How will climate change impact the nutritional quality of freshwater organisms?
(QUALITY)


Main funder

Funder's project number: 333564


Funds granted by main funder (€)

  • 505 158,00


Funding program


Project timetable

Project start date: 01/09/2020

Project end date: 31/08/2024


Summary

Aquatic primary production offers essential biomolecules for zooplankton and fish growth and finally for human nutrition. Distinct phytoplankton taxa differ in their ability to synthetize amino acids (AA) and long chain ω-3 polyunsaturated fatty acids (PUFA, Fig. 1, Table 1, Taipale et al., 2013, 2016a, b; Peltomaa et al. 2017). In optimal situation high-quality phytoplankton fuels long-chain w-3 PUFA and essential amino acids (EAA) for whole food web (Galloway et al. 2014). However, anthropogenic pressures and climate change modify physical and chemical parameters and thus indirectly affect the synthesis and transfer of essential biomolecules. Previous studies (Muller-Navarra et al., 2004; Taipale et al., 2016, 2018) has shown that eutrophication and browning decrease sestonic EPA and DHA (see definitions in Table1) content resulting in considerably lower (50%) nutritional value of fish in eutrophic lakes compared with clear-water lakes. Moreover, mathematical model by Colombo et al. (2019) based on global warming have estimated result in a 10 to 58% loss of globally-available DHA in the next 80 years, that will be more severe in freshwater than marine fishing zones. Changes in availability of DHA may therefore have a greater impact on populations in certain areas of the world, especially inland Africa. However, it is not well-known how several simultaneous environmental changes (temperature, nutrients, light, humic substances) induced by climate change influence the concentration of EPA, DHA and EAA in aquatic food web (µg per mg C). Moreover, cyanobacteria blooms are predicted to invade lakes even with moderate total phosphorus content, due to the temperature increase (Pätynen et al. 2014; Deng et al. 2016). Therefore consumers (zooplankton and fish) ability for endogenous EPA and DHA production may become crucial for survival of zooplankton and fish species in these harsh circumstances. Recent study (Taipale et al. 2018) with juvenile trout showed that their development cease without docosahexaenoic acid (DHA, 22:6w3) that is together with eicosapentaenoic acid (EPA) required for the eye and brain tissue development and immunity function (Tocher 2010). Endogenous production of DHA is complex and requires specific elongase and desaturase genes, e.g. fatty acid desaturase 2 (fads 2) is a key desaturate enzyme in DHA biosynthesis. Furthermore, study of Ishikawa et al. (Science 2019) demonstrated that this gene is a key metabolic gene for overcoming nutritional constrains with freshwater colonization in fishes. The purpose of the proposed project is to experimentally investigate how land use and climate change (eutrophication, browning, temperature increase) influence the phytoplankton synthesis of EPA, DHA and EAA. The purpose of field sampling is to define trophic retaining of EPA, DHA and EAA in pelagic food webs (from phytoplankton to fish) and determine consumers (zooplankton and fish) ability for endogenous production of EPA /DHA by using fatty acid specific isotope analysis and defining fad2 gene from zooplankton and fish. Field sampling includes lakes from different climatic zones to have ecorealistic estimations whether freshwater systems can provide these essential biomolecules in the future.


Principal Investigator


Primary responsible unit


Last updated on 2020-20-10 at 13:08