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20 Posts tagged with the marine_biology tag
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Dr Adrian Glover (Zoology) has just returned from an oceanographic research cruise to the Bransfield Strait and Scotia Sea, Antarctica, both to the south of South America, near the Antarctic Peninsula.  He was working aboard the RRS James Cook,  one of three UK research ships operating as part of the Natural Environment Research Council's activities.

 

Adrian was searching for new hydrothermal vent ecosystems with scientists from the National Oceanography Centre, Southampton and British Antarctic Survey. The team also found the dead body of a whale on the sea bed.  This is a particular interest of Adrian's because such corpses are important sources of nutrition in the sea for specialist marine species such as Osedax mucofloris.

 

During the cruise, Adrian made three live voice links to Nature Live shows in the Attenborough Studio in the Museum's Darwin Centre, coupled with video clips and images that he had already sent over the ship's satellite system. The public and science staff in the audience were able to interact directly with scientists in the field in the Antarctic, and were some of the first people to see video of Antarctic hydrothermal vents at 2500m water depth in the Scotia Sea.

 

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Adelie penguins - a photograph taken during Captain Scott's expedition in 1911-12

 

The audiences were spellbound with the live descriptions of passing penguins and albatrosses as Adrian gave a vivid account of the ups and downs of life as a research marine biologist on a research cruise. Given the size of the waves in the Southern Ocean, the ups and downs can be pretty extreme - if you can imagine living on a small rollercoaster for a week or two, you might have some idea of what it is like!

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The Mid-Atlantic ridge is the zone running north to south along the bed of the Atlantic Ocean where two major tectonic plates are gradually moving apart, causing volcanic and other geological activity.  As the plates separate slowly, the rock fractures and sea water becomes heated by contact with hot and molten rock below the surface.  This hot water dissolves minerals and contains highly concentrated levels of a range of chemical substances. 

In places this water is forced from hydrothermal vents on the bed of the sea, forming plumes of superheated hot water that rise into the ocean, sometimes carrying thick black particulates.  As the water cools slightly at the vent, various dissolved chemicals are deposited to make large mineral structures such as chimneys and other forms. Exploration of this environment has been increasing over the past forty years with the development of advanced equipment and remotely-operated vehicles: small submarines that carry sophisticated scientific probes and cameras.

The bottom of the ocean is not generally fertile in comparison to coastal seas, but hydrothermal vents are home to dense populations of animals, supported by bacteria that flourish in the chemical-rich waters. The high sulphur and mineral content of the water would make it toxic to most organisms, but some species have evolved to tolerate the temperature and chemical environment.  The animals either consume the bacteria (or one another) directly, or have, in the case of bivalve mussels, symbiotic bacteria in their gill tissue that enables them to use sulphur compounds to produce energy.  These environments are small islands of fertility on the ocean floor, of great evolutionary and ecological interest.

Dr Adrian Glover (Zoology) is part of a team of co-authors in an international team from Portugal, France and the UK who have recently described assemblages of animals from the 11m-high Eiffel Tower structure in the Lucky Strike hydrothermal vent field 1700 metres deep on the Mid-Atlantic Ridge, just to the south of the Azores. Pictures of the Eiffel Tower can be seen on the IFREMER site.

They sampled temperature and sulphide were measured in the water at two different assemblages: one dominated by shrimps and the other by mussels. Temperature, rather than sulphide concentration, appeared to be the major environmental factor affecting the distributions of the resident hydrothermal vent species. The highest temperature variability and the highest maximum recorded temperatures were found in the assemblages visibly inhabited by alvinocaridid shrimp and dense mussel beds of large Bathymodiolus azoricus, whereas the less variable and more stable habitats were inhabited by smaller-sized mussels with increasing bare surface in between.

 

D Cuvelier et al. (2011) Hydrothermal faunal assemblages and habitat characterisation at the Eiffel Tower edifice (Lucky Strike, Mid-Atlantic Ridge). Marine Ecology (2011) doi:10.1111/j.1439-0485.2010.00431.x.

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The discovery of hydrothermal vents in the late 1970s triggered an  enormous biological interest in chemoautotrophic organisms dependant on  previously unknown symbioses with sulphide and methane oxidising  bacteria. Molluscs, particularly bivalves, are the most diverse and  widespread group of chemosymbiotic animals ranging from the intertidal  to hadal depths. Thirteen international speakers will review the  biology, diversity, evolution,host-symbiont interactions and habitats of  these molluscs.

 

The Malacological Society of London and Department of Zoology, The Natural History Museum, are organising a meeting 7 - 8 April 2011 Chemosymbiotic molluscs and their environments: from intertidal to hydrothermal vents at The Natural History Museum, Cromwell Road, London SW7 5BD

 

1000-1800h, 7 April 2011, Flett Theatre
1000-1300h, 8 April 2011, Sir Neil Chalmers Seminar Room

 

No registration fee but for catering purposes PLEASE LET US KNOW IN ADVANCE if you will be attending.

 

Organisers and contact: John Taylor and Emily Glover  j.taylor@nhm.ac.uk

 

 

Speakers and titles

 

  • Sarah Samadi (Systématique, Adaptation et Evolution, Université Pierre et Marie Curie, Paris) ‘Mytilids associated with sunken wood shed new light on the evolution of Bathymodiolinae’
  • Sebastien Duperron (Systématique, Adaptation et Evolution, Université Pierre & Marie Curie, Paris) ‘Connectivity and flexibility of mussel symbioses: how to cope with fragmented and variable habitats?’
  • Nicole Dubilier (Max Planck Institute of Marine Microbiology, Bremen) ‘The unrecognized diversity of bacterial symbionts in chemosymbiotic molluscs’
  • Clara Rodrigues (Universidade de Aveiro, Portugal) ‘Chemosymbiotic bivalves from mud volcanoes in the Gulf of Cadiz: an overview’
  • Graham Oliver (National Museum of Wales, Cardiff) ‘Thyasiridae: the known and the unknown: setting priorities for future research’
  • Heiko Sahling (Geosciences, University of Bremen) ‘The geological and geochemical environment of vesicomyid clams’
  • Elena Krylova (Institute of Oceanology, Moscow) ‘Vesicomyidae (Bivalvia): current systematics and distribution’
  • Steffen Kiel (Geobiology, University of Göttingen) ‘The fossil history of chemosymbiotic bivalves’
  • John Taylor and Emily Glover (Zoology, NHM London) ‘Ancient chemosymbioses – contrasting diversification histories of Lucinidae and Solemyidae’
  • Olivier Gros (Université des Antilles et de la Guyane, Guadeloupe) ‘Codakia orbicularis gill-endosymbiont produces quorum-sensing signals of the AHLclass: putative impact on the bacterial population control in lucinids’
  • Caroline Verna (Max Planck Institute of Marine Microbiology, Bremen) ‘Lucinid symbiont diversity: influence of host selection, geography, habitat and depth’
  • Jenna Judge (Integrative Biology, University of California Berkeley) ‘Testing diversification processes in chemosymbiotic gastropods: a phylogenetic approach’
  • Adrian Glover (Zoology, NHM London) 'Chemosynthetic ecosystems of the Antarctic: a test of dispersal'
  • Paul Dando Marine Biological Association, Plymouth "Fjord thyasirid populations and sediment geochemistry"
  • Matthijs van der Geest (Royal Netherlands Institute for Sea Research) "Ecological importance of chemoautotrophic lucinid bivalves in the Banc d'Arguin (Mauritania) intertidal ecosystem"
  • Karina van der Heijden (Max Planck Institute of Marine Microbiology, Bremen) ‘Biogeography of Mid-Atlantic Ridge hydrothermal vent mussels and associated bacterial symbionts’
  • Graham Oliver & John Taylor 'First confirmation of bacterial symbiosis in Nucinellidae'
  • John Hartley (Hartley Anderson Ltd, Aberdeen) ’Chemosynthetic bivalve responses to oil contamination around North Sea wells and platforms’
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Charles Darwin spent much of his later life at Downe in Kent: thinking, writing and experimenting in an emphatically rural landscape.  But he retained an interest in marine animals, a fascination that developed in his early years at university and during his extended voyage around the world on HMS Beagle.


Professor Phil Rainbow (Keeper of Zoology) has published a keynote presentation in the journal Marine Ecology on the influence of marine biology on Charles Darwin - and the influence of Darwin on marine biology.

 

Darwin made his first forays into the world of marine biology as a medical student in Edinburgh from 1825 to 1827. He came under the influence there of the Lamarckian Robert Grant, and developed an understanding of the simple organisation of the early developmental stages of marine invertebrates. Yet Darwin could not accept Lamarckian transmutation - a complex set of ideas on evolution that preceded the idea of natural selection.  (Lamarck was a French scientist who, among other ideas, argued that a characteristic [such as larger muscles as a result of frequent exercise] acquired during an organism's life would be passed on to descendants and resulted in evolutionary change: Darwin's later development of natural selection as an explanation for evolution discredited Lamarck's ideas.)

 

The voyage of the Beagle gave him intense exposure to a wide range of marine environments around the world and led to Darwin's perceptive theory on the origin of coral reefs, an origin still mainly accepted today. This theory was linked closely to the uniformitarianism (gradual geological change over millions of years) of the geologist Charles Lyell, depending on the slow, gradual growth of billions of coral polyps keeping pace at sea level with slow sinking of land to produce an atoll.

 

Darwin's interest in variation in animals and plants led him to examine many different organisms, both wild and domestic. However, he was aware that his unusual scientific background meant that he had not developed a his reputation on the basis of detailed scientific study in a particular area.  Therefore, from 1846 to 1854 Darwin focused on barnacle diversity and revolutionised understanding of barnacles, producing the monographs Living Cirripedia that are still relevant today.

 

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Capitulum mitella

 

Darwin's barnacle studies gave him the credibility to pronounce on the origin of species; he found great variation in morphology, and a series of related species with remarkable reproductive adaptation, culminating in the presence of dwarf males. Barnacles laid out an evolutionary narrative before him, and contributed greatly to his qualification and confidence to write with authority on the origin of species by 1859.


PS Rainbow (2011) Charles Darwin and marine biology. Marine Ecology. doi:10.1111/j.1439-0485.2010.00421.x

 

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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)

 

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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.

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