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An interdisciplinary team of Museum mineralogists and zoologists,  with external collaborators, have been looking at the impacts of nano  particles on the environment for some years.  Silver nanoparticles  (AgNPs) are widely used in industry for manufactured goods and this may result in environmental impacts, notably within aquatic ecosystems. Silver can be toxic to living organisms when they are exposed to it by selected routes and in particular forms.  It's important that in pursuing the positive benefits of NPs, we are able to understand and avoid the negative impacts.

 

Scientists have over many years developed understanding of which substances are toxic, and why.  Sometimes this knowledge will have come about as a result of seeing the effects of unintended exposure to humans in factories or accidentally contaminated food. Exposure to toxic substances can result in death or very serious health effects to humans or other organisms.  However, we have a lot to learn - much of our understanding has arisen from particular cases or studies and one area of particular complexity is exposure through the environment.

 

We are exposed to a whole range of chemical substances in our environment, often at very low levels of concentration and sometimes over many years.  The same is true of other organisms - although the effects of particular substances will be different for different species, as a result of their different genetic makeup, diet, habitat and other factors.  Further, exposure to different combinations of chemical substances can lead to the toxic effect of a particular substance being decreased or increased in a particular and often unexpected way.

 

The use of nanoparticles has increased tremendously in recent years in industry.  Nanoparticles are very tiny particles of a substance - less than 100 nanometres in all three dimensions (one nanometre is one billionth of a metre).  This size means that they can have different chemical, physical and biological properties from larger particles, and this includes their toxic effects.

 

The study looked at estuaries, which are complex environments and often the site of human industrial developments.  Sediments in estuaries are sinks for numerous pollutants, but also habitat and food for deposit feeders (eating the sediments) such as the polychaete worm Nereis diversicolor.

 

Ingested sediments were investigated as an important route of uptake for NPs. The Museum scientists looked at N. diversicolor that had eaten sediment contaminated with either citrate-capped AgNPs (30 +/- 5 nm) or aqueous silver for 10 days. The experimental results indicate separate routes for silver to enter the cells of the worms and differing final locations of Ag delivered in dissolved and NP form.

 

N div1.jpg

 

For AgNPs an endocytotic pathway appears to be a key route of cellular uptake - endocytosis means that the NPs are ingested by the cells of the organism, engulfing the NPs into a vacuole within the cell, in contrast to the usual cross-membrane transport of dissolved substances.

 

All these findings lead to a better understanding of how organisms respond, interact and deal with NPs - this is complex and will have a substantial influence on toxic effects and environmental impact.


GARCIA-ALONSO J, KHAN F R, MISRA S K, Turmaine M, SMITH B D, RAINBOW P S, LUOMA S N, VALSAMI-JONES E 2011. Cellular internalization of silver nanoparticles in gut epithelia of the Estuarine Polychaete Nereis diversicolor. Environmental Science and Technology 45: 4630-4636.

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There is considerable international interest in the impacts of invasive species on biodiversity.  Species are described as being invasive when they cause impacts on biodiversity outside their normal range as a result of introduction or spread as a consequence of human activity.  This impact can lead to loss of native species, spread of disease, impacts on native habitats or other effects.  They are often described as invasive alien species. In the marine environment this can happen as a result of transport by ships in ballast water, or migration through new sea routes such as the Suez Canal.


Recent work from the Museum provides more evidence that the flood of invasive Red Sea species entering the Mediterranean via the Suez Canal includes fish parasites.  Dr Hoda El-Rashidy (who obtained her PhD while researching in the Zoology Department at the NHM) and Prof Geoff Boxshall (Zoology) have described two more new species of parasitic copepods from Egyptian Mediterranean waters off the coast of Alexandria.

 

Their hosts, two species of Red Sea rabbitfish (Siganus luridus and S. rivulatus) have established populations in the Mediterranean. Invasive species often leave their parasites behind, due to the sampling effect of passing through a small founder population, but the continuing discovery of invasive parasitic copepods combined with the absence of any genetic evidence of a bottleneck in their host populations, highlights the remarkable scale of the faunal invasion of the eastern Mediterranean.

 

International concern and efforts to monitor and control impacts of invasive species are significant, with an EU Strategy,  a major focus from the Convention on Biological Diversity, and a UK Non-Native Species Secretariat.  Even on a city level here in London there is coordination on selected species such as Japanese knotweed and various invasive crayfish.


El-Rashidy, H.H. & Boxshall, G.A.  2011. Two new species of Parasitic Copepods (Crustacea) on two immigrant fishes from the Red Sea of Family Siganidae. Systematic Parasitology 19: 175-193. DOI 10.1007/s11230-011-9298-7


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Fin loss in a spiny eel

Posted by John Jackson Jul 19, 2011

Vertebrates - mammals, birds, fish and amphibians - have broadly the same body plan with two pairs of limbs.  However, over time, some species and groups have lost one or both pairs of limbs.  Many others have reduced limbs.  Whales, snakes, caeclian amphibians and a range of fish are some of the examples.

 

Modern scientific research has a strong interest both in the patterns of development and in how and why these change as a result of genetic evolution - it does appear that different genes can be involved in limb reduction and loss in different groups. 

 

Drs Ralf Britz and Lukas Rüber (NHM Zoology) and colleagues from University College London and the South African Institute for Aquatic Biodiversity, Grahamstown reported the first case of pectoral fin loss in the Mastacembelidae (Teleostei: Synbranchiformes) with the discovery of a new species of spiny eel from Lake Tanganyika in the Journal of Zoology.

 

A previous evolutionary phylogeny of mastacembelids using comparisons of genetic differences between different species,  coauthored by Dr Rüber , had placed the new species Mastacembelus apectoralis sp. nov. within the Lake Tanganyikan species flock, having diverged from its sister species M. micropectus around 4.5 million years ago. M. micropectus also shows a reduction in the size of its pectoral fin and endoskeletal girdle, and has largely cartilaginous pectoral radials and a reduced number of pectoral-fin rays. This is in contrast to the bony skeletons of most fish species in this group

 

The loss of pectoral fins and reduction of associated girdle elements in M. apectoralis represent another independent occurrence of this evolutionary phenomenon within teleosts. The discovery of this species highlights the exceptional diversity of the biodiversity hotspot, Lake Tanganyika, the understanding of which is of critical importance with the pressures of pollution, overfishing and climate change threatening the speciose and evolutionarily significant diversity of this ancient lake.


Brown, K. J., Britz, R., Bills R., Rüber, L. & Day J. J. (2011). Pectoral fin loss in the Mastacembelidae: a new species from Lake Tanganyika. Journal of Zoology April 2011 doi:10.1111/j.1469-7998.2011.00804.x

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Palaeontology Department Seminar

 

Thursday 21st July
Neil Chalmers Seminar Room, DC2, 16:00

 

pic1.bmp

 

Whale skeletons as ecological reefs in the shallow marine Eocene of Egypt .

 

Dr. Charles Underwood, Department of Earth and Planetary Sciences, Birkbeck College, Univerisity of London

 

The Late Eocene shallow marine sediments of Wadi Al-Hitan, Egypt are famous for their fossil whales. Many of the whale skeletons are present in shallow marine sandstones that also contain common teeth of sharks and rays. The assemblages of sharks and rays in the sandstones away from the whale skeletons are similar to those that would be expected in shallow marine sandy environments today, dominated by stingrays (Dasyatidae) and Lemon sharks (Negaprion). Teeth collected from amongst whale bones are different, with higher diversity faunas including taxa that are otherwise only common in deeper marine facies. These are sometimes associated with possible chemosymthetic bivalves (Lucinidae). It is therefore likely that the whale skeletons acted as reefs, giving cover to shark and ray species that were otherwise rare or absent in shallow water.

 

 

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Sir Joseph Banks

Posted by John Jackson Jul 13, 2011
Not really news, but just for interest - up in the top of the galleries is this statue of Sir Joseph Banks by Francis Chantrey, and given by his friends to the British Museum (see also the print in the BM).  Our latin is not quite good enough to attempt a translation, but the inscription is below for the enthusiasts.


IMG_0993.jpg

JOSEPHVS.BANKS.BARONETTVS

QVI

QVAM.VNIVERSAE.RERVM.NATVRAE.SCIENTIAM

PER.MARE.PER.TERRAS

APVD.VLTIMAS.GENTES

BARBARAS.ETIAM.INCOGNITAS.PERPETIENDO

IN.ANNIS.IVVENILIBUS.CONQVISIVERAT

EANDEM

IN.PATRIAM.REDVX

ET.SOCIETATIS.REGIAE.APVD.LONDINIENSES.PRAESES

CVNCTIS.SVFFRAGIIS.FACTVS

PER.RELIQVAM.VITAM.SVMMA.IPSE.CVM.DILIGENIA.COLVIT

ET.SINGVLARI.SVA.LIBERALITATE.AC.MVNIFICENTIA

AEMVLO.ALIORVM.PATROCINIO

POVENDAM.AMPLIANDAM.HONESTANDAM.PROPOSVII

AMICI

VIRTVTIS.EIVS.MEMORES

IMAGINEM.EX.COLLATIONE.DEDICAVERVNT

ET.MVSEI.BRITANNICI.IN.ORNAMENTVM

DONO.DEDERVNT

VIXIT.ANNOS.LXXVI.MENSES.VI.DIES.VI

DECESSIT.XIII.KAL IVL.A.S.M.DCCC.XX