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3 Posts tagged with the deep_sea tag
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Friday 17 May 11:00


Sir Neil Chalmers seminar room, Darwin Centre LG16 (below Attenborough studio)

 

The Energetic Niche of Species: Lessons from the Deep Sea

 

Craig R. McClain, Assistant Director of Science, National Evolutionary Synthesis Center

 

Life requires energy. Biological organization—the culmination of life in all its forms—is determined largely by the flow and transformation of energy. Three distinct types of energy affect biological systems: solar radiation (in the form of photons), thermal kinetic energy (as indexed by temperature), and chemical potential energy stored in reduced carbon compounds (i.e. food). 

 

I contend and will discuss that much like organisms possess thermal niches so do they possess chemical energetic niches (CEN). Evidence from both local and oceanic scale studies of beta-diversity, i.e. species turnover, suggests unique suites of species inhabit different regimes of carbon availability.  The evolution of body size and life history strategies in molluscs appear to be linked to productivity gradients and may have promoted diversification in this group.  Thus, changes in ocean productivity as a result of climate change may greatly impact biodiversity by modifying available niche space for ocean species.

 

For additional details on attending this or other seminars see http://www.nhm.ac.uk/research-curation/seminars-events/index.html

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Helena Wiklund and Adrian Glover, together with collaborators from the USA and Sweden, have described six new species in the polychaete worm genus Ophryotrocha. The six new species were discovered on five whale-falls and two wood-falls in deep-sea water off the Californian coast.

 

Worms in the genus Ophryotrocha were until recently only known from shallow seas rich in nutrients, but as deep sea exploration has progressed, they have been found to be common in organically-enriched habitats such as hydrothermal vents,  cold seeps, whale-falls and in  areas impacted by human pollution (such as underneath fish farms), and  may well play an important ecosystem function role in the biodegradation  and decomposition of organic-rich materials. The new data also  highlight the poorly known biodiversity of the deep sea, and how  deep-sea species evolved.

 

The scientists have examined both the morphology and DNA of the worms.  Identification of one of the species is only possible by looking at differences in their DNA - its physical form is otherwise identical to another species found in the Atlantic. This is of additional interest because some marine species are found in all oceans but others will be found in only one.  The difference in DNA suggests the evolution of different species as a result of geographical separation.  It is suggested that there will be significantly more diversity in this and other groups in deep sea habitats with implications for understanding of these mysterious ecosystems.


Wiklund H, Altamira I, Glover AG, Smith CR, Baco A, Dahlgren TG. (2012) Systematics and biodiversity of Ophryotrocha (Annelida, Dorvilleidae) with descriptions of six new species from deep-sea whale-fall and wood-fall habitats in the north-east Pacific. Systematics and Biodiversity 10(2): 243-259.

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Adrian Glover (Zoology) and Helena Wiklund have also been awarded a Marie Curie Intra-European Fellowship for Helena to work on deep sea biology.  This Marie Curie scheme, funded by the European Union, allows experienced EU researchers to work in other EU countries to develop skills and collaboration, producing high-quality science.  The NHM bids successfully for funds to a wide range of research funding agencies each year in the UK and elsewhere.

 

They will be working on worms in the deep sea: the last unexplored frontier on Earth, where in recent years many hundreds of new species have been discovered. We are familar with shallow coastal seas affected by tidal currents, richly productive and fertile.  In contrast, the deep sea has many areas where nutrients are scarce, cold and subject to high pressure, deep ocean basins over 4 kilometres below the surface.  The lives of organisms in the deep sea are often very different from those of related species near the surface.

 

A key question in deep-sea biology is that of whether and how deep-sea animals are able to disperse. Many organisms, such as worms, have limited abilty to move over any distance as adults: some have planktonic young that can be carried over distance by currents.

 

The dominant idea for the deep sea has been one of cosmopolitanism: that animals are relatively mobile at certain stages of their lfe cycle and have easy access to all ocean basins around the world. However, this has been recently challenged and for many species there may be barriers to dispersal in the form of substrate specialisation (the requirement to live in particular types of sediment) limited mobility or particular reproductive characteristics.

 

This study will target one of the most abundant and species-rich groups, the polychaetes. To answer questions of dispersal and evolution in the deep sea Helena will study three contrasting groups of polychaetes:one group with mobile planktonic larvae; a second group with direct-developing larvae, similar in form to the adults; and a third group, the newly discovered genus of ’bone-eating’ worms, Osedax, that are sessile (non-mobile) and exist on the most specialised of habitats – whale bones on the sea floor. (One of which, Osedax mucofloris, was a NHM species of the day in 2010)

 

osedax-sem_69101_1.jpg

Osedax mucofloris


The study will use molecular data (such as from DNA analysis) from material from several ocean basins to construct phylogenies (evolutionary trees) to evaluate the relationships within the three groups.  It will have great value in understanding species formation, population connections and the processes that drive biodiversity in the deep sea.