2026-10-14T17:14:36Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33797680 2026-09-15T13:56:59Z category_8 portal_316 item_type_3 month_year_09_2026

Supplementary file 1_Temperature effects on productivity, respiration, and dissolved organic matter degradation in subtropical Florida waters following hurricane-driven riverine runoff and brownification.docx Bruna F. Sobrinho (24939448) Amanda Muni-Morgan (24939451) Cynthia A. Heil (23200375) Patricia M. Glibert (5732255) Microbiology brownification humic substances hypoxia primary production respiration <p>Increasing ocean warming and storm-driven terrestrial inputs are reshaping subtropical coastal ecosystems. This study investigated how elevated temperature and humic acid enrichment, under both pre- and post-hurricane (Idalia, Debby, Helene and Milton) in situ and manipulated conditions, affect the metabolic rates of phytoplankton communities on the West Florida Shelf (WFS). We hypothesized that warming, combined with hurricane-driven humic inputs, would decrease primary production rates while enhancing respiration and dissolved organic matter (DOM) degradation, shifting system toward net heterotrophy. Using ¹⁸O techniques combined with oxygen concentration measurements, the differences between light-dependent respiration (hereafter Gross Respiration, GR, representing only that associated with algal respiration) and dark respiration (hereafter Community Respiration, CR, representing the sum of microbial respiration) were measured in addition to rates of Gross Primary Production (GPP), and Net Primary Production (NPP). Across stations and experiments, increasing temperature consistently reduced GPP and shifted NPP toward negative values due to enhanced GR. Rates of algal light-dependent GR compared favorably to total CR, in some cases exceeding CR. Changes in the Fluorescent Dissolved Organic Matter (FDOM) composition were also analyzed using spectrofluorometric methods. Increasing temperature was associated with enhanced biological production of labile, protein-like FDOM and concurrent shifts toward lower humification. Together, these changes increased oxygen demand while decreasing oxygen solubility, creating conditions favorable to hypoxia. These results show that warming and hurricane-driven brownification are associated with enhanced algal respiratory metabolism in addition to enhanced CR, highlighting a potential pathway through which climate change could intensify hypoxia in subtropical coastal systems.</p> 2026-09-15T13:56:59Z Dataset Dataset 10.3389/fmicb.2026.1884823.s001 https://figshare.com/articles/dataset/Supplementary_file_1_Temperature_effects_on_productivity_respiration_and_dissolved_organic_matter_degradation_in_subtropical_Florida_waters_following_hurricane-driven_riverine_runoff_and_brownification_docx/33797680 CC BY 4.0