Navigation Links
Nitrogen fixation and phytoplankton blooms in the southwest Indian Ocean

Observations made by Southampton scientists help understand the massive blooms of microscopic marine algae phytoplankton in the seas around Madagascar and its effect on the biogeochemistry of the southwest Indian Ocean.

The observations were made by researchers based at the National Oceanography Centre, Southampton (NOCS) during a 2005 hydrographic survey south and east of Madagascar while aboard the royal research ship RRS Discovery. The fully analysed results are published in the journal Geophysical Research Letters.

Nitrogen-fixing bacteria convert atmospheric nitrogen into nitrogen compounds that organisms can then use as food. This process is thought to be important in areas of the ocean where nitrogen-based nutrients are otherwise in short supply, and the researchers confirm that this is indeed the case in the region south of Madagascar.

But there were some surprises. Previously, it has been thought that the large-scale autumn bloom that develops in this region is driven by nitrogen-fixing blue-green algae, or cyanobacteria, called Trichodesmium, colonies of which the researchers found to be abundant. However, the 2005 bloom was dominated by a diatom a type of phytoplankton the cells of which play host to another nitrogen-fixing cyanobacterium called Richella intracellularis, with Trichodesmium apparently playing second fiddle.

Diatoms have relatively large cells, and when they die they sink down the water column, carrying with them carbon that is ultimately derived from carbon dioxide drawn from the atmosphere though the process of photosynthesis. "Carbon dioxide is a greenhouse gas, and enhanced export of carbon to the deep ocean in the bodies of diatoms is an important natural mechanism by which the ocean regulates atmospheric carbon dioxide and our climate," says team member Dr Alex Poulton of NOCS.

The researchers believe that their findings will have an impact on modelling and satellite studies of the Madagascar bloom. "Future research will also need to account for the magnitude of carbon export associated with diatoms and their nitrogen-fixing guests in the southwest Indian Ocean, and indeed other subtropical oceanic settings," says Dr Poulton.


Contact: Dr. Rory Howlett
National Oceanography Centre, Southampton (UK)

Related biology news :

1. Ozone, nitrogen change the way rising CO2 affects Earths water
2. Nitrogen research shows how some plants invade, take over others
3. UC Davis begins $2.8 million in studies of agricultural nitrogens impacts
4. Illinois Soil Nitrogen Test measures microbial nitrogen
5. Tree species composition influences nitrogen loss from forests
6. Researchers call for nitrogen and phosphorus reductions to combat eutrophication in aquatic systems
7. Cropland diversity reduces nitrogen pollution
8. Lichens function as indicators of nitrogen pollution in forests
9. Nitrogen applied
10. A little nitrogen can go a long way
11. EPA releases science assessment on health effects of nitrogen oxides
Post Your Comments:
(Date:11/9/2015)... , Nov. 9, 2015  Synaptics Inc. (NASDAQ: ... today announced broader entry into the automotive market with ... match the pace of consumer electronics human interface innovation. ... are ideal for the automotive industry and will be ... Europe , Japan ...
(Date:10/29/2015)... 29, 2015 Daon, a global leader in ... released a new version of its IdentityX Platform ... North America have already installed IdentityX v4.0 ... a FIDO UAF certified server component as ... activate FIDO features. These customers include some of the ...
(Date:10/27/2015)... In the present market scenario, security is ... industry verticals such as banking, healthcare, defense, electronic gadgets, ... for secure & simplified access control and growing rate ... of bank accounts, misuse of users, , and so ... laptops, and smartphones are expected to provide potential opportunities ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... - iCo Therapeutics ("iCo" or "the Company") (TSX-V: ICO) ... quarter ended September 30, 2015. Amounts, unless specified ... under International Financial Reporting Standards ("IFRS"). ... Andrew Rae , President & CEO of iCo ... value enriching for this clinical program, but also ...
(Date:11/24/2015)... ... November 24, 2015 , ... ... the year and one of the premier annual events for pharmaceutical manufacturing: 2015 ... 8–11 November 2015, where ISPE hosted the largest number of attendees in more ...
(Date:11/24/2015)... , Nov. 24, 2015  Clintrax Global, Inc., a worldwide provider ... , today announced that the company has set a new ... 391% quarter on quarter growth posted for Q3 of 2014 to ... and Mexico , with the establishment of an ... 2015. --> United Kingdom and ...
(Date:11/24/2015)... ... November 24, 2015 , ... This fall, global software solutions leader SAP ... states to develop and pitch their BIG ideas to improve health and wellness in ... for votes to win the title of SAP's Teen Innovator, an all-expenses paid trip ...
Breaking Biology Technology: