A paper published today in Science reviews the spread of ‘dead zones’, which are regions of the ocean floor that are so deprived of oxygen that marine species can’t survive.
Dead zones are formed when excess nutrients, mostly nitrogen and phosphorus, enter coastal waters and help fertilize blooms of algae. When these tiny plants die and sink to the sea bottom, they provide a food source for bacteria, which consume dissolved oxygen from surrounding waters. As a result, there are large areas of sea floor with insufficient oxygen to support most marine life.
Dead zones are spreading at an alarming rate and have now been reported from more than 245,000 square kilometers.
Reference: Diaz RJ & Rosenberg R. Spreading Dead Zones and Consequences for Marine Ecosystems. Science 15 August 2008: Vol 321. no.5891, p926-929.
More information can be found on the Reuters website.
This study adds to the concern about marine ecosystems highlighted in New Zealand this week by young scientist award winner Rebecca McLeod. McLeod’s research, carried out in Fiordland, raises concerns that marine ecosystems have been impacted and altered by the clearance of coastal forests.
For more information and media coverage of Rebecca’s research, see:
To listen to a podcast of Rebecca’s acceptance speech at the awards ceremony, see the news section of this website.
To interview Rebecca McLeod, please contact Katherine Edmond: 06 877 2170 or 027 274 0465