Enhanced heterotrophic activity in the surface microlayer of the Mediterranean Sea

Obernosterer, Ingrid; Catala, Philippe; Reinthaler, Thomas; Herndl, Gerhard J.; Lebaron, Philippe

doi:10.3354/ame039293

Cited by 69 publications

(90 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Namely [18]. At all three stations, both in the Baltic Sea and the Pacific open ocean, SML samples showed the strongest respiration rates in dark incubations compared to underlying water depths; which is in line with previous observations on enhanced heterotrophic respiration within the SML [16,17].…”

Section: Resultssupporting

confidence: 79%

“…Heterotrophic microbes in particular benefit from the enrichment of organic substrates, allowing them to thrive and form distinctive communities within the SML compared to the underlying water [13,14]. Increased abundance of heterotrophic microorganisms within the SML is a typical observation [15], and is accompanied by remarkably enhanced respiratory activity [16,17].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

SISI: A New Device for In Situ Incubations at the Ocean Surface

Rahlff

Stolle

Wurl

2017

JMSE

View full text Add to dashboard Cite

Abstract:The sea-surface microlayer (SML) forms the uppermost boundary layer between atmosphere and ocean, and has distinctive physico-chemical and biological features compared to the underlying water. First findings on metabolic contributions of microorganisms to gas exchange processes across the SML raised the need for new in situ technologies to explore plankton-oxygen turnover in this special habitat. Here, we describe an inexpensive research tool, the Surface In Situ Incubator (SISI), which allows simultaneous incubations of the SML, and water samples from 1 m and 5 m, at the respective depths of origin. The SISI is deployed from a small boat, seaworthy up to 5 bft (Beaufort scale), and due to global positioning system (GPS) tracking, capable of drifting freely for hours or days. We tested the SISI by applying light/dark bottle incubations in the Baltic Sea and the tropical Pacific Ocean under various conditions to present first data on planktonic oxygen turnover rates within the SML, and two subsurface depths. The SISI offers the potential to study plankton-oxygen turnover within the SML under the natural influence of abiotic parameters, and hence, is a valuable tool to routinely monitor their physiological role in biogeochemical cycling and gas exchange processes at, and near, the sea surface.

show abstract

Section: Resultssupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

SISI: A New Device for In Situ Incubations at the Ocean Surface

Rahlff

Stolle

Wurl

2017

JMSE

View full text Add to dashboard Cite

show abstract

“…The partial pressure of CO 2 in the top layer (2 cm) of the ocean was recently reported to be linked to microbial community metabolism (Calleja et al, 2005). The consistently enhanced rates of respiration in samples collected from the surface microlayer in different coastal and offshore marine environments support this notion (Garabétian, 1990;Obernosterer et al, 2005;Reinthaler et al, 2008). The biogenic gases dimethylsulfoxide (DMSO) and dimethylsulfoniopropionate (DMSP) were markedly enriched in the surface microlayer as compared to surface waters during calm wind conditions (Zemmelink et al, 2005).…”

Section: Introductionmentioning

confidence: 60%

Biochemical characteristics and bacterial community structure of the sea surface microlayer in the South Pacific Ocean

et al. 2008

View full text Add to dashboard Cite

Abstract. The chemical and biological characteristics of the surface microlayer were determined during a transect across the South Pacific Ocean in October-December 2004. Concentrations of particulate organic carbon (1.3 to 7.6-fold) and nitrogen (1.4 to 7-fold), and POC:PON ratios were consistently higher in the surface microlayer as compared to surface waters (5 m). The large variability in particulate organic matter enrichment was negatively correlated to wind speed. No enhanced concentrations of dissolved organic carbon were detectable in the surface microlayer as compared to 5 m, but chromophoric dissolved organic matter was markedly enriched (by 2 to 4-fold) at all sites. Based on pigment analysis and cell counts, no consistent enrichment of any of the major components of the autotrophic and heterotrophic microbial community was detectable. CE-SSCP fingerprints and CARD FISH revealed that the bacterial communities present in the surface microlayer had close similarity (>76%) to those in surface waters. By contrast, bacterial heterotrophic production ( 3 H-leucine incorporation) was consistently lower in the surface microlayer than in surface waters. By applying CARD-FISH and microautoradiography, we observed that Bacteroidetes and Gammaproteobacteria dominated leucine uptake in the surface microlayer, while in surface waters Bacteroidetes and Alphaproteobacteria were the major groups accounting for leucine incorporation. Our results demonstrate that the microbial community in the surface microlayer closely resembles that of the surface Correspondence to: I. Obernosterer (ingrid.obernosterer@obs-banyuls.fr)waters of the open ocean. Even a short residence in the surface microlayer influences leucine incorporation by different bacterial groups, probably as a response to the differences in the physical and chemical nature of the two layers.

show abstract

“…energy (del Giorgio et al, 2011;del Giorgio and Gasol, 2008;Carlson et al, 2007). Obernosterer et al (2005) also reported enhanced community respiration rates in the surface microlayer compared to subsurface waters, whilst a depletion in dimethylsulfide at 10 cm depth compared to underlying waters was consistently reported by Zemmelink et al (2005). Although, high outliers in BGE m of between 8-26 %, due to relatively high rates of methanol incorporated into cellular particulate material, suggest that hot spots of methylotrophic activity exist in the near-surface layers.…”

Section: Discussionmentioning

confidence: 99%

Fine-scale variability in methanol uptake and oxidation: from the microlayer to 1000 m

Dixon

2012

Biogeosciences

View full text Add to dashboard Cite

Abstract. The aim of this research was to make the first depth profiles of the microbial assimilation of methanol carbon and its oxidation to carbon dioxide and use as an energy source from the microlayer to 1000 m. Some of the highest reported methanol oxidation rate constants of 0.5-0.6 d −1 were occasionally found in the microlayer and immediately underlying waters (10 cm depth), albeit these samples also showed the greatest heterogeneity compared to other depths down to 1000 m. Methanol uptake into the particulate phase was exceptionally low in microlayer samples, suggesting that any methanol utilised by microbes in this environment is for energy generation. The sea surface microlayer and 10 cm depth also showed a higher proportion of bacteria with a low DNA content, and bacterial leucine uptake rates in surface microlayer samples were either less than or the same as those in the underlying 10 cm layer. The average methanol oxidation and particulate rates were however statistically the same throughout the depths sampled, although the latter were highly variable in the near-surface 0.25-2 m compared to deeper depths. The statistically significant relationship demonstrated between uptake of methanol into particles and bacterial leucine incorporation suggests that many heterotrophic bacteria could be using methanol carbon for cellular growth. On average, methanol bacterial growth efficiency (BGE m ) in the top 25 m of the water column is 6 % and decreases with depth. Although, for microlayer and 10 cm-depth samples, BGE m is less than the near-surface 25-217 cm, possibly reflecting increased environmental UV stress resulting in increased maintenance costs, i.e. energy required for survival. We conclude that microbial methanol uptake rates, i.e. loss from seawater, are highly variable, particularly close to the seawater surface, which could significantly impact upon seawater concentrations and hence the air-sea flux.

show abstract

Enhanced heterotrophic activity in the surface microlayer of the Mediterranean Sea

Cited by 69 publications

References 40 publications

SISI: A New Device for In Situ Incubations at the Ocean Surface

SISI: A New Device for In Situ Incubations at the Ocean Surface

Biochemical characteristics and bacterial community structure of the sea surface microlayer in the South Pacific Ocean

Fine-scale variability in methanol uptake and oxidation: from the microlayer to 1000 m

Contact Info

Product

Resources

About