Parasites in marine food webs

2020 ◽  
pp. 45-60
Author(s):  
John P. McLaughlin ◽  
Dana N. Morton ◽  
Kevin D. Lafferty
Keyword(s):  
Food Webs ◽  
Trophic Levels ◽  
Free Living ◽  
Ecosystem Integrity ◽  
Marine Systems ◽  
Marine Food Webs ◽  
Living Species ◽  
Marine Food ◽  
Food Web Complexity ◽  
Insight Into

Parasites have important and unique impacts on marine food webs. By infecting taxa across all trophic levels, parasites affect both bottom-up and top-down processes in marine systems. When host densities are high enough, parasites can regulate or even decimate their populations, causing regime shifts in marine systems. As consumers and resources, parasites are enmeshed in food webs in ways that are different from free-living species. Their unique lifestyle renders parasites more susceptible to perturbations than their free-living hosts. As a result, parasites serve as useful indicators of ecosystem integrity. A theory for how food webs affect parasites will help us better understand why a particular infectious disease has become problematic, give insight into how restoration might reduce a costly marine disease, or let us use parasites as indicators to follow changes in food-web complexity.

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.

scholarly journals Selective and context-dependent effects of chemical stress across trophic levels at the basis of marine food webs

2018 ◽  
Vol 28 (5) ◽  
pp. 1342-1353 ◽  
Author(s):  
Christoph Mensens ◽  
Frederik De Laender ◽  
Colin R. Janssen ◽  
Frances Camille Rivera ◽  
Koen Sabbe ◽  
...  
Keyword(s):  
Food Webs ◽  
Trophic Levels ◽  
Chemical Stress ◽  
Marine Food Webs ◽  
Marine Food ◽  
Context Dependent

Stable nitrogen and carbon isotopes in sediments and biota from three tropical marine food webs: Application to chemical bioaccumulation assessment

2017 ◽  
Vol 36 (9) ◽  
pp. 2521-2532 ◽  
Author(s):  
Hui Zhang ◽  
Yun Teng ◽  
Tra Thi Thanh Doan ◽  
Yun Wei Yat ◽  
Sheot Harn Chan ◽  
...  
Keyword(s):  
Food Webs ◽  
Carbon Isotopes ◽  
Marine Food Webs ◽  
Marine Food

scholarly journals Krill: a potential vector for domoic acid in marine food webs

2002 ◽  
Vol 237 ◽  
pp. 209-216 ◽  
Author(s):  
S Bargu ◽  
CL Powell ◽  
SL Coale ◽  
M Busman ◽  
GJ Doucette ◽  
...  
Keyword(s):  
Food Webs ◽  
Domoic Acid ◽  
Potential Vector ◽  
Marine Food Webs ◽  
Marine Food

scholarly journals Untangling the roles of parasites in food webs with generative network models

2015 ◽  
Author(s):  
Abigail Z. Jacobs ◽  
Jennifer A. Dunne ◽  
Cristopher Moore ◽  
Aaron Clauset
Keyword(s):  
Food Web ◽  
Food Webs ◽  
Statistical Physics ◽  
Network Models ◽  
Food Web Structure ◽  
Free Living ◽  
Web Structure ◽  
Living Species ◽  
Parasitic Interactions ◽  
The Impact

Food webs represent the set of consumer-resource interactions among a set of species that co-occur in a habitat, but most food web studies have omitted parasites and their interactions. Recent studies have provided conflicting evidence on whether including parasites changes food web structure, with some suggesting that parasitic interactions are structurally distinct from those among free-living species while others claim the opposite. Here, we describe a principled method for understanding food web structure that combines an efficient optimization algorithm from statistical physics called parallel tempering with a probabilistic generalization of the empirically well-supported food web niche model. This generative model approach allows us to rigorously estimate the degree to which interactions that involve parasites are statistically distinguishable from interactions among free-living species, whether parasite niches behave similarly to free-living niches, and the degree to which existing hypotheses about food web structure are naturally recovered. We apply this method to the well-studied Flensburg Fjord food web and show that while predation on parasites, concomitant predation of parasites, and parasitic intraguild trophic interactions are largely indistinguishable from free-living predation interactions, parasite-host interactions are different. These results provide a powerful new tool for evaluating the impact of classes of species and interactions on food web structure to shed new light on the roles of parasites in food webs.

scholarly journals The origin of phagocytosis in Earth history

2020 ◽  
Vol 10 (4) ◽  
pp. 20200019 ◽  
Author(s):  
Daniel B. Mills
Keyword(s):  
Plasma Membrane ◽  
Particulate Matter ◽  
Food Webs ◽  
Host Cell ◽  
Crown Group ◽  
Cytological Evidence ◽  
Specific Process ◽  
Marine Food Webs ◽  
Bona Fide ◽  
Marine Food

Phagocytosis, or ‘cell eating’, is a eukaryote-specific process where particulate matter is engulfed via invaginations of the plasma membrane. The origin of phagocytosis has been central to discussions on eukaryogenesis for decades­, where it is argued as being either a prerequisite for, or consequence of, the acquisition of the ancestral mitochondrion. Recently, genomic and cytological evidence has increasingly supported the view that the pre-mitochondrial host cell—a bona fide archaeon branching within the ‘Asgard’ archaea—was incapable of phagocytosis and used alternative mechanisms to incorporate the alphaproteobacterial ancestor of mitochondria. Indeed, the diversity and variability of proteins associated with phagosomes across the eukaryotic tree suggest that phagocytosis, as seen in a variety of extant eukaryotes, may have evolved independently several times within the eukaryotic crown-group. Since phagocytosis is critical to the functioning of modern marine food webs (without it, there would be no microbial loop or animal life), multiple late origins of phagocytosis could help explain why many of the ecological and evolutionary innovations of the Neoproterozoic Era (e.g. the advent of eukaryotic biomineralization, the ‘Rise of Algae’ and the origin of animals) happened when they did.

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