Marine Copepods, The Wildebeest of the Ocean

Copepods are amongst the most abundant animals on our planet. Who knew?! These small (typically 1–10 mm) crustaceans are found in all of the world’s oceans and play an important role in regulating Earth’s climate. Like wildebeest in the Serengeti graze on grasslands and are food for lions, herbivorous copepods represent a vital link in oceanic food chains between microscopic algae and higher predators, such as fish, birds, and whales. A group of copepods called Calanus are particularly important in the Northern Hemisphere. These tiny-but-mighty animals also share the wildebeest’s need to make a large annual migration—but in their case, they sink thousands of meters downwards to spend the winter in the deep, dark ocean. Understanding the lives of marine copepods, and how their populations will respond to climate change, is crucial for predicting the future health of the marine environment and how it helps our planet

Rates of egg production, grazing and mortatlity of Calanus finmarchicus measured experimentally in the North Atlantic during the Maria S. Merian cruise MSM26, spring 2013

An incubation experiment at five different temperatures was used to assess the potential for adaptation of Calanus finmarchicus to future warming of the ocean. During a short term (3 h) and long term (6 day) exposure of individual females to a gradient of temperature stress, egg production and fecal pellet production were monitored to indicate secondary production and grazing rates. A longer term (10 day) exposure to elevated temperatures followed by a return to ambient sea temperatures was used to assess the potential recovery of individuals exposed to temperature stress. Females were picked out from WP2 net samples and acclimatised in 2 L bottles of GFF filtered seawater with Thalassiosira weissflogii as prey for >48 h at ambient SST. Experimental bottles were filled with filtered seawater (GFF filtered from non-toxic seawater supply) and acclimated to experimental temperature overnight (0, 5, 10, 15 and 20 °C). Individual females were transferred into bottles using forceps and the bottles were inoculated with T. weissflogii to a final concentration of 5 µg chl L-1. Bottles were then placed into water baths and incubated for 3h or 6 d, and monitored for egg and fecal pellet production rates. A 10 day exposure experiment was used to test the potential for recovery from temperature stress, by returning females incubated at 5, 10, 15 and 20 °C back to 10 °C for 24 h and counting egg and fecal pellet production

Diversity of zooplankton assemblages at Station L4, Western English Channel, measured using next generation DNA sequencing

Background: Zooplankton play an important role in our oceans, in biogeochemical cycling and providing a food source for commercially important fish larvae. However, difficulties in correctly identifying zooplankton hinder our understanding of their roles in marine ecosystem functioning, and can prevent detection of long term changes in their community structure. The advent of massively parallel Next Generation Sequencing technology allows DNA sequence data to be recovered directly from whole community samples. Here we assess the ability of such sequencing to quantify the richness and diversity of a mixed zooplankton assemblage from a productive monitoring site in the Western English Channel. Methodology/Principle Findings: Plankton WP2 replicate net hauls (200 µm) were taken at the Western Channel Observatory long-term monitoring station L4 in September 2010 and January 2011. These samples were analysed by microscopy and metagenetic analysis of the 18S nuclear small subunit ribosomal RNA gene using the 454 pyrosequencing platform. Following quality control a total of 419,042 sequences were obtained for all samples. The sequences clustered in to 205 operational taxonomic units using a 97% similarity cut-off. Allocation of taxonomy by comparison with the National Centre for Biotechnology Information database identified 138 OTUs to species level, 11 to genus level and 1 to order, <2.5% of sequences were classified as unknowns. By comparison a skilled microscopic analyst was able to routinely enumerate only 75 taxonomic groups. Conclusions: The percentage of OTUs assigned to major eukaryotic taxonomic groups broadly aligns between the metagenetic and morphological analysis and are dominated by Copepoda. However, the metagenetics reveals a previously hidden taxonomic richness, especially for Copepoda and meroplankton such as Bivalvia, Gastropoda and Polychaeta. It also reveals rare species and parasites. We conclude that Next Generation Sequencing of 18S amplicons is a powerful tool for estimating diversity and species richness of zooplankton communities

Intra-specific genetic structuring in Calanus helgolandicus european populations associated with latitudinal differences

Symposium GLOBEC-IMBER España celebrado del 28-30 marzo de 2007 en Valencia.-- 2 pagesThe marine copepod Calanus helgolandicus is of considerable importance in the marine food web. It plays a critical role in marine ecosystems as a grazer of microplankton and as a major food source for commercially important fish. The distribution of C. helgolandicus in European waters covers a wide range of habitats, from open ocean to coastal environments. Recent studies [Reid et al., 2003; Bonnet et al., 2005] have shown that C. helgolandicus is sensitive to changes in climate, particularly along the European shelf of the northeast Atlantic. On the fringes of its distribution the range and abundance of C. helgolandicus has increased as water in the North Atlantic has warmed over recent decades. Building on the network of laboratories created by Bonnet et al. for their review on C. helgolandicus(2005), we collected samples in 95% ethanol from 19 European sites. From several individuals at each site a region of the mitochondrial large subunit (16S) ribosomal RNA (rRNA) gene was amplified and sequenced. Significant genetic differences have been identified for the first time between and within basins (Northern Fjords, Northeast Atlantic, West and East Mediterranean, and Black Sea) as well as a decrease of prosome length with the latitude. Our study provides a molecular evaluation of the intra-specific structuring in this key species in relation to variation in morphological characters. REFERENCES D. Bonnet, A. Richardson, R. Harris, A. Hirst, G. Beaugrand, M. Edwards, S. Ceballos, R. Diekman, A. Lopez-Urrutia, L. Valdes, F. Carlotti, J.C. Molinero, H. Weikert, W. Greve, D. Lucic, A. Albaina, Daly N. Yahia, S. Fonda Umani, A. Miranda, A. Dos Santos, K. Cook, S. Robinson and M.L. Fernandez Puelles, 2005. An overview of Calanus helgolandicus ecology in European waters. Prog. Oceanogr., 65, 1-53. P.C. Reid, M. Edwards, G. Beaugrand, M. Skogen and D. Stevens, 2003. Periodic changes in the zooplankton of the North Sea during the twentieth century linked to oceanic inflow. Fish. Oceanogr., 12, 260-26

Microplastics in water samples from the Fram Strait and the Arctic from July 2018 and August 2019

This dataset presents microplastics in water samples collected from the underway system and CTD alongside the August 2019 zooplankton samples presented in https://doi.pangaea.de/10.1594/PANGAEA.950296. These samples were initially digested using a homogenising solution and then filtered in preparation for Fourier Transform Infrared spectroscopy (FTIR) analysis in combination with an automated polymer identification approach (SIMPLE software) to identify polymer types, shape and size. Microplastics were also visualised using a microscope to further determine shape and size, particularly of fibres. Data collected on the microplastics found includes; polymer type, shape, size, species ingestion and location

Microplastics in zooplankton samples from the the Fram Strait and the Arctic from July 2018 and August 2019

Zooplankton (amphipod and copepod) were collected using nets in the Fram Strait and the Arctic, in July 2018 and August 2019 for microplastic analysis. Water samples were also collected from the underway system and CTD alongside the August 2019 zooplankton samples (https://doi.pangaea.de/10.1594/PANGAEA.950239). All samples were initially digested using a homogenising solution and then filtered in preparation for Fourier Transform Infrared spectroscopy (FTIR) analysis in combination with an automated polymer identification approach (SIMPLE software) to identify polymer types, shape and size. Microplastics were also visualised using a microscope to further determine shape and size, particularly of fibres. Data collected on the microplastics found includes polymer type, shape, size, species ingestion and location

Comparative ecology of over-wintering Calanus finmarchicus in the northern North Atlantic, and implications for life-cycle patterns

Data from plankton net and Optical Plankton Counter sampling during 12 winter cruises between 1994 and 2002 have been used to derive a multi-annual composite 3-D distribution of the abundance of over-wintering Calanus finmarchicus in a swath across the North Atlantic from Labrador to Norway. Dense concentrations occurred in the Labrador Sea, northern Irminger Basin, northern Iceland Basin, eastern Norwegian Sea, Faroe–Shetland Channel, and in the Norwegian Trench of the North Sea. A model of buoyancy regulation in C. finmarchicus was used to derive the lipid content implied by the in situ temperature and salinity at over-wintering depths, assuming neutral buoyancy. The Faroe–Shetland Channel and eastern Norwegian Sea emerged as having the highest water column-integrated abundances of copepodites, the lowest over-wintering temperature, and the highest implied lipid content. The results are discussed in the context of spatial persistence of populations, seasonal patterns of abundance, and relationships between over-wintering and lipid accumulation in the surface waters

Identifying potential high-risk zones for land-derived plastic litter to marine megafauna and key habitats within the North Atlantic

The pervasive use of plastic in modern society has led to plastic litter becoming ubiquitous within the ocean. Land-based sources of plastic litter are thought to account for the majority of plastic pollution in the marine environment, with plastic bags, bottles, wrappers, food containers and cutlery among the most common items found. In the marine environment, plastic is a transboundary pollutant, with the potential to cause damage far beyond the political borders from where it originated, making the management of this global pollutant particularly complex. In this study, the risks of land-derived plastic litter (LDPL) to major groups of marine megafauna – seabirds, cetaceans, pinnipeds, elasmobranchs, turtles, sirenians, tuna and billfish – and a selection of productive and biodiverse biogenic habitats – coral reefs, mangroves, seagrass, saltmarsh and kelp beds – were analysed using a Spatial Risk Assessment approach. The approach combines metrics for vulnerability (mechanism of harm for megafauna group or habitat), hazard (plastic abundance) and exposure (distribution of group or habitat). Several potential high-risk zones (HRZs) across the North Atlantic were highlighted, including the Azores, the UK, the French and US Atlantic coasts, and the US Gulf of Mexico. Whilst much of the modelled LDPL driving risk in the UK originated from domestic sources, in other HRZs, such as the Azores archipelago and the US Gulf of Mexico, plastic originated almost exclusively from external (non-domestic) sources. LDPL from Caribbean islands - some of the largest generators of marine plastic pollution in the dataset of river plastic emissions used in the study - was noted as a significant input to HRZs across both sides of the Atlantic. These findings highlight the potential of Spatial Risk Assessment analyses to determine the location of HRZs and understand where plastic debris monitoring and management should be prioritised, enabling more efficient deployment of interventions and mitigation measures.</p

The impact of polystyrene microplastics on feeding, function and fecundity in the marine copepod Calanus helgolandicus.

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Environmental Science and Technology, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see the DOI in this record.Microscopic plastic debris, termed “microplastics”, are of increasing environmental concern. Recent studies have demonstrated that a range of zooplankton, including copepods, can ingest microplastics. Copepods are a globally abundant class of zooplankton that form a key trophic link between primary producers and higher trophic marine organisms. Here we demonstrate that ingestion of microplastics can significantly alter the feeding capacity of the pelagic copepod Calanus helgolandicus. Exposed to 20 μm polystyrene beads (75 microplastics mL(–1)) and cultured algae ([250 μg C L(–1)) for 24 h, C. helgolandicus ingested 11% fewer algal cells (P = 0.33) and 40% less carbon biomass (P < 0.01). There was a net downward shift in the mean size of algal prey consumed (P < 0.001), with a 3.6 fold increase in ingestion rate for the smallest size class of algal prey (11.6–12.6 μm), suggestive of postcapture or postingestion rejection. Prolonged exposure to polystyrene microplastics significantly decreased reproductive output, but there were no significant differences in egg production rates, respiration or survival. We constructed a conceptual energetic (carbon) budget showing that microplastic-exposed copepods suffer energetic depletion over time. We conclude that microplastics impede feeding in copepods, which over time could lead to sustained reductions in ingested carbon biomass.NER