Search results for "Oceans and Sea"
showing 10 items of 55 documents
Temperature-associated habitat selection in a cold-water marine fish.
2015
1. Habitat selection is a complex process, which involves behavioural decisions guided by the multiple needs and constraints faced by individuals. Climate-induced changes in environmental conditions may alter those trade-offs and resulting habitat use patterns. 2. In this study, we investigated the effect of sea temperature on habitat selection and habitat use of acoustically tagged Atlantic cod (Gadus morhua) at the Norwegian Skagerrak coast. 3. Significant relationships between ocean temperature and habitat selection and use were found. Under favourable sea temperature thresholds (<16 °C), cod selected vegetated habitats, such as eelgrass and macroalgae beds, available in shallow areas. S…
Resistance of seagrass habitats to ocean acidification via altered interactions in a tri-trophic chain
2020
Despite the wide knowledge about prevalent effects of ocean acidification on single species, the consequences on species interactions that may promote or prevent habitat shifts are still poorly understood. Using natural CO2 vents, we investigated changes in a key tri-trophic chain embedded within all its natural complexity in seagrass systems. We found that seagrass habitats remain stable at vents despite the changes in their tri-trophic components. Under high pCO2, the feeding of a key herbivore (sea urchin) on a less palatable seagrass and its associated epiphytes decreased, whereas the feeding on higher-palatable green algae increased. We also observed a doubled density of a predatory wr…
Shift in Tuna Catches due to Ocean Warming.
2017
Ocean warming is already affecting global fisheries with an increasing dominance of catches of warmer water species at higher latitudes and lower catches of tropical and subtropical species in the tropics. Tuna distributions are highly conditioned by sea temperature, for this reason and their worldwide distribution, their populations may be a good indicator of the effect of climate change on global fisheries. This study shows the shift of tuna catches in subtropical latitudes on a global scale. From 1965 to 2011, the percentage of tropical tuna in longliner catches exhibited a significantly increasing trend in a study area that included subtropical regions of the Atlantic and western Pacifi…
Evolution of Hemoglobin Genes in Codfishes Influenced by Ocean Depth
2017
AbstractUnderstanding the genetic basis of adaptation is one of the main enigmas of evolutionary biology. Among vertebrates, hemoglobin has been well documented as a key trait for adaptation to different environments. Here, we investigate the role of hemoglobins in adaptation to ocean depth in the diverse teleost order Gadiformes, with species distributed at a wide range of depths varying in temperature, hydrostatic pressure and oxygen levels. Using genomic data we characterized the full hemoglobin (Hb) gene repertoire for subset of species within this lineage. We discovered a correlation between expanded numbers of Hb genes and ocean depth, with the highest numbers in species occupying sha…
Best performances by men and women open-water swimmers during the ‘English Channel Swim’ from 1900 to 2010
2012
Eichenberger, Evelyn | Knechtle, Beat | Knechtle, Patrizia | Ruest, Christoph Alexander | Rosemann, Thomas | Lepers, Romuald; International audience; ''Little research has examined ultra-endurance swimming performances. The 'English Channel Swim', where swimmers have to cover a distance of 32 km between England and France represents a unique long-distance, open-water, sea-swimming challenge, and each year swimmers from all over the world try to succeed in this challenge. The best times in minutes and the nationality of successful men and women swimmers were analysed from 1900 to 2010. A total of 1,533 swimmers (455 women and 1,078 men) from more than 40 countries have successfully completed…
Deep-Sea Bioluminescence Blooms after Dense Water Formation at the Ocean Surface
2013
The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June 2010 at the ANTARES underwater neutrino telescope in the deep NW Mediterranean Sea, jointly with synchronous hydrological records. This is the longest continuous time-series of deep-sea bioluminescence ever recorded. Our record reveals several weeks long, seasonal bioluminescence blooms with light intensity up to two orders of magnitude higher than background values, which correlate to changes in th…
Energetic coupling between plastids and mitochondria drives CO2 assimilation in diatoms.
2015
International audience; Diatoms are one of the most ecologically successful classes of photosynthetic marine eukaryotes in the contemporary oceans. Over the past 30 million years, they have helped to moderate Earth's climate by absorbing carbon dioxide from the atmosphere, sequestering it via the biological carbon pump and ultimately burying organic carbon in the lithosphere. The proportion of planetary primary production by diatoms in the modern oceans is roughly equivalent to that of terrestrial rainforests. In photosynthesis, the efficient conversion of carbon dioxide into organic matter requires a tight control of the ATP/NADPH ratio which, in other photosynthetic organisms, relies prin…
Paleoceanography of the Late Cretaceous northwestern Tethys Ocean: Seasonal upwelling or steady thermocline?
2020
In this study we attempted to assess whether seasonal upwelling or a steady thermocline persisted at the western margin of the Tethys Ocean during the late Turonian-early Coniacian interval. For this scope, we employed novel and published stable oxygen isotope (δ18O) data of various organisms (bivalves, bivalves, brachiopods, fish and belemnites). New seasonally resolved temperature estimates were based on the δ18O record of sequentially sampled inoceramid (Inoceramus sp.) and rudist (Hippurites resectus) shells from the Scaglia Rossa and Gosau deposits of northern Italy and western Austria, respectively. Diagenetic screening was performed using reflected light, cathodoluminescence (CL), sc…
Bioaccumulation of hepatotoxins : A considerable risk in the Latvian environment
2014
Abstract The Gulf of Riga, river Daugava and several interconnected lakes around the City of Riga, Latvia, form a dynamic brackish-freshwater system favouring occurrence of toxic cyanobacteria. We examined bioaccumulation of microcystins and nodularin-R in aquatic organisms in Latvian lakes, the Gulf of Riga and west coast of open Baltic Sea in 2002–2007. The freshwater unionids accumulated toxins efficiently, followed by snails. In contrast, Dreissena polymorpha and most lake fishes (except roach) accumulated much less hepatotoxins. Significant nodularin-R concentrations were detected also in marine clams and flounders. No transfer of nodularin-R and microcystins between lake and brackish …
Effect ofMicrocystis aeruginosa andNodularia spumigena on survival ofEurytemora affinis and the embryonic and larval development of the Baltic herrin…
2003
Laboratory experiments were carried out to investigate the effect of two strains of Microcystis aeruginosa and a strain of Nodularia spumigena on the survival of Eurytemora affinis (Copepoda) and on the embryonic and larval development of the Baltic spring-spawning herring Clupea harengus membras. The trials were made in water taken from Parnu Bay, at a salinity of 3.7–5.1 psu, a constant temperature (15°C ± 1°C in trials with Eurytemora and herring embryos; 18°C ± 2°C with herring larvae), and an oxygen concentration of 8.8–10.4 ppm. The strains tested had a negative impact on the survival of Eurytemora, as well as on the embryonic development and hatching regime of the Baltic herring. In …