The microbiological drivers of temporally dynamic Dimethylsulfoniopropionate cycling processes in Australian coastal shelf waters

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in O’Brien, J., McParland, E. L., Bramucci, A. R., Ostrowski, M., Siboni, N., Ingleton, T., Brown, M. V., Levine, N. M., Laverock, B., Petrou, K., & Seymour, J. The microbiological drivers of temporally dynamic Dimethylsulfoniopropionate cycling processes in Australian coastal shelf waters. Frontiers in Microbiology, 13, (2022): 894026, https://doi.org/10.3389/fmicb.2022.894026.The organic sulfur compounds dimethylsulfoniopropionate (DMSP) and dimethyl sulfoxide (DMSO) play major roles in the marine microbial food web and have substantial climatic importance as sources and sinks of dimethyl sulfide (DMS). Seasonal shifts in the abundance and diversity of the phytoplankton and bacteria that cycle DMSP are likely to impact marine DMS (O) (P) concentrations, but the dynamic nature of these microbial interactions is still poorly resolved. Here, we examined the relationships between microbial community dynamics with DMS (O) (P) concentrations during a 2-year oceanographic time series conducted on the east Australian coast. Heterogenous temporal patterns were apparent in chlorophyll a (chl a) and DMSP concentrations, but the relationship between these parameters varied over time, suggesting the phytoplankton and bacterial community composition were affecting the net DMSP concentrations through differential DMSP production and degradation. Significant increases in DMSP were regularly measured in spring blooms dominated by predicted high DMSP-producing lineages of phytoplankton (Heterocapsa, Prorocentrum, Alexandrium, and Micromonas), while spring blooms that were dominated by predicted low DMSP-producing phytoplankton (Thalassiosira) demonstrated negligible increases in DMSP concentrations. During elevated DMSP concentrations, a significant increase in the relative abundance of the key copiotrophic bacterial lineage Rhodobacterales was accompanied by a three-fold increase in the gene, encoding the first step of DMSP demethylation (dmdA). Significant temporal shifts in DMS concentrations were measured and were significantly correlated with both fractions (0.2–2 μm and >2 μm) of microbial DMSP lyase activity. Seasonal increases of the bacterial DMSP biosynthesis gene (dsyB) and the bacterial DMS oxidation gene (tmm) occurred during the spring-summer and coincided with peaks in DMSP and DMSO concentration, respectively. These findings, along with significant positive relationships between dsyB gene abundance and DMSP, and tmm gene abundance with DMSO, reinforce the significant role planktonic bacteria play in producing DMSP and DMSO in ocean surface waters. Our results highlight the highly dynamic nature and myriad of microbial interactions that govern sulfur cycling in coastal shelf waters and further underpin the importance of microbial ecology in mediating important marine biogeochemical processes.This research was supported by the Australian Research Council Grants FT130100218 and DP180100838 awarded to JS and DP140101045 awarded to JS and KP, as well as an Australian Government Research Training Program Scholarship awarded to JO’B

The ocean sampling day consortium.

Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world's oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits

The ocean sampling day consortium

Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits

The Ocean Sampling Day Consortium

Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits

Macquarie Marshes: evidence of recent channel movement and discontinuous biological records in floodplain sediments

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Identifying sediment compartment dynamics on the Illawarra Coast

This project aims to produce a framework for assessing compartment dynamics within two sediment compartments in the Illawarra region to assist in assessing coastal hazards. Sediment sources, pathways and sinks will be examined for the Wollongong and Illawarra Coast - South compartments, defined by Geoscience Australia and CoastAdapt. A compartment based approach allows for more holistic coastal planning and management which considers sediment transport at differing scales, and interconnectivity of beaches. This type of approach underpins national guidance on open coast risk assessment and has been incorporated within the NSW Coastal Reforms and the Draft Coastal Management Manual. The adjacent sectors of the Wollongong Coast and Illawarra Coast-South compartments extend for approximately 30 km from Bellambi Point to Bass Point. The rock platform of Red Point marks the shoreline division between these two contrasting compartments. The Wollongong Coast is an urbanized relatively little studied leaky compartment, whereas the Illawarra Coast-South is a well-defined and confined compartment whose main sedimentary characteristics are represented by the infilling of the Lake Illawarra barrier estuary and the erosionprone Warilla Beach. This detailed examination of sediment resources brings together the state-wide coastal seabed mapping program being undertaken by the NSW Office of Environment and Heritage (OEH), and coastal geomorphological investigations being undertaken along the southern NSW coast by the University of Wollongong (UOW). These initiatives involve collation of historical data, sediment sampling, and the use of recently available sophisticated remote sensing technologies, such as terrestrial airborne LiDAR, single and multibeam bathymetry, sidescan sonar imagery, and underwater video and still camera

Palaeolimnological study of the Macquarie Marshes, Australia: evidence of channel movement during the Holocene based on algae (Charophytes, diatoms), macrophytes and invertebrates

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Short-term response of nutrients, carbon and plankton microbial communities to floodplain wetland inundation

Environmental flows were released to the Macquarie Marshes (~210,000 ha) in north-west NSW of Australia between October and December 2005, inundating an estimated 24,600 ha of floodplain area. According to the flood pulse concept, the marsh floodplains would have stored large amounts of nutrients and carbon during dry antecedent conditions, which would be released into the overlaying flood water. Field studies were conducted in mid-December 2005 at two sites, one on open floodplain woodland with a sparse canopy of River Red Gum and ground cover dominated by saltbushes and the other on open floodplain with black rolypoly. At each site, nutrients, dissolved organic carbon (DOC), planktonic bacteria and phytoplankton were monitored daily for a 6-day period from the overlaying water of a floodplain inundated by the environmental water release. Those in mesocosms deployed in situ, containing marsh floodplain sediments that had been inundated artificially, were also monitored