Crabs Are Getting Bigger - Is Carbon Dioxide to Blame?

A recent study of blue crabs from the Chesapeake Bay and other areas shows that crabs and other crustaceans are growing at up to four times their normal rate. But the same conditions are causing oysters and scallops to grow at a rate of one–fourth of their normal speed. So what’s causing this ecological chaos? It looks like it’s carbon dioxide that is gradually falling from the air into the world’s oceans. And that’s bad news for the oysters.

A research team from the University of North Carolina’s Aquarium Research Center, led by marine geologist Justin Baker Ries conducted a study in 2009 in which they raised crabs in high- carbon tanks. They found that the creatures grew bigger and bigger, but that they actually ate fewer oysters. They also found that while the animals grew bigger and faster, which helped make them less vulnerable to predators, they spent much of their energy producing new shells rather than gaining flesh.

Oysters and scallops, on the other hand, are growing much more slowly than normal because of the same carbon dioxide levels. Smaller oysters are easier prey, so the number of survivors living to adulthood is almost certain to be lower than it was in the past despite the crabs’ loss of appetite.

Maryland and Virginia have worked hard to improve oyster populations in Chesapeake Bay.  One of the reasons is that oysters filter pollutants from the bay’s waters. Over the last hundred years, however, drops in oyster populations have reduced the filtering cycle in the bay from once every three weeks to approximately once every three years. Some experts predict the current trend will continue so long as atmospheric carbon dioxide levels continue to rise.

It is hoped that a way will be found to stabilize the Chesapeake Bay ecosystem. Oysters help to increase biodiversity in the bay’s environment and are credited with helping to reduce erosion on shorelines.

Seafood lovers are also losing out. Even though the crustaceous are growing faster, they are no meatier than their ancestors. Fewer, smaller scallops and oysters also will negatively impact the fishing industry.

Can the denizens of Chesapeake Bay and other affected areas adjust to the new levels of carbon dioxide in time? We can only hope that “life finds a way.”

There’s more discussion about the crabs and their potential effect on Chesapeake Bay here

Antarctica’s Ancient Rainforest - What It Might Teach Us About Global Warming

If you think it’s warm now, you should have been here around 52 million years ago. Back then you could have basked beneath palm trees on the coast of Antarctica in an area that’s now under about 1.9 to 2.5 miles (3 to 4 kilometers) of ice.

Rock samples obtained from the seabed off the coast of Wilkes Land, Antarctica were found to contain fossil pollen and spores that included palm pollen and another type of pollen from trees related to today’s baobab trees. They also found evidence of bacteria which would have lived in the soils along the Antarctic coast at the time. They concluded that average temperatures at the time were about 68 degrees Fahrenheit or roughly 20 degrees Celsius. Although they believe that the interior was somewhat colder due to higher elevations and would have been populated with the ancesstors of trees that can be found today in places like New Zealand.

Some climatologists concluded that this warming period, which lasted roughly from 53 to 46 million years ago, was likely caused by high levels of carbon dioxide in the atmosphere. They estimate that concentrations at the time ranged somewhere between 990 to a few thousand parts per million compared with today’s carbon dioxide level, which is estimated at about 395 ppm. If the warming effects of high carbon dioxide levels are a primary cause of global warming, the earth was much warmer at that time than it is today.
There is an interesting concept here. Human beings weren’t around 53 million years ago to burn fossil fuels, which is currently thought to be behind the current rise in carbon dioxide levels. Therefore, it seems logical that some other mechanism besides man may be at fault. Throughout this planet’s history, there have been both glacial and interglacial periods. Some of the interglacial periods were in fact generally much warmer than those we are experiencing now. And it is likely that local weather conditions during those times were as severe and threatening as those being faced in much of the world today. What does that mean for mankind? Climatologists are still divided, of course. As for the rest of us, it seems that the only thing we can do is wait and see.

There are two interesting articles about the Antarctica findings and their possible significance to climate change. One is here, the other is here.
If you’re interested in finding out about other natural forces that can cause climate change, visit here