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Showing posts with the label Oceans

Genetic clocks in zooplankton species regulate what is likely the largest daily movement of biomass worldwide

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The copepod species Calanus finmarchicus schedules its day using a genetic clock that works independently of external stimuli. The clock shapes the copepod's metabolic rhythms and daily vertical migration. This, in turn, has an enormous influence on the entire food web in the North Atlantic, where Calanus finmarchicus is a central plankton species. Wherever the high-calorie copepod is found determines where its predator species are. The results of the study will be published in the journal Current Biology . Calanus finmarchicus is a central plankton species with an enormous influence on the entire food web  in the North Atlantic [Credit: Alfred Wegener Institute] The world's oceans are home to a massive vertical migration. At dusk, countless plankton species, like copepods and krill, rise to the surface, where they gorge themselves on single-celled algae that can only thrive where there is sufficient sunlight. The cover of night offers the plankton protection from predators lik

Climate change deepens threat to Pacific island wildlife

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Land mammals and reptiles in the Pacific islands facing extinction due to habitat loss, hunting and other threats could be decimated by climate change, a study published Thursday said. Climate change poses a serious threat to Pacific island wildlife, such as on the Marshall Islands,  pictured in March 2016 when the islands flooded, from storms [Credit: AFP] Ocean-bound wildlife is particularly vulnerable to environmental pressures, especially endemic species living on only one or a handful of islands. Among other things, this remoteness makes migrating to another land mass nearly impossible. Dozens of species -- especially birds -- have also been wiped out over the last century by invasive species and disease brought by human settlers. For most Pacific island vertebrates -- animals with a backbone -- the current risk of extinction has been measured and catalogued in the Red List of threatened species, maintained by the International Union for the Conservation of Nature (IUCN). Scientis

Big, shape-shifting animals from the dawn of time

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Why did life on Earth change from small to large when it did? Researchers from the University of Cambridge and the Tokyo Institute of Technology have determined how some of the first large organisms, known as rangeomorphs, were able to grow up to two metres in height, by changing their body size and shape as they extracted nutrients from their surrounding environment. Artist's impression of rangeomorphs [Credit: Jennifer Hoyal Cuthill] The results, reported in the journal Nature Ecology and Evolution , could also help explain how life on Earth, which once consisted only of microscopic organisms, changed so that huge organisms like dinosaurs and blue whales could ultimately evolve. Rangeomorphs were some of the earliest large organisms on Earth, existing during a time when most other forms of life were microscopic in size. Some rangeomorphs were only a few centimetres in height, while others were up to two metres tall. These organisms were ocean dwellers that lived during the Ediaca

Rising temperatures are curbing ocean's capacity to store carbon

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If there is anywhere for carbon dioxide to disappear in large quantities from the atmosphere, it is into the Earth’s oceans. There, huge populations of plankton can soak up carbon dioxide from surface waters and gobble it up as a part of photosynthesis, generating energy for their livelihood. When plankton die, they sink thousands of feet, taking with them the carbon that was once in the atmosphere, and stashing it in the deep ocean. MIT climate scientists have found that the ocean’s export efficiency, or the fraction of total plankton growth  that is sinking to its depths, is decreasing, due mainly to rising global temperatures [Credit: MIT News] The oceans, therefore, have served as a natural sponge in removing greenhouse gases from the atmosphere, helping to offset the effects of climate change. But now MIT climate scientists have found that the ocean’s export efficiency, or the fraction of total plankton growth that is sinking to its depths, is decreasing, due mainly to rising glob

Genetic clocks in zooplankton species regulate what is likely the largest daily movement of biomass worldwide

Image
The copepod species Calanus finmarchicus schedules its day using a genetic clock that works independently of external stimuli. The clock shapes the copepod's metabolic rhythms and daily vertical migration. This, in turn, has an enormous influence on the entire food web in the North Atlantic, where Calanus finmarchicus is a central plankton species. Wherever the high-calorie copepod is found determines where its predator species are. The results of the study will be published in the journal Current Biology . Calanus finmarchicus is a central plankton species with an enormous influence on the entire food web  in the North Atlantic [Credit: Alfred Wegener Institute] The world's oceans are home to a massive vertical migration. At dusk, countless plankton species, like copepods and krill, rise to the surface, where they gorge themselves on single-celled algae that can only thrive where there is sufficient sunlight. The cover of night offers the plankton protection from predators lik

Climate change deepens threat to Pacific island wildlife

Image
Land mammals and reptiles in the Pacific islands facing extinction due to habitat loss, hunting and other threats could be decimated by climate change, a study published Thursday said. Climate change poses a serious threat to Pacific island wildlife, such as on the Marshall Islands,  pictured in March 2016 when the islands flooded, from storms [Credit: AFP] Ocean-bound wildlife is particularly vulnerable to environmental pressures, especially endemic species living on only one or a handful of islands. Among other things, this remoteness makes migrating to another land mass nearly impossible. Dozens of species -- especially birds -- have also been wiped out over the last century by invasive species and disease brought by human settlers. For most Pacific island vertebrates -- animals with a backbone -- the current risk of extinction has been measured and catalogued in the Red List of threatened species, maintained by the International Union for the Conservation of Nature (IUCN). Scientis