Editors Michael Cunliffe Oliver Wurl Guide to best practices to study the ocean’s surface 1 PREFACE 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 2 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. ISSN 0260-2784 3 CONTENTS CONTRIBUTORS ................................................................................................................. 7 INTRODUCTION .................................................................................................................. 9 Air-Ocean gas transfer ...................................................................................................... 9 Aerosol formation ............................................................................................................ 10 Neuston ecosystems ....................................................................................................... 10 Marine Pollution ............................................................................................................... 10 Summary of previous sea surface microlayer sampling reviews ...................................... 11 What is different about this guide? ................................................................................... 14 1. SELECTION OF SAMPLING SITES AND SUITABLE SAMPLING PLATFORMS ........ 16 1.1. Selecting and characterising a sampling site ............................................................ 16 1.2. Selection of suitable sampling platforms ................................................................... 17 2. SAMPLING TECHNIQUE: SCREEN SAMPLER ............................................................ 19 2.1. Design and characteristics ........................................................................................ 19 2.2. Procedures for handling ............................................................................................ 22 2.2.1. Sampling prerequisites ....................................................................................... 22 2.2.2. Sampling procedure ........................................................................................... 23 2.2.3. Cleaning ............................................................................................................. 26 2.2.4. Transport and storage ........................................................................................ 27 2.3. Advantages and disadvantages ................................................................................ 28 2.3.1. Advantages ........................................................................................................ 28 2.3.2. Disadvantages ................................................................................................... 30 3. SAMPLING TECHNIQUE: GLASS PLATE SAMPLER .................................................. 32 3.1. Design and characteristics ........................................................................................ 32 3.2. Procedures for handling ............................................................................................ 33 3.2.1. Sampling prerequisites ....................................................................................... 33 3.2.2. Sampling procedure ........................................................................................... 34 3.2.3. Cleaning ............................................................................................................. 34 3.2.3. Transport and storage ........................................................................................ 34 3.3. Advantages and disadvantages ................................................................................ 35 2.3.1. Advantages ........................................................................................................ 35 2.3.2. Disadvantages ................................................................................................... 36 4 4. SAMPLING TECHNIQUE: MEMBRANE SAMPLER ...................................................... 40 4.1. Design and characteristics ........................................................................................ 40 4.2. Procedures for handling ............................................................................................ 40 4.3. Advantages and disadvantages ................................................................................ 42 4.3.1. Advantages ........................................................................................................ 42 4.3.2. Disadvantages ................................................................................................... 42 5. AUTONOMOUS SAMPLING DEVICES .......................................................................... 44 5.1. Introduction ............................................................................................................... 44 5.2. Autonomous microlayer sampler design criteria ........................................................ 45 5.3. Multi-sensor autonomous microlayer sampler, an example ....................................... 46 5.4. Deployment and sampling operation ......................................................................... 49 6. NEUSTON NET SAMPLING ........................................................................................... 51 6.1. Introduction ............................................................................................................... 51 6.2. Design and characteristics of neuston nets ............................................................... 52 6.2.1. Surface sampling nets ........................................................................................ 53 6.2.2. Multiple