphorus in oligotropic mountain lake sediments: Differences in composition measured with NMR spectroscopy2006In: Water Research, no 40, p. 3705-3712Article in journal (Refereed)
  • 19.
    Ahlgren, Joakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Reitzel, Kasper
    Tranvik, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Degradation of organic phosphorus compounds in anoxic Baltic Sea sediments: A P-31 nuclear magnetic resonance study2006In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 51, no 5, p. 2341-2348Article in journal (Refereed)
    Abstract [en]

    The composition and abundance of phosphorus extracted by NaOH-ethylenediaminetetraacetic acid from anoxic Northwest Baltic Sea sediment was characterized and quantified using solution P-31 nuclear magnetic resonance. Extracts from sediment depths down to 55 cm, representing 85 yr of deposition, contained 18.5 g m(-2) orthophosphate. Orthophosphate monoesters, teichoic acid P, microbial P lipids, DNA P, and pyrophosphate corresponded to 6.7, 0.3, 1.1, 3.0, and 0.03 g P m(-2), respectively. The degradability of these compound groups was estimated by their decline in concentration with sediment depth. Pyrophosphate had the shortest half-life (3 yr), followed by microbial P lipids with a half-life of 5 yr, DNA P (8 yr), and orthophosphate monoesters (16 yr). No decline in concentration with sediment depth was observed for orthophosphate or teichoic acid P.

  • 20.
    Ahlgren, Joakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Tranvik, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Waldebäck, Monica
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Markides, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Sediment Depth Attenuation of Biogenic Phosphorus Compounds Measured by 31P NMR2005In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 39, no 3, p. 867-872Article in journal (Refereed)
    Abstract [en]

    Being a major cause of eutrophication and subsequent loss of water quality, the turnover of phosphorus (P) in lake sediments is in need of deeper understanding. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. This P is incorporated in a poorly described mixture of autochthonous and allochthonous sediment and forms the primary storage of P available for recycling to the water column, thus regulating lake trophic status. To identify and quantify biogenic sediment P and assess its lability, we analyzed sediment cores from Lake Erken, Sweden, using traditional P fractionation, and in parallel, NaOH extracts were analyzed using 31P NMR. The surface sediments contain orthophosphates (ortho-P) and pyrophosphates (pyro-P), as well as phosphate mono- and diesters. The first group of compounds to disappear with increased sediment depth is pyrophosphate, followed by a steady decline of the different ester compounds. Estimated half-life times of these compound groups are about 10 yr for pyrophosphate and 2 decades for mono- and diesters. Probably, these compounds will be mineralized to ortho-P and is thus potentially available for recycling to the water column, supporting further growth of phytoplankton. In conclusion, 31P NMR is a useful tool to asses the bioavailability of certain P compound groups, and the combination with traditional fractionation techniques makes quantification possible.

  • 21.
    Ahnesjö, Ingrid
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Behavioural temperature preference in a brooding male pipefish Syngnathus typhle2008In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 73, no 4, p. 1039-1045Article in journal (Refereed)
    Abstract [en]

    In the broad-nosed pipefish Syngnathus typhle, brooding males positioned themselves significantly more often towards the warmer part (18 degrees C) of an aquarium. whereas females were indifferent in this respect. This behavioural temperature preference may increase male brooding rate and indirectly influence patterns of mating competition. (c) 2008 The Author Journal compilation (c) 2008 The Fisheries Society of the British Isles.

  • 22.
    Ahnesjö, Ingrid
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Seahorses and Their Relatives2010In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 77, no 1, p. 308-309Article, book review (Other academic)
  • 23. Aho, T
    et al.
    Rönn, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Piironen, J
    Björklund, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology. Zooekologi.
    Impacts of effective population size on genetic diversity and relatedness in hatchery reared Brown trout (Salmo trutta L.)2006In: Aquaculture, Vol. 253, p. 244-248Article in journal (Refereed)
  • 24. Aikio, S
    et al.
    Pakkasmaa, S
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Relatedness and competitive assymetry - implications for growth and population dynamics2003In: Oikos, Vol. 100, p. 283-290Article in journal (Refereed)
  • 25.
    Alatalo, Rauno V
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Lundberg, Arne
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Sundberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Can Female Preference Explain Sexual Dichromatism In The Pied Flycatcher, Ficedula-Hypoleuca1990In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 39, p. 244-252Article in journal (Refereed)
    Abstract [en]

    How important female choice is for the evolution of male secondary sexual characteristics is controversial. Two field and one laboratory experiment, using the pied flycatcher, were performed to test the female choice aspect of sexual selection. In addition, non-manipulative data from 5 years are presented. The observational data suggest a slight preference for dark males by females but in field experiments in which males had territories at random sites (i.e. they did not choose a territory) or the colour of concurrently arriving males was altered, there was no preference for darker ones. Similarly, oestradiol-treated females did not prefer black or brown males in the laboratory. Thus, there is little support for the idea that female choice has been an important mechanism in the evolution of sexual dichromatism in the pied flycatcher.

  • 26. Algesten, Grete
    et al.
    Brydsten, Lars
    Jonsson, Per
    Kortelainen, Pirkko
    Löfgren, Stefan
    Rahm, Lars
    Räike, Antti
    Sobek, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution.
    Tranvik, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution.
    Wikner, Johan
    Jansson, Mats
    Organic carbon budget for the Gulf of Bothnia2006In: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 63, no 3-4, p. 155-161Article in journal (Refereed)
    Abstract [en]

    We calculated input of organic carbon to the unproductive, brackish water basin of the Gulf of Bothnia from rivers, point sources and the atmosphere. We also calculated the net exchange of organic carbon between the Gulf of Bothnia and the adjacent marine system, the Baltic Proper. We compared the input with sinks for organic carbon; permanent incorporation in sediments and mineralization and subsequent evasion of CO2 to the atmosphere. The major fluxes were riverine input (1500 Gg C year(-1)), exchange with the Baltic Proper (depending on which of several possible DOC concentration differences between the basins that was used in the calculation, the flux varied between an outflow of 466 and an input of 950 Gg C year(-1)), sediment burial (1100 Gg C year) and evasion to the atmosphere (3610 Gg C year(-1)). The largest single net flux was the emission of CO2 to the atmosphere, mainly caused by bacterial mineralization of organic carbon. Input and output did not match in our budget which we ascribe uncertainties in the calculation of the exchange of organic carbon between the Gulf of Bothnia and the Baltic Proper, and the fact that CO2 emission, which in our calculation represented 1 year (2002) may have been overestimated in comparison with long-term means. We conclude that net heterotrophy of the Gulf of Bothnia was due to input of organic carbon from both the catchment and from the Baltic Proper and that the future degree of net heterotrophy will be sensible to both catchment export of organic carbon and to the ongoing eutrophication of the Baltic Proper.

  • 27. Algesten, Grete
    et al.
    Sobek, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Bergström, Ann-Kristin
    Jonsson, Anders
    Tranvik, Lars J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Jansson, Mats
    Contribution of sediment respiration to summer CO2 emission from low productive boreal and subarctic lakes2005In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 50, no 4, p. 529-535Article in journal (Refereed)
    Abstract [en]

    We measured sediment production of carbon dioxide (CO2) and methane (CH4) and the net flux of CO2 across the surfaces of 15 boreal and subarctic lakes of different humic contents. Sediment respiration measurements were made in situ under ambient light conditions. The flux of CO2 between sediment and water varied between an uptake of 53 and an efflux of 182 mg C m−2 day−1 from the sediments. The mean respiration rate for sediments in contact with the upper mixed layer (SedR) was positively correlated to dissolved organic carbon (DOC) concentration in the water (r 2 = 0.61). The net flux of CO2 across the lake surface [net ecosystem exchange (NEE)] was also closely correlated to DOC concentration in the upper mixed layer (r 2 = 0.73). The respiration in the water column was generally 10-fold higher per unit lake area compared to sediment respiration. Lakes with DOC concentrations <5.6 mg L−1 had net consumption of CO2 in the sediments, which we ascribe to benthic primary production. Only lakes with very low DOC concentrations were net autotrophic (<2.6 mg L−1) due to the dominance of dissolved allochthonous organic carbon in the water as an energy source for aquatic organisms. In addition to previous findings of allochthonous organic matter as an important driver of heterotrophic metabolism in the water column of lakes, this study suggests that sediment metabolism is also highly dependent on allochthonous carbon sources.

  • 28. Algesten, Grete
    et al.
    Sobek, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Bergström, Ann-Kristin
    Ågren, Anneli
    Tranvik, Lars J.
    Jansson, Mats
    Role of lakes for organic carbon cycling in the boreal zone2004In: Global Change Biology, Vol. 10, p. 141-147Article in journal (Refereed)
  • 29. Algesten, Grete
    et al.
    Wikner, Johan
    Sobek, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Limnologi.
    Tranvik, Lars J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Limnologi.
    Jansson, Mats
    Seasonal variation of CO2 saturation in the Gulf of Bothnia: indications of marine net heterotrophy2004In: Global Biogeochemical Cycles, ISSN 1944-9224 EISSN, Vol. 18, no 4, p. GB4021-Article in journal (Refereed)
    Abstract [en]

    [1] Seasonal variation of pCO2 and primary and bacterioplankton production were measured in the Gulf of Bothnia during an annual cycle. Surface water was supersaturated with CO2 on an annual basis, indicating net heterotrophy and a source of CO2 to the atmosphere. However, the Gulf of Bothnia oscillated between being a sink and a source of CO2 over the studied period, largely decided by temporal variation in bacterial respiration (BR) and primary production (PP) in the water column above the pycnocline. The calculated annual respiration-production balance (BR-PP) was very similar to the estimated CO2 emission from the Gulf of Bothnia, which indicates that these processes were major determinants of the exchange of CO2 between water and atmosphere. The southern basin (the Bothnian Sea) had a lower net release of CO2 to the atmosphere than the northern Bothnian Bay (7.1 and 9.7 mmol C m−2 d−1, respectively), due to higher primary production, which to a larger extent balanced respiration in this basin.

  • 30. Alho, Jussi S.
    et al.
    Herczeg, Gabor
    Söderman, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution.
    Jönsson, K. Ingemar
    Merilä, Juha
    Increasing melanism along a latitudinal gradient in a widespread amphibian: local adaptation, ontogenic or environmental plasticity?2010In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 10, no 1, p. 317-Article in journal (Refereed)
    Abstract [en]
    Background: The thermal benefits of melanism in ectothermic animals are widely recognized, but relatively little is known about population differentiation in the degree of melanism along thermal gradients, and the relative contributions of genetic vs. environmental components into the level of melanism expressed. We investigated variation in the degree of melanism in the common frog (Rana temporaria; an active heliotherm thermoregulator) by comparing the degree of melanism (i) among twelve populations spanning over 1500 km long latitudinal gradient across the Scandinavian Peninsula and (ii) between two populations from latitudinal extremes subjected to larval temperature treatments in a common garden experiment. Results: We found that the degree of melanism increased steeply in the wild as a function of latitude. Comparison of the degree of population differentiation in melanism (P-ST) and neutral marker loci (F-ST) revealed that the P-ST >F-ST, indicating that the differences cannot be explained by random genetic drift alone. However, the latitudinal trend observed in the wild was not present in the common garden data, suggesting that the cline in nature is not attributable to direct genetic differences. Conclusions: As straightforward local adaptation can be ruled out, the observed trend is likely to result from environment-driven phenotypic plasticity or ontogenetic plasticity coupled with population differences in age structure. In general, our results provide an example how phenotypic plasticity or even plain ontogeny can drive latitudinal clines and result in patterns perfectly matching the genetic differences expected under adaptive hypotheses.
  • 31.
    Allander, Klas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Sundberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Temporal variation and reliability of blood parasite levels in captive Yellowhammer males Emberiza citrinella1997In: Journal of Avian Biology, ISSN 0908-8857, E-ISSN 1600-048X, Vol. 28, no 4, p. 325-330Article in journal (Refereed)
    Abstract [en]

    The temporal variation of blood parasites in captive Yellowhammer males was studied in order to investigate possible costs of parasites. Birds were caught in the wild in early April and kept in aviaries during the study period. Blood samples were taken, body mass measured, and moult was scored twelve times for the same individuals from April to October. Blood parasites were detectable in smears during the whole study period with an intensity peak coinciding with breeding in the wild. Young birds had more parasites and a consistently higher body mass than older birds. There was no relationship between parasite intensity and mass in older birds but possibly one in young birds. Parasites did not seem to affect moult in either age class. Repeatability of parasite counts of smears from the same individual was very high and smears are therefore a reliable method for estimating parasite intensity. We conclude that blood parasites are probably most severe during, but occur in their hosts long after, the breeding season. Possible costs of parasites outside the breeding season require further study.

  • 32.
    Alonso-Saez, Laura
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Galand, Pierre E.
    Casamayor, Emilio O.
    Pedros-Alio, Carlos
    Bertilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    High bicarbonate assimilation in the dark by Arctic bacteria2010In: ISME Journal, ISSN 1751-7362, Vol. 4, no 12, p. 1581-1590Article in journal (Refereed)
    Abstract [en]

    Although both autotrophic and heterotrophic microorganisms incorporate CO2 in the dark through different metabolic pathways, this process has usually been disregarded in oxic marine environments. We studied the significance and mediators of dark bicarbonate assimilation in dilution cultures inoculated with winter Arctic seawater. At stationary phase, bicarbonate incorporation rates were high (0.5-2.5 mu gC L-1 d(-1)) and correlated with rates of bacterial heterotrophic production, suggesting that most of the incorporation was due to heterotrophs. Accordingly, very few typically chemoautotrophic bacteria were detected by 16S rRNA gene cloning. The genetic analysis of the biotin carboxylase gene accC putatively involved in archaeal CO2 fixation did not yield any archaeal sequence, but amplified a variety of bacterial carboxylases involved in fatty acids biosynthesis, anaplerotic pathways and leucine catabolism. Gammaproteobacteria dominated the seawater cultures (40-70% of cell counts), followed by Betaproteobacteria and Flavobacteria as shown by catalyzed reporter deposition fluorescence in situ hybridization (CARDFISH). Both Beta-and Gammaproteobacteria were active in leucine and bicarbonate uptake, while Flavobacteria did not take up bicarbonate, as measured by microautoradiography combined with CARDFISH. Within Gammaproteobacteria, Pseudoalteromonas-Colwellia and Oleispira were very active in bicarbonate uptake (ca. 30 and 70% of active cells, respectively), while the group Arctic96B-16 did not take up bicarbonate. Our results suggest that, potentially, the incorporation of CO2 can be relevant for the metabolism of specific Arctic heterotrophic phylotypes, promoting the maintenance of their cell activity and/or longer survival under resource depleted conditions.

  • 33.
    Alonso-Saez, Laura
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Unanue, Marian
    Latatu, Ainhoa
    Azua, Inigo
    Ayo, Begona
    Artolozaga, Itxaso
    Iriberri, Juan
    Changes in marine prokaryotic community induced by varying types of dissolved organic matter and subsequent grazing pressure2009In: Journal of Plankton Research, ISSN 0142-7873, E-ISSN 1464-3774, Vol. 31, no 11, p. 1373-1383Article in journal (Refereed)
    Abstract [en]

    We analysed changes in the abundance, biomass, activity and composition of coastal marine prokaryotic communities after the addition of organic substrates, such as glucose, leucine and yeast extract, and the effect of grazing pressure exerted by nanoflagellates. The addition of a carbon source (i.e. glucose) promoted the growth of Gammaproteobacteria, while a combined source of C and N (i.e. leucine) favoured the development of Alphaproteobacteria. The addition of yeast extract, a complex substrate rich in N and growth factors, promoted the proliferation of Alphaproteobacteria and Gammaproteobacteria. Grazing pressure exerted by nanoflagellates produced marked differences on the size structure of the prokaryotic biomass. A pronounced tendency to filamentation and aggregation was observed in the glucose treatment, while in the case of yeast extract, small and mainly freely dispersed prokaryotes were maintained throughout the incubations. Thus, the final community in the yeast extract treatment showed a high percentage of edible biomass, while an important fraction of potentially grazing-resistant prokaryotes (more than 50% of total prokaryotic biomass) was detected in the microcosms enriched with glucose. These results suggest a marked effect of DOM sources on the development of grazing-resistant prokaryotes.

  • 34.
    Alonso-Saez, Laura
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Vazquez-Dominguez, Evaristo
    Cardelus, Clara
    Pinhassi, Jarone
    Sala, M. Montserrat
    Lekunberri, Itziar
    Balague, Vanessa
    Vila-Costa, Maria
    Unrein, Fernando
    Massana, Ramon
    Simo, Rafel
    Gasol, Josep M.
    Factors controlling the year-round variability in carbon flux through bacteria in a coastal marine system2008In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 11, no 3, p. 397-409Article in journal (Refereed)
    Abstract [en]

    Data from several years of monthly samplings are combined with a 1-year detailed study of carbon flux through bacteria at a NW Mediterranean coastal site to delineate the bacterial role in carbon use and to assess whether environmental factors or bacterial assemblage composition affected the in situ rates of bacterial carbon processing. Leucine (Leu) uptake rates [as an estimate of bacterial heterotrophic production (BHP)] showed high interannual variability but, on average, lower values were found in winter (around 50 pM Leu(-1) h(-1)) as compared to summer (around 150 pM Leu(-1) h(-1)). Leu-to-carbon conversion factors ranged from 0.9 to 3.6 kgC mol Leu(-1), with generally higher values in winter. Leu uptake was only weakly correlated to temperature, and over a full-year cycle (in 2003), Leu uptake peaked concomitantly with winter chlorophyll a (Chl a) maxima, and in periods of high ectoenzyme activities in spring and summer. This suggests that both low molecular weight dissolved organic matter (DOM) released by phytoplankton, and high molecular weight DOM in periods of low Chl a, can enhance BHP. Bacterial respiration (BR, range 7-48 mu g C l(-1) d(-1)) was not correlated to BHP or temperature, but was significantly correlated to DOC concentration. Total bacterial carbon demand (BHP plus BR) was only met by dissolved organic carbon produced by phytoplankton during the winter period. We measured bacterial growth efficiencies by the short-term and the long-term methods and they ranged from 3 to 42%, increasing during the phytoplankton blooms in winter (during the Chl a peaks), and in spring. Changes in bacterioplankton assemblage structure (as depicted by denaturing gradient gel electrophoresis fingerprinting) were not coupled to changes in ecosystem functioning, at least in bacterial carbon use.

  • 35.
    Amcoff, Mirjam
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Arnqvist, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Kolm, Niclas
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Courtship signalling with a labile bilateral signal: males show their best side2009In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 63, no 12, p. 1717-1725Article in journal (Refereed)
    Abstract [en]

    Asymmetries in courtship signals can result from both developmental instability during ontogeny and from temporary or permanent damage following mating, fighting, or interactions with predators. These two types of asymmetries, which can be divided into fluctuating asymmetry (FA) and damage asymmetry (DA), have both been suggested to play an important role in mate choice as potential honest indicators of phenotypic and/or genetic quality, while at the same time, DA may affect ornament asymmetry in a random manner. Interestingly, despite the massive research effort that has been devoted to the study of asymmetry during the past decades, very little is known about how an individual's behaviour relates to asymmetry. Here, we measure and characterise asymmetry in morphological courtship signals in Corynopoma riisei, a fish where males carry elaborate paddle-like appendices on each side of the body that they display in front of females during courtship. Moreover, we investigate whether male courtship display, employing this bilateral morphological trait, reflects trait asymmetry. Finally, we assess whether males respond to phenotypic manipulations of DA with corresponding changes in courtship behaviour. We show that male display behaviour is asymmetric in a manner that reflects asymmetry of their morphological courtship trait and that male display behaviour responds to manipulations of asymmetry of these paddles. Our results thus suggest that males preferentially use their best side and, hence, that males respond adaptively to temporary changes in signal trait asymmetry.

  • 36.
    Amcoff, P
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Limnology.
    Elofsson, U O E
    Börjesson, H
    Norrgren, L
    Nilsson, G
    Alterations of dopaminergic and serotonergic activity in the brain of sea-run Baltic salmon suffering a thiamine deficiency-related disorder.2002In: J. Fish Biol, Vol. 60, p. 1407-1416Article in journal (Refereed)
  • 37.
    Ammenberg, P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Centre for Image Analysis. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis.
    Flink, P
    Lindell, T.
    Strömbeck, N.
    Bio-optical Modelling Combined with Remote Sensing to Assess Water Quality2002In: International Journal of Remote Sensing, ISSN 0143-1161, Vol. 23, no 8, p. 1621-1638Article in journal (Refereed)
  • 38.
    Anderson, NJ
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Limnology.
    Blomqvist, Peter
    Renberg, I
    An experimental and palaeoecological study of algal responses to lake acidification and liming in three central Swedish lakes1997In: EUROPEAN JOURNAL OF PHYCOLOGY, ISSN 0967-0262, Vol. 32, no 1, p. 35-48Article in journal (Refereed)
    Abstract [en]

    Contemporary phytoplankton and palaeolimnological studies were made of the algal response to acidification and liming in three lakes in Halsingland, central Sweden (Njupfatet, Sjosjon, Djuptjarn). Surveys and experimental studies of the phytoplankton resp

  • 39.
    Andersson, Anders F.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Banfield, Jillian F.
    Virus population dynamics and acquired virus resistance in natural microbial communities.2008In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 320, no 5879, p. 1047-1050Article in journal (Refereed)
    Abstract [en]

    Viruses shape microbial community structure and function by altering the fitness of their hosts and by promoting genetic exchange. The complexity of most natural ecosystems has precluded detailed studies of virus-host interactions. We reconstructed virus and host bacterial and archaeal genome sequences from community genomic data from two natural acidophilic biofilms. Viruses were matched to their hosts by analyzing spacer sequences that occur among clustered regularly interspaced short palindromic repeats (CRISPRs) that are a hallmark of virus resistance. Virus population genomic analyses provided evidence that extensive recombination shuffles sequence motifs sufficiently to evade CRISPR spacers. Only the most recently acquired spacers match coexisting viruses, which suggests that community stability is achieved by rapid but compensatory shifts in host resistance levels and virus population structure.

  • 40.
    Andersson, Anders F.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Lindberg, Mathilda
    Jakobsson, Hedvig
    Bäckhed, Fredrik
    Nyrén, Pål
    Engstrand, Lars
    Comparative analysis of human gut microbiota by barcoded pyrosequencing2008In: PloS one, ISSN 1932-6203, Vol. 3, no 7, p. e2836-Article in journal (Refereed)
    Abstract [en]

    Humans host complex microbial communities believed to contribute to health maintenance and, when in imbalance, to the development of diseases. Determining the microbial composition in patients and healthy controls may thus provide novel therapeutic targets. For this purpose, high-throughput, cost-effective methods for microbiota characterization are needed. We have employed 454-pyrosequencing of a hyper-variable region of the 16S rRNA gene in combination with sample-specific barcode sequences which enables parallel in-depth analysis of hundreds of samples with limited sample processing. In silico modeling demonstrated that the method correctly describes microbial communities down to phylotypes below the genus level. Here we applied the technique to analyze microbial communities in throat, stomach and fecal samples. Our results demonstrate the applicability of barcoded pyrosequencing as a high-throughput method for comparative microbial ecology

  • 41.
    Andersson, Anders F.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Pelve, Erik A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Molecular Evolution.
    Lindeberg, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Molecular Evolution.
    Lundgren, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Molecular Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Microbiology.
    Nilsson, Peter
    Bernander, Rolf
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Molecular Evolution.
    Replication-biased genome organisation in the crenarchaeon Sulfolobus2010In: BMC Genomics, ISSN 1471-2164, E-ISSN 1471-2164, Vol. 11, p. 454-Article in journal (Refereed)
    Abstract [en]

    Background: Species of the crenarchaeon Sulfolobus harbour three replication origins in their single circular chromosome that are synchronously initiated during replication. Results: We demonstrate that global gene expression in two Sulfolobus species is highly biased, such that early replicating genome regions are more highly expressed at all three origins. The bias by far exceeds what would be anticipated by gene dosage effects alone. In addition, early replicating regions are denser in archaeal core genes (enriched in essential functions), display lower intergenic distances, and are devoid of mobile genetic elements. Conclusion: The strong replication-biased structuring of the Sulfolobus chromosome implies that the multiple replication origins serve purposes other than simply shortening the time required for replication. The higher-level chromosomal organisation could be of importance for minimizing the impact of DNA damage, and may also be linked to transcriptional regulation.

  • 42.
    Andersson, Anders F
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Riemann, Lasse
    Bertilsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Pyrosequencing reveals contrasting seasonal dynamics of taxa within Baltic Sea bacterioplankton communities2010In: ISME J, ISSN 1751-7362, Vol. 4, no 2, p. 171-181Article in journal (Refereed)
    Abstract [en]

    Variation in traits causes bacterial populations to respond in contrasting ways to environmental drivers. Learning about this will help us understand the ecology of individual populations in complex ecosystems. We used 454 pyrosequencing of the hypervariable region V6 of the 16S rRNA gene to study seasonal dynamics in Baltic Sea bacterioplankton communities, and link community and population changes to biological and chemical factors. Surface samples were collected from May to October 2003 and in May 2004 at the Landsort Deep in the central Baltic Sea Proper. The analysis rendered, on average, 20 200 sequence reads for each of the eight samples analyzed, providing the first detailed description of Baltic Sea bacterial communities. Community composition varied dramatically over time, supporting the idea of strong temporal shifts in bacterioplankton assemblages, and clustered according to season (including two May samples from consecutive years), suggesting repeatable seasonal succession. Overall, community change was most highly correlated with change in phosphorus concentration and temperature. Individual bacterial populations were also identified that tightly co-varied with different Cyanobacteria populations. Comparing the abundance profiles of operational taxonomic units at different phylogenetic distances revealed a weak but significant negative correlation between abundance profile similarity and genetic distance, potentially reflecting habitat filtering of evolutionarily conserved functional traits in the studied bacterioplankton.

  • 43.
    Andersson, Anna-Carin
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Conservation Biology and Genetics.
    Lack of mitochondrial DNA structure between chromosome races of the common shrew, Sorex araneus, in Sweden. Implications for chromosomal evolution.Manuscript (Other academic)
  • 44.
    Andersson, Anna-Carin
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Conservation Biology and Genetics.
    Postglacial Population History of the Common Shrew (Sorex araneus) in Fennoscandia: Molekylära studier av återkolonisation, könsbundet genflöde och kromosomrasbildning.2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The common shrew, Sorex araneus, has one of the most variable karyotypes among mammals, displaying numerous chromosomes races throughout its distribution, which can be categorized into different karyotypic groups. The objective of this thesis was to examine the postglacial population history of Fennoscandian common shrews using autosomal microsatellites, mitochondrial DNA (mtDNA) and a Y chromosome specific microsatellite (L8Y).

    Autosomal microsatellites and mtDNA revealed weak genetic structure over a hybrid zone between the karyotypically divergent Northern and Western karyotypic groups. However, the genetic structure displayed by the Y chromosome microsatellite was orders of magnitude higher. Hence, considerable chromosomal differences between the groups do not prevent female gene flow, while male gene flow is reduced (cf. Haldane's rule). Further, the results suggest that the Haldane effect may be caused by the chromosomal differences between the karyotypic groups.

    No mtDNA differentiation was observed either between chromosome races or between the Northern and Western karyotypic groups in Fennoscandia. The combined pattern of karyotypic and mtDNA variation of Fennoscandian common shrews, suggest bi-directional postglacial recolonisation from a single refugium in Europe. The variation of the Y-linked microsatellite supported this conclusion. In contrast, significant mtDNA structure, discordant with the karyotypic variation, revealed that common shrews in southern Finland belong to a different lineage than remaining Fennoscandian regions, implying postglacial recolonisation from a different source.

    MtDNA variation of the chromosome races in Sweden supports the hypothesis that three races of the Western karyotypic group have been formed through whole arm reciprocal translocations (WARTs), as suggested by their mutual karyotypic variation. The variation of the molecular markers supports the theory of rapid karyotypic evolution in the common shrew.

    List of papers
    1. No apparent reduction of gene flow in a hybrid zone between the West and North European karyotypic groups of the common shrew, Sorex araneus.
    Open this publication in new window or tab >>No apparent reduction of gene flow in a hybrid zone between the West and North European karyotypic groups of the common shrew, Sorex araneus.
    2004 In: Molecular Ecology, ISSN 1365-294X, Vol. 13, no 5, p. 1205-1215.Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-91849 (URN)
    Available from: 2004-05-13 Created: 2004-05-13Bibliographically approved
    2. Lack of mitochondrial DNA structure between chromosome races of the common shrew, Sorex araneus, in Sweden. Implications for chromosomal evolution.
    Open this publication in new window or tab >>Lack of mitochondrial DNA structure between chromosome races of the common shrew, Sorex araneus, in Sweden. Implications for chromosomal evolution.
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-91850 (URN)
    Available from: 2004-05-13 Created: 2004-05-13 Last updated: 2010-01-13Bibliographically approved
    3. Fennoscandian phylogeography of the common shrew Sorex araneus. Postglacial recolonisation-combining information from chromosomal variation with mitochondrial DNA data
    Open this publication in new window or tab >>Fennoscandian phylogeography of the common shrew Sorex araneus. Postglacial recolonisation-combining information from chromosomal variation with mitochondrial DNA data
    2011 (English)In: Acta Theriologica, ISSN 0001-7051, E-ISSN 2190-3743, Vol. 56, no 2, p. 103-116Article in journal (Refereed) Published
    Abstract [en]

    We examine mtDNA variation of the common shrew in Fennoscandia to explore the incongruence found in previous studies using chromosomal and mitochondrial markers, aiming to reveal post-glacial recolonisation patterns. A total of 241 common shrews from 51 localities in Fennoscandia were analysed. This area includes a secondary contact zone between two groups (the Northern group and the Western group) showing distinct karyotypes. All individuals were sequenced for 447 bp of the mitochondrial control region. No significant differentiation in the mtDNA variation was observed between the two major chromosomal groups in Fennoscandia. The star-like shape of the sequence network for the entire study area shows the most common haplotype A as ancestral in all regions but one, in situ formation of most haplotypes and population expansion. The only significant mtDNA structure observed occurs between south Finland and the rest of Fennoscandia. We propose that the Northern and Western group shared a common refugium during the Last Glacial Maximum but recolonised Fennoscandia via two routes. Karyotypic differences between south and north Finland has led researchers to suggest that both regions originate from the same ancestral population east of Finland. The observed divergence of mtDNA variation between these two regions supports this hypothesis.

    Keywords
    Control region, Common shrew, Glacial refugia, Colonization history, Chromosome race
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-91851 (URN)10.1007/s13364-010-0022-9 (DOI)000290689600001 ()
    Available from: 2004-05-13 Created: 2004-05-13 Last updated: 2017-12-14Bibliographically approved
    4. Reduced levels of male gene flow in a hybrid zone between the North and West European karyotypic groups of the common shrew, Sorex araneus. Chromosomally based explanation for Haldane's rule?
    Open this publication in new window or tab >>Reduced levels of male gene flow in a hybrid zone between the North and West European karyotypic groups of the common shrew, Sorex araneus. Chromosomally based explanation for Haldane's rule?
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-91852 (URN)
    Available from: 2004-05-13 Created: 2004-05-13 Last updated: 2010-01-13Bibliographically approved
    5. Y-chromosome microsatellite variation among common shrews (Sorex araneus) in northern Europe.
    Open this publication in new window or tab >>Y-chromosome microsatellite variation among common shrews (Sorex araneus) in northern Europe.
    Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-91853 (URN)
    Available from: 2004-05-13 Created: 2004-05-13 Last updated: 2010-01-13Bibliographically approved
  • 45.
    Andersson, Anna-Carin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Conservation Biology and Genetics.
    Alström-Rapaport, Cecilia
    Tegelström, Håkan
    Reduced levels of male gene flow in a hybrid zone between the North and West European karyotypic groups of the common shrew, Sorex araneus. Chromosomally based explanation for Haldane's rule?Manuscript (Other academic)
  • 46.
    Andersson, Anna-Carin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Conservation Biology and Genetics.
    Narain, Yolanda
    Tegelström, Håkan
    Fredga, Karl
    No apparent reduction of gene flow in a hybrid zone between the West and North European karyotypic groups of the common shrew, Sorex araneus.2004In: Molecular Ecology, ISSN 1365-294X, Vol. 13, no 5, p. 1205-1215.Article in journal (Refereed)
  • 47.
    Andersson, Anna-Carin
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Conservation Biology and Genetics.
    Utter, Marianne
    Alström-Rapaport, Cecilia
    Tegelström, Håkan
    Y-chromosome microsatellite variation among common shrews (Sorex araneus) in northern Europe.Manuscript (Other academic)
  • 48.
    Andersson, Eva
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution.
    Benthic-Pelagic Microbial Interactions and Carbon Cycling in Clearwater Lakes2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis focuses on the interactions among microbiota in clearwater lakes. Field sampling and field experiments were performed to evaluate interactions among microbiota and the importance of benthic versus pelagic microbiota in terms of biomass and production. In addition, carbon cycling in an oligotrophic clearwater lake was calculated.

    Biomass and production of microbiota was clearly focused to the benthic habitat. During natural nutrient concentrations growth of heterotrophic bacteria (benthic and pelagic) was coupled to production of microphytobenthos in Lake Eckarfjärden, indicating interactions between autotrophic and heterotrophic microbiota in, as well as between, habitats. At increased nutrient concentrations, growth of heterotrophic bacteria was not correlated to microphytobenthos production. This was explained by less release of dissolved organic carbon (DOC) from microphytobenthos when they got access to more nutrients. Further investigations showed different scenarios in oligotrophic clearwater lakes following increased nutrient concentrations. The interactions between microbiota may be altered following increased nutrient concentrations and the microbial mat either positively or negatively affect the pelagic microbiota. The most striking result was that the expected shift towards dominance of pelagic primary production does not necessarily occur.

    Major flows of carbon were identified between different habitats in the oligotrophic clearwater Lake Eckarfjärden, and the net result was that the benthic habitat provided carbon to the pelagial. High DOC concentrations in the lake together with low pelagic production are factors that would indicate net heterotrophy. Accordingly, the pelagial of Lake Eckarfjärden was net heterotrophic but when the benthic and littoral habitats were included in the calculations, the lake turned out to be net autotrophic.

    In conclusion, the benthic microbiota contributed significantly to the total production in the investigated lakes and had a major role in the lake metabolism. Thus, this thesis emphasises the importance of benthic microbiota in shallow clearwater lakes.

    List of papers
    1. Characteristics of oligotrophic hardwater lakes in a postglacial land-rise area in mid-Sweden
    Open this publication in new window or tab >>Characteristics of oligotrophic hardwater lakes in a postglacial land-rise area in mid-Sweden
    2002 (English)In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 47, no 8, p. 1451-1462Article in journal (Refereed) Published
    Abstract [en]

    1. We describe some remarkable ephemeral, oligotrophic hardwater lakes formed becauseof land rise in the coastal areas of the Baltic Sea, that are unique in Sweden and probablyalso worldwide. Two younger, coastal lakes were studied by regular sampling for 1 yearand compared with an older (i.e. greater altitude) lake, that passed through theoligotrophic hardwater stage some 3–4000 years ago.

    2. Despite some differences in composition of the catchment, the two younger lakes weresimilar with regard to water chemistry and plankton community composition. Theconcentration of phosphorus was low while nitrogen was high, resulting in very high N/Pquotients (101 and 131). Although water colour was moderate, the concentration of organiccarbon was extremely high (average values of ‡ 20 lg TOC L–1), consisting mainly ofdissolved compounds (DOC).

    3. While the plankton was poorly developed, sediments in both lakes were covered by alayer of photosynthesising micro-organisms. This substantial 'microbial mat', which hasnot been described in detail before, was up to 15 cm thick and dominated by cyanobacteriaand purple sulphur bacteria. The concentration of sediment phosphorus was extremelylow (352 lg g–1 dw) in one of the lakes and dominated by organic-bound (residual)phosphorus.

    4. Deep sediments in the older lake, representing its oligotrophic hardwater period,differed in phosphorus composition from the currently oligotrophic hardwater lakes byhaving a strong dominance of HCl-extractable (Ca-bound) phosphorus. This indicates thatphosphorus, initially organic-bound within the microbial mat, is subsequently bound tocalcium. We hypothesise that this is promoted by the environmental conditions created bythe benthic photosynthetic activity, in combination with the prevailing hardwaterconditions.

    5. The rich and flourishing microbial community on the sediments may also explain thehigh concentration of DOC in the lake.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-93054 (URN)
    Available from: 2005-05-11 Created: 2005-05-11 Last updated: 2018-06-05Bibliographically approved
    2. Net autotrophy in an oligotrophic lake rich in dissolved organic carbon and with high benthic primary production
    Open this publication in new window or tab >>Net autotrophy in an oligotrophic lake rich in dissolved organic carbon and with high benthic primary production
    2006 (English)In: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 43, no 1, p. 1-10Article in journal (Refereed) Published
    Abstract [en]

    Biomass and production of microbiota—primary producers as well as heterotrophic bacteria—were studied both in the pelagial and in the benthic habitat over 2 yr in the shallow oligotrophic Lake Eckarfjärden, Sweden. Both biomass and production of microbiota were concentrated in the benthic habitat. Despite a high dissolved organic carbon (DOC) concentration of about 25 mg C l–1 in the water, the total bacterial production was lower than the total primary production. Moreover, measurements of DOC concentrations in the in- and outflow, and CO2-saturation measurements, indicate that the system is net autotrophic. Generally, low-productive systems (<100 µg C l–1 d–1) tend to be net heterotrophic. In contrast, we found a low-productive (55 µg C l–1 d–1) but net autotrophic system, the conditions of which were largely influenced by benthic production. Many lakes in the world are shallow and may provide substantial benthic areas suitable for primary production. Hence, it is important to include this habitat when evaluating whether lakes are autotrophic or heterotrophic systems.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-93055 (URN)10.3354/ame043001 (DOI)
    Available from: 2005-05-11 Created: 2005-05-11 Last updated: 2018-06-05Bibliographically approved
    3. Inorganic nutrient acquisition in a shallow clearwater lake: dominance of benthic microbiota
    Open this publication in new window or tab >>Inorganic nutrient acquisition in a shallow clearwater lake: dominance of benthic microbiota
    2006 (English)In: Aquatic Sciences, ISSN 1015-1621, E-ISSN 1420-9055, Vol. 68, no 2, p. 172-180Article in journal (Refereed) Published
    Abstract [en]

    This mesocosm study from the oligotrophic Lake Eckarfjärden in Sweden shows, in contrast to many previous studies, that benthic microbiota dominated production following elevated nutrient concentrations in the water. Increased nutrient concentrations favoured microphytobenthos, whereas phytoplankton biomass remained roughly the same. Microphytobenthos biomass and production were clearly stimulated by nitrogen addition, while phytoplankton showed signs of phosphorus limitation. There were tight interactions between pelagic and benthic habitats and between organisms, and pelagic as well as benthic heterotrophic bacteria were disfavoured when microphytobenthos had access to nitrogen.

    We conclude that increased nutrient concentrations in the water column may trigger immediate responses in both habitats, altering the tight interactions between microbiota, but not necessarily resulting in a shift towards pelagic production.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-93056 (URN)10.1007/s00027-006-0805-x (DOI)
    Available from: 2005-05-11 Created: 2005-05-11 Last updated: 2018-06-05Bibliographically approved
    4. Benthic-pelagic coupling in a shallow clearwater lake - effects of nutrient addditions on plankton
    Open this publication in new window or tab >>Benthic-pelagic coupling in a shallow clearwater lake - effects of nutrient addditions on plankton
    (English)Manuscript (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-93057 (URN)
    Available from: 2005-05-11 Created: 2005-05-11 Last updated: 2014-07-14Bibliographically approved
    5. A carbon budget for an oligotrophic clearwater lake in mid-Sweden
    Open this publication in new window or tab >>A carbon budget for an oligotrophic clearwater lake in mid-Sweden
    2006 (English)In: Aquatic Sciences, ISSN 1015-1621, E-ISSN 1420-9055, Vol. 68, no 1, p. 52-64Article in journal (Refereed) Published
    Abstract [en]

    In this study, a whole-lake carbon budget for the oligotrophic, clearwater Lake Eckarfjärden was established both on an annual and seasonal basis. For budget calculations, the lake was divided into three habitats (pelagial, littoral and benthic) and the biota into 19 functional groups. In the lake, major parts of biomass (97%) and primary production (91%) are concentrated in benthic and littoral habitats and to a few functional groups. Respiration on the other hand, is focused on benthic and pelagial habitats where 60% and 39%, respectively, of the respiration took place. Our conceptual model indicates strong interactions between habitats. For instance, the pelagial is fed with carbon fixed by primary producers in the benthic and littoral zones. On an annual basis, total primary production exceeds total respiration and the lake is net autotrophic. However, there are clear differences between habitats and between seasons. For instance, the littoral is net autotrophic during spring, summer and autumn, the benthic habitat is net autotrophic only during summer, and the pelagial is always net heterotrophic. Our results demonstrate clear couplings between habitats and organisms and the importance of a holistic view when studying lake ecosystems.

    Keywords
    Lake Eckarfjärden, functional groups, carbon flows, habitat interactions, metabolic processes
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-93058 (URN)10.1007/s00027-005-0807-0 (DOI)
    Available from: 2005-05-11 Created: 2005-05-11 Last updated: 2017-12-14Bibliographically approved
  • 49.
    Andersson, Eva
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution.
    Brunberg, Anna-Kristina
    Benthic-pelagic coupling in a shallow clearwater lake - effects of nutrient addditions on planktonManuscript (Other academic)
  • 50.
    Andersson, Eva
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Swedish Nuclear Fuel and Waste Management.
    Brunberg, Anna-Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Inorganic nutrient acquisition in a shallow clearwater lake: dominance of benthic microbiota2006In: Aquatic Sciences, ISSN 1015-1621, E-ISSN 1420-9055, Vol. 68, no 2, p. 172-180Article in journal (Refereed)
    Abstract [en]

    This mesocosm study from the oligotrophic Lake Eckarfjärden in Sweden shows, in contrast to many previous studies, that benthic microbiota dominated production following elevated nutrient concentrations in the water. Increased nutrient concentrations favoured microphytobenthos, whereas phytoplankton biomass remained roughly the same. Microphytobenthos biomass and production were clearly stimulated by nitrogen addition, while phytoplankton showed signs of phosphorus limitation. There were tight interactions between pelagic and benthic habitats and between organisms, and pelagic as well as benthic heterotrophic bacteria were disfavoured when microphytobenthos had access to nitrogen.

    We conclude that increased nutrient concentrations in the water column may trigger immediate responses in both habitats, altering the tight interactions between microbiota, but not necessarily resulting in a shift towards pelagic production.

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