«PREFACE Scientific Committee on Oceanic Research (SCOR) The Scientific Committee on Oceanic Research (SCOR) was founded 1957 by the International ...»
Guide to best practices to study
the ocean’s surface
Scientific Committee on Oceanic Research (SCOR)
The Scientific Committee on Oceanic Research (SCOR) was founded 1957 by the
International Council for Science (ICSU) to develop an interdisciplinary approach to ocean
science. SCOR is the leading international non-governmental organisation for the promotion
and coordination of international oceanographic activities, with the aim to solve conceptual and methodological problems that hinder marine research.
SCOR activities include the setup and facilitation of scientific working groups, which are formed from small and focused international groups that address specific scientific topics. All SCOR working groups have defined objectives that must be fulfilled within the period of the working group and that deliver significant advancements to the science field.
SCOR Sea Surface Microlayer (SML) Working Group The SCOR SML working group (WG 141) was approved in October 2012 and is sponsored by SCOR and the National Science Foundation (NSF). The working group includes scientists from various chemical, biological and physical disciplines, and is focused on understanding the governing mechanisms that underlie SML processes, including the role of the SML in the earth system. The SCOR SML working group is comprised of 22 full and associate members from 10 different countries (United Kingdom, Germany, Croatia, Brazil, USA, Malaysia, Sweden, China, Finland, and Canada).
Terms of Reference of the SCOR Sea Surface Microlayer (SML) Working Group;
Review sampling techniques and provide best practice sampling protocols.
Create a consensus definition of the SML in terms of physical, chemical and biological perspectives for a better understanding within the ocean science community, and discuss the SML’s role in a changing ocean. This will be delivered as an opinion/position paper in a peer-reviewed journal and will support future international projects concerning the SML and ocean change.
Initiate sessions on SML research during major meetings to increase the awareness of the importance of the SML within the general ocean science community.
Summarise and publish the latest advances in microlayer research in a special issue of a peer-reviewed journal, including consolidation of existing sea surface microlayer datasets among different disciplines (chemistry, biology, atmospheric, physics).
Purpose of this guide This guide is a deliverable of the SCOR SML working group. It reviews the most widely used SML sampling techniques and provides best practice sampling protocols for studying the ocean’s surface. This guide is a source of practical knowledge in the sampling and analysis of the ocean's surface that is communicated in a logical manner with step-by-step guidelines. It should help new researchers to implement SML sampling techniques and in situ monitoring into new projects, and to apply them quickly and reliably. The guide includes standard designs and handling of microlayer samplers and other devices, but also includes related sub-surface sampling techniques and the use of subsurface (water column) reference samples. The guide promotes the standardisation of sample collection and the use of descriptive parameters, including standard parameters to describe certain surface condition of the ocean, i.e. meteorology, chemical and biological indicators, and slick conditions.
This guide is available for free download from the National Marine Biological Library website (http://www.mba.ac.uk/NMBL/) from the “Download Occasional Publications of the MBA” section.
Photograph on cover page by M. Shinki (with permission).
Citation Cunliffe, M & Wurl, O (2014) Guide to best practices to study the ocean’s surface.
Occasional Publications of the Marine Biological Association of the United Kingdom, Plymouth, UK. 118 pp.
© 2014 by the Marine Biological Association of the United Kingdom. No part of this publication should be reproduced in any form without consulting the Editors.
Air-Ocean gas transfer
Summary of previous sea surface microlayer sampling reviews
What is different about this guide?
1. SELECTION OF SAMPLING SITES AND SUITABLE SAMPLING PLATFORMS........ 16
1.1. Selecting and characterising a sampling site
1.2. Selection of suitable sampling platforms
2. SAMPLING TECHNIQUE: SCREEN SAMPLER
2.1. Design and characteristics
2.2. Procedures for handling
2.2.1. Sampling prerequisites
2.2.2. Sampling procedure
2.2.4. Transport and storage
2.3. Advantages and disadvantages
3. SAMPLING TECHNIQUE: GLASS PLATE SAMPLER
3.1. Design and characteristics
3.2. Procedures for handling
3.2.1. Sampling prerequisites
3.2.2. Sampling procedure
3.2.3. Transport and storage
3.3. Advantages and disadvantages
4. SAMPLING TECHNIQUE: MEMBRANE SAMPLER
4.1. Design and characteristics
4.2. Procedures for handling
4.3. Advantages and disadvantages
5. AUTONOMOUS SAMPLING DEVICES
5.2. Autonomous microlayer sampler design criteria
5.3. Multi-sensor autonomous microlayer sampler, an example
5.4. Deployment and sampling operation
6. NEUSTON NET SAMPLING
6.2. Design and characteristics of neuston nets
6.2.1. Surface sampling nets
6.2.2. Multiple layer plankton-neuston samplers
6.3. Procedure for handling
6.4. Advantages and disadvantages
7. SUBSURFACE SAMPLING
7.2. Subsurface sampling strategies
7.2.1. Overview of subsurface sampling techniques
7.2.2. Prevention of sample contamination
7.2.3. Multilayer surface sampling
7.3. Hand-dip sampling and pump systems
7.3.1. Advantages and disadvantages
7.4. Niskin and GO-FLO samplers
7.4.1. Advantages and disadvantages
7.5. Rosette/carousel sampling devices
7.5.1. Advantages and disadvantages
8. PHYSICAL AND IN-SITU TECHNIQUES
8.1. Meteorological fluxes
8.2. Ocean wave characterization
8.2.1. Polarimetric ocean wave slope sensing
8.2.2. Fixed and linear scanning laser altimeters
8.2.3. Marine wave radar (X-Band)
8.3. Ocean surface and near-surface characterization
8.3.1. Ocean skin temperature
8.3.2. Ocean wave breaking characterization
8.3.3. Ocean surface thermography
8.3.4. Ocean near-surface turbulence
8.4. Additional platforms and sensors
8.4.2. Wave Glider from Liquid Robotics
8.4.3. Air-Sea Interaction Profiler (ASIP)
9. DESCRIPTIVE INDICATORS FOR SURFACE CONDITIONS
9.1. How to describe and differentiate slick conditions
9.2. Defining microlayer enrichment
9.3. Standardization of descriptive physical, chemical and biological indicators............... 98
9.4. Reporting metorological data
CONTRIBUTORSMichael Cunliffe Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UNITED KINGDOM email@example.com Oliver Wurl Institute for Chemistry and Biology of the Marine Environment, Carl-vonOssietzky University Oldenburg, Emsstrasse 20, 26382 Wilhelmshaven, GERMANY firstname.lastname@example.org Anja Engel Biologische Ozeanographie GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Düsternbrooker Weg 20, 24105 Kiel, GERMANY email@example.com Sanja Frka Ruđer Bošković Institute, Institute for Marine and Environmental Research, Bijenička c. 54, 10000 Zagreb, CROATIA firstname.lastname@example.org William Landing Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, Florida 32306-4320, USA email@example.com Mohd T. Latif School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor MALAYSIA firstname.lastname@example.org Gui-Peng Yang Key Laboratory of Marine Chemistry Theory and Technology, Ocean University of China, No. 238, Song Ling Road, Qingdao, CHINA email@example.com Christopher Zappa Lamont-Doherty Earth Observatory, 204E Oceanography, P.O. Box 1000, Palisades, NY 10964-8000, USA firstname.lastname@example.org Robert Upstill-Goddard School of Marine Science and Technology, Newcastle University Newcastle upon Tyne, NE1 7RU, UNITED KINGDOM email@example.com Blaženka Gašparović Ruđer Bošković Institute, Institute for Marine and Environmental Research, Bijenička 54, 10000 Zagreb, CROATIA Blazenka.Gasparovic@irb.hr Anna Lindroos Finnish Environment Institute, Marine Research Centre, Mechelininkatu 34a P.O.Box 140, FI-00251 Helsinki, FINLAND firstname.lastname@example.org Miguel Leal Universidade de aveiro, Centro de estudos do ambiente e do mar Campus Uuniversitario de Santiago, 3810-193 Aveiro, PORTUGAL email@example.com Svein Vagle Ocean Sciences Division Institute of Ocean Sciences, 9860 West Saanich Road, Sidney, BC, V8L 4B2, CANADA svein.Vagle@dfo-mpo.gc.ca Christian Stolle Leibniz-Institute for Baltic Sea Research, Seestrasse 15, 18119 Rostock, GERMANY firstname.lastname@example.org Werner Ekau Leibniz Center for Tropical Marine Ecology, Fahrenheitstr. 6, D-28359 Bremen GERMANY email@example.com Alexander Soloviev Oceanographic Center, Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, FL 33004, USA firstname.lastname@example.org Kristian Laß Institut für Physikalische Chemie, Christian-Albrechts-Universität Kiel, MaxEyth-Str. 2, 24118 Kiel, GERMANY email@example.com
The sea surface microlayer (SML) is the boundary interface between the atmosphere and ocean, covering 70% of the Earth’s surface. Many studies have shown that the SML typically has measurably distinct physical, chemical and biological properties from underlying waters (Cunliffe et al., 2013). Because the SML has a unique position at the interface between the marine environment and the atmosphere, the SML plays a central role in a diverse range of global biogeochemical cycles and climate-related processes. It is not within the scope of this guide to fully review SML processes. Below is a brief summary of selected key topics that highlight the global scale significance of the SML.
Figure 1: Diagram illustrating some of the key topics that highlight the global scale significance of the SML (modified from Cunliffe et al., 2013).
Air-Ocean gas transfer The SML modifies the transfer of dissolved gases in seawater to the atmosphere, and atmospheric gases into the ocean (Upstill-Goddard, 2006). Surface active (surfactant) material is a major component that is enriched in the SML, and is dominated by biogenic material, such as polysaccharides (Wurl and Holmes, 2008) and amino acids (Kattner et al., 1983; Kutznetsova et al., 2004). SML surfactants can act as a physical barrier to gas transfer, and modify sea surface hydrodynamics, which subsequently alter turbulent energy transfer (Upstill-Goddard, 2006). Artificial release of surfactant to the SML in the North Atlantic caused up to 55% suppression of gas transfer velocity, even at high wind speeds (Salter et al., 2011).
Biological processes that are active in the SML can also directly modify air-sea gas transfer by changing concentrations of gases, such as methane, in the SML (Cunliffe et al., 2011).
The net balance of general community metabolism (i.e. heterotrophy or autotrophy dominating) can control carbon dioxide transfer (Calleja et al., 2005). Specific functional groups within neuston communities, such as methane-oxidising bacteria, may also potentially modify gas transfer rates (Upstill-Goddard et al., 2003).
Aerosol formation Carbohydrate-enriched particles, including gels, accumulating in the SML can be injected into the marine boundary layer during bubble bursting (Russell et al., 2010). Subsequently, SML derived organics may be an important source of aerosols that lead to the production of cloud condensation nuclei (CCN) (Orellana et al., 2011, Quinn and Bates, 2011).
Neuston ecosystems The SML is a novel ecosystem, often referred to as the neuston, which can be distinct from those found in underlying waters (Cunliffe and Murrell, 2009). Most research has focused on microbial communities in the neuston, and in particular bacterioneuston communities using molecular-based approaches (Cunliffe et al., 2011). Bacterioneuston communities are equally as complex as bacterioplankton communities, and have many potential functional roles in SML biogeochemical processes, such as air-sea gas transfer, gelatinous particle cycling and pollution degradation (Cunliffe et al., 2013). Neustons also harbour distinct eukaryote communities that can be very dissimilar to those in underlying waters, resulting in different food web structures compared to the plankton (Cunliffe and Murrell, 2010).
Figure 2: Neustonic ciliates feeding on biogenic aggregates in the SML isolated from coastal UK waters.
Marine Pollution A diverse range of pollutants are found in the SML that are typically enriched in concentration compared to underlying waters and that can impact upon neuston ecosystems (Wurl and Obbard, 2004). SML pollutant concentrations are generally higher in the coastal zone where they occur via direct inputs, however pollutants can also entire the SML by wet and dry deposition (Cunliffe et al., 2013, Guitart et al., 2007).