Poster Presentation 2024 Australian Marine Sciences Association Annual Meeting combined with NZMSS

Phytoplankton Community Composition across Submesoscale Fronts in the East Australian Current. (#728)

Chantal Mears 1 , Christina Schallenberg 2 , Pete Strutton 1 , Tamara Schlosser 1
  1. Institute for Marine and Antarctic Studies , University of Tasmania, Hobart, Tasmania, Australia
  2. CSIRO, Hobart, Tasmania, Australia

Submesoscale (1-10km) instabilities, such as fronts, have been hypothesised to play a large role in global oceanic transports of heat, carbon, and nutrients. Despite globally a near ubiquitous distribution, locating these features can be challenging, limiting our understanding of their importance. Submesoscale fronts are frequently found between mesoscale eddies, such as those in the East Australian Current (EAC). Although submesoscale fronts are often highly productive, the governing mechanisms and resulting biogeochemical responses are still largely unknown. In this study, we investigate how phytoplankton community composition and biogeochemical tracers differ across fronts, comparing frontal transition zones to the surrounding water masses. On a recent voyage to the EAC (aboard the R/V Investigator, October 2023) underway data was collected for analysing the phytoplankton community composition. Observations included phytoplankton pigments, particulate absorption, carbon:chl ratios, and spectral absorption and attenuation sensor (acs) measurements. By placing this data in the context of water mass properties such as nutrients, temperature, and salinity, a better understanding of the EAC's frontal structures was built. Ultimately, this study aims to facilitate greater understanding of how phytoplankton community composition varies with changing biogeochemistry at a submesoscale level.