Particle size-fractionated kinetics of DMS production: where does DMSP cleavage occur at the microscale?

Scarratt, Michael; Cantin, Guy; Levasseur, Maurice; Michaud, Sonia

doi:10.1016/s1385-1101(00)00019-8

Cited by 62 publications

(33 citation statements)

References 27 publications

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“…It cannot be excluded that such PA bacterioplankton were present in our experiment, in association with the DMSP-rich phytoplankton groups identified, leading to overall low S assimilation efficiencies from consumed 35 S-DMSP d despite changes in bacterial C production. This idea is supported by conclusions from Scarratt et al (2000) suggesting that PA bacteria can "afford" to make use of DMSP simply as a C source because their S requirements are amply satisfied. The fate of S in DMSP-metabolizing bacterial communities is complex and most likely affected by numerous factors, at least one of which is the S requirement relative to the availability of organic S. Findings from this study are consistent with the hypothesis that organic S in excess of bacterial requirements biases DMSP metabolism against demethylation (Kiene et al, 2000;Levasseur et al, 1996;Pinhassi et al, 2005).…”

Section: Microbial Dms Yield and Gross Production Of Dms From Dmsp Dmentioning

confidence: 82%

“…2) indicate high accessibility for free-living (FL) bacteria of these methylated S compounds directly in the water column but also potentially for particleassociated (PA) bacteria in microzones surrounding phytoplankton cells and detrital particles such as faecal pellets and marine snow (see review by Ramanan et al, 2016). These phycospheres and other microzones of enhanced gradients of dissolved organic matter (Amin et al, 2015;Bell and Mitchell, 1972;Simon et al, 2002) are often associated with populations of bacteria that are distinct from the surrounding open habitat, that can vary according to phytoplankton community composition Smith, 2015, Rieck et al, 2015), and that may possess higher uptake kinetics for substrates such as DMSP d (Scarratt et al, 2000). It cannot be excluded that such PA bacterioplankton were present in our experiment, in association with the DMSP-rich phytoplankton groups identified, leading to overall low S assimilation efficiencies from consumed 35 S-DMSP d despite changes in bacterial C production.…”

Section: Microbial Dms Yield and Gross Production Of Dms From Dmsp Dmentioning

confidence: 99%

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Dimethylsulfoniopropionate (DMSP) and dimethyl sulfide (DMS) cycling across contrasting biological hotspots of the New Zealand subtropical front

Lizotte¹,

Levasseur²,

Law

et al. 2017

Ocean Sci.

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Abstract. The oceanic frontal region above the Chatham Rise east of New Zealand was investigated during the late austral summer season in February and March 2012. Despite its potential importance as a source of marine-originating and climate-relevant compounds, such as dimethyl sulfide (DMS) and its algal precursor dimethylsulfoniopropionate (DMSP), little is known of the processes fuelling the reservoirs of these sulfur (S) compounds in the water masses bordering the subtropical front (STF). This study focused on two opposing short-term fates of DMSP-S following its uptake by microbial organisms (either its conversion into DMS or its assimilation into bacterial biomass) and has not considered dissolved non-volatile degradation products. Sampling took place in three phytoplankton blooms (B1, B2, and B3) with B1 and B3 occurring in relatively nitraterich, dinoflagellate-dominated subantarctic waters, and B2 occurring in nitrate-poor subtropical waters dominated by coccolithophores. Concentrations of total DMSP (DMSP t ) and DMS were high across the region, up to 160 and 14.5 nmol L −1 , respectively. Pools of DMSP t showed a strong association with overall phytoplankton biomass proxied by chlorophyll a (r s = 0.83) likely because of the persistent dominance of dinoflagellates and coccolithophores, both DMSP-rich taxa. Heterotrophic microbes displayed low S assimilation from DMSP (less than 5 %) likely because their S requirements were fulfilled by high DMSP availability. Rates of bacterial protein synthesis were significantly correlated with concentrations of dissolved DMSP (DMSP d , r s = 0.86) as well as with the microbial conversion efficiency of DMSP d into DMS (DMS yield, r s = 0.84). Estimates of the potential contribution of microbially mediated rates of DMS production (0.1-27 nmol L −1 day −1 ) to the near-surface concentrations of DMS suggest that bacteria alone could not have sustained DMS pools at most stations, indicating an important role for phytoplankton-mediated DMS production. The findings from this study provide crucial information on the distribution and cycling of DMS and DMSP in a critically under-sampled area of the global ocean, and they highlight the importance of oceanic fronts as hotspots of the production of marine biogenic S compounds.

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Section: Microbial Dms Yield and Gross Production Of Dms From Dmsp Dmentioning

confidence: 82%

Section: Microbial Dms Yield and Gross Production Of Dms From Dmsp Dmentioning

confidence: 99%

Dimethylsulfoniopropionate (DMSP) and dimethyl sulfide (DMS) cycling across contrasting biological hotspots of the New Zealand subtropical front

Lizotte¹,

Levasseur²,

Law

et al. 2017

Ocean Sci.

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“…Niki et al (2000) calculated that the algal lyase pathway is as important as the bacterial lyase pathway, in samples from Tokyo Bay. Also other size fractionation experiments have shown that lyase activity is often associated with the large size fractions (Cantin et al 1999;Scarratt et al 2000), although it cannot be excluded that attached bacteria are partly responsible for this activity. In a modelling study of the seasonal evolution of DMS in the Southern Bight of the North Sea, van den Berg et al (1996) showed that the presence of an algal DMSP-lyase associated with the occurrence of Phaeocystis was essential to properly describe the DMS spring peak.…”

Section: Maintenance Of Intracellular Dmsp Concentration: Algal Dmsp-mentioning

confidence: 96%

Environmental constraints on the production and removal of the climatically active gas dimethylsulphide (DMS) and implications for ecosystem modelling

et al. 2007

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Seawater concentrations of the climatecooling, volatile sulphur compound dimethylsulphide (DMS) are the result of numerous production and consumption processes within the marine ecosystem. Due to this complex nature, it is difficult to predict temporal and geographical distribution patterns of DMS concentrations and the inclusion of DMS into global ocean climate models has only been attempted recently. Comparisons between individual model predictions, and ground-truthing exercises revealed that information on the functional relationships between physical and chemical ecosystem parameters, biological productivity and the production and consumption of DMS and its precursor dimethylsulphoniopropionate (DMSP) is necessary to further refine future climate models. In this review an attempt is made to quantify these functional relationships. The description of processes includes: (1) parameters controlling DMSP production such as species composition and abiotic factors; (2) the conversion of DMSP to DMS by algal and bacterial enzymes; (3) the fate of DMSPsulphur due to, e.g., grazing, microbial consumption and sedimentation and (4) factors controlling DMS removal from the water column such as microbial consumption, photo-oxidation and emission to the atmosphere. We recommend the differentiation of six phytoplankton groups for inclusion in future models: eukaryotic and prokaryotic picoplankton, diatoms, dinoflagellates, and other phytoflagellates with and without DMSP-lyase activity. These functional groups are characterised by their cell size, DMSP content, DMSP-lyase activity and interactions with herbivorous grazers. In this review, emphasis is given to ecosystems dominated by the globally relevant haptophytes Emiliania huxleyi and Phaeocystis sp., which are important DMS and DMSP producers.

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“…The potential of phytoplankton cultures or natural plankton to convert Dimethylsulfoniopropionate (DMSP) into DMS has been measured either with in vivo (whole cell) assays (Stefels and VanBoekel, 1993;Scarratt et al, 2000) or with in vitro assays Steinke et al, 2000). Addition of exogenous DMSPd to whole cell assays typically increases DMS production (Stefels and VanBoekel, 1993;Scarratt et al, 2000), however, in most cases it is unclear whether the dependence of DMS production rate on added DMSPd concentration in such assays reflects the capacity of plankton to transport DMSPd into cells and to the site of the lyases, or the capacity of extracellular lyases to cleave DMSP.…”

Section: Introductionmentioning

confidence: 99%

“…Addition of exogenous DMSPd to whole cell assays typically increases DMS production (Stefels and VanBoekel, 1993;Scarratt et al, 2000), however, in most cases it is unclear whether the dependence of DMS production rate on added DMSPd concentration in such assays reflects the capacity of plankton to transport DMSPd into cells and to the site of the lyases, or the capacity of extracellular lyases to cleave DMSP. DLA can also be measured at saturating levels of substrate DMSP after collecting cells on filters or preparing cell-free extracts Steinke et al, 2000;Harada et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Assessment and Characteristics of DMSP Lyase Activity in Seawater and Phytoplankton Cultures

Harada¹,

Kiene²

2011

Publ. SMBL

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Dimethylsulfoniopropionate (DMSP) is produced by a wide variety of marine phytoplankton, and it can be enzymatically cleaved to dimethylsulfide (DMS) and acrylate by DMSP lyases. DMS formation in the sea plays an important role in the global sulfur cycle, yet the factors regulating production of DMS are poorly understood. We evaluated various procedures used for in vitro assays of DMSP lyase activity (DLA) of cells captured on filters. We also compared in vitro DLA from plankton material collected from diverse water samples, as well as from cultures of different phytoplankton species. The type of filter used to collect plankton material affected the apparent in vitro DLA, with glass fiber filters (Whatman GF/F) yielding higher rates than polycarbonate filters. Treatment of filtered plankton with Tris buffer (200 mM in 500 mM NaCl), with vigorous mixing, appeared to permeablize cells allowing maximal DLA. We found that buffer pH and dithiothreitol (DTT) affected DLA positively or negatively depending on the phytoplankton species or water sample tested. In general, natural seawater plankton and cultured dinoflagellates had higher DLA with higher pH buffers (pH range 6.5 -8.5). In contrast, the prymnesiophytes Emiliania huxleyi and Phaeocystis antarctica had higher in vitro DLA at lower pH (pH range 6.5 -8.5), and DTT and Triton X-100 significantly increased the apparent enzyme activities. Not all phytoplankton contained detectable DLA, and DLA varied greatly among strains of the same species. DLA was however, detectable in all samples of particulate materials collected from a wide range of marine surface waters, including those from the coastal Gulf of Mexico, North Atlantic and Southern Ocean, and these samples showed patterns of high Chl a normalized DLA where high irradiances and low nutrients occur. Consistent with this observation, the phytoplankton cultures isolated from such environments also showed high DLA. Thus, light and nutrients may be important factors determining DLA. However, not all the variations in DLA were explained by light and nutrients, and these variations may be due to the different functions of DMSP lyases such as osmotic regulation, anti-grazing, and antioxidant activity.

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Particle size-fractionated kinetics of DMS production: where does DMSP cleavage occur at the microscale?

Cited by 62 publications

References 27 publications

Dimethylsulfoniopropionate (DMSP) and dimethyl sulfide (DMS) cycling across contrasting biological hotspots of the New Zealand subtropical front

Dimethylsulfoniopropionate (DMSP) and dimethyl sulfide (DMS) cycling across contrasting biological hotspots of the New Zealand subtropical front

Environmental constraints on the production and removal of the climatically active gas dimethylsulphide (DMS) and implications for ecosystem modelling

Assessment and Characteristics of DMSP Lyase Activity in Seawater and Phytoplankton Cultures

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