Navigation Links
Seabed biodiversity of the Straits of Magellan and Drake Passage
Date:1/28/2010

A study of animals visible to the naked eye and living in and on the seabed the 'macrobenthos' of the Straits of Magellan and Drake Passage will help scientists understand the biodiversity, biogeography and ecology of the Magellanic region.

"The biodiversity data are from my very first oceanographic cruise with the Chilean Navy in the Magellanic region in 1997, as an early undergraduate," said Dr Sven Thatje of the University of Southampton's School of Ocean and Earth Science at the National Oceanography Centre, Southampton: "The beauty of this dataset is the comprehensive diversity analysis with probably more than 10 per cent of species new to science." The cruise was part of the Chilean 'Cimar Fiordo III' expedition.

The soft sediments at the seafloor were sampled at depths ranging between 35 and 571 metres using a 'box corer' lowered from the Chilean navy vessel RV Vidal Gormaz. Samples were taken within the Straits of Magellan, the seaway separating mainland South America and the islands of the Tierra Del Fuego archipelago, and the eastern part of the Beagle Channel which separates South America from Antarctica. Samples were also taken from adjacent channels and fjords, some of which had been visited for the first time ever during the cruise.

A total of 173 species or morphological variants of species were identified, including crustaceans, molluscs and echinoderms. But polychaete worms, the group that includes ragworms dug by anglers for bait on sandy beeches at low tide, dominated both in terms of abundance and biomass.

At some locations the abundance of invertebrates peaked at more than 10,000 individuals per square metre, even without counting rare species that were missed or fast moving species that eluded capture. However, abundance, biomass and species richness all decreased with depth, consistent with reports from other regions such as the high Antarctic Weddell and Lazarev Seas.

The animals living at the seafloor depend for food on organic matter that rains down from the overlying ocean. "Variation in this flux of organic matter from the pelagic to the benthic is probably the major factor structuring these communities," said Dr Thatje.

It has been argued for the polychaetes of the Pacific coast of South America that shallow areas act as sources of colonisation, helping to maintain species diversity in deeper regions in the face of local extinction. "Such colonisation-extinction dynamics may also explain the patterns of diversity that we see in the Magellanic region," said Dr Thatje.

The Magellanic region was covered by ice 21,000 years ago, and the sea level was much lower than it is today. The Straits of Magellan probably did not fully open until approximately 7,000 years ago, after the ice had receded. The species now present in Magellanic waters must therefore have recolonised the region from adjacent Atlantic and Pacific areas, and indeed some of the polychaetes found in the Magellanic region are known from the Antarctic shelf.

The larvae of polychaetes can live as plankton for many months before resettling and developing into adults. "The dispersal of Antarctic species through larval transport in easterly circumpolar currents may explain their occurrence in the Magellanic region," said Dr Thatje.


'/>"/>

Contact: Dr. Rory Howlett
r.howlett@noc.soton.ac.uk
44-080-598-490
National Oceanography Centre, Southampton (UK)
Source:Eurekalert  

Related biology news :

1. New report underlines multiple benefits but also new challenges to biodiversity-rich sites
2. TEEB report released on the economics of ecosystems and biodiversity for policy makers
3. ERC provides millions for biodiversity research
4. World will miss 2010 target to stem biodiversity loss, experts say
5. Amid rising concerns, 600 global biodiversity experts meet in Cape Town Oct. 13-16
6. Cool new tools let public contribute to massive interactive online biodiversity encyclopedia
7. Scientists demonstrate importance of niche differences in biodiversity
8. Climate-caused biodiversity booms and busts in ancient plants and mammals
9. New theory gives more precise estimates of large-scale biodiversity
10. Academy Library accepted to prestigious Biodiversity Heritage Library
11. Scorpion biodiversity
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Seabed biodiversity of the Straits of Magellan and Drake Passage
(Date:6/2/2016)... 2016 The Department of Transport Management ... 44 million US Dollar project, for the , ... Personalization, Enrolment, and IT Infrastructure , to ... and implementation of Identity Management Solutions. Numerous renowned international vendors ... Decatur was selected for the most compliant and ...
(Date:5/20/2016)... 2016  VoiceIt is excited to announce its ... By working together, VoiceIt and VoicePass will ... VoicePass take slightly different approaches to voice biometrics, ... and usability. ... partnership. "This marketing and technology partnership ...
(Date:4/28/2016)... and BANGALORE, India , April ... EdgeVerve Systems, a product subsidiary of Infosys (NYSE: ... today announced a global partnership that will provide ... to use mobile banking and payment services.      ... a key innovation area for financial services, but it also ...
Breaking Biology News(10 mins):
(Date:6/27/2016)...  Global demand for enzymes is forecast to ... $7.2 billion.  This market includes enzymes used in ... production, animal feed, and other markets) and specialty ... and beverages will remain the largest market for ... products containing enzymes in developing regions.  These and ...
(Date:6/27/2016)... SAN DIEGO , June 27, 2016  Sequenom, ... company committed to enabling healthier lives through the development ... Supreme Court of the United States ... Federal courts that the claims of Sequenom,s U.S. Patent ... the patent eligibility criteria established by the Supreme Court,s ...
(Date:6/27/2016)... ... June 27, 2016 , ... Parallel 6 , the ... today the Clinical Reach Virtual Patient Encounter CONSULT module which enables both ... physician and clinical trial team. , Using the CONSULT module, patients and physicians can ...
(Date:6/27/2016)... ... June 27, 2016 , ... Rolf K. ... the faculty of the University of North Carolina Kenan-Flagler Business School ... entrepreneurship at UNC Kenan-Flagler, with a focus on the school’s international efforts, leading ...
Breaking Biology Technology: