scholarly journals Elevated temperature and browning increase dietary methylmercury, but decrease essential fatty acids at the base of lake food webs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pianpian Wu ◽  
Martin J. Kainz ◽  
Fernando Valdés ◽  
Siwen Zheng ◽  
Katharina Winter ◽  
...  
Keyword(s):  
Climate Change ◽  
Fatty Acids ◽  
Organic Matter ◽  
Food Webs ◽  
Essential Fatty Acids ◽  
Trophic Levels ◽  
Climate Change Scenarios ◽  
Essential Nutrients ◽  
Aquatic Food Webs ◽  
Aquatic Food

AbstractClimate change scenarios predict increases in temperature and organic matter supply from land to water, which affect trophic transfer of nutrients and contaminants in aquatic food webs. How essential nutrients, such as polyunsaturated fatty acids (PUFA), and potentially toxic contaminants, such as methylmercury (MeHg), at the base of aquatic food webs will be affected under climate change scenarios, remains unclear. The objective of this outdoor mesocosm study was to examine how increased water temperature and terrestrially-derived dissolved organic matter supply (tDOM; i.e., lake browning), and the interaction of both, will influence MeHg and PUFA in organisms at the base of food webs (i.e. seston; the most edible plankton size for zooplankton) in subalpine lake ecosystems. The interaction of higher temperature and tDOM increased the burden of MeHg in seston (< 40 μm) and larger sized plankton (microplankton; 40–200 μm), while the MeHg content per unit biomass remained stable. However, PUFA decreased in seston, but increased in microplankton, consisting mainly of filamentous algae, which are less readily bioavailable to zooplankton. We revealed elevated dietary exposure to MeHg, yet decreased supply of dietary PUFA to aquatic consumers with increasing temperature and tDOM supply. This experimental study provides evidence that the overall food quality at the base of aquatic food webs deteriorates during ongoing climate change scenarios by increasing the supply of toxic MeHg and lowering the dietary access to essential nutrients of consumers at higher trophic levels.

scholarly journals Selenium Interactions with Algae: Chemical Processes at Biological Uptake Sites, Bioaccumulation, and Intracellular Metabolism

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 528 ◽  
Author(s):  
Dominic E. Ponton ◽  
Stephanie D. Graves ◽  
Claude Fortin ◽  
David Janz ◽  
Marc Amyot ◽  
...  
Keyword(s):  
Food Webs ◽  
Mechanistic Model ◽  
Trophic Levels ◽  
Primary Producers ◽  
Organic Selenium ◽  
Selenium Uptake ◽  
Aquatic Food Webs ◽  
Uptake Sites ◽  
Aquatic Food ◽  
Lentic Systems

Selenium (Se) uptake by primary producers is the most variable and important step in determining Se concentrations at higher trophic levels in aquatic food webs. We gathered data available about the Se bioaccumulation at the base of aquatic food webs and analyzed its relationship with Se concentrations in water. This important dataset was separated into lotic and lentic systems to provide a reliable model to estimate Se in primary producers from aqueous exposure. We observed that lentic systems had higher organic selenium and selenite concentrations than in lotic systems and selenate concentrations were higher in lotic environments. Selenium uptake by algae is mostly driven by Se concentrations, speciation and competition with other anions, and is as well influenced by pH. Based on Se species uptake by algae in the laboratory, we proposed an accurate mechanistic model of competition between sulfate and inorganic Se species at algal uptake sites. Intracellular Se transformations and incorporation into selenoproteins as well as the mechanisms through which Se can induce toxicity in algae has also been reviewed. We provided a new tool for risk assessment strategies to better predict accumulation in primary consumers and consequently to higher trophic levels, and we identified some research needs that could fill knowledge gaps.

scholarly journals Tracking Dissolved Organic Matter in Coastal Ecosystems

Eos ◽  
2019 ◽  
Vol 100 ◽  
Author(s):  
Elizabeth Thompson
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Food Webs ◽  
Coastal Ecosystems ◽  
Coastal Systems ◽  
Aquatic Food Webs ◽  
Aquatic Food

Dissolved organic matter supports aquatic food webs and holds as much carbon as the atmosphere. A new study tracks which sources and processes play the biggest role in coastal systems.

scholarly journals Reconciling the role of organic matter pathways in aquatic food webs by measuring multiple tracers in individuals

Ecology ◽  
2015 ◽  
Vol 96 (12) ◽  
pp. 3257-3269 ◽  
Author(s):  
Timothy D. Jardine ◽  
Ryan Woods ◽  
Jonathan Marshall ◽  
James Fawcett ◽  
Jaye Lobegeiger ◽  
...  
Keyword(s):  
Organic Matter ◽  
Food Webs ◽  
Aquatic Food Webs ◽  
Aquatic Food

Lipids at the plant–animal interface: a stable isotope labelling method to evaluate the assimilation of essential fatty acids in the marine copepod Calanus finmarchicus

2019 ◽  
Vol 41 (6) ◽  
pp. 909-924 ◽  
Author(s):  
Laura Helenius ◽  
Suzanne Budge ◽  
Steven Duerksen ◽  
Emmanuel Devred ◽  
Catherine L Johnson
Keyword(s):  
Fatty Acids ◽  
Food Webs ◽  
Essential Fatty Acids ◽  
Trophic Levels ◽  
Calanus Finmarchicus ◽  
Fundamental Aspect ◽  
Omega 3 ◽  
Marine Food Webs ◽  
Marine Copepod ◽  
Marine Food

Abstract Linking production, transfer and subsequent bioavailability of nutritionally significant matter from phytoplankton to higher trophic levels is a fundamental aspect in understanding marine food webs. The plant–animal interface is of interest because of the highly variable transfer between producers and consumers, and the myriad of factors that influence it. Essential fatty acids (EFAs) are dietary nutrients that are necessary for normal function in all consumers, yet it remains unclear how efficiently they are transferred through marine food webs. We introduced a 13C-labelled carbon source to the cryptophyte Rhodomonas salina to quantify primary production of two omega-3 long-chain polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). We investigated transfer and assimilation efficiencies of these EFAs from phytoplankton to the calanoid copepod Calanus finmarchicus in an 8-day feeding experiment. We found low production of both EFAs in R. salina. Assimilation efficiencies of both EFAs ranged from 5 to 15% throughout the experiment, remaining slightly higher on average for DHA. This was mirrored in more efficient trophic transfer of DHA (up to 28%, compared to 13% for EPA). These results add to previously scarce experiments empirically quantifying the assimilation and transfer efficiency of EFAs in a basic marine planktonic food chain.

Modelling the role of highly unsaturated fatty acids in planktonic food web processes: a mechanistic approach

2012 ◽  
Vol 20 (3) ◽  
pp. 155-172 ◽  
Author(s):  
Gurbir Perhar ◽  
George B. Arhonditsis ◽  
Michael T. Brett
Keyword(s):  
Fatty Acids ◽  
Food Webs ◽  
Unsaturated Fatty Acids ◽  
Trophic Levels ◽  
Efficient Energy Transfer ◽  
Highly Unsaturated Fatty Acids ◽  
Planktonic Food ◽  
Aquatic Food ◽  
Biochemical Research

Highly unsaturated fatty acids (HUFAs) are a subgroup of fatty acids characterized by chains of 20 or more carbon atoms with multiple double bonds, which potentially limit the growth of zooplankton. Zooplankton require high HUFA concentrations during periods of rapid growth, but co-limitation with nutrients is also likely to occur. Recent modelling results suggest food webs with high quality (nutritional and biochemical) primary producers can attain inverted biomass distributions with efficient energy transfer between trophic levels. In this study, our objective is to highlight the recent advances in studying the role of HUFAs in aquatic food webs. We take a first-principles approach to investigate the chemical nature of HUFAs, and the role they play in zooplankton ecology. To this end, we introduce a novel zooplankton growth sub model that tracks the interplay between nitrogen, phosphorus, and HUFAs in plankton population models. Our aim is to produce a sub model that incorporates the knowledge gained from decades of biochemical research into management-oriented predictive tools.

Sign in / Sign up

Export Citation Format

Share Document