uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Henderiks, Jorijntje
Publications (10 of 71) Show all publications
Waelbroeck, C., Lougheed, B. C., Riveiros, N. V., Missiaen, L., Pedro, J., Dokken, T., . . . Ziegler, M. (2019). Consistently dated Atlantic sediment cores over the last 40 thousand years. Scientific Data, 6, Article ID 165.
Open this publication in new window or tab >>Consistently dated Atlantic sediment cores over the last 40 thousand years
Show others...
2019 (English)In: Scientific Data, E-ISSN 2052-4463, Vol. 6, article id 165Article in journal (Refereed) Published
Abstract [en]

Rapid changes in ocean circulation and climate have been observed in marine-sediment and ice cores over the last glacial period and deglaciation, highlighting the non-linear character of the climate system and underlining the possibility of rapid climate shifts in response to anthropogenic greenhouse gas forcing. To date, these rapid changes in climate and ocean circulation are still not fully explained. One obstacle hindering progress in our understanding of the interactions between past ocean circulation and climate changes is the difficulty of accurately dating marine cores. Here, we present a set of 92 marine sediment cores from the Atlantic Ocean for which we have established age-depth models that are consistent with the Greenland GICC05 ice core chronology, and computed the associated dating uncertainties, using a new deposition modeling technique. This is the first set of consistently dated marine sediment cores enabling paleoclimate scientists to evaluate leads/lags between circulation and climate changes over vast regions of the Atlantic Ocean. Moreover, this data set is of direct use in paleoclimate modeling studies.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2019
National Category
Climate Research
Identifiers
urn:nbn:se:uu:diva-394203 (URN)10.1038/s41597-019-0173-8 (DOI)000483426900001 ()31477737 (PubMedID)
Funder
EU, European Research Council, 339108
Available from: 2019-10-04 Created: 2019-10-04 Last updated: 2019-10-04Bibliographically approved
Auer, G., De Vleeschouwer, D., Smith, R. A., Bogus, K., Groeneveld, J., Grunert, P., . . . Henderiks, J. (2019). Timing and Pacing of Indonesian Throughflow Restriction and Its Connection to Late Pliocene Climate Shifts. PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY, 34(4), 635-657
Open this publication in new window or tab >>Timing and Pacing of Indonesian Throughflow Restriction and Its Connection to Late Pliocene Climate Shifts
Show others...
2019 (English)In: PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY, ISSN 2572-4517, Vol. 34, no 4, p. 635-657Article in journal (Refereed) Published
Abstract [en]

The Pliocene was characterized by a gradual shift of global climate toward cooler and drier conditions. This shift fundamentally reorganized Earth's climate from the Miocene state toward conditions similar to the present. During the Pliocene, the progressive restriction of the Indonesian Throughflow (ITF) is suggested to have enhanced this shift toward stronger meridional thermal gradients. Reduced ITF, caused by the northward movement of Australia and uplift of Indonesia, impeded global thermohaline circulation, also contributing to late Pliocene Northern Hemisphere cooling via atmospheric and oceanographic teleconnections. Here we present an orbitally tuned high-resolution sediment geochemistry, calcareous nannofossil, and X-ray fluorescence record between 3.65 and 2.97 Ma from the northwest shelf of Australia within the Leeuwin Current. International Ocean Discovery Program Site U1463 provides a record of local surface water conditions and Australian climate in relation to changing ITF connectivity. Modern analogue-based interpretations of nannofossil assemblages indicate that ITF configuration culminated similar to 3.54 Ma. A decrease in warm, oligotrophic taxa such as Umbilicosphaera sibogae, with a shift from Gephyrocapsa sp. to Reticulofenestra sp., and an increase of mesotrophic taxa (e.g., Umbilicosphaera jafari and Helicosphaera spp.) suggest that tropical Pacific ITF sources were replaced by cooler, fresher, northern Pacific waters. This initial tectonic reorganization enhanced the Indian Oceans sensitivity to orbitally forced cooling in the southern high latitudes culminating in the M2 glacial event (similar to 3.3 Ma). After 3.3 Ma the restructured ITF established the boundary conditions for the inception of the Sahul-Indian Ocean Bjerknes mechanism and increased the response to glacio-eustatic variability.

Place, publisher, year, edition, pages
AMER GEOPHYSICAL UNION, 2019
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-390050 (URN)10.1029/2018PA003512 (DOI)000467950300013 ()
Funder
Swedish Research Council, VR-2016-04434
Available from: 2019-08-02 Created: 2019-08-02 Last updated: 2019-08-02Bibliographically approved
Supraha, L., Ljubesic, Z. & Henderiks, J. (2018). Combination coccospheres from the Eastern Adriatic coast: New, verified and possible life-cycle associations. Marine Micropaleontology, 141, 23-30
Open this publication in new window or tab >>Combination coccospheres from the Eastern Adriatic coast: New, verified and possible life-cycle associations
2018 (English)In: Marine Micropaleontology, ISSN 0377-8398, E-ISSN 1872-6186, Vol. 141, p. 23-30Article in journal (Refereed) Published
Abstract [en]

Coccolithophore life cycles involve the alternation between morphologically distinct life-cycle phases. This often leads to taxonomic issues where the life-cycle phases of the same species are described as distinct taxa. This issue can be resolved by the observation of combination coccospheres, i.e. cells bearing the coccoliths of both life-cycle phases. This study presents new observations on combination coccospheres from the highly diverse and ecologically important coccolithophore order Syracosphaerales and the genus Alisphaera. New life-cycle associations are revealed between Syracosphaera hirsuta and Corisphaera strigilis, and between Alisphaera unicornis and a nannolith-producing Polycrater galapagensis. The life-cycle association of Syracosphaera marginiporata Anthosphaera sp. type B is verified. A possible association between Rhabdosphaera xiphos and an unidentified holococcolith-bearing morphotype is proposed and needs to be verified in future investigations. The appropriate taxonomic revisions are conducted following the taxonomic principle of priority and recommended practices for naming the coccolithophore life-cycle phases.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2018
Keywords
Haptophytes, Coccolithophores, Combination coccospheres, Holococcoliths, Heterococcoliths, Life cycle, Taxonomy
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-360995 (URN)10.1016/j.marmicro.2018.04.001 (DOI)000436915000003 ()
Funder
Knut and Alice Wallenberg Foundation, KAW 2009.0287
Available from: 2018-09-26 Created: 2018-09-26 Last updated: 2018-09-26Bibliographically approved
Gerecht, A., Supraha, L., Langer, G. & Henderiks, J. (2018). Phosphorus limitation and heat stress decrease calcification in Emiliania huxleyi. Biogeosciences, 15, 833-845
Open this publication in new window or tab >>Phosphorus limitation and heat stress decrease calcification in Emiliania huxleyi
2018 (English)In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 15, p. 833-845Article in journal (Refereed) Published
Abstract [en]

Calcifying haptophytes (coccolithophores) sequester carbon in the form of organic and inorganic cellular components (coccoliths). We examined the effect of phosphorus (P) limitation and heat stress on particulate organic and inorganic carbon (calcite) production in the coccolithophore Emiliania huxleyi. Both environmental stressors are related to rising CO2 levels and affect carbon production in marine microalgae, which in turn impacts biogeochemical cycling. Using semi-continuous cultures, we show that P-limitation and heat stress decrease the calcification rate in E. huxleyi. This could lessen the ballasting effect of coccoliths and weaken carbon export out of the photic zone. However, using batch cultures, we show that different culturing approaches (batch versus semi-continuous) induce different physiologies. This affects the ratio of inorganic (PIC) to organic (POC) carbon and complicates general predictions on the effect of P-limitation on the PIC / POC ratio. Furthermore, heat stress increases P-requirements in E. huxleyi, possibly leading to lower standing stocks in a warmer ocean, especially if this is linked to lower nutrient input. In summary, the predicted rise in global temperature and resulting decrease in nutrient availability may first of all decrease CO2 sequestration by coccolithophores through lower overall carbon production. Secondly, the export of carbon may be diminished by a decrease in calcification and a weaker coccolith ballasting effect.

National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-321897 (URN)10.5194/bg-15-833-2018 (DOI)000424704700003 ()
Funder
Knut and Alice Wallenberg Foundation, KAW 2009.0287
Available from: 2017-05-11 Created: 2017-05-11 Last updated: 2018-03-21Bibliographically approved
De Vleeschouwer, D., Auer, G., Smith, R., Bogus, K., Christensen, B., Groeneveld, J., . . . Paelike, H. (2018). The amplifying effect of Indonesian Throughflow heat transport on Late Pliocene Southern Hemisphere climate cooling. Earth and Planetary Science Letters, 500, 15-27
Open this publication in new window or tab >>The amplifying effect of Indonesian Throughflow heat transport on Late Pliocene Southern Hemisphere climate cooling
Show others...
2018 (English)In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 500, p. 15-27Article in journal (Refereed) Published
Abstract [en]

An unusually short glaciation interrupted the warm Pliocene around 3.3 Ma (Marine Isotope Stage (MIS) M2). Different hypotheses exist to explain why this glaciation event was so pronounced, and why the global climate system returned to warm Pliocene conditions relatively quickly afterwards. One of these proposed mechanisms is a reduced equator-to-pole heat transfer, in response to a tectonically reduced Indonesian Throughflow (ITF). The ITF is a critical part of the global thermohaline ocean circulation, transporting heat from the Indo-Pacific Warm Pool to the Indian Ocean. When ITF connectivity is reduced, the water and heat supply for the Leeuwin Current, flowing poleward along Australia's west coast, is also diminished. To assess the possible relationship between mid-Pliocene glaciations and latitudinal heat transport through the Indonesian Throughflow, we constructed a multi-proxy orbital scale record for the 3.7-2.8 Ma interval from International Ocean Discovery Program (IODP) Site U1463, off northwest Australia. The comparison of the Site U1463 record with paleoclimate records from nearby Site 763 and West Pacific Warm Pool Site 806 allows for a detailed regional reconstruction of Pliocene paleoceanography and thus for testing the proposed hypothesis. An astronomically-paced decrease in potassium content characterizes the late Pliocene interval of U1463. This record documents the increasing aridity of northwest Australia, periodically alleviated by reinforced summer monsoon precipitation under summer insolation maxima. The 3180 record of the planktonic foraminifer Globigerinoides sacculifer correlates exceptionally well with the sea surface temperature (SST) record from Site 806 in the West Pacific Warm Pool, even during MIS M2. Hence, Site U1463 preserves an uninterrupted ITF signal even during Pliocene glaciations. However, the U1463 delta O-18(G.sacculifer) record exhibits a 0.5 parts per thousand offset with the nearby Site 763A record around MIS M2. This implies that Site 763A, about 500 km west of U1463, more closely tracks Indian Ocean SST records across MIS M2. The U1463 data reveal that heat-transport through the Indonesian Throughflow did not shut down completely during MIS M2, but rather its intensity decreased prior to and during MIS M2, causing Site 763A to temporarily reflect an Indian Ocean, rather than an ITF signal. We conclude that ITF variability significantly influenced latitudinal heat transport by means of the Leeuwin Current and hence contributed to the relative intensity of MIS M2. We propose the ITF valve between the Pacific and Indian Ocean as a positive feedback mechanism, in which an initial sea level lowering reduces ITF heat transport, in turn amplifying global cooling by advancing the thermal isolation of Antarctica.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2018
Keywords
Indonesian Throughflow, Pliocene, astronomical forcing, Leeuwin Current, West Pacific Warm Pool, M2 event
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-363201 (URN)10.1016/j.epsl.2018.07.035 (DOI)000445718700002 ()
Funder
EU, European Research Council, 617462German Research Foundation (DFG), 319497259
Available from: 2018-10-18 Created: 2018-10-18 Last updated: 2018-10-18Bibliographically approved
Gallagher, S. J., Reuning, L., Himmler, T., Henderiks, J., De Vleeschouwer, D., Groeneveld, J., . . . Bogus, K. (2018). The enigma of rare Quaternary oolites in the Indian and Pacific Oceans: A result of global oceanographic physicochemical conditions or a sampling bias?. Quaternary Science Reviews, 200, 114-122
Open this publication in new window or tab >>The enigma of rare Quaternary oolites in the Indian and Pacific Oceans: A result of global oceanographic physicochemical conditions or a sampling bias?
Show others...
2018 (English)In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 200, p. 114-122Article in journal (Refereed) Published
Abstract [en]

Marine ooids are iconic indicators of shallow seawater carbonate saturation state, and their formation has traditionally been ascribed to physicochemical processes. The Indo-Pacific stands out as a region devoid of oolites, particularly during the Quaternary: the "ooid enigma". Here we present results from recent coring by the International Ocean Discovery Program (IODP Expedition 356) off west Australia that shows that ooid horizons are common in Pleistocene strata up to 730,000 years old. Extensive "ooid factories" were created due to the presence of long-lived tidally influenced flat topped tropical platforms suitable for intermittent ooid accretion over hundreds to thousands of years during highstands and times of lower sea level. This work suggests marine ooids may actually be more common in Indo-Pacific than previously reported. Past global ocean alkalinity was elevated during Pleistocene glacial periods and continental climate was generally more arid in the Indo-Pacific region compared to interglacials and the Holocene. Therefore, increased aridity associated with higher alkalinity conditions during the glacials facilitated ooid precipitation on adjacent tropical carbonate platforms particularly offshore from arid Australia. This confluence of factors suggests that more "ooid factories" may be encountered by further coring Indo-Pacific regions with Pleistocene flat long-lived carbonate shelves. However, Indo-Pacific Quaternary ooid occurrences outside Australia are rare, suggesting that the Northwest Shelf may be a unique archive of this non-skeletal precipitate. Further investigations into the petrography and geochemistry of pre-Holocene ooid occurrences will provide insights into their origin and the relative role of biotic, physicochemical and other factors in their formation. (C) 2018 Elsevier Ltd. All rights reserved.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2018
Keywords
Quaternary, Holocene, Southern Pacific, Oolites, Ooids, Indo-Pacific, Northwest Shelf Australia, Aridity, Skeletal grains, Indian Ocean, Pacific Ocean
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-371875 (URN)10.1016/j.quascirev.2018.09.028 (DOI)000449900900007 ()
Funder
Swedish Research Council, VR 2016-04434
Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-01-07Bibliographically approved
Zhang, Y. G., Pagani, M., Henderiks, J. & Ren, H. (2017). A long history of equatorial deep-water upwelling in the Pacific Ocean. Earth and Planetary Science Letters, 467, 1-9
Open this publication in new window or tab >>A long history of equatorial deep-water upwelling in the Pacific Ocean
2017 (English)In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 467, p. 1-9Article in journal (Refereed) Published
Abstract [en]

Cold, nutrient-and CO2-rich waters upwelling in the eastern equatorial Pacific (EEP) give rise to the Pacific cold tongue. Quasi-periodic subsidence of the thermocline and attenuation in wind strength expressed by El Niño conditions decrease upwelling rates, increase surface-water temperatures in the EEP, and lead to changes in regional climates both near and far from the equatorial Pacific. EEP surface waters have elevated CO2concentrations during neutral (upwelling) or La Niña (strong upwelling) conditions. In contrast, approximate air–sea CO2equilibrium characterizes El Niño events. One hypothesis proposes that changes in physical oceanography led to the establishment of a deep tropical thermocline and expanded mixed-layer prior to 3 million years ago. These effects are argued to have substantially reduced deep-water upwelling rates in the EEP and promoted a “permanent El Niño-like” climate state. For this study, we test this supposition by reconstructing EEP “excess CO2” and upwelling history for the past 6.5million years using the alkenone-pCO2methodology. Contrary to previous assertions, our results indicate that average temporal conditions in the EEP over the past ∼6.5 million years were characterized by substantial CO2disequilibrium and high nutrient delivery to surface waters — characteristics that imply strong upwelling of deep waters. Upwelling appears most vigorous between ∼6.5 to 4.5 million years ago coinciding with high accumulation rates of biogenic material during the late Miocene – early Pliocene “biogenic bloom”.

Keywords
alkenone-pCO2, deep-water upwelling, eastern equatorial Pacific, late Miocene – early Pliocene “biogenic bloom”
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-321895 (URN)10.1016/j.epsl.2017.03.016 (DOI)000401385500001 ()
Funder
The Royal Swedish Academy of SciencesKnut and Alice Wallenberg Foundation, KAW 2009.0287
Available from: 2017-05-11 Created: 2017-05-11 Last updated: 2017-06-20Bibliographically approved
Groeneveld, J., Henderiks, J., Renema, W., McHugh, C. M., De Vleeschouwer, D., Christensen, B. A., . . . Ishiwa, T. (2017). Australian shelf sediments reveal shifts in Miocene Southern Hemisphere westerlies. Science Advances, 3(5), Article ID e1602567.
Open this publication in new window or tab >>Australian shelf sediments reveal shifts in Miocene Southern Hemisphere westerlies
Show others...
2017 (English)In: Science Advances, ISSN 0036-8156, E-ISSN 2375-2548, Vol. 3, no 5, article id e1602567Article in journal (Refereed) Published
Abstract [en]

Global climate underwent a major reorganization when the Antarctic ice sheet expanded ~14 million years ago (Ma) (1). This event affected global atmospheric circulation, including the strength and position of the westerlies and the Intertropical Convergence Zone (ITCZ), and, therefore, precipitation patterns (25). We present new shallow-marine sediment records from the continental shelf of Australia (International Ocean Discovery Program Sites U1459 and U1464) providing the first empirical evidence linking high-latitude cooling around Antarctica to climate change in the (sub)tropics during the Miocene. We show that Western Australia was arid during most of the Middle Miocene. Southwest Australia became wetter during the Late Miocene, creating a climate gradient with the arid interior, whereas northwest Australia remained arid throughout. Precipitation and river runoff in southwest Australia gradually increased from 12 to 8 Ma, which we relate to a northward migration or intensification of the westerlies possibly due to increased sea ice in the Southern Ocean (5). Abrupt aridification indicates that the westerlies shifted back to a position south of Australia after 8 Ma. Our midlatitude Southern Hemisphere data are consistent with the inference that expansion of sea ice around Antarctica resulted in a northward movement of the westerlies. In turn, this may have pushed tropical atmospheric circulation and the ITCZ northward, shifting the main precipitation belt over large parts of Southeast Asia (4).

Keywords
Miocene, Australia, Southern Hemisphere, Westerlies, Hadley Cell, Precipitation
National Category
Earth and Related Environmental Sciences
Research subject
Earth Science with specialization in Historical Geology and Palaeontology
Identifiers
urn:nbn:se:uu:diva-321896 (URN)10.1126/sciadv.1602567 (DOI)000401955300027 ()
Funder
Swedish Research Council, 2016-04434German Research Foundation (DFG), GR 3528/3-1Swedish Research Council, 2011-4866Australian Research Council
Note

D. C. Potts & W. Zhang are part of the group Expedition 356 Scientists. For complete list of authors see https://doi.org/10.1126/sciadv.1602567

Available from: 2017-05-11 Created: 2017-05-11 Last updated: 2017-07-12Bibliographically approved
Christensen, B. A., Renema, W., Henderiks, J., De Vleeschouwer, D., Groeneveld, J., Castaneda, I. S., . . . Fulthorpe, C. S. (2017). Indonesian Throughflow drove Australian climate from humid Pliocene to arid Pleistocene. Geophysical Research Letters, 44(13), 6914-6925
Open this publication in new window or tab >>Indonesian Throughflow drove Australian climate from humid Pliocene to arid Pleistocene
Show others...
2017 (English)In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 44, no 13, p. 6914-6925Article in journal (Refereed) Published
Abstract [en]

Late Miocene to mid-Pleistocene sedimentary proxy records reveal that northwest Australia underwent an abrupt transition from dry to humid climate conditions at 5.5 million years (Ma), likely receiving year-round rainfall, but after similar to 3.3 Ma, climate shifted toward an increasingly seasonal precipitation regime. The progressive constriction of the Indonesian Throughflow likely decreased continental humidity and transferred control of northwest Australian climate from the Pacific to the Indian Ocean, leading to drier conditions punctuated by monsoonal precipitation. The northwest dust pathway and fully established seasonal and orbitally controlled precipitation were in place by similar to 2.4 Ma, well after the intensification of Northern Hemisphere glaciation. The transition from humid to arid conditions was driven by changes in Pacific and Indian Ocean circulation and regional atmospheric moisture transport, influenced by the emerging Maritime Continent. We conclude that the Maritime Continent is the switchboard modulating teleconnections between tropical and high-latitude climate systems. Plain Language Summary Australia is themost arid habitable continent on earth, however its climate is capable of dramatic changewith seasonalmonsoon rains in the otherwise arid northwest. We analyzed natural gamma radiation in a recently drilled borehole (IODP Expedition 356 Site U1463) off NW Australia to examine long-term climate changes over the last 6 million years. Based on variations in potassium, thorium and uranium, as well as common clay minerals, we show that the NW continent was more humid during the Pliocene period, between similar to 5.5 and 3.3 million years ago (Humid Interval), and became arid by the early Pleistocene, similar to 2.4 million years ago (Arid Interval). We attribute the Humid Interval to an expansion of warm surface waters in the western Pacific, supplying warm and moist air to the continent. As Australia moved north, the Maritime Continent (islands to the north) emerged, restricting the flow of warm surface currents from the Pacific (Indonesian Throughflow), resulting in drier conditions on land. The Arid Interval ushered in amodern-like Australian climate, with seasonal rainfall and dust storms, and a more modern Indian Ocean circulation. Our results show that the Maritime Continent is an important control on both Australian climate and Indian Ocean circulation.

National Category
Geology
Identifiers
urn:nbn:se:uu:diva-332420 (URN)10.1002/2017GL072977 (DOI)000406257400052 ()
Funder
Swedish Research Council, 2011-4866, 2016-04434
Available from: 2017-11-02 Created: 2017-11-02 Last updated: 2017-11-02Bibliographically approved
Bordiga, M., Sulas, C. & Henderiks, J. (2017). Reticulofenestra daviesii: Biostratigraphy and paleogeographic distribution across the Eocene-Oligocene boundary. Geobios, 50(5-6), 349-358
Open this publication in new window or tab >>Reticulofenestra daviesii: Biostratigraphy and paleogeographic distribution across the Eocene-Oligocene boundary
2017 (English)In: Geobios, ISSN 0016-6995, E-ISSN 1777-5728, Vol. 50, no 5-6, p. 349-358Article in journal (Refereed) Published
Abstract [en]

Improving the biostratigraphy across the Eocene-Oligocene is fundamental to better constrain the timing and causes of an important global climate change of the Cenozoic, the Eocene-Oligocene Transition (EOT; 34-33.5 Ma). Across the EOT, only few nannofossil bioevents are considered globally synchronous and reliable. One of these is the first common occurrence (Bc) of the species Reticulofenestra daviesii that has been proven to be useful for biostratigraphical correlations in the Southern Ocean, but the potential of R. daviesii as a biostratigraphical marker at mid- and low latitudes has not been explored yet in detail. We investigate three deep-sea drill sites located across a N-S transect at mid-low latitudes of the Atlantic Ocean spanning from 34.4 to 33 Ma, reviewing the temporal and geographical distribution together with the intraspecific variability of R. daviesii. Our data quantify the occurrence of R. daviesii in (sub)tropical regions of the Atlantic Ocean, although with lower abundances (similar to 4-12%) compared to Southern Ocean assemblages (40-95%). This suggests that R. daviesii was a cosmopolitan species capable to adapt to a wider range of sea surface temperatures and environmental conditions than previously thought. However, the temporal distributions of R. daviesii at the three studied sites are not comparable to the trends recorded in the Southern Ocean. Its Bc is clearly identifiable only at the equatorial site, occurring similar to 500,000 years before the age estimated in the Southern Ocean (33.705 Ma). Thus, we suggest caution when using the Bc of R. daviesii as a reliable biostratigraphical event at mid- and low latitudes. In addition, our biometrical data reveal that up to 38% of R. daviesii coccoliths is > 8-10 mu m in major axis size, thus bigger than the medium size range (5-8 mu m) originally described. Refining the size range of R. daviesii is important for estimating its cell volume versus surface area and coccolith carbonate mass. (C) 2017 Elsevier Masson SAS. All rights reserved.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Eocene-Oligocene, Reticulofenestra daviesii, Calcareous nannofossils, Atlantic Ocean, Placolith size
National Category
Geology Biological Sciences
Identifiers
urn:nbn:se:uu:diva-347664 (URN)10.1016/j.geobios.2017.07.002 (DOI)000424314100001 ()
Funder
Swedish Research Council, 2011-4866
Available from: 2018-04-06 Created: 2018-04-06 Last updated: 2018-04-06Bibliographically approved
Organisations

Search in DiVA

Show all publications