scholarly journals Lipids in Marine Ecosystems

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Christopher C. Parrish

Lipids provide the densest form of energy in marine ecosystems. They are also a solvent and absorption carrier for organic contaminants and thus can be drivers of pollutant bioaccumulation. Among the lipids, certain essential fatty acids and sterols are considered to be important determinants of ecosystem health and stability. Fatty acids and sterols are also susceptible to oxidative damage leading to cytotoxicity and a decrease in membrane fluidity. The physical characteristics of biological membranes can be defended from the influence of changing temperature, pressure, or lipid peroxidation by altering the fatty acid and sterol composition of the lipid bilayer. Marine lipids are also a valuable tool to measure inputs, cycling, and loss of materials. Their heterogeneous nature makes them versatile biomarkers that are widely used in marine trophic studies, often with the help of multivariate statistics, to delineate carbon cycling and transfer of materials. Principal components analysis has a strong following as it permits data reduction and an objective interpretation of results, but several more sophisticated multivariate analyses which are more quantitative are emerging too. Integrating stable isotope and lipid data can facilitate the interpretation of both data sets and can provide a quantitative estimate of transfer across trophic levels.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pianpian Wu ◽  
Martin J. Kainz ◽  
Fernando Valdés ◽  
Siwen Zheng ◽  
Katharina Winter ◽  
...  

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.


2019 ◽  
Vol 41 (6) ◽  
pp. 909-924 ◽  
Author(s):  
Laura Helenius ◽  
Suzanne Budge ◽  
Steven Duerksen ◽  
Emmanuel Devred ◽  
Catherine L Johnson

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.


Open Biology ◽  
2021 ◽  
Vol 11 (4) ◽  
Author(s):  
Naoki Kabeya ◽  
Masanari Ogino ◽  
Hideki Ushio ◽  
Yutaka Haga ◽  
Shuichi Satoh ◽  
...  

The long-standing paradigm establishing that global production of Omega-3 (n–3) long-chain polyunsaturated fatty acids (LC-PUFA) derived almost exclusively from marine single-cell organisms, was recently challenged by the discovery that multiple invertebrates possess methyl-end (or ω x) desaturases, critical enzymes enabling the biosynthesis of n–3 LC-PUFA. However, the question of whether animals with ω x desaturases have complete n–3 LC-PUFA biosynthetic pathways and hence can contribute to the production of these compounds in marine ecosystems remained unanswered. In the present study, we investigated the complete enzymatic complement involved in the n–3 LC-PUFA biosynthesis in Tigriopus californicus , an intertidal harpacticoid copepod. A total of two ω x desaturases, five front-end desaturases and six fatty acyl elongases were successfully isolated and functionally characterized. The T. californicus ω x desaturases enable the de novo biosynthesis of C 18 PUFA such as linoleic and α-linolenic acids, as well as several n–3 LC-PUFA from n–6 substrates. Functions demonstrated in front-end desaturases and fatty acyl elongases unveiled various routes through which T. californicus can biosynthesize the physiologically important arachidonic and eicosapentaenoic acids. Moreover, T. californicus possess a Δ4 desaturase, enabling the biosynthesis of docosahexaenoic acid via the ‘Δ4 pathway’. In conclusion, harpacticoid copepods such as T. californicus have complete n–3 LC-PUFA biosynthetic pathways and such capacity illustrates major roles of these invertebrates in the provision of essential fatty acids to upper trophic levels.


2021 ◽  
Author(s):  
Keira M. McKee

Recently, there has been a call for the inclusion of free-living stages of trematode parasites in food web models as they are present in high numbers in aquatic ecosystems and serve as prey for higher trophic levels. I investigated the presence of lipids in cercariae, specifically neutral energy reserve lipid stores and long-chain polyunsaturated fatty acids (LC-PUFA), as they are considered the primary energy currency in aquatic ecosystems. Cercariae of all investigated taxa contained distinct neutral lipid compositions and Ribeiroia ondatrae cercariae had significant quantities of total lipids, as well as essential fatty acids (EFA). I also investigated the viability of cercariae as prey items for dragonfly larvae (Leucorrhinia intacta) and detected indistinguishable proportions of EFA in larvae subsisting on equivalent quantities of R. ondatrae and Daphnia spp. This suggests that cercariae may contribute to nutrient subsidies in aquatic ecosystems, thereby supporting aquatic organism growth and fitness.


2021 ◽  
Author(s):  
Keira M. McKee

Recently, there has been a call for the inclusion of free-living stages of trematode parasites in food web models as they are present in high numbers in aquatic ecosystems and serve as prey for higher trophic levels. I investigated the presence of lipids in cercariae, specifically neutral energy reserve lipid stores and long-chain polyunsaturated fatty acids (LC-PUFA), as they are considered the primary energy currency in aquatic ecosystems. Cercariae of all investigated taxa contained distinct neutral lipid compositions and Ribeiroia ondatrae cercariae had significant quantities of total lipids, as well as essential fatty acids (EFA). I also investigated the viability of cercariae as prey items for dragonfly larvae (Leucorrhinia intacta) and detected indistinguishable proportions of EFA in larvae subsisting on equivalent quantities of R. ondatrae and Daphnia spp. This suggests that cercariae may contribute to nutrient subsidies in aquatic ecosystems, thereby supporting aquatic organism growth and fitness.


2012 ◽  
Vol 69 (11) ◽  
pp. 1870-1880 ◽  
Author(s):  
Anja Wenzel ◽  
Ann-Kristin Bergström ◽  
Mats Jansson ◽  
Tobias Vrede

Terrestrial organic material (t-OM) can subsidize lake food webs indirectly via incorporation of dissolved t-OM by bacteria and subsequent transfer to higher trophic levels or directly through metazoan consumption of particulate t-OM (t-POM). We tested the effects of peat layer t-POM on Daphnia galeata performance. A pure t-POM diet could not sustain survival, growth, and reproduction of D. galeata. Mixtures of heterotrophic bacteria (Pseudomonas sp.) and phytoplankton (Rhodomonas lacustris) gave higher survival, growth, and reproduction than mixtures of t-POM and Rhodomonas. Daphnids performed best when feeding on pure Rhodomonas diets. Quantification of phosphorus (P) and essential biochemicals (i.e., fatty acids) revealed that Rhodomonas had the highest amounts of all these components. Pseudomonas, while rich in P, contained few essential fatty acids, and t-POM had low concentrations of both P and fatty acids. We therefore suggest that the poor food quality of t-POM in our experiment was due to its suboptimal mineral and biochemical composition and that a substantial proportion of high-quality phytoplankton is necessary to sustain zooplankton biomass.


2020 ◽  
Vol 638 ◽  
pp. 107-121 ◽  
Author(s):  
BS Rangel ◽  
NE Hussey ◽  
Y Niella ◽  
LA Martinelli ◽  
AD Gomes ◽  
...  

Throughout evolutionary history, elasmobranchs have developed diverse reproductive strategies. Little focused work, however, has addressed how neonatal nutritional state is affected by differing degrees of maternal investment associated with these markedly different reproductive strategies. To investigate the effect of maternal investment on the nutritional quality of pups during the early life history of an extremely viviparous elasmobranch, quantitative biomarker analysis including lipids, fatty acids and stable isotopes was conducted. Using the cownose ray Rhinoptera bonasus (histotrophic viviparous) as a model, we found that pups were initially born in a positive nutritional state, enriched in physiologically important essential fatty acids and nitrogen and carbon stable isotope values (δ15N and δ13C), a result of maternal intrauterine transfer. A systematic decrease in some fatty acids and δ15N values, as well as a decrease in cholesterol with growth, confirmed that these substrates were derived from maternal resources and used in initial metabolic processes following birth. An observed increase in condition factor, plasma essential fatty acids and triglyceride:cholesterol ratio with increasing body size identified a progression towards successful independent foraging with pups not displaying marked nutritional deficiency or fasting phases. Our multi-tracer approach allowed the identification of 2 size classes of young rays (<50 and <70 cm disc width) that displayed distinct physiological states. Since prenatal maternal investment is critical for offspring condition and to promote successful foraging post birth, understanding the trophic ecology and physiological state of pups during their first year is critical to guide management and conservation within nursery grounds.


2018 ◽  
Vol 28 (4) ◽  
pp. 1219-1225
Author(s):  
Filip Jovanovski ◽  
Toni Mitrovski ◽  
Viktorija Bezhovska

Food is not just a pleasure in life, it is also an important factor for our health. Human nutrition is a mixture of nutrients, which are the only source of energy needed for survival. Energy-poor diet endangers many life functions, and above all the working ability. In the world, the meaning of the diet is very serious, and hence the demands for a –rational, healthy and safe diet are growing. Human nutrition contains saturated and unsaturated fatty acids. Essential fatty acids (EFAs) must be ingested in everyday diet because the body does not produce it. They are very important for human health. They are present in each cell of the human body and are an important factor for the normal growth, development and functioning of cells, muscles, nerves and organs. They are also used in the production of certain hormones - such as prostaglandins, which are crucial for the performance of certain important processes. The deficit from EFAs is due to a number of health problems, including more serious diseases.


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