The Hamdan Lab had two papers published this week, both led by Dr. Rachel Mugge. Dr. Mugge is a recent PhD graduate of the Hamdan Lab and the papers stem from her dissertation research . The first, “Proximity to built structures on the seabed promotes biofilm development and diversity” by Rachel Mugge, Chet Rakocinski, Max Woolsey, and Leila Hamdan, was published in Biofouling . This study involved short-term seafloor experiments containing steel surfaces placed near six structures, including historic shipwrecks and modern decommissioned energy platforms. Biofilms were analyzed for changes in phylogenetic composition, richness, and diversity relative to proximity to the structures. The biofilm core microbiome was primarily composed of iron-oxidizing Mariprofundus, sulfur-oxidizing Sulfurimonas, and biofilm-forming Rhodobacteraceae. Alpha diversity and richness significantly declined as a function of distance from structures. This study explores how built structures influence marine biofilms and contributes knowledge on how anthropogenic activity impacts microbiomes on the seabed. See more here.

The second, “Substrate Specificity of Biofilms Proximate to Historic Shipwrecks” by Rachel Mugge, Rachel Moseley, and Leila Hamdan, was published in Microorganisms. The goal of this study was to understand the substrate- and site-specific impacts of built structures on short-term biofilm composition and functional potential. Seafloor experiments were conducted wherein steel and wood surfaces were deployed for four months at distances extending up to 115 m away from three historic (>50 years old) shipwrecks in the Gulf of Mexico. A bioinformatics analysis revealed that the taxonomic composition was significantly different between substrates and sites, with substrate being the primary determining factor. Regardless of site, the steel biofilms had a higher abundance of genes related to biofilm formation, and sulfur, iron, and nitrogen cycling, while the wood biofilms showed a higher abundance of manganese cycling and methanol oxidation genes. This study demonstrates how substrate composition shapes biofilm microbiomes and suggests that marine biofilms may contribute to nutrient cycling at depth. See more here.

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RDM