title: Climate change-related regime shifts have altered spatial synchrony of plankton dynamics in the North Sea.
abstract: During the 1980s, the North Sea plankton community underwent a well-documented ecosystem regime shift, including both spatial changes (northward species range shifts) and temporal changes (increases in the total abundances of warmer water species). This regime shift has been attributed to climate change. Plankton provide a link between climate and higher trophic-level organisms, which can forage on large spatial and temporal scales. It is therefore important to understand not only whether climate change affects purely spatial or temporal aspects of plankton dynamics, but also whether it affects spatiotemporal aspects such as metapopulation synchrony. If plankton synchrony is altered, higher trophic-level feeding patterns may be modified. A second motivation for investigating changes in synchrony is that the possibility of such alterations has been examined for few organisms, in spite of the fact that synchrony is ubiquitous and of major importance in ecology. This study uses correlation coefficients and spectral analysis to investigate whether synchrony changed between the periods 1959-1980 and 1989-2010. Twenty-three plankton taxa, sea surface temperature (SST), and wind speed were examined. Results revealed that synchrony in SST and plankton was altered. Changes were idiosyncratic, and were not explained by changes in abundance. Changes in the synchrony of Calanus helgolandicus and Para-pseudocalanus spp appeared to be driven by changes in SST synchrony. This study is one of few to document alterations of synchrony and climate-change impacts on synchrony. We discuss why climate-change impacts on synchrony may well be more common and consequential than previously recognized.
authors.affiliation: Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK.
authors.forename: Emma J
authors.initials: EJ
authors.lastname: Defriez
authors.affiliation: Department of Ecology and Evolutionary Biology and Kansas Biological Survey, University of Kansas, Lawrence, KS, 66047, USA.
authors.forename: Lawrence W
authors.initials: LW
authors.lastname: Sheppard
authors.affiliation: The Laboratory, Sir Alister Hardy Foundation for Ocean Science, Citadel Hill, Plymouth, PL1 2PB, UK.|Marine Institute, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK.|The Laboratory, Marine Biological Association of the UK, Citadel Hill, Plymouth, PL1 2PB, UK.
authors.forename: Philip C
authors.initials: PC
authors.lastname: Reid
authors.affiliation: Department of Ecology and Evolutionary Biology and Kansas Biological Survey, University of Kansas, Lawrence, KS, 66047, USA.|Laboratory of Populations, Rockefeller University, 1230 York Ave, New York, NY, 10065, USA.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Reuman
mesh_terms: D000818:Animals; D057231:Climate Change; D033342:Copepoda / Q000502:physiology; D033364:Decapoda / Q000502:physiology; D017377:Diatoms / Q000502:physiology; D017753:Ecosystem; D020387:Food Chain; D009659:North Sea; D010933:Plankton / Q000502:physiology*; D011157:Population Dynamics; D062211:Spatio-Temporal Analysis; D013696:Temperature
keywords: North Sea; cospectrum; plankton; power spectrum; regime shift; synchrony