SELECTIVE UPTAKE OF BIOACTIVE TRACE ELEMENTS BY ATLANTIC SARGASSUM

The Great Atlantic Sargassum Belt spans the width of the Atlantic Ocean, extending from western Africa and into the Gulf of Mexico. Coastal regions are especially vulnerable to potential hazards resulting from nearshore Sargassum inundation, including the release of potential toxicants during the degradation of massive accumulations of seaweed biomass. Few published studies have included the trace element composition of Sargassum, but those that have highlight the importance of bioactive trace elements (both nutrient and toxicant) to the growth of Sargassum. Here, we present the initial results of an intensive field campaign to investigate the trace element concentrations in ~1000 samples of Sargassum collected from the beaches and coastal waters of Florida, USA (June 2023-August 2024). Special care was taken throughout the sampling and analysis process to minimize contamination and optimize the determination of major and trace elements in the Sargassum, including the use of high precision balances and antistatic devices, multiple certified reference materials, and instrumental quantitation methods to account for matrix effects. Our ongoing analyses have already confirmed the close relationship between potentially toxic trace elements like As and imbalances in the elemental ratios of major nutrients like N and P in Sargassum biomass. Our presentation will describe the application of an expanded suite of bioactive elements (including oxyanions) which indicate uptake mechanisms by Sargassum under different nutrient deplete or replete conditions in a natural setting.

Presentation Preference: Either

Primary Presenter: Riley Stallings, Texas A&M University (rileyastall@tamu.edu)

Authors:

Riley Stallings, Texas A&M University  (rileyastall@tamu.edu)

Peter Morton, Texas A&M Univeristy  (pete.morton@tamu.edu)

Brian Lapointe, Florida Atlantic University  (blapoin1@fau.edu)

Rachel Brewton, Florida Atlantic University  (brewtonr@fau.edu)

Greer Babbe, Florida Atlantic University  (gbabbe2020@fau.edu)