Unique and highly variable bacterial communities inhabiting the surface microlayer of an oligotrophic lake

ABSTRACT The occurrence of foams at oceans’ surfaces is patchy and generally short-lived, but a detailed understanding of bacterial communities inhabiting sea foams is lacking. Here, we investigated how marine foams differ from the sea-surface microlayer (SML), a <1-mm-thick layer at the air–sea interface, and underlying water from 1 m depth. Samples of sea foams, SML and underlying water collected from the North Sea and Timor Sea indicated that foams were often characterized by a high abundance of small eukaryotic phototrophic and prokaryotic cells as well as a high concentration of surface-active substances (SAS). Amplicon sequencing of 16S rRNA (gene) revealed distinctive foam bacterial communities compared with SML and underlying water, with high abundance of Gammaproteobacteria. Typical SML dwellers such as Pseudoalteromonas and Vibrio were highly abundant, active foam inhabitants and thus might enhance foam formation and stability by producing SAS. Despite a clear difference in the overall bacterial community composition between foam and SML, the presence of SML bacteria in foams supports the previous assumption that foam is strongly influenced by the SML. We conclude that active and abundant bacteria from interfacial habitats potentially contribute to foam formation and stability, carbon cycling and air–sea exchange processes in the ocean.

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Comparison of sea surface microlayer and subsurface water bacterial communities in the Baltic Sea

Aquatic Microbial Ecology ◽

10.3354/ame01532 ◽

2011 ◽

Vol 65 (1) ◽

pp. 29-42 ◽

Cited By ~ 7

Author(s):

A Lindroos ◽

HM Szabo ◽

M Nikinmaa ◽

P Leskinen

Keyword(s):

Baltic Sea ◽

Bacterial Communities ◽

Sea Surface ◽

Subsurface Water ◽

Surface Microlayer ◽

The Baltic Sea ◽

Sea Surface Microlayer ◽

The Baltic

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Phytoplankton and Bacterial Community Structure in Two Chinese Lakes of Different Trophic Status

Microorganisms ◽

10.3390/microorganisms7120621 ◽

2019 ◽

Vol 7 (12) ◽

pp. 621

Author(s):

Cui Feng ◽

Jingyi Jia ◽

Chen Wang ◽

Mengqi Han ◽

Chenchen Dong ◽

...

Keyword(s):

Bacterial Communities ◽

Energy Flow ◽

Aquatic Ecosystems ◽

Trophic Status ◽

Bacterial Abundance ◽

Eutrophic Lake ◽

Oligotrophic Lake ◽

Phytoplankton Communities ◽

Aquatic Food ◽

Abundance And Diversity

Phytoplankton are the primary producers at the basis of aquatic food webs, and bacteria play an important role in energy flow and biochemical cycling in aquatic ecosystems. In this study, both the bacterial and phytoplankton communities were examined in the oligotrophic Lake Basomtso and the eutrophic Lake South (China). The results of this study showed that the phytoplankton density and diversity in the eutrophic lake were higher than those in the oligotrophic lake. Furthermore, Chlorophyta (68%) and Cryptophyta (24%) were the dominant groups in the eutrophic lake, while Bacillariophyta (95%) dominated in the oligotrophic lake. The bacterial communities in the waters and sediments of the two lakes were mainly composed of Proteobacteria (mean of 32%), Actinobacteria (mean of 25%), Bacteroidetes (mean of 12%), and Chloroflexi (mean of 6%). Comparative analysis showed that the abundance of bacteria in the eutrophic lake was higher than that in the oligotrophic lake (p < 0.05), but the bacterial diversity in the oligotrophic lake was higher than that in the eutrophic lake (p < 0.05). Finally, the bacterial abundance and diversity in the sediments of the two lakes were higher than those in the water samples (p < 0.05), and the Latescibacteria and Nitrospinae groups were identified only in the sediments. These results suggest that both the phytoplankton and bacterial communities differed considerably between the oligotrophic lake and the eutrophic lake.

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Sea foams are ephemeral hotspots for distinctive bacterial communities contrasting sea-surface microlayer and underlying surface water

10.1101/820696 ◽

2019 ◽

Cited By ~ 1

Author(s):

Janina Rahlff ◽

Christian Stolle ◽

Helge-Ansgar Giebel ◽

Nur Ili Hamizah Mustaffa ◽

Oliver Wurl ◽

...

Keyword(s):

Bacterial Community ◽

Bacterial Communities ◽

Bacterial Community Composition ◽

Thick Layer ◽

Sea Surface ◽

High Abundance ◽

Surface Microlayer ◽

Rrna Gene ◽

Foam Formation ◽

Sea Surface Microlayer

AbstractThe occurrence of foams at oceans’ surfaces is patchy and generally short-lived but a detailed understanding of bacterial communities inhabiting sea foams is lacking. Here we investigated how marine foams differ from the sea-surface microlayer (SML), a <1 mm thick layer at the air-sea interface and underlying water from 1 m depth. Samples of sea foams, SML and underlying water collected from the North Sea and Timor Sea indicated that foams were often characterized by a high abundance of small eukaryotic phototrophic and prokaryotic cells as well as a high concentration of surface-active substances (SAS). Amplicon sequencing of 16S rRNA (gene) revealed a distinctive foam bacterial community compared to SML and underlying water, with high abundance of Gammaproteobacteria. Especially Pseudoalteromonas and Vibrio, typical SML dwellers, were highly abundant, active foam inhabitants and thus might enhance foam formation and stability by producing SAS. Despite a clear difference in the overall bacterial community composition between foam and SML, the presence of SML bacteria in foams supports previous assumptions that foam is strongly influenced by the SML. We conclude that active and abundant bacteria from interfacial habitats potentially contribute to foam formation and stability, carbon cycling and air-sea exchange processes in the ocean.One-sentence summaryFloating foams at the oceans’ surface have a unique bacterial community signature in contrast to sea-surface microlayer and underlying water but receive and select for bacterial inhabitants from surface habitats.

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Sampling and analysis of the air-water interface with SEM and EDS of microlayers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157000 ◽

1989 ◽

Vol 47 ◽

pp. 1004-1005

Author(s):

Randall W. Smith ◽

John Dash

Keyword(s):

Heavy Metals ◽

Surface Microlayer ◽

Surface Films ◽

Water Interface ◽

Physical Processes ◽

Infrared Spectroscopic Analysis ◽

Eds Analysis ◽

Air Water Interface ◽

Significant Area ◽

Bulk Chemical

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.

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