Analysis of surfactant-associated bacteria in the sea surface microlayer using deoxyribonucleic acid sequencing and synthetic aperture radar

Georgia Parks,Cayla W Dean,John A Kluge,Alexander V Soloviev,Mahmood Shivji,Aurelien Tartar,Kathryn L Howe,Susanne Lehner,Egbert Schwarz,Hui Shen,William Perrie,Paul Schuler

doi:10.1080/01431161.2019.1708508

Abstract

ABSTRACTThe sea surface microlayer (SML) is the upper 1 mm of the ocean, where Earth’s biogeochemical processes occur between the ocean and atmosphere. It is physicochemically distinct from the water below and highly variable in space and time due to changing physical conditions. Some microorganisms influence the composition of the SML by producing surfactants for biological functions that accumulate on the surface, decrease surface tension, and create slicks. Slicks can be visible to the eye and in synthetic aperture radar (SAR) satellite imagery. This study focuses on surfactant-associated bacteria in the near-surface layer and their role in slick formation where oil is present.

Highlights

The sea surface microlayer (SML) is an important boundary layer between the atmosphere and ocean
We focus on the presence of surfactant-associated bacteria in slick areas
Following the experience in LAngrangian Submesoscale Experiment (LASER), where in situ measurements were conducted from a research vessel including several groups competing for the ship time, in situ measurements were done from a small boat in SPLASH, which provided more flexibility for coordination with satellite overpasses and significantly added to the synthetic aperture radar (SAR) imaging statistics obtained during LASER

Summary

Introduction

The sea surface microlayer (SML) is an important boundary layer between the atmosphere and ocean. The hydrophilic polycarbonate filter used in this study has a maximum sampling depth of 40μm, which falls within the boundaries defined by Soloviev and Lukas (2014), who describe the physical structure of the SML as a viscous sublayer (approximately 1500μm thick), thermal sublayer (approximately 500μm thick), and salinity diffusion sublayer (approximately 50μm thick). The structure of these layers is dependent on wind speed. Under moderate wind speed conditions, these layers are controlled by gravity-capillary wave breaking and in turn impact gas exchange

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Conclusion