Bridging marine ecosystem and biogeochemistry research: Lessons and recommendations from comparative studies B. Salihoglu a, ⁎, S. Neuer b , S. Painting c , R. Murtugudde d , E.E. Hofmann e , J.H. Steele f , R.R. Hood g , L. Legendre h , M.W. Lomas i , J.D. Wiggert j , S. Ito k , Z. Lachkar l , G.L. Hunt Jr. m , K.F. Drinkwater n , C.L. Sabine o a Institute of Marine Sciences, Middle East Technical University, Erdemli, Turkey b School of Life Sciences, Arizona State University, Tempe, AZ 85287–4501, USA c The Centre for Environment, Fisheries and Aquaculture Science, Pakefield Rd., Lowestoft, Norfolk, NR33 0HT, UK d ESSIC, University of Maryland, College Park, College Park, Maryland, USA e Center for Coastal Physical Oceanography, Old Dominion University, Norfolk, VA 23529, USA f Woods Hole Oceanographic Institution, 266 Woods Hole Rd., MS# 41, Woods Hole, MA 02543–1050, USA g Horn Point Laboratory, University of Maryland Center for Environmental Science, P.O. Box 775, Cambridge, MD 21613, USA h Laboratoire d'Oceanographie de Villefranche (LOV) B.P. 28, 06234 Villefranche-sur-Mer Cedex, France i Bermuda Institute of Ocean Sciences, 17 Biological Lane, St. George, GE 01, Bermuda j Univ. of Southern Mississippi Dept. of Marine Sciences, 1020 Balch Blvd. Stennis Space Center, MS 39529–9904, USA k Fisheries Research Agency, Tohoku National Fisheries Research Institute, 3-27-5 Shinhama-cho, Shiogama, Miyagi 985–0001, Japan l ETH Zürich Inst.f.Biogeochemie u.Schadstoffdynamik CHN E 23.1, Universitätstrasse 16 8092 Zürich, Switzerland m School of Aquatic and Fishery Sciences, Box 355020, University of Washington, Seattle WA 98195, USA n Institute of Marine Research and the Bjerknes Center for Climate Research Box 1870, Nordnes, N-5817 Bergen, Norway o National Oceanic and Atmospheric Administration (NOAA) Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, WA 98115, USA abstract article info Article history: Received 22 November 2011 Received in revised form 23 June 2012 Accepted 5 July 2012 Available online 13 July 2012 Keywords: Marine Ecosystems Biogeochemistry Comparative studies There is growing interest in linking marine biogeochemistry with marine ecosystems research in response to the increasing need to understand and predict the effect of global change on the marine ecosystem. Such a holistic approach combines oceanographic and biogeochemical processes and information on organisms, ranging from microbes to higher-trophic-levels. Comparative studies offer a means to improve understanding of critical mech- anisms that influence marine systems by showing differences in ecosystem response to changing ocean condi- tions. Comparing similar biomes that differ in a particular set of physical or biological characteristics can provide insight into the susceptibility of the key features of a system to perturbation. Also, comparative studies based on long-term observations at fixed time-series stations enable the evaluation of long-term changes in the physical and biological environment, such as those driven by climate patterns. Moreover, the comparative approach provides a feasible alternative to costly and complex research programs designed to provide detailed end-to-end evaluations of marine systems. Planned and unplanned perturbations allow the investigation of the sensitivity of ecosystems and their biogeochemical processes to change at different time and space scales. In well-studied regions where sufficient data are available, models can provide comprehensive syntheses, mech- anistic insights and even predictions. We present examples of successful comparative studies that incorporate both biogeochemical and ecosystems aspects. A framework for a basic approach for comparative studies is pro- posed that considers the interactions between biogeochemical cycles and ecosystems. This approach is based on constructing a minimalistic observational framework grounded within a conceptual model. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Marine ecosystems are undergoing rapid and observable changes as a result of both natural climate cycles (e.g., El Niño-Southern Oscillation, ENSO) and human-induced effects (e.g., harvesting resources and in- creased atmospheric CO 2 ). Predicting future responses to these changes requires an improved understanding of the complex interactions and linkages that define present day marine ecosystems. Studies that include characterizations of habitat, food web components, and biogeo- chemical cycles allow important processes to be defined and provide the basis for comparisons within and across marine ecosystems (Fig. 1). The understanding gained from these comparative studies al- lows development of modeling systems that then provide the frame- work for investigation of potential future states and the consequences of change for present day marine ecosystems. A comparative marine ecosystem approach underpinned much of the research undertaken in the Global Ocean Ecosystem Dynamics Journal of Marine Systems 109–110 (2013) 161–175 ⁎ Corresponding author. E-mail address: baris@ims.metu.edu.tr (B. Salihoglu). 0924-7963/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.jmarsys.2012.07.005 Contents lists available at SciVerse ScienceDirect Journal of Marine Systems journal homepage: www.elsevier.com/locate/jmarsys