Dimethylsulfoniopropionate producing and cycling in diverse environments

Zhu, Xiaoyu (2026) Dimethylsulfoniopropionate producing and cycling in diverse environments. Doctoral thesis, University of East Anglia.

PDF Restricted to Repository staff only until 31 January 2029. Request a copy

Abstract

Dimethylsulfoniopropionate (DMSP) is a major organosulfur compound in marine and coastal environments, playing central roles in microbial physiology, biogeochemical cycling and climate regulation through its degradation to the climate-active gases dimethyl sulfide (DMS) and methanethiol (MeSH). Although the molecular pathways of DMSP synthesis and degradation are well characterised, the identities of the organisms actively producing and cycling DMSP across different habitats remain poorly resolved. This thesis integrates process measurements with multi-omics approaches to investigate the biological drivers and pathways of DMSP cycling across three DMSP hotspot environments.

First, DMSP and DMS dynamics were examined during a natural spring–summer phytoplankton bloom in coastal surface waters of the western English Channel. By combining DMSP production rate measurements with metagenomic and metatranscriptomic analyses, this study reveals pronounced temporal variability in DMSP-cycling communities and highlights the unexpected contributions of bacteria and microalgae to DMSP synthesis and degradation, respectively.

Second, DMSP degradation in plant-associated environments was investigated using DNA stable isotope probing with ¹³C-labelled DMSP, alongside multi-omics and isolate-based assays. Focusing on the leaf and root microhabitats of the high-DMSP-producing saltmarsh plant Spartina anglica, this work identifies distinct, microhabitat-specific DMSP-degrading communities and reveals substantial novelty in both the taxa involved and the catabolic genes they employ.

Third, the biological sources and sinks of DMSP were investigated in saltmarsh pond sediments lacking Spartina vegetation and exhibiting exceptionally high DMSP accumulation. This chapter identifies benthic microalgae as key drivers of DMSP production in both surface and deeper sediments, and demonstrates strong niche partitioning of DMSP degradation, as well as of downstream DMS and MeSH metabolism.

Together, these studies provide a process-based and molecularly resolved framework for understanding DMSP cycling across coastal systems and highlight the strong environmental control of organosulfur cycling.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Kitty Laine
Date Deposited:	06 May 2026 13:53
Last Modified:	06 May 2026 13:53
URI:	https://ueaeprints.uea.ac.uk/id/eprint/102917
DOI:

Actions (login required)

View Item