Investigating Recalcitrant Dissolved Organic Matter Production through a Probabilistic Method in Marine Bacterial Metabolism

About 90% of the ocean’s dissolved organic matter pool consists of long-lived recalcitrant dissolved organic matter (RDOM), which comprises stable compounds resistant to biological degradation. This stability allows RDOM to store significant amounts of fixed carbon, playing a crucial role in mitigating the effects of anthropogenic climate change. According to the microbial carbon pump hypothesis, vast quantities of RDOM may originate from marine heterotrophic bacteria through the successive transformation of labile dissolved organic matter (LDOM). However, the bacterial-mediated pathways from LDOM to RDOM remain poorly studied due to the naturally low concentrations and rapid turnover rates of microbial metabolites, complicating their detection and analysis.To further investigate RDOM production from the utilization and transformation of LDOM by marine heterotrophic bacteria, we will employ a probabilistic method inspired by percolation theory to calculate the metabolic capabilities of individual genome-scale metabolic models (GEMs) in producing precursors of carboxyl-rich alicyclic molecules (CRAM), a major component of RDOM throughout the water column. Utilizing 80 draft GEMs representing a diverse set of marine bacterial strains from temperate and cold waters, as well as deep and surface environments, we will predict the biosynthetic capabilities of various CRAM-like metabolites across each strain. Our analysis of the predicted results will explore potential taxonomic and depth-related trends, aiming to identify possible drivers of RDOM production by marine bacteria.

Presentation Preference: Poster

Primary Presenter: Loreto Paulino, Boston University (lpaulino@bu.edu)

Authors:

Helen Scott, Boston University  (hscott@bu.edu)

Daniel Segrè, Boston University  (dsegre@bu.edu)