Language：Japanese   Publisher：Progress in Oceanography  

Major forage fishes spend their vulnerable early life stages in the Kuroshio and its neighboring waters where phytoplankton standing stocks are much lower than in coastal areas. Nevertheless, little is known of how mesozooplankton and fish larvae with their high biodiversity are supported in the Kuroshio ecosystem. Here we report stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) for mesozooplankton and fish larvae from coastal to pelagic sites in the East China Sea to evaluate trophic sources and pathways at lower trophic levels in planktonic food webs under different environmental regimes. Although δ13C and δ15N in mesozooplankton and fish larvae varied among taxonomic groups and sites, mesozooplankton δ13C and δ15N tended to be lower for particle-feeders than carnivores and fish larvae and at more pelagic sites than in coastal waters. There were significant linear regressions between δ15N and δ13C of mesozooplankton communities, with the similar slopes among sites and lower intercepts at more pelagic sites. The δ15N and δ13C of small copepods, euphausiids, ostracods, appendicularians and fish larvae were aligned close to the regression line covering all regions, indicating that these were trophic sources and pathways to mesozooplankton and fish larvae. Our results suggest that trophic sources of mesozooplankton and fish larvae are supported through copepods and appendicularian-integrated microbial production and are more dependent on diazotrophic production in more pelagic waters.

DOI： 10.1016/j.pocean.2022.102952

Scopus

Language：English   Publisher：Journal of Marine Systems  

DOI： 10.1016/j.jmarsys.2022.103767

Scopus

Language：English   Publisher：Frontiers in Marine Science  

DOI： 10.3389/fmars.2021.725227

Scopus

Language：Japanese   Publisher：Estuarine, Coastal and Shelf Science  

DOI： 10.1016/j.ecss.2021.107472

Scopus

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

Institutional Repository URL

Language：Japanese   Publisher：The Oceanographic Society of Japan  

<p>Temporal and spatial variations in the taxonomic composition, standing stocks (abundance and biomass), and protein synthetases activity of the mesozooplankton community in the northern Satsunan area were investigated. Although both variations in sources were significant for their standing stocks, temporal variability was predominant for their protein synthetases activity. A multivariate analysis on their taxonomic compositions identified six groups with large seasonality at the mouth of the Kagoshima Bay and two groups with less temporal variability. These were characterized by calanoids and poecilostomatoids. The mesozooplankton community demonstrated a higher abundance and biomass inside as compared to the outside of the Kagoshima Bay. However, similar protein synthetases activity was seen for both locations. Mesozooplankton protein synthetases activity was high, even when there was a low chlorophyll <i>a</i> average in the sampling layer owing to the increased presence of smaller mesozooplankton. In the sampling layer, individual body mass was lower and mesozooplankton abundance was higher at lower salinity averages. These results suggest that the temporal and spatial variations in the mesozooplankton standing stocks and protein synthetases activity are associated with the advections or extensions of small calanoids and poecilostomatoids with less saline waters.</p>

DOI： 10.5928/kaiyou.29.6_217

CiNii Research

Language：Japanese  

Institutional Repository URL

Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

Institutional Repository URL

Language：Japanese  

Language：English   Publishing type：Research paper (bulletin of university, research institution)  

Institutional Repository URL

Language：Japanese