Sampling Constraints and Variability in the Analysis of Bacterial Community Structures in the Sea Surface Microlayer

Abstract

The sea surface microlayer (SML) is a thin surface film located at the interface between oceans and the atmosphere. In this study, three SML samplers—polycarbonate membrane (PC), glass plate (GP), and drum sampler (DS)—were used to collect microbiological DNA samples for molecular analysis. Among the three samplers, DS only took half the time to sample the SML compared to GP while PC were able to sample the thinnest SML depth. Biological matter and distinct bacterial communities in the SML were apparent during low wind conditions in samples collected by three samplers. Signs of biological matter [transparent exopolymer particles (TEP) and chlorophyll-a concentrations] depletion, and an increased similarity in the biological communities of the SML and underlying water (UW), were more pronounced during high wind speed conditions in samples collected by GP and DS. GP samples had lower biological matter enrichment than DS samples compared with UW. The depletion of biological matter in GP samples were more apparent during periods of high chl-a concentrations in the SML. In contrast, PC was able to consistently sample an SML community distinct from that of the UW, regardless of wind conditions. Bacterial community DNA samples obtained by the three SML samplers showed relatively consistent patterns of community structure, despite large fluctuations between seasons (summer vs. winter) and layers (SML vs. UW) being observed. Although no SML-specific taxon was detected in this study, a comparison of the representation of taxonomic groups in each sample suggested that certain taxa (15 orders) were specifically enriched or depleted in the SML, especially taxa belonging to Actinobacteria, Cyanobacteria, Deferribacteria, and Proteobacteria. This trend was consistent regardless of sampling method, implying that these bacterial groups are key taxa in the biogeochemical processes occurring at the air-sea interface.

Draft genome sequences of three rhodopsin possessing Croceitalea sp. strains, isolated from the sea surface microlayer in Japan

“…Strains used in this study were isolated from the sea surface microlayer (SML) of coastal Sagami Bay, Japan (35°09′04″N, 139°08′47″E). SML samples were collected by placing 47 mm polycarbonate membrane filters (Whatman, United Kingdom) onto the water surface for 10 s and spread onto 1/10-strength ZoBell agar plates ( 6 – 8 ). The plates were irradiated with UV-C (254 nm) at 595 μW/cm 2 for 60 s using a handy UV lamp (UVGL-25, Funakoshi, Japan) and incubated at 25°C for 2 weeks under white light condition.…”

Marine bacterial enrichment in the sea surface microlayer, and surface taxa aerosolization potential in the Western Mediterranean Sea

“…Nevertheless, while some studies found that the bacterioneuston was enriched in specific taxa compared to the ULW (Franklin et al, 2005, Zäncker et al, 2018, others report no significant differences between the two layers (Agogue et al, 2005, Obernosterer et al, 2008. These discrepancies might be the results of spatiotemporal variations, winds, and SSML chemical properties but also be the results of the SSML collection method (Stolle et al, 2010, Cunliffe et al, 2011, Rahlff et al, 2017, Wong et al, 2021.…”

Leaching Material from Antarctic Seaweeds and Penguin Guano Affects Cloud-Relevant Aerosol Production

“…We choose these two leaching material sources due to the evidence that the potential impact of Antarctic coastal ecosystems on aerosol composition has been overlooked in past studies (Decesari et al, 2020;Rinaldi et al, 2020). The sea-surface microlayer (SML) -a <1 mm layer at the air-sea boundary, and spontaneously emerging surface phenomena, such foams -patches floating on the water surface (Wong et al, 2021;Rahlff et al, 2021) -are found increasing research interest (Wurl et al, 2017;Engel et al, 2017). The main objective of this work is to test whether organic leaching material from ecologically rich coastal ecosystems has an effect on sea spray aerosol production in the sensitive area of the AP.…”