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Lauria V.,Marine Biology and Ecology Research Center | Lauria V.,National University of Ireland | Attrill M.J.,University of Plymouth | Brown A.,Natural England | And 2 more authors.
Marine Ecology Progress Series | Year: 2013

Climate change has profoundly altered the structure and biodiversity of marine ecosystems worldwide, and for many upper-trophic-level predators changes in lower-trophiclevel prey has been the main driver of this alteration. To better understand the nature of marine ecosystem response to global change requires detailed knowledge of predator-prey dynamics, but this is hampered by our poor understanding of spatial variation in the strength of trophic linkages. The aim of this study was to test for bottom-up effects across 4 trophic levels (phytoplankton, zooplankton, fish larvae and seabirds) over 17 yr, as well as testing for regional differences in 3 distinct marine ecosystems of the Northeast Atlantic: the Irish Sea, the Celtic Sea and the English Channel, where sea surface temperature has increased substantially in recent decades. Our results showed little evidence of bottom-up regulation from phytoplankton, zooplankton, fish larvae and seabirds, which is in contrast with the nearby North Sea, probably due to different oceanographic conditions. Despite this, we found a significant positive relationship between kittiwake productivity and the abundance of fish larvae at one colony in the Irish Sea. We speculate that during the period 1991 to 2007 these ecosystems were weakly regulated by climate change, and seabird populations in these regions might be more heavily influenced by other extrinsic factors. The spatial effects of climate change appear to vary across ecosystems, even within a relatively small geographic area. In this context, we urge complex multi-trophic-level studies to elucidate the effect of climate impacts on marine ecosystems. © Inter-Research 2013.

Melatunan S.,Marine Biology and Ecology Research Center | Melatunan S.,Pattimura University | Calosi P.,Marine Biology and Ecology Research Center | Rundle S.D.,Marine Biology and Ecology Research Center | And 2 more authors.
Marine Ecology Progress Series | Year: 2013

Phenotypic plasticity is a mechanism by which organisms can alter their morphology, life history or behaviour in response to environmental change. Here, we investigate shell plasticity in the intertidal gastropod Littorina littorea in response to the ocean acidification and elevated temperature values predicted for 2100, focusing on shell traits known to relate to protection from predators (size, shape and thickness) and resistance to desiccation (aperture shape). We also measured and desiccation rates (measured as percentage water loss). Ocean acidification was simulated by bubbling carbon dioxide into closed-circuit tanks at concentrations of 380 and 1000 ppm, giving respective pH levels of 8.0 and 7.7; temperatures were set at 15 or 20°C. Both low pH and elevated temperature disrupted the overall investment in shell material; snails in acidified seawater and elevated temperature in isolation or in combination had lower shell growth rates than control individuals. The percentage increase in shell length was also lower for individuals kept under combined acidified seawater and elevated temperature, and the percentage of shell thickness increase at the growing edge was lower under acidified and combined conditions. Shells were also more globular (i.e. had lower aspect ratios) under elevated temperature and lower pH. Desiccation rates were lower at low pH and high temperature. Counter to predictions, water loss did not relate to shell biometric measures but was negatively correlated with adenosine triphosphate (ATP) concentrations. Finally, ATP concentration was positively correlated with shell thickening and weight, confirming the idea that negative effects of exposure to elevated pCO2/low pH and elevated temperature on shell morphology may occur (at least in part) through metabolic disruption. © Inter-Research 2013.

Holt R.E.,Marine Biology and Ecology Research Center | Foggo A.,Marine Biology and Ecology Research Center | Neat F.C.,Marine Scotland - Marine Laboratory | Howell K.L.,Marine Biology and Ecology Research Center
ICES Journal of Marine Science | Year: 2013

Holt, R. E., Foggo, A., Neat, F. C., and Howell, K. L. 2013. Distribution patterns and sexual segregation in chimaeras: implications for conservation and management. - ICES Journal of Marine Science, 70: 1198-1205.Chimaeras such as Chimaera monstrosa and Hydrolagus mirabilis are commonly found in commercial bycatch of deep-sea fisheries in the Northeast Atlantic. Very little information exists on their life history, ecology or behaviour. Segregation of populations by sex and/or age classes has been demonstrated in several elasmobranchs, but whether segregation occurs in chimaeras, and if so what mechanisms are involved, remains unknown. This study investigates the distribution and sexual segregation of four species of chimaera (C. monstrosa, H. mirabilis, C. opalescens n. sp. and Harriotta raleighana) in relation to sex, size (maturity) class, bottom depth, and latitude. Data were obtained from annual trawl surveys undertaken by Marine Scotland, Aberdeen, from 1998-2009, at 400-2000 m in the Northeast Atlantic (55-59°N 5-11°W). A factorial General Linear Model (GLM) with planned contrasts indicated complex patterns of age- and sex-related segregation. All adult males and females were sexually segregated by depth: in all four species investigated females occurred at greater depths than males. Potential birthing grounds were identified for H. mirabilis. Latitudinal spatial segregation was not evident in relation to sex or maturity stage. The patterns of segregation reported here suggest a potential for differential exploitation of the sexes by spatially focused fisheries. © 2013 International Council for the Exploration of the Sea.

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