761 / 2024-09-19 11:20:05
Release, degradation, and transformation of dissolved organic carbon in Gracilaria macrophylla under the influence of ocean acidification and enriched nutrients
Gracilaria DOC CDOM Photo-transformation Microbial degradation
Session 31 - Blue Carbon: from Science, Restoration and Trading
Abstract Accepted
Gracilaria lemaneiformis (Gracilaria) is a large economic seaweed that can release some of its photosynthetic products into the water in the form of dissolved organic carbon (DOC). This DOC can be transformed into recalcitrant dissolved organic carbon (RDOC) through microbially-mediated carbon pumps and photo-transformation, making it an important component of marine algal carbon sinks. Ocean acidification and eutrophication are two major global environmental issues, yet their impact on the release of DOC by large seaweeds is poorly understood, and research of the fate of algal-derived DOC is relatively scarce. In this study, we aimed to compare the release of DOC by G.lemaneiformis at multi-growth states under different pH and nutrients conditions, while analyzing the optical parameters of the released organic matter, such as chromophoric dissolved organic matter (CDOM) and fluorescent dissolved organic matter (FDOM). The study also investigates the photodegradation and microbial degradation of the released organic matter and characterizes it through Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR) to track the fate of DOC. This research will contribute to a deeper understanding of the direct relationships between environmental factors and algal-derived dissolved organic carbon, providing important scientific basis for evaluating biological carbon pumps and marine carbon sinks.