skip to main content

Title: Climate change‐related regime shifts have altered spatial synchrony of plankton dynamics in the North Sea

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 inSSTand plankton was altered. Changes were idiosyncratic, and were not explained by changes in abundance. Changes in the synchrony ofCalanus helgolandicusandPara‐pseudocalanusspp appeared to be driven by changes inSSTsynchrony. 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.

more » « less
Award ID(s):
Author(s) / Creator(s):
 ;  ;  ;  
Publisher / Repository:
Date Published:
Journal Name:
Global Change Biology
Page Range / eLocation ID:
p. 2069-2080
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. 1. Thermal tolerance has a strong predictive power for understanding the ecology and distribution of organisms, as well as their responses to changes in land use and global warming. However, relatively few studies have assessed thermal tolerances for bees.

    2. The present study aimed to determine whether the critical thermal maximum (CTmax) of carpenter bees (Apidae: genusXylocopaLatreille) varies with different patterns of foraging activity and elevation. In addition, the influence of body size, body water content and relative age was examined with respect to their CTmaxand differences in thoracic temperature (Tth) among species were evaluated.

    3. The CTmaxof one crepuscular (Xylocopaolivieri) and two diurnal species (XylocopaviolaceaandXylocopairis) of carpenter bees was assessed at sea level on the Greek island of Lesvos. To detect variation as a result of elevation, the CTmaxof a population ofX. violaceaat 625 m.a.s l. was assessed and compared with that from sea level.

    4.Xylocopa olivieridisplayed a similar CTmaxto that ofX. violaceabut lower than that ofX. iris. Body size, body water content, and relative age did not affect CTmax. InX. violacea, CTmaxdecreased with elevation and all three species have highTthindependent of ambient temperatures.

    5. The results of the present study are consistent with variations in CTmaxpredicted by broad spatial and temporal patterns reported for other insects, including honey and bumble bees. The implications of the results are discussed aiming to understand the differences in the foraging pattern of these bees.

    more » « less
  2. Abstract

    The western Antarctic Peninsula (WAP) is a bellwether of global climate change and natural laboratory for identifying interactions between climate and ecosystems. The Palmer Long‐Term Ecological Research (LTER) project has collected data on key ecological and environmental processes along theWAPsince 1993. To better understand how key ecological parameters are changing across space and time, we developed a novel seascape classification approach based on in situ temperature, salinity, chlorophylla, nitrate + nitrite, phosphate, and silicate. We anticipate that this approach will be broadly applicable to other geographical areas. Through the application of self‐organizing maps (SOMs), we identified eight recurrent seascape units (SUs) in these data. These SUs have strong fidelity to known regional water masses but with an additional layer of biogeochemical detail, allowing us to identify multiple distinct nutrient profiles in several water masses. To identify the temporal and spatial distribution of these SUs, we mapped them across the PalmerLTERsampling grid via objective mapping of the original parameters. Analysis of the abundance and distribution of SUs since 1993 suggests two year types characterized by the partitioning of chlorophyllainto SUs with different spatial characteristics. By developing generalized linear models for correlated, time‐lagged external drivers, we conclude that early spring sea ice conditions exert a strong influence on the distribution of chlorophyllaand nutrients along theWAP, but not necessarily the total chlorophyllainventory. Because the distribution and density of phytoplankton biomass can have an impact on biomass transfer to the upper trophic levels, these results highlight anticipated links between theWAPmarine ecosystem and climate.

    more » « less
  3. Abstract

    Binding across sensory modalities yields substantial perceptual benefits, including enhanced speech intelligibility. The coincidence of sensory inputs across time is a fundamental cue for this integration process. Recent work has suggested that individuals with diagnoses of schizophrenia (SZ) and autism spectrum disorder (ASD) will characterize auditory and visual events as synchronous over larger temporal disparities than their neurotypical counterparts. Namely, these clinical populations possess an enlarged temporal binding window (TBW). Although patients withSZandASDshare aspects of their symptomatology, phenotypic similarities may result from distinct etiologies. To examine similarities and variances in audiovisual temporal function in these two populations, individuals diagnosed withASD(n = 46; controlsn = 40) andSZ(n = 16, controls = 16) completed an audiovisual simultaneity judgment task. In addition to standard psychometric analyses, synchrony judgments were assessed using Bayesian causal inference modeling. This approach permits distinguishing between distinct causes of an enlargedTBW: ana prioribias to bind sensory information and poor fidelity in the sensory representation. Findings indicate that bothASDandSZpopulations show deficits in multisensory temporal acuity. Importantly, results suggest that while the widerTBWs inASDmost prominently results from atypical priors, the widerTBWs inSZresults from a trend toward changes in prior and weaknesses in the sensory representations. Results are discussed in light of currentASDandSZtheories and highlight that different perceptual training paradigms focused on improving multisensory integration may be most effective in these two clinical populations and emphasize that similar phenotypes may emanate from distinct mechanistic causes.

    more » « less
  4. Abstract

    Ocean warming ‘hotspots’ are regions characterized by above‐average temperature increases over recent years, for which there are significant consequences for both living marine resources and the societies that depend on them. As such, they represent early warning systems for understanding the impacts of marine climate change, and test‐beds for developing adaptation options for coping with those impacts. Here, we examine five hotspots off the coasts of eastern Australia, South Africa, Madagascar, India and Brazil. These particular hotspots have underpinned a large international partnership that is working towards improving community adaptation by characterizing, assessing and projecting the likely future of coastal‐marine food resources through the provision and sharing of knowledge. To inform this effort, we employ a high‐resolution global ocean model forced by Representative Concentration Pathway 8.5 and simulated to year 2099. In addition to the sea surface temperature, we analyse projected stratification, nutrient supply, primary production, anthropogenicCO2‐driven ocean acidification, deoxygenation and ocean circulation. Our simulation finds that the temperature‐defined hotspots studied here will continue to experience warming but, with the exception of eastern Australia, may not remain the fastest warming ocean areas over the next century as the strongest warming is projected to occur in the subpolar and polar areas of the Northern Hemisphere. Additionally, we find that recent rapid change inSSTis not necessarily an indicator that these areas are also hotspots of the other climatic stressors examined. However, a consistent facet of the hotspots studied here is that they are all strongly influenced by ocean circulation, which has already shown changes in the recent past and is projected to undergo further strong change into the future. In addition to the fast warming, change in local ocean circulation represents a distinct feature of present and future climate change impacting marine ecosystems in these areas.

    more » « less
  5. Abstract

    We examined the hypothesis that ecological niche models (ENMs) more accurately predict species distributions when they incorporate information on population genetic structure, and concomitantly, local adaptation. Local adaptation is common in species that span a range of environmental gradients (e.g., soils and climate). Moreover, common garden studies have demonstrated a covariance between neutral markers and functional traits associated with a species’ ability to adapt to environmental change. We therefore predicted that genetically distinct populations would respond differently to climate change, resulting in predicted distributions with little overlap. To test whether genetic information improves our ability to predict a species’ niche space, we created genetically informed ecological niche models (gENMs) usingPopulus fremontii(Salicaceae), a widespread tree species in which prior common garden experiments demonstrate strong evidence for local adaptation. Four major findings emerged: (i)gENMs predicted population occurrences with up to 12‐fold greater accuracy than models without genetic information; (ii) tests of niche similarity revealed that three ecotypes, identified on the basis of neutral genetic markers and locally adapted populations, are associated with differences in climate; (iii) our forecasts indicate that ongoing climate change will likely shift these ecotypes further apart in geographic space, resulting in greater niche divergence; (iv) ecotypes that currently exhibit the largest geographic distribution and niche breadth appear to be buffered the most from climate change. As diverse agents of selection shape genetic variability and structure within species, we argue thatgENMs will lead to more accurate predictions of species distributions under climate change.

    more » « less