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:2/28/2017)...  EyeLock LLC, ein marktführendes Unternehmen im Bereich ... Lösung zur Iris-Erkennung auf der neuesten Mobilplattform ... dem Mobile World Congress 2017 (27. Februar ... 3, Stand 3E10, vorstellen. Der ... – eine Kombination aus Hardware, Software und ...
(Date:2/26/2017)... , Feb. 25, 2017  Securus Technologies, ... technology solutions for public safety, investigation, corrections and ... Recidivism and Reentry. "Too often, too ... prisons and county jails are trying to tackle ... inmates and friends and family members. While significant steps ...
(Date:2/22/2017)... -- With the biometrics market to exceed $10 ... that innovative and agile startups must incorporate into ... changing competitive landscape: multifactor authentication (MFA), point-of-sale (PoS), ... "Companies can no longer afford to cut corners ... Pavlakis , Industry Analyst at ABI Research. "Pairing ...
Breaking Biology News(10 mins):
(Date:3/23/2017)... MILFORD, Mass. , March 23, 2017 ... leading partner to global in vitro diagnostics ... launch of the industry,s first multiplexed ... inherited disease testing by next-generation sequencing ... materials were developed with input from industry ...
(Date:3/23/2017)... ... March 23, 2017 , ... Ellen Matloff, president ... Technology Council (CTC) as a 2017 Women of Innovation® finalist. Matloff will be ... Awards Dinner. , The dinner recognizes women accomplished in science, technology, engineering and ...
(Date:3/23/2017)... New York , March 23, 2017 ... blood plasma products and derivatives market is fragmented due to the presence ... players, such as Proliant, Thermo Fisher , and Sigma-Aldrich, compete ... leader, these three companies, collectively, held more than 76% of this ... ...
(Date:3/23/2017)... , ... March 23, 2017 , ... ... solutions, today announced the hire of Dr. Sigmund “Sig” Floyd as Vice President ... strategic partnerships and joint development activities. , “Dr. Floyd’s career has spanned 30 ...
Breaking Biology Technology: