Phytoplankton biomass controls tocopherol concentrations in Baltic Sea zooplankton
(English)In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599Article in journal (Refereed) Submitted
Nearly all organisms are constantly exposed to oxidative threat, because every reaction where oxygen is involved gives rise to oxidants. Efficient protection is provided by antioxidants. Vitamin E (tocopherol) is an essential plant-derived antioxidant and poorly studied so far in marine food webs. In 2004 and 2005 eight offshore expeditions were conducted in the Baltic Sea to explore the dynamics of α-tocopherol in the pelagic food web. In order to analyze tocopherol production and transition to the next food web level, two plankton size classes were sampled; <100 µm (dominated by phytoplankton) and >200 µm (dominated by calanoid copepods). HPLC analysis revealed lowest values of α-tocopherol per L seawater in March in both size classes and highest in May for <100 µm (31.5 ng L-1) and August for >200 µm (1.3 ng L-1). No consistent seasonal pattern could be observed in α-tocopherol per unit biomass for the zooplankton. Concentrations ranged in <100 µm from 0.05 to 0.10 ng µg C-1 and in >200 µm from 0.05 to 0.11 ng µg C-1. Partial least square regression (PLS) revealed nutrional status and species composition of the phytoplankton biomass as driving factors of α-tocopherol production in phytoplankton. Abiotic factors, as depth and temperature were only of significant influence in May. In zooplankton, the α-tocopherol concentration was negatively associated with phytoplankton biomass in May. Therefore we concluded that assimilation efficiency of zooplankton in combination with high phytoplankton biomass is the bottle-neck in tocopherol transport from phytoplankton to higher levels in the food web.
Vitamin E; Food web; Phytoplankton; Zooplankton; Baltic Sea
IdentifiersURN: urn:nbn:se:uu:diva-130140OAI: oai:DiVA.org:uu-130140DiVA: diva2:346643