Ocean Blog

The last time the Arctic was completely free of ice, during the Pliocene Era about 3.5 million years ago, an ice-free passage across the Arctic facilitated the movement of mollusks into the North Atlantic. The open water route was rich with floating phytoplankton, which fed the mollusks during their traverse. When Arctic temperatures cooled, the path was blocked and the phytoplankton declined.

Well, here we go again.

Scientists believe this invasion may soon be repeated if global warming persists at its current rate, most likely causing the Arctic to become ice-free by or before 2050. This would once again allow the invasion of shellfish and other mollusks, along with algae, fish, barnacles, and other marine organisms into the North Atlantic from the Pacific via the Bering Sea causing a shift in the area's biodiversity.

Interestingly, the overall consequences of a mollusk invasion on the North Atlantic ecosystem remain uncertain, but shifts in the abundance of some species are anticipated.

Poor coral.

With global warming-generated ocean acidification already hindering the essential production of the calcium carbonate (CaCO3) skeletons in coral species, scientists now suspect another threat to corals and reef ecosystems caused by climate change.

You probably know methane as the stinky greenhouse gas. It's potent, long-lived, and is released from places like agricultural lands and wetlands. But a new study published in Nature discusses how the gas may also be released from destabilized clathrates, or forms of methane that are stabilized beneath ice sheets.

The New York Times reports that diplomats from the United States, Canada, Russia, Norway, and Denmark recently came to agreements about the possibility that global warming will make Arctic waters more accessible to shipping fleets and energy extractors.

And you thought DDT was a thing of the past...

Although worldwide use of DDT has decreased from 40,000 tons per year in 1980 to 1,000 tons per year today, with the U.S. banning most uses in 1972, DDT is still showing up in the Antarctic. Spurred by global warming, previously frozen insecticide particles are being released through glacier meltdown.

Ocean water dissolving the shells of marine life? Sounds like the plot of a science fiction movie, but for many shelled marine organisms it's a reality due to anthropogenic emissions of carbon dioxide. With the atmospheric concentration of carbon dioxide at its highest point in the last 650,000 years, the oceans are becoming more acidic as the water turns carbon dioxide into carbonic acid.

Continued carbon emissions are increasing the acidity of the oceans; in fact, approximately a third of anthropogenic carbon emissions are absorbed by the oceans each year. Scientists worry that not enough research has been done on the possible effects that ocean acidification will have on marine wildlife, ecosystems and food webs.

The global shipping fleet is a major emitter of carbon dioxide and other global

A new series of reports from USGS suggest that two thirds of the world's polar bear population could be gone within 50 years. As the sea ice continues to recede with warming temperatures the polar bears will find it increasingly difficult to hunt.

Some commentators have suggested that this report is conservative and that Arctic sea ice could be a thing of the past by 2030, suggesting that polar bear losses could happen much earlier than 2050. You can read the press release from USGS here.

Scientists recently declared that the first victim to become extinct due to climate change has finally succumbed.

The purple or banded snail (Rachistia aldabrae) living on an island in the Seychelles has not been seen, despite extensive surveys, since the 1990s.

The snail was unable to tolerate changes in its environment because of climate change. Unfortunately, this will not be a one-off event; scientists have suggested that over a quarter of all species could be lost due to climate change.

You can read more about the extinction of the purple snail at Mongabay or read the scientific article in Biology Letters.



-- Ellycia is the climate change science fellow at Oceana.