Salps in the NW Atlantic Slope Water: metabarcoding and compound-specific stable isotope analysis of diet diversity and trophic interactions

• Published in: Marine biology 2024-12, Vol.171 (12), p.233, Article 233
• Main Authors: Batta-Lona, Paola G., Gardner, Kayla, Questel, Jennifer M., Thorrold, Simon R., Llopiz, Joel K., Wiebe, Peter H., Bucklin, Ann
• Format: Article
• Language: English
• Subjects: Amino acids; Biomass; Biomedical and Life Sciences; Carbon; Chlorophyll; Climate change; Diatoms; Diet; Dinoflagellates; DNA barcoding; Environmental impact; Filter feeders; Food chains; Food selection; Food sources; Food webs; Freshwater & Marine Ecology; Gelatinous zooplankton; Geographical distribution; Isotopes; Life Sciences; Marine & Freshwater Sciences; Marine biology; Marine invertebrates; Marine microorganisms; Mesopelagic zone; Microbiology; Microorganisms; Migrations; Oceanography; Original Paper; Plankton; Prey; rRNA 18S; Slope water; Species diversity; Stable isotopes; Trophic relationships; Vertical advection; Vertical distribution; Water; Zoology; Zooplankton
• ISSN: 0025-3162; 1432-1793
• DOI: 10.1007/s00227-024-04535-x

Mesopelagic zones of the NW Atlantic Slope Water support pelagic assemblages with high biomass and high diversity. Species of salps (Phylum Urochordata, Class Thaliacea) are bloom-forming, filter-feeding, gelatinous zooplankton, with significant impacts on pelagic food webs and vertical transport of organic material. Questions remain of their diet diversity, prey selectivity, and timing of feeding with respect to vertical distribution and migration. This study analyzed three salp species, Soestia (Iasis) zonaria, Salpa aspera , and Salpa fusiformis , collected from the NW Atlantic Slope Water during July and August 2018 and 2019. DNA metabarcoding using V4 and V9 regions of 18S rRNA found dinoflagellates to be predominant prey for all three salp species in both years. Analysis of five prey groups detected by metabarcoding revealed differences in proportions of prey. Compound-specific stable isotope analysis of essential amino acids, which integrates over several months, found diatoms to be the dominant end-member source for all three species. Our findings on salp diet diversity broaden our understanding of trophic pathways in the mesopelagic food web, including sources of productivity and possible impacts of climate change.