NEW PAPER SAYS COASTAL OCEANS ACT AS A CARBON SINK
This story is brought to you in part by Glenergy
By Ronan O'Doherty
It has been long known that the open ocean has been acting as a buffer against climate change by removing a great quantity of carbon from the atmosphere; what a new paper posits is that the coastal oceans are also serving as considerable carbon sinks too.
The paper, which was published on January 31 in Nature Communications, is the work of a team of scientists from Belgium, Hawaii, the United States and Switzerland.
Wei Jun Cai, one of the key authors of the paper, is an Oceanographer with the University of Delaware who has spent almost his entire career studying coastal oceans, which is the water sitting on top of continental shelves.
"In the early 2000s I was one of the first to do a global compilation and synthesis to look at whether the coastal ocean is a sink or a source of CO2," Dr. Cai said, "In the last 10 to 15 years we've had more and more data accumulating to allow us to say coastal ocean is a CO2 sink."
Peers of the scientists were a little wary of findings. When the paper was first submitted, Dr. Cai said that his team was sharply criticised by other oceanographers who were saying there's not enough data in coastal ocean research to look at this issue correctly.
"We looked exhaustively and checked our statistics again and again and they show that more coastal oceans were taking up more C02."
Dr. Cai and his team only took data from areas where there was at least 10 years of observation. Often times in locations that had been surveying for ocean acidification.
Although it cannot be said with certainty what causes the coastal ocean to act as a sink for CO2, Dr. Cai has a couple ideas.
"The coastal ocean is so small, so it can't just take up CO2," Dr. Cai said, "It has to send the C02 that it takes from the atmosphere to somewhere and that somewhere is the deep ocean because there is a rapid exchange between the coastal ocean and the deep open ocean, so that opens up a new pathway for the open ocean to take up CO2 via the coastal ocean pathway."
In addition, it would appear that human involvement in the coastal ocean makes a difference too.
"We humans are sending more nutrients into the coastal ocean because our activities promote biological production in coastal oceans that could turn CO2 into organic carbon and then send it to the open ocean."
It is odd that our agricultural and human waste would help balance out the CO2 we release into the air but the CO2 does lead to more acidification of the ocean, which in the long run could be catastrophic to the many life forms it supports.
"On a global scale for the earth system model, people still haven't seriously taken the coastal ocean into the whole picture, so I hope this paper will motivate people to do so," Dr. Cai said.