Featured Research

from universities, journals, and other organizations

Nitrogen Fixation And Phytoplankton Blooms In The Southwest Indian Ocean

Date:
August 19, 2009
Source:
National Oceanography Centre, Southampton (UK)
Summary:
New observations 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.

Researchers based at the National Oceanography Centre, Southampton report on a 2005 hydrographic survey south and east of Madagascar while aboard the royal research ship RRS Discovery
Credit: Image courtesy of National Oceanography Centre, Southampton

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.

Related Articles


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.


Story Source:

The above story is based on materials provided by National Oceanography Centre, Southampton (UK). Note: Materials may be edited for content and length.


Journal Reference:

  1. Poulton, A.J., Stinchcombe, M.C. & Quartly, G.D. High numbers of Trichodesmium and diazotrophic diatoms in the southwest Indian Ocean. Geophysical Research Letters, 2009; 36 (15): L15610 DOI: 10.1029/2009GL039719

Cite This Page:

National Oceanography Centre, Southampton (UK). "Nitrogen Fixation And Phytoplankton Blooms In The Southwest Indian Ocean." ScienceDaily. ScienceDaily, 19 August 2009. <www.sciencedaily.com/releases/2009/08/090814103233.htm>.
National Oceanography Centre, Southampton (UK). (2009, August 19). Nitrogen Fixation And Phytoplankton Blooms In The Southwest Indian Ocean. ScienceDaily. Retrieved December 21, 2014 from www.sciencedaily.com/releases/2009/08/090814103233.htm
National Oceanography Centre, Southampton (UK). "Nitrogen Fixation And Phytoplankton Blooms In The Southwest Indian Ocean." ScienceDaily. www.sciencedaily.com/releases/2009/08/090814103233.htm (accessed December 21, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Sunday, December 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Lava Inches Closer to Highway

Raw: Lava Inches Closer to Highway

AP (Dec. 21, 2014) Officials have opened a new road on Hawaii's Big Island for drivers to take care of their daily needs if encroaching lava from Kilauea Volcano crosses a highway and cuts them off from the rest of the island. (Dec. 20) Video provided by AP
Powered by NewsLook.com
Raw: Scuba Diving Santa Off Florida Keys

Raw: Scuba Diving Santa Off Florida Keys

AP (Dec. 20, 2014) A scuba diving Santa Claus explored the waters of the Florida Keys National Marine Sanctuary. Dive shop owner Spencer Slate makes the dive each year to help raise money for charity. (Dec. 20) Video provided by AP
Powered by NewsLook.com
Obama: Better Ways to Create Jobs Than Keystone Pipeline

Obama: Better Ways to Create Jobs Than Keystone Pipeline

AFP (Dec. 19, 2014) US President Barack Obama says that construction of the Keystone pipeline would have 'very little impact' on US gas prices and believes there are 'more direct ways' to create construction jobs. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Lava on Track to Hit Hawaii Market

Raw: Lava on Track to Hit Hawaii Market

AP (Dec. 19, 2014) Lava from an active volcano on Hawaii's Big Island slowed slightly but stayed on track to hit a shopping center in the small town of Pahoa. (Dec. 19) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins