Sturm R.,Institute of Coastal Research |
Ahrens L.,Environment Canada
Environmental Chemistry | Year: 2010
Environmental context Polyfluoroalkyl compounds are used in a variety of industrial and consumer applications, including polymer production and for surface treatment of textiles and paper. Research over the last 10 years has shown that these compounds are ubiquitous environmental contaminants they are extremely persistent, show toxic effects and accumulate in the food chain. We evaluate global, temporal and spatial trends of these important emerging contaminants. Abstract This review gives an overview of existing knowledge of polyfluoroalkyl compounds (PFCs) in humans and in marine biota. Temporal trends and spatial distribution of PFCs were globally compared in humans, marine mammals, seabirds and fish. In general, PFC concentrations in the environment have increased significantly from the beginning of the production up to the 1990s. After the phase-out of perfluorooctane sulfonyl fluoride (POSF) production starting in 2000, PFC concentrations in humans generally decreased. In marine biota no clear temporal trends were observed. The temporal trends depended on the species, their trophic levels and the geographical locations. PFC patterns in humans and in marine wildlife species were compared regarding perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), their shorter and longer chain homologues (C 4C 15) and precursor compounds. Finally knowledge gaps were identified and recommendations for future work were presented. © CSIRO 2010.
Karimova S.,Institute of Coastal Research
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2014
Satellite imagery of visible and infrared ranges frequently visualizes the manifestations of hydrological fronts at different spatial scales. Despite high availability of optical-range satellite imagery and the great interest of researchers to the Black Sea hydrodynamics, hydrological fronts in this basin have not got a thorough consideration so far. In the present paper, Aqua Moderate Resolution Imaging Spectrometer (MODIS) data were implemented to get some general information on thermal and optical frontal zones in the Black Sea. The edge detection was performed by means of the Sobel operator. Obtained in such a way gradient norms were summed and normalized by the number of covering images. As a result, the areas of the highest front density and the most persistent synoptic- and mesoscale circulation features were retrieved. © 2014 IEEE.
Van De Wolfshaar K.E.,Wageningen University |
HilleRisLambers R.,World Wildlife Fund |
Gardmark A.,Institute of Coastal Research
Marine Ecology Progress Series | Year: 2011
In this paper we study the consequences of habitat switching and the corresponding ontogenetic diet shifts between adult and juvenile life stages for harvesting and management of exploited populations using a consumer-resource model with stage-specific mortality. Specifically, we study how differences in stage-specific habitat productivity regulate exploited populations and affect yield. We show that the ratio of adult to juvenile habitat productivity determines whether the population is regulated by processes in the juvenile or adult stage and that population responses to changes in mortality (e.g. fishing) or habitat productivity (e.g. eutrophication or physical destruction) depend critically on the mechanism regulating the population. This result has important consequences for the management of marine fish. For example, in fisheries where the exploited population is regulated by processes in the juvenile stage, management measures aimed at protecting the juvenile habitat may be much more effective than regulating fishing effort on the adults. We find also that intermediate differences in habitat productivity lead to alternative stable states between a population regulated by processes in the juvenile or the adult stage. These alternative stable states may lead to counterintuitive population responses to harvesting. © Inter-Research 2011.
Huss M.,Umeå University |
Huss M.,Institute of Coastal Research |
Nilsson K.A.,Umeå University
Journal of Animal Ecology | Year: 2011
1.Recent theoretical insights have shown that predator species may help each other to persist by size-selective foraging on a shared prey. By feeding on a certain prey stage, a predator may induce a compensatory response in another stage of the same prey species, thereby favouring other predators; a phenomenon referred to as emergent facilitation. 2.To test whether emergent facilitation may occur in a natural system, we performed an enclosure experiment where we mimicked fish predation by selectively removing large zooplankton and subsequently following the response of the invertebrate predator Bythotrephes longimanus. 3.Positive responses to harvest were observed in the biomass of juvenile individuals of the dominant zooplankton Holopedium gibberum and in Bythotrephes densities. Hence, by removing large prey, we increased the biomass of small prey, i.e. stage-specific biomass overcompensation was present in the juvenile stage of Holopedium. This favoured Bythotrephes, which preferentially feed on small Holopedium. 4.We argue that the stage-specific overcompensation occurred as a result of increased per capita fecundity of adult Holopedium and as a result of competitive release following harvest. If shown to be common, emergent facilitation may be a major mechanism behind observed predator extinctions and patterns of predator invasions. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.
Barrett R.D.H.,University of British Columbia |
Paccard A.,Institute Of Biologie |
Healy T.M.,University of British Columbia |
Bergek S.,Institute of Coastal Research |
And 3 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2011
Climate change is predicted to lead to increased average temperatures and greater intensity and frequency of high and low temperature extremes, but the evolutionary consequences for biological communities are not well understood. Studies of adaptive evolution of temperature tolerance have typically involved correlative analyses of natural populations or artificial selection experiments in the laboratory. Field experiments are required to provide estimates of the timing and strength of natural selection, enhance understanding of the genetics of adaptation and yield insights into the mechanisms driving evolutionary change. Here, we report the experimental evolution of cold tolerance in natural populations of threespine stickleback fish (Gasterosteus aculeatus). We show that freshwater sticklebacks are able to tolerate lower minimum temperatures than marine sticklebacks and that this difference is heritable. We transplanted marine sticklebacks to freshwater ponds and measured the rate of evolution after three generations in this environment. Cold tolerance evolved at a rate of 0.63 haldanes to a value 2.5°C lower than that of the ancestral population, matching values found in wild freshwater populations. Our results suggest that cold tolerance is under strong selection and that marine sticklebacks carry sufficient genetic variation to adapt to changes in temperature over remarkably short time scales. © 2011 The Royal Society.
Florin A.-B.,Institute of Coastal Research |
Franzen F.,Institute of Coastal Research
Fisheries Research | Year: 2010
Tagging of more than 2000 turbot in the eastern Gotland basin in the central Baltic Sea revealed strong spawning site fidelity. Only 4 out of 653 recaptures were made outside the Gotland area and 95% of recaptures, 1-4 years after tagging, were found less than 30 km from the original tagging site. Within the summer spawning season turbot were almost stationary and 95% of them were recaptured less than 16 km from the tagging site. During the spawning they dwelled close to shore at a mean depth of only 5 m while migration to deeper areas was evident in the feeding season. Indications of differences in the spawning behavior between sexes were found together with a positive correlation between recapture probability and body length. The revealed spawning site fidelity has implications for management practices of turbot in the Baltic Sea. © 2009 Elsevier B.V. All rights reserved.
Von Storch H.,Institute of Coastal Research
Procedia IUTAM | Year: 2013
Storm surges are behind the geophysical risk of short term and abrupt inundating low-lying coastal regions known along most coasts of the world. They are related to meteorological phenomena, mostly wind storms. Storm surges represent a challenge for science and risk management with respect to short term forecasts of specific events but also with long-term changes of the statistics of storm surges due to anthropogenic global climate change, sinking coasts and estuarine water works. Storm surges are expected to become more severe in the coming decades and centuries because of ongoing and expected accelerated mean sea level, and much less so because of more energetic wind storms. © 2013 Published by Elsevier Ltd.
Lindegren M.,Technical University of Denmark |
OStman O.,Institute of Coastal Research |
Gardmark A.,Institute of Coastal Research
Ecology | Year: 2011
Small pelagic fish occupy a central position in marine ecosystems worldwide, largely by determining the energy transfer from lower trophic levels to predators at the top of the food web, including humans. Population dynamics of small pelagic fish may therefore be regulated neither strictly bottom-up nor top-down, but rather through multiple external and internal drivers. While in many studies single drivers have been identified, potential synergies of multiple factors, as well as their relative importance in regulating population dynamics of small pelagic fish, is a largely unresolved issue. Using a statistical, age-structured modeling approach, we demonstrate the relative importance and influence of bottom-up (e.g., climate, zooplankton availability) and top-down (i.e., fishing and predation) factors on the population dynamics of Bothnian Sea herring (Clupea harengus) throughout its life cycle. Our results indicate significant bottom-up effects of zooplankton and interspecific competition from sprat (Sprattus sprattus), particularly on younger age classes of herring. Although top-down forcing through fishing and predation by grey seals (Halichoerus grypus) and Atlantic cod (Gadus morhua) also was evident, these factors were less important than resource availability and interspecific competition. Understanding key ecological processes and interactions is fundamental to ecosystem-based management practices necessary to promote sustainable exploitation of small pelagic fish. © 2011 by the Ecological Society of America.
Bjorklund M.,Uppsala University |
Almqvist G.,University of Stockholm |
Almqvist G.,Institute of Coastal Research
Biological Invasions | Year: 2010
We analysed the pattern of genetic differentiation among six newly established (around 10 generations) sites of the round goby (Neogobius melanostomus) in the southern Baltic Sea by means of nine microsatellite loci and in total 183 individuals. All but one site were within 30 km from each other. We found statistically significant genetic differentiation in ten out of 15 comparisons after Bonferroni correction, and since the species is newly introduced this has happened in less than ten generations. The largest genetic differentiation was found between the two most divergent habitats, while sites with a similar habitat were not significantly differentiated. Estimates of gene flow (Nm) were low and ranged from 1.5 to 5.5. A large proportion of individuals were assigned to one site (Puck), suggesting that this site has acted as a source to the other sites. © 2009 Springer Science+Business Media B.V.
Florin A.-B.,Institute of Coastal Research |
Lavados G.,University of Stockholm
Estuarine, Coastal and Shelf Science | Year: 2010
To investigate feeding habits of juvenile flounder (Platichthys flesus) and turbot (Psetta maxima) in relation to habitat characteristics a field survey with push net sampling was conducted in nursery areas with different ecological characteristics in the northern Baltic proper. Sampling sites were stratified to cover several different habitat types defined by substrate and wave exposure. Apart from flatfishes and epifauna, samples of macrofauna, meiofauna and hyperbenthic planktons were collected from each site together with data on vegetation, depth, salinity, temperature and turbidity. The diet differed between species where flounder diet was dominated by chironomids, copepods and oligochaetes while turbot apart from chironomids had a high incidence of amphipods, gobies and mysids. In both species there was a shift in diet with size, although this shift was influenced by the habitat. Among the environmental variables investigated, wave exposure was found to significantly influence flounder diet. Food preference in the most exposed areas was dominated by oligochaetes and copepods instead of chironomids, which dominated in sheltered areas. This study shows that habitat characteristics can have a major influence on feeding habits of juvenile flatfish. © 2009 Elsevier Ltd. All rights reserved.