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Science Friday: Beyond the Sea

This is a post on the mostly dire state of the oceans, the first article documents the over-fishing of the Atlantic; the 2nd, is a report on a study by the International Programme on the State of the Ocean on how human action has resulted in warming, acidification and increased hypoxia; the 3rd, talks about how the California Current teems with life; and lastly, a youtube of the song, Beyond the Sea

What were the oceans like before over-fishing? David McCandless visualises the Atlantic's past

    It's hard to imagine the damage over-fishing is wrecking on the oceans. The effects are literally invisible, hidden deep in the ocean. But there is data out there. And when you visualise it, the results are shocking.

    This image shows the biomass of popularly-eaten fish in the North Atlantic Ocean in 1900 and in 2000. Popularly eaten fish include: bluefin tuna, cod, haddock, hake, halibut, herring, mackerel, pollock, salmon, sea trout, striped bass, sturgeon, turbot. Many of which are now vulnerable or endangered.

    Dr Villy Christensen and his colleagues at the University Of British Columbia used ecosystem models, underwater terrain maps, fish catch records and statistical analysis to render the biomass of Atlantic fish at various points this century (see the study)



The state of the ocean (dire)

    Alex Rogers, Professor of Conservation Biology at the Department of Zoology at Oxford, and scientific director of the International Programme on the State of the Ocean describes the main problems affecting the global ocean — and discusses some of the things we could do to address them in this new video. The IPSO has just launched the summary of its forthcoming report on the state of the oceans1 — PDF here. The key findings make sobering reading:

    • Human actions have resulted in warming and acidification of the oceans and are now causing increased hypoxia.
    • The speeds of many negative changes to the ocean are near to or are tracking the worst case scenarios from IPCC and other predictions. Some are as predicted, but many are faster than anticipated, and many are still accelerating.
    • The magnitude of the cumulative impacts on the ocean is greater than previously understood.
    • Timelines for action are shrinking.
    • Resilience of the ocean to climate change impacts is severely compromised by other stressors from human activities, including fisheries, pollution and habitat destruction.
    • Ecosystem collapse is occurring as a result of both current and emerging stressors.
    • The extinction threat to marine species is rapidly increasing.

    The bottom line is not pretty:

    [...] we now face losing marine species and entire marine ecosystems, such as coral reefs, within a single generation. Unless action is taken now, the consequences of our activities are at a high risk of causing, through the combined effect of climate change, over exploitation, pollution and habitat loss, the next globally significant extinction event in the ocean.


Teeming With Life, Pacific's California Current Likened to Africa's Serengeti Plain

    ScienceDaily (June 22, 2011) — Like the vast African plains, two huge expanses of the North Pacific Ocean are major corridors of life, attracting an array of marine predators in predictable seasonal patterns, according to final results from the Census of Marine Life Tagging of Pacific Predators (TOPP) project published June 22 in the journal Nature.

    The paper culminates the TOPP program's decade-long effort to track top marine predator movements in the Pacific Ocean. It presents for the first time the results for all 23 tagged species and reveals how migrations and habitat preferences overlap -- a remarkable picture of critical marine life pathways and habitats.

    The study found that major hot spots for large marine predators are the California Current, which flows south along the US west coast, and a trans-oceanic migration highway called the North Pacific Transition Zone, which connects the western and eastern Pacific on the boundary between cold sub-arctic water and warmer subtropical water -- about halfway between Hawaii and Alaska.

    "These are the oceanic areas where food is most abundant, and it's driven by high primary productivity at the base of the food chain -- these areas are the savanna grasslands of the sea," say co-authors and project originators Barbara Block of Stanford University's Hopkins Marine Station and Daniel Costa, professor of ecology and evolutionary biology at the University of California, Santa Cruz.

    "Knowing where and when species overlap is valuable information for efforts to manage and protect critical species and ecosystems."