Validation of an Eulerian population model for the marine copepod Calanus finmarchicus in the Norwegian Sea

The essential fatty acids (EFA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are critical nutrients for all organisms, and the temperature sensitivity of their trophic transfer in marine systems is of concern because of rising ocean temperatures. Laboratory-reared copepodites of the marine calanoid Calanus finmarchicus were used to test the effects of temperature (at 6°C, 12°C and increasing temperature stress) and prey type (the dinoflagellate Heterocapsa triquetra and the diatom Thalassiosira weissflogii ) on the extent and efficiency of dietary EPA and DHA incorporation from phytoplankton to copepods in a set of feeding experiments using 13 C labelling. Temperature was a significant determinant of C . finmarchicus copepodites' EFA incorporation and gross growth efficiency, defined as the fraction of ingested EFA retained in copepod tissue. Ingestion and incorporation of both EFA were higher at warmer temperature, except in the case of DHA in copepods feeding on diatoms. DHA-associated growth efficiency was higher at the higher temperature for copepodites consuming the dinoflagellate, but temperature-related variation in algal EFA content was also a predictive factor. Moreover, our results strongly suggest that copepodites are capable of synthesizing EPA when consuming an EPA-depleted diet. Our study implies that the copepod link of marine food webs is resilient in terms of EFA transfer when confronted with alterations of ambient temperature and prey type availability. Measurements presented here are critical for estimating how EFA transfer dynamics respond to intra- and interannual environmental variability. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers’: evidence and significance of consumer modification of dietary fatty acids’.

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Towards population genomics in non-model species with large genomes: a case study of the marine zooplankton Calanus finmarchicus

Royal Society Open Science ◽

10.1098/rsos.180608 ◽

2019 ◽

Vol 6 (2) ◽

pp. 180608 ◽

Cited By ~ 11

Author(s):

Marvin Choquet ◽

Irina Smolina ◽

Anusha K. S. Dhanasiri ◽

Leocadio Blanco-Bercial ◽

Martina Kopp ◽

...

Keyword(s):

Population Genomics ◽

Single Copy ◽

Calanus Finmarchicus ◽

Model Species ◽

Reduced Representation ◽

Marine Copepod ◽

Marine Zooplankton ◽

Sequencing Technologies ◽

A Genome ◽

Large Genomes

Advances in next-generation sequencing technologies and the development of genome-reduced representation protocols have opened the way to genome-wide population studies in non-model species. However, species with large genomes remain challenging, hampering the development of genomic resources for a number of taxa including marine arthropods. Here, we developed a genome-reduced representation method for the ecologically important marine copepod Calanus finmarchicus (haploid genome size of 6.34 Gbp). We optimized a capture enrichment-based protocol based on 2656 single-copy genes, yielding a total of 154 087 high-quality SNPs in C. finmarchicus including 62 372 in common among the three locations tested. The set of capture probes was also successfully applied to the congeneric C. glacialis . Preliminary analyses of these markers revealed similar levels of genetic diversity between the two Calanus species, while populations of C. glacialis showed stronger genetic structure compared to C. finmarchicus . Using this powerful set of markers, we did not detect any evidence of hybridization between C. finmarchicus and C. glacialis . Finally, we propose a shortened version of our protocol, offering a promising solution for population genomics studies in non-model species with large genomes.

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Importance of Feeding, Direct Uptake from Seawater, and Transfer from Generation to Generation in the Accumulation of an Organochlorine (p,p′-DDT) by the Marine Planktonic Copepod Calanus finmarchicus

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f81-013 ◽

1981 ◽

Vol 38 (1) ◽

pp. 101-119 ◽

Cited By ~ 19

Author(s):

Gareth C. Harding ◽

W. Peter Vass ◽

Ken F. Drinkwater

Keyword(s):

Equilibrium Concentration ◽

Calanus Finmarchicus ◽

Planktonic Copepod ◽

Model Simulations ◽

Marine Copepod ◽

Planktonic Crustaceans

The accumulation of an organochlorine by the marine copepod Calanus finmarchicus, through feeding on contaminated phytoplankton, 14C-p,p′-DDT labeled Thalassiosira weisflogii, was measured. At "normal" densities, ≈ 60 μg C/L, the copepod retained 60–70% of the DDT ingested following gut egestion, but under "bloom" conditions, ≈ 600 μg C/L, retained as little as 10%. These results enable us to incorporate feeding and generation transfer terms into an earlier model of DDT flux between seawater and planktonic crustaceans. Model simulations indicate that it is not necessary to invoke direct uptake from seawater to arrive at published levels of ΣDDT in copepods, even when our lowest experimental DDT feeding efficiencies are used. We predict that the potential for rapidly developing Calanus to accumulate DDT from generation to generation will reach an equilibrium concentration after 12 generations but that an alternating equilibrium of generations will occur within four generations in a two-season temperature environment.Key words: p,p′-DDT, uptake, clearance, feeding, assimilation, copepods, Calanus finmarchicus

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