More Trophic Cascade Collapse ...Tiny Invertebrates Spell Big Trouble for Southern Ocean Fishhttps://phys.org/news/2019-02-nutritious-diet-southern-ocean-fish.htmlLike collapsing ice shelves, the surge of barrel-bodied salps in the Southern Ocean tells us that other life forms in Antarctica and its surrounding waters are in decline. Blooms of a gelatinous plankton, known as salp, have been identified in waters south of 60°S, in the Indian Sector of the Southern Ocean, by researcher Paige Kelly
... "In the Southern Ocean, waters south of 60°S are typically full of Antarctic krill, which are a crucial food source for mammals and fish," says Paige, a Ph.D. student at the Institute for Marine and Antarctic Studies and Antarctic Climate and Ecosystems Cooperative Research Centre.
"The presence of salps so far south means that these mammals and fish might have to eat salps instead of krill. And this could have serious consequences for the ecosystem."
The consumption of these East Antarctic salps—which contain less than one third of the calories and protein of krill—could change the weight, reproduction and behaviour of commercially fished species that prefer to feed on krill.
When salps are abundant, Antarctic krill are scarce. Krill are a keystone species here. Everything eats them directly or indirectly. Penguins, baleen whales, seals, seabirds and fish, even krill eat krill. No krill, no Antarctica.Since the 1970s krill populations have dropped by as much as 70 per cent in their most critical habitat, the southwest Atlantic sector of the Southern Ocean. Krill, especially juveniles, depend on sea ice subsurface matrix of brine channels and crevices, a microcosm of life where innumerable plankton live, feed and hide from predators. Summer krill abundance is correlated with the extent of the previous winter's sea ice.

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Dutch Scientists Probing Mystery of Mass Bird Deathshttps://phys.org/news/2019-02-dutch-scientists-probing-mystery-mass.html... Why, for example, are only guillemots dying all along the Dutch coastline? Leopold said he has received no similar reports from Belgium or Germany. "They are pretty robust birds," he said, but now, dead birds are washing up "in their thousands"
"That's pointing out that there is something wrong at sea, and that's alarming."