Relative contribution of multiple stressors on copepod density and diversity dynamics in the Belgian part of the North Sea

Abstract

The effect of multiple stressors on marine ecosystems is poorly understood. To partially bridge this knowledge gap we investigated the relative contribution of environmental variables to density and diversity dynamics of the zooplankton community in the Belgian part of the North Sea. We applied multimodel inference on generalized additive models to quantify the relative contribution of chlorophyll a, temperature, nutrients, salinity and anthropogenic chemicals (i.e. polychlorinated biphenyls and polycyclic aromatic hydrocarbons) to the dynamics of calanoid copepod species in the Belgian part of the North Sea. Temperature was the only predictor consistently showing a high importance in all models predicting the abundances of the selected copepod species. The relative contribution of other predictors was species-dependent. Anthropogenic chemicals were important predictors for three out of six species indicating that chemical mixtures at low concentrations should not be left unattended when performing risk assessments in a natural environment.

Evaluating the potential of direct RNA nanopore sequencing: Metatranscriptomics highlights possible seasonal differences in a marine pelagic crustacean zooplankton community

“…Other detected copepod species in our metatranscriptome were calanoids Paracalanus parvus Claus, Centropages spp., Pseudocalanus elongatus Boeck, Calanus helgolandicus Claus and the harpacticoid Euterpina acutifrons Dana. These findings correspond with earlier observations in the BPNS made by Daro et al (2006), Van Ginderdeuren et al (2014) and Deschutter et al (2017). Also, in Dutch coastal waters, calanoids T. longicornis, A. clausi and Centropages hamatus have been ranked as the stock-forming copepod species (Fransz, 1975).…”

“…This is in line with the lower mapping percentage of the summer sample replicates against the T. longicornis transcriptome (Table 1). This decline in abundance of Temora numbers, at the end of the summer, was already described by Deschutter et al (2017), Fransz et al (1989) and Van Ginderdeuren et al (2014) and is the result of both a reduced fecundity (low egg production rates) and an increase of the mortality rate (Fransz et al, 1989). Other detected copepod species in our metatranscriptome were calanoids Paracalanus parvus Claus, Centropages spp., Pseudocalanus elongatus Boeck, Calanus helgolandicus Claus and the harpacticoid Euterpina acutifrons Dana.…”

“…Moreover, the most abundant pelagic species in the North Sea, i.e. the omnipresent calanoid copepods Acartia clausi Giesbrecht and T. longicornis (Deschutter et al, 2017;Van Ginderdeuren et al, 2014), were also represented by the most SSU and COI reads in the metatranscriptome. Comparing the two samples, we observed a low number of T. longicornis individuals in the summer sample (pers.…”

“…Batten et al, 2003;O'Brien et al, 2017). In the Belgian Part of the North Sea (BPNS), most recent mesoscale zooplankton surveys were carried out by Van Ginderdeuren et al (2014) between 2009 and 2010 and by Deschutter et al (2017) between 2016 and 2017, investigating differences in zooplankton dynamics. With 70 species (51% of all species recorded), Crustacea is the most found taxon in the BPNS (Van Ginderdeuren et al, 2014).…”

LifeWatch observatory data: Zooplankton observations in the Belgian part of the North Sea

“…Zooplankton is ubiquitous in the BPNS, and is found in every season with densities up to 40.000 ind.m ‐3 (Van Ginderdeuren, ), although average densities are much lower at around 1–400 ind.m ‐3 (Van Ginderdeuren, ). Although the pelagic ecosystem is huge and of significant importance, it is scarcely studied in Belgian waters: recent studies on marine zooplankton in the BPNS are increasing (Van Ginderdeuren, Fiers, et al , ; Van Ginderdeuren, Hostens, et al , ; Van Ginderdeuren, ; Deschutter et al , ,; Mortelmans et al , ). In contrast, the Belgian estuarine zooplankton has received more attention throughout the time (Bakker and De Pauw, ; Soetaert and Van Rijswijk, ; Appeltans et al , ; Tackx et al , ; Mialet et al , ).…”