Inter-seasonal and inter-annual changes in the zooplankton community structure in a fixed coastal sampling station from Patagonia, Argentina (2018–2023)

HERNÁNDEZ MORESINO RODRIGO; HALTER BRISA; EPHERRA LUCÍA; PISONI JUAN PABLO; BARBIERI ELENA; CRESPI ABRIL AUGUSTO; MARTELLI ANTONELA; DE CIAN ANTONELLA

Plymouth

Simposio; Trevor Platt Symposium 2023; 2023

Plymouth marine Laboratory

Environmental conditions around the world ocean are drastically changing in response to greenhouse gases from anthropogenic activities. Continue time-series measurements at fixed locations are necessary to monitor ocean trends. The Nuevo Gulf Oceanographic Station (GNEO) is a coastal monitoring effort in Patagonia Argentina, measuring the temporal variability of physical, chemical, and biological processes in these waters, and supplying data to the NANO-DOAP project (A global study of coastal Deoxygenation, Ocean Acidification and Productivity) since 2018. At this time, we will present trends in the mesozooplankton community structure from 2018 to the present. Vertical trawls were monthly performed, with a Hensen net from the dock of Puerto Madryn City. Taxonomic identification and quantification were conducted by semi-automatic analysis of digital images with ZooImage software. Changes in the community structure reflect changes in the taxonomic composition among seasons, however, no differences were evidenced among years up to date. There is an increase in the abundance from autumn to summer. The slopes of the size structure are similar from autumn to spring, where small copepods dominate with 60%. In summer, the abundance duplicates, increasing the proportion of small copepods to 70%, stepping the slope of the size spectra from -3 to -4 compared with the rest of the seasons. Small copepods dominated all seasons, followed by large copepods and appendicularians, the last ones mainly during the cold seasons. These surveys of zooplankton communities using semi-automatic tools are an effective and low-labour effort way of assessing the health status of urban coastal marine ecosystems.