Occurrence and Turnover of Biogenic Sulfur in the Bering Sea During Summer

Abstract

The horizontal/geographical variations in dissolved dimethylsulfide (DMS), its precursor dimethylsulfoniopropionate (DMSPd and DMSPp), and chlorophyll a (Chl a), as well as the oceanographic parameters influencing the concentrations of dimethylated sulfur compounds, were investigated in the Bering Sea from July to August 2012. Similar to Chl a, the surface DMS and DMSPp levels, as well as DMS(P) production and consumption rates, exhibited a declining gradient from the central basin to the continental shelf, with high‐value areas appearing in the central basin, the slope regions, and Anadyr Strait but a low‐value area occurring on the outer‐middle continental shelf. Considerably high values of DMS and DMSP were measured in the saline Bering Sea Basin Deep Water (>2,000 m) located at the southwest of the Bering Basin because of the release of resuspension in 2,000 m depth and the DMSP production from endogenous benthic bacteria and cyanobacteria population. Chl a was positively correlated with DMSPp and DMS in the surface waters and the upper water of the basin, whereas significant negative correlations were found between DMS and nutrients (dissolved inorganic nitrogen [DIN], phosphorus, and silicate) in the inner shelf of the Bering Sea. DMS microbial consumption was approximately 6.26 times faster than the DMS sea‐air exchange, demonstrating that the major loss of DMS in the surface water occurred through biological consumption relative to evasion into the atmosphere. Average sea‐to‐air DMS fluxes were estimated to be 4.66 μmol/(m2·d), and consequently oceanic biogenic DMS emission had a dominant contribution to the sulfur budget over the observational area.

Phytoplankton Community Structure at Subsurface Chlorophyll Maxima on the Western Arctic Shelf: Patterns, Causes, and Ecological Importance

“…During the open‐water season, phytoplankton spread to the nutrient‐rich subsurface because of the depletion of surface nutrients, forming SCM layers (Zhuang et al, 2016) that become an important carbon source for the food chain and sediment (Martin et al, 2010). Because of the large contribution of the SCM layers to the phytoplankton biomass in the water column, spatiotemporal changes in the phytoplankton community in the SCM layers will affect the CO 2 flux (Bates et al, 2006; Mathis et al, 2010), biogenic sulfur production (Li et al, 2017), organic carbon cycling (Lepore et al, 2007), and ecosystem processes (Grebmeier et al, 2015).…”

Spatial and Interannual Variability in Distributions and Cycling of Summer Biogenic Sulfur in the Bering Sea

“…The production and consumption rates of DMS and DMSPd in seawater were determined by the inhibitor addition method (Li et al, ). A complete description of measurements above was presented by Li et al (). Profiles of temperature, salinity, and chlorophyll a (Chl a ) concentrations were recorded in situ using a SBE‐911 Plus CTD system and calibrated before use.…”

“…Three cruises to the Bering Sea during summer, one covering the cold year (2012) and two covering warm years (2014 and 2016), provided an opportunity to study how oceanic biogenic dimethylated sulfur compounds may respond to ocean warming resulting from climate change. Our previous study provided unique data about the spatial/geographical variations in DMS and DMSP during the summer of 2012 in the Bering Sea (Li et al, ). In this paper, data in the summers of 2014 and 2016 are compared with those collected in 2012 cruise to gain insights into the response of spatial distributions and interannual variations of DMS and DMSP to contrasting seawater temperature within the same season in the Bering Sea.…”

Response of distributions and emissions of summer biogenic sulfur in the Pacific Arctic to enhanced Pacific Water inflow

“…3; Supporting Information Fig. S2; Li, Wang et al 2017), although the surface DMSPd biological gross production rate was 1.44 times faster in 2014 than in 2012 west of 169 W (Table 1; Supporting Information Table S1). On average, the standing stock of DMS relative to DMSPt (DMSPd + DMSPp), that is, DMS : DMSPt ratio, in the upper 10.5 m during 2014 (0.058) was much higher than that in 2012 (0.0023), also suggesting that either DMS degradation is low or formation is high during the warm year.…”

“…3; Supporting Information Fig. S2; Li, Wang et al 2017). Overall, owing to the accumulation of DMS in response to the osmotic stress of salinity downshift, together with a potentially significant contribution of euryhaline diatoms to the DMSP production, low-salinity Alaska Coastal Water enhancement induced by increased snowmelt runoff may create conditions conducive to the production and cycling of dimethylated sulfur compounds under warming scenarios.…”