Zooplankton long-term changes in the NW Mediterranean Sea: Decadal periodicity forced by winter hydrographic conditions related to large-scale atmospheric changes?

García‐Comas, Carmen; Stemmann, Lars; Ibañez, Frédéric; Berline, Léo; Mazzocchi, Maria Grazia; Gasparini, Stéphane; Picheral, Marc; Gorsky, Gabriel

doi:10.1016/j.jmarsys.2011.04.003

Cited by 89 publications

(97 citation statements)

References 62 publications

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“…On the other hand, our findings for this site are consistent with the observations of decadal oscillations in zooplankton found by García-Comas et al [80] and Vandromme et al [81]. They proposed that the long-term warming of seawaters in the northwest supplementary material, table B).…”

Section: Discussionsupporting

confidence: 93%

Synchronous marine pelagic regime shifts in the Northern Hemisphere

Beaugrand

Conversi

Chiba

et al. 2015

Phil. Trans. R. Soc. B

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Regime shifts are characterized by sudden, substantial and temporally persistent changes in the state of an ecosystem. They involve major biological modifications and often have important implications for exploited living resources. In this study, we examine whether regime shifts observed in 11 marine systems from two oceans and three regional seas in the Northern Hemisphere (NH) are synchronous, applying the same methodology to all. We primarily infer marine pelagic regime shifts from abrupt shifts in zooplankton assemblages, with the exception of the East Pacific where ecosystem changes are inferred from fish. Our analyses provide evidence for quasi-synchronicity of marine pelagic regime shifts both within and between ocean basins, although these shifts lie embedded within considerable regional variability at both year-to-year and lower-frequency time scales. In particular, a regime shift was detected in the late 1980s in many studied marine regions, although the exact year of the observed shift varied somewhat from one basin to another. Another regime shift was also identified in the mid- to late 1970s but concerned less marine regions. We subsequently analyse the main biological signals in relation to changes in NH temperature and pressure anomalies. The results suggest that the main factor synchronizing regime shifts on large scales is NH temperature; however, changes in atmospheric circulation also appear important. We propose that this quasi-synchronous shift could represent the variably lagged biological response in each ecosystem to a large-scale, NH change of the climatic system, involving both an increase in NH temperature and a strongly positive phase of the Arctic Oscillation. Further investigation is needed to determine the relative roles of changes in temperature and atmospheric pressure patterns and their resultant teleconnections in synchronizing regime shifts at large scales.

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Section: Discussionsupporting

confidence: 93%

Synchronous marine pelagic regime shifts in the Northern Hemisphere

Beaugrand

Conversi

Chiba

et al. 2015

Phil. Trans. R. Soc. B

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“…Therefore, rather than a threshold size for gamete production, maturation of gonads may depend on an abundant source of prey, possibly of gelatinous origin. Salps and siphonophores are among the more numerous gelatinous prey available in the Ligurian Sea, typically blooming in spring (Licandro et al 2010, Garcia-Comas et al 2011, and may serve as a signal to synchronise the growth observed in populations of P. noctiluca. High mortality of young ephyrae has been recorded previously for P. noctiluca (Malej & Malej 1992, Rosa et al 2013), and we also observed this in Run 1.…”

Section: Discussion Culturing Pelagia Noctilucamentioning

confidence: 99%

Culture and growth of the jellyfish Pelagia noctiluca in the laboratory

Lilley¹,

Ferraris²,

Elineau³

et al. 2014

Mar. Ecol. Prog. Ser.

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Four cohorts of the scyphozoan jellyfish Pelagia noctiluca were grown in the laboratory. For the first time, P. noctiluca was grown from eggs through to reproductive adults. The maximum life span in the laboratory was 17 mo. Pelagia noctiluca were first observed to release gametes at an umbrella diameter of 2.4 cm. Laboratory growth under steady feeding conditions showed initial growth followed by stagnation until dietary conditions were altered. A mismatch between the availability of optimal food and the presence of developmental stages may significantly increase the mortality rates of the young stages. Non-motile prey improved survival of ephyrae stages compared with zooplankton, but good survival and ephyrae growth were only obtained with a high-energy sea urchin egg diet. Maximal growth rates were up to 30% d −1 for young ephyrae and 1.5−4% d −1 for adults. Maximal growth rates were comparable between laboratory and in situ growth observations in the Ligurian Sea during 1969 and 2013. Combining observations would suggest that 230 d of continuous growth are required to reach the largest mean size observed in the wild (June 2013, mean ± SD = 15.6 ± 2.8 cm, range = 12−21 cm). We suggest that 90−120 d of continuous growth from planula larvae would yield reproductive individuals under ideal growing conditions. We discuss the daily prey abundances required by each individual to sustain basal metabolism and the observed growth rates.

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“…The site experiences strong seasonality, with chl a maxima during the spring months (Berline et al 2012). The conditions during winter have been shown to strongly influence the productivity of the following year (Buecher et al 1997, Garcia-Comas et al 2011.…”

Section: Sampling Sitementioning

confidence: 99%

“…The preserved weekly samples were sorted using the Zooscan digital imaging system (www.obs-vlfr.fr/LOV/ ZooPart/ ZooScan/; Gorsky et al 2010). Each sample was split and analysed in 2 size fractions to avoid biased representation of large, rare organisms (Garcia-Comas et al 2011). Zooplankton analysis with the Zooscan works in 4 steps: (1) digitalisation of the sample, (2) image analysis and morphological feature extraction, (3) automatic recognition using a training set, and (4) validation by an expert.…”

Section: Zooplankton Time Seriesmentioning

confidence: 99%

“…They have also been shown to be sensitive to warming in the North Atlantic (Beaugrand et al 2002), although evidence of the same effect has not been found in the Mediterranean Sea, where decadal cycles appear to predominate. Garcia-Comas et al (2011) linked fluctuations in zooplankton abundances at Point B in the Bay of Villefranche-sur-Mer to the NAO (North Atlantic Oscillation) cycles and to a 'bottom up' control on populations, driven by more intense spring blooms following cold and dry winter conditions. Thecosome pteropods are cosmopolitan holoplanktonic opisthobranchs representing a major group of aragonite-producing pelagic calcifiers that contribute between 20 to 42% of the global carbonate budget (Bednaršek et al 2012a).…”

Section: Introductionmentioning

confidence: 99%

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Pteropod time series from the North Western Mediterranean (1967-2003): impacts of pH and climate variability

Howes¹,

Stemmann²,

Assailly³

et al. 2015

Mar. Ecol. Prog. Ser.

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Environmental changes resulting from anthropogenic CO 2 emissions occur at global and local levels and have potentially harmful effects, particularly for calcifying taxa in the marine environment. A time series of pteropod abundance covering the period 1967−2003 was isolated from the Point B (northwestern Ligurian Sea) zooplankton time series. Inter-and intra-annual changes in the abundance of 3 families (Limacinidae, Cavoliniidae and Creseidae) were compared with the copepod time series to identify any differential effects driven by ocean acidification and temperature. pH values were hind-cast from total alkalinity estimated from local temperature and salinity measurements, and atmospheric CO 2 taken from the Mauna Loa time series. Although surface waters were supersaturated with respect to aragonite throughout the study period, it is estimated that pH declined by 0.05 units. All pteropod groups displayed a trend of increasing abundance, suggesting that any deleterious effect of declining pH T in the range of 0.05 units has not caused sufficient reductions in fitness as to decrease local abundances between 1967−2003. Pteropod populations are influenced by inter-annual changes in summer temperatures. Spectral analysis identified a ~14 yr periodic oscillation in sea surface temperature. Similarly timed oscillations in abundance are present for all pteropod families but not for copepods, indicating a possible influence of the North Atlantic quasi-decadal mode on pteropod populations. While laboratory studies have shown pteropods to be sensitive to changes in pH, this analysis suggests that local and regional scale drivers have had a greater effect on pteropod populations in the northwestern Mediterranean Sea in recent decades. It should be noted that pH changes in laboratory studies exceed 0.05 pH units and that the saturation state with respect to aragonite (Ω ar ) is usually much lower than that of the Mediterranean.

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Zooplankton long-term changes in the NW Mediterranean Sea: Decadal periodicity forced by winter hydrographic conditions related to large-scale atmospheric changes?

Cited by 89 publications

References 62 publications

Synchronous marine pelagic regime shifts in the Northern Hemisphere

Synchronous marine pelagic regime shifts in the Northern Hemisphere

Culture and growth of the jellyfish Pelagia noctiluca in the laboratory

Pteropod time series from the North Western Mediterranean (1967-2003): impacts of pH and climate variability

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