• Ongoing global warming could persist far into the future, because natural processes require decades to hundreds of thousands of years to remove carbon dioxide from fossil-fuel burning from the atmosphere. Future warming may have large global impacts including ocean oxygen depletion and associated adverse effects on marine life, such as more frequent mortality events, but long, comprehensive simulations of these impacts are currently not available. Here we project global change over the next 100,000 years using a low-resolution Earth system model, and find severe, long-term ocean oxygen depletion, as well as a great expansion of ocean oxygen-minimum zones for scenarios with high emissions or high climate sensitivity. We find that climate feedbacks within the Earth system amplify the strength and duration of global warming, ocean heating and oxygen depletion. Decreased oxygen solubility from surface-layer warming accounts for most of the enhanced oxygen depletion in the upper 500 m of the ocean. Possible weakening of ocean overturning and convection lead to further oxygen depletion, also in the deep ocean. We conclude that substantial reductions in fossil-fuel use over the next few generations are needed if extensive ocean oxygen depletion for thousands of years is to be avoided.

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  Crustaceans rule!

• Massive releases of methane from arctic seafloors could create oxygen-poor dead zones, acidify the seas and disrupt ecosystems in broad parts of the northern oceans, new preliminary analyses suggest.

      

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  Such a cascade of geochemical and ecological ills could result if global warming triggers a widespread release of methane from deep below the Arctic seas, scientists propose in the June 28 Geophysical Research Letters.

   

  Worldwide, particularly in deeply buried permafrost and in high-latitude ocean sediments where pressures are high and temperatures are below freezing, icy deposits called hydrates hold immense amounts of methane (SN: 6/25/05, p. 410). Studies indicate that seafloor sediments beneath the Kara, Barents and East Siberian seas in the Arctic Ocean, as well as the Sea of Okhotsk and the Barents Sea in the North Pacific, have large reservoirs of the planet-warming greenhouse gas, says study coauthor Scott M. Elliott, a marine biogeochemist at Los Alamos National Laboratory in New Mexico.
• That methane would be an unexpected bounty for methane-munching marine microbes that consume dissolved oxygen and produce carbon dioxide. As a result, the researchers’ model suggests, the waters down-current of a large methane plume, especially in an ocean basin with poor circulation, could lose as much as 95 percent of their oxyg

• Besides generating large volumes of acidified water and low-oxygen dead zones, the microbial activity will rob the waters of key nutrients — including nitrate, copper and iron — that otherwise would be used by microorganisms that don’t feed on methane. Many of these nutrients are already sparse, and the resulting shift in populations among the fiercely competitive microorganisms at the base of the ocean’s food chain in many regions could be devastating, the researchers suggest.

   

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• Much of the spill - estimated at up to 182 million gallons of oil and around 12 billion cubic feet of natural gas - was broken into small droplets by chemical dispersants at the site of the leaking well head. That reduced the direct impact to the shoreline and kept much of the oil and natural gas suspended in the water.

   

  But immature crabs born offshore are suspected to be bringing that oil - tucked into their shells - into coastal estuaries from Pensacola, Fla., to Galveston, Texas. Oil being carried by small organisms for long distances means the spill's effects could be wider than previously suspected, said Tulane professor Caz Taylor.

   

  Chemical oceanographer John Kessler from Texas A&M University and geochemist David Valentine from the University of California-Santa Barbara recently spent about two weeks sampling the waters in a six-mile radius around the BP-operated Deepwater Horizon rig. More than 3,000 feet below the surface, they found natural gas levels have reached about 100,000 times normal, Kessler said.

• The death of pyrosomes could set off a ripple effect. One species that could be directly affected by what is happening to the pyrosomes would be sea turtles, said Laurence Madin, a research director at the Woods Hole Oceanographic Institution in Cape Cod, Mass. Some larger fish, such as tuna, may also feed on pyrosomes.

   

  "If the pyrosomes are dying because they've got hydrocarbons in their tissues and then they're getting eaten by turtles, it's going to get into the turtles," said Madin. It was uncertain whether that would kill or sicken the turtles.

• Scientists have discovered that the phytoplankton of the oceans has declined by about 40 per cent over the past century, with much of the loss occurring since the 1950s. They believe the change is linked with rising sea temperatures and global warming.

  If the findings are confirmed by further studies it will represent the single biggest change to the global biosphere in modern times, even bigger than the destruction of the tropical rainforests and coral reefs, the scientists said yesterday.
• "If this holds up, something really serious is underway and has been underway for decades. I've been trying to think of a biological change that's bigger than this and I can't think of one," said marine biologist Boris Worm of Canada's Dalhousie University in Halifax, Nova Scotia. He said: "If real, it means that the marine ecosystem today looks very different to what it was a few decades ago and a lot of this change is happening way out in the open, blue ocean where we cannot see it. I'm concerned about this finding."

• Because of the central importance of photosynthesis to biological processes in the sea, the rate at which it proceeds is called primary production.

  In addition to being the foodstock for ocean life, the tiny phytoplankton are mighty geochemical factories. Our present atmosphere, and in particular the oxygen that sustains most animals, is almost entirely derived from the activities of photosynthetic bacteria living some 2.5 billion years ago. The oil and gas deposits that we exploit to fly our planes, drive our cars and heat our houses were produced by the sinking and burial of phytoplankton in the geological past. The absorption of solar energy warms and stabilises the upper ocean and as a result affects circulation in both atmosphere and ocean.

  The phytoplankton exhibit a vast diversity of species, and range in size from less than a micron to half a millimeter – a factor of over 1,000. Many are really bacteria, while others have all of the cellular machinery commonly found in higher plants. They have diversity in metabolism as well, with some species able to not only photosynthesise, but also to ingest other organisms. Some species produce dimethyl sulphide, which has been implicated as a cloud-forming compound in the atmosphere. Still others are toxic, and contribute to illness and many human deaths each year.

• The study estimates the decline in marine algae has been approximately 40 percent since 1950.

   

  “I think that if this study holds up, it will be one of the biggest biological changes in recent times simply because of its scale,” said Worm. “The ocean is two-thirds of the earth’s surface area, and because of the depth dimension it is probably 80 to 90 percent of the biosphere. Even the deep sea depends on phytoplankton production that rains down. On land, by contrast, there is only a very thin layer of production.”

• And here's the sirens blaring version from Michael O'Hare:

   

   

  This finding — and I’m trying hard not to hyperventilate here — is not too far down the scary scale from discovering a small inbound asteroid. This is the whole ocean we’re talking about: the earth’s production of organic material is going down half a percent per year.

   

  ....We can’t live without the ocean, every time we look at climate change it’s worse than we thought....We are so f____ed.

• In effect, warming surface waters have acted as a lid, preventing deeper, nutrient-rich waters from mixing upward to feed phytoplankton at the surface.

  Too dramatic too be believed?

  While Boyce says the process of gathering and analyzing the information was a challenge, colleague Marlon Lewis says that for him, the most difficult part of the study was was believing the results.

  "The toughest hurdle I had was coming to grips with the results," Dr. Lewis says. "We sent Daniel back I can't tell you how many times to redo the calculations or look at it in different ways."

  In the end, however, the results held.

• The State of the Climate 2009 report, published Wednesday as a special supplement to the Bulletin of the American Meteorological Society, was compiled by 300 scientists from 48 countries and drew on measures of 10 crucial climate indicators.

• The scientists reported that they were surprised to find Greenland's glaciers were losing ice at an accelerating rate. They also concluded that 90% of planetary warming over the past 50 years has gone into the oceans. Most of it had accumulated in near-surface layers, home to phytoplankton, tiny plants crucial to virtually all life in the sea.

  A new study has found that rising sea temperature may have had a harmful effect on global concentrations of phytoplankton over the past century.

• Halifax, Nova Scotia, Canada (AHN) - A Dalhousie University study released on Wednesday showed that the world’s phytoplankton population is down by 40 percent in 60 years. Study lead author Boris Worm explained the population decline to rising sea surface temperatures and changing water conditions.

• Worm said the phytoplankton are critical to planetary life-support it produces half of the oxygen humans breathe. Seabirds, fish and tiny zooplankton are among the marine population that feed on phytoplankton. With the population decline, everything in the food chain is affected, according to the three-year study.

  Over the past six decades, the decline translated into a 40 percent drop in phytoplankton population. The population decline was observed in eight of 10 ocean regions.

  Boyce said in a statement, “Phytoplankton is also important in maintaining sustainable fisheries operations and the overall health of the ocean. We need to make sure that the numbers do not continue to decline.”