Current research in my group

​

Biogeochemical cycling in the oceans.

​

• The cycling of oceanic dissolved organic matter is critical for sustaining global marine primary production. Our research pioneered the discovery of novel metabolic pathways and enzymes that remineralize organic nitrogen (e.g. nitrogenous osmolytes and methylated amines) in surface waters. This work redefines the ecological roles of key cosmopolitan marine heterotrophs, including the Roseobacter and SAR11 clades (Chen et al., PNAS, 2011; Lidbury et al., PNAS, 2014; Mausz et al., 2025 PNAS).    

 

• Additionally, our research focuses on organosulfur cycling (e.g. dimethylsulfoniopropionate and oceanic sufonates) which mediates phytoplankton–bacteria interactions and marine biogeochemistry (Li et al., 2021 eLife; Li et al., 2023 The ISME Journal; Teng et al., Nat Microbiol. 2021). 

 

Membrane lipids in stress and nutrient limitation response.

​

• We recently demonstrated that marine heterotrophic bacteria can remodel their lipid composition in response to nutrient limitation (e.g. phosphorus) (Sebastian et al., 2016, The ISME Journal). Key to the lipid remodelling process in these marine heterotrophs is a novel intracellular phospholipase C, which is particularly abundant in natural marine bacterial communities, especially in areas characterised by low phosphate concentrations. We have recently characterised a novel pathway leading to the formation of these unique aminolipids in marine bacteria (Smith et al., 2019 The ISME Journal; Smith et al., 2021 The ISME Journal). These results pointed to the previously overlooked key role of lipid substitution as an adaptive strategy, enabling heterotrophs to thrive in the vast phosphorus-depleted areas of the oceans and resolved the paradox of SAR11-phytoplankton competition in oligotrophic oceans. Such a membrane remodelling strategy also comes with unforeseen ecophysiological consequences in trade-offs of certain traits (e.g. Guillonneau et al., 2022 PNAS).

​

• In parallel, we are also beginning to understand the role of lipids in bacterial pathogens, particularly how lipid remodelling enables evasion of host immunity and antibiotic resistance.(e.g. Jones et al., 2021 The ISME Journal;  Shropshire et al., 2026 J Biol Chem).​​

​​​

Methane cycle and methanotrophy

​

• Our research investigates the ecophysiology of environmental methanotrophs, with a focus on discovering novel microbes and pathways in coastal marine sediments and salt marshes (Jones et al., 2019 Microbiome; Jameson et al., 2019 ISME J) and determining how nutrient limitation impacts methane oxidation (Scanlan et al., 2022 mBio).​