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Curator of Micropalaeontology's blog

3 Posts tagged with the ocean_acidification tag
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I'm so tempted to say that a microfossil curator attends meetings and writes e-mails. Sometimes it feels like that. I decided to document a typical day back in January where e-mails and meetings helped prepare towards a loan for an art exhibition, gave news of a potentially exciting new acquisition and a possible research opportunity involving micro-CT scanning.

 

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One of Irene Kopelman's items in the Gasworks Gallery based on microfossils from our collection

 

The bulk of the e-traffic involves preparations towards an exhibition that opened on 10 Feb at the Gasworks Gallery near the Oval Cricket Ground. Artist Irene Kopelman's work was partly inspired by some slides of radiolarian microfossils from our collections. We are preparing an exhibition loan of the slides and today there is a lot of correspondence discussing arrangements for two open day tours I am holding to accompany the exhibition.

 

Most microfossils are so small that I have to deal with images rather than the specimens themselves. We recently sent some specimens on loan to the Smithsonian Institution in Washington where a researcher has made some images for a publication and left them on an ftp site for me to collect. I am also making arrangements for other images of our specimens to be sent to us by one of our regular visitors. They have posted them on an excellent site for people interested in foraminiferal microfossils.

 

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Aggerostramen rustica, a type of foraminiferal microfossil that builds a shell from sediment. In this case, sponge spicules have been chosen. This image has been posted on-line at the foraminifera.eu site mentioned above

 

Typically a day will not pass without some correspondence with future visitors to the collections and/or an actual visit from a scientist. Two visitors want to come in a couple of days time and another wants to visit the following week to discuss a short paper on a major collection of 2,500 slides that they donated last year.

 

In a few days time I'm off to our collections outstation in Wandsworth to meet OU PhD student Kate Salmon who is using our collections to study ocean acidification. I need to book a Museum vehicle to transport me to Wandsworth and to bring the collections back that she would like to borrow.

 

I mentioned meetings but you'll be glad to know that I'm not going to go into detail here. From one meeting I come away with two additional enquiries to answer; a request by a journalism student for a 5 minute mock radio interview and a student wants images of some of our specimens for their thesis.

 

I am also asked to assess a destructive sampling request as my boss is away. Sometimes our samples or specimens need further analysis to reveal their true scientific potential. In this case the borrower wants to make thin sections of fragments of fish fossils and to carry out 3-D imaging using a synchrotron (see my previous blog on sex in the Cretaceous for details of synchrotrons). The work will potentially give important details about early fish evolution so the request is ratified.

 

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Erasmus student Angelo Mossoni using one of the scanning electron microscopes at the Museum.

 

 

The excellent research facilities here at the Museum offer many exciting possibilities. Today an e-mail has come in requesting bids for use of the micro-CT scanner. I want to test whether this method can provide 3-D images of some tiny specimens the reverse sides of which we cannot analyse at the moment because they are stored embedded in wax. If it works, some 3-D images of some of our most important specimens will be delivered to the web. Some of these species have been used extensively in studies on climate change and oceanography.

 

One message informs me that an exciting new sample has just been sent as a donation from Oman. When it arrives I will need to dissolve some of it in acid (vinegar) to release the tiny fossils. Traces of fish microfossil are clearly visible on the surface of the rock so this sounds very promising and possibly the subject of a new paper on early fish evolution.

 

It would appear from everything listed above that there is not much time for any other activities. However, documenting the collections for the web is one of our core duties so I find time in the afternoon to work towards a documentation project. I am also on duty for an hour to answer questions from my fellow curators and my mentee Jacqui about using the databasing system.

 

A number of people including my two new colleagues Tom and Steve, pop their heads round my door to ask questions about the collections or bring me information. Retired Museum Associate Richard Hodgkinson is in today and has some questions about his project. Another retired member of staff brings me a copy of his latest paper and former volunteer and now colleague Lyndsey Douglas comes to tell me that my blog has been quoted in the January edition of the Museums Journal!

 

It's an amazingly variable job being a microfossil curator and no day is ever the same as another. I love my job and I think of it as unique. I don't know of anyone else in the world who has a similar job in Micropalaeontology. If you have a similar job, I'd love to hear from you.

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Ocean acidification is one of the major effects of increased carbon dioxide levels in the atmosphere caused by the burning of fossil fuels (coal, oil, gas). Museum collections of samples from the ocean bottom worldwide are housed at our Wandsworth outstation and are vital to working out how much more acidic the oceans have become since the 19th Century and to helping create models for future changes.

 

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Three bottles of ocean sediment collected in 1891 as part of the H.M.S. Penguin cruise to the Mediterranean

 

Our outstation at Wandsworth holds the Mineralogy Department's Ocean Bottom Sediment Collection. These are sediment samples from many cruises including the first oceanographic voyage the Challenger Expedition of 1872-1876. I mentioned previously that we hold residues including microfossils at South Kensington so why are these bottles of sediment at Wandsworth of interest to micropalaeontologists?

 

Potentially these bottles contain many thousands of microfossils (the ones above mention the foraminferal genus Globigerina) and as a result, they have been of interest for two PhD students studying the effects of ocean acidification on micro-organisms.

 

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Open University PhD student Kate Salmon accessing the Ocean Bottom Sediment Collection at the Museum outstation at Wandsworth. Curator Dave Smith is in the background.

 

Kate Salmon is using mainly foraminiferal microfossils to measure the scale of ocean acidification in the area around Bermuda. To do this she is studying samples collected every 2 weeks for the past 20-30 years in sediment traps on the ocean bottom.

 

The weights and shell thicknesses of these micro-organisms that use the ocean water to produce their shells of calcium carbonate should be different in pre-industrial samples. If ocean acidification is happening we should see lighter more fragile shells in the present day. Kate is using the Ocean Bottom Sediment Collection at the Museum to find comparative material from pre-industrial times.

 

Kate recently told me, 'If I do the same shell analyses on these samples, it will give a good comparison of low carbon dioxide conditions with higher carbon dioxide conditions (present day) and I will be able to see how conditions have changed for the calcifying biology of the oceans. I can then use these results to predict any future changes in the calcification of foraminifera and the implications this will have for other creatures living in the water column'.

 

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Part of the residue collection from the H.M.S. Penguin expedition collected in 1891.

 

Ella Howes, a student at the Laboratoire d'Océanographie de Villefranche sur Mer, France approached us to see if we had any sediment including the remains of tiny organisms called pteropods. These are small planktonic gastropods (floating snails) that have been used extensively in ocean acidification studies. Ella has recent material from near Bear Island in the Mediterranean and wants to compare the composition and structure of these faunas prior to major industrial activity.

 

She is searching for a particular pteropod species Limacina helicina as well as foraminifera. As with Kate Salmon, she is looking to make measurements of shell thickness to assess possible outcomes of ocean acidification between the Mediterranean and colder water areas.

'In Polar regions the cold temperatures allow increased carbon dioxide in water, potentially causing more extreme repercussions for animals living in these areas. A geographical comparison between the effects on ocean acidification on shell thickness in Polar pteropods and the warmer Mediterranean Sea will be undertaken using modern samples of Limacina helicina and old sediment samples provided by the Natural History Museum' says Ella.

 

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Part of one of four rows of cabinets containing the Ocean Bottom Sediment Collection at the Museum.

 

When you consider the quantity of material at our Wandsworth outstation, there is limitless potential for similar studies to be carried out. There are literally millions of micro-organsims from the ocean bottom waiting to be studied. Listings of these collections can be found on the Museum web site. In the meantime, I will wait with interest to hear from Kate and Ella if a trip to Wandsworth can help quantify ocean acidification.

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Microfossils of the day

Posted by Giles Miller Aug 12, 2011

To celebrate the United Nation's Year of Biodiversity last year, the Museum published details of a different species every day on its web site under the title Species of the Day. These records were delivered last week to another web site The Encyclopedia of Life. Each species was chosen and written about by a museum scientist so this week's blog is to point you in the direction of the microfossils which were chosen for their importance in studies on climate change, ocean acidification, north sea oil exploration and the fossil record of sexual reproduction. Follow the links below to find out more about each species and the groups to which they belong.

 

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Emiliania huxleyi

 

Emiliania huxleyi is a coccolithophore which is a unicellular plant that lives in the upper layers of the ocean and forms tiny calcareous coccolith plates like the ones you can see above. These are artificially coloured images from a scanning electron microscope. This very high powered microscope is needed as they are only tens of microns in size and as a result are usually referred to as nannofossils. The ones above are only slightly larger than a thousanth of a millimetre in size. If you were to dip a bucket in the ocean you could find literally tens of thousands of these types of cells. In early summer, E. huxleyi forms enormous blooms across the northwest European shelf that can be seen from space. Coccoliths are susceptible to changes in climate and ocean acidification. This, combined with an excellent fossil record makes them an essential group in the study of recent changes to our oceans and environment.

 

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Harbinia micropapillosa

 

Harbinia micropapillosa is an ostracod, a microscopic crustacean with two calcareous shells. Ostracods can be found in virtually any current aquatic environment and very rarely on land in damp habitats near to water. They have an extensive fossil record because their two shells preserve well as fossils but usually the soft body parts decay soon after death. H. micropapillosa is exceptional because the soft body parts have been preserved in a rock formation that is roughly 140 million years ago. Recent analysis using new techniques has shown the reproductive organs of this ancient organism are identical to those of present day ostracods and suggest that they reproduced using giant sperm back in the Cretaceous period. If you can't wait to find our more about this interesting fossil then follow the link above. However, I will be expanding the story of these important specimens in our collections as the subject of a future blog.

 

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Nannoceratopsis gracilis

 

Nannoceratopsis gracilis is a dinoflagellate cyst from the Jurassic period about 145-200 million years ago. Dinoflagellates are marine photosynthetic algae that play an important role at the base of the food chain and the carbon cycle. At stages throughout their life cycle they form resistant organic cysts that can be found in the fossil record by dissolving suitable rocks in nasty acids like hydroflouric acid. Nannoceratopsis is one of the earliest forms of dinoflagellate cyst so studies of this genus can tell us a lot about the early evolution of dinoflagellates. The shape is also very distinctive and easily recognisable. N. gracilis can be found in rocks 168-185 million years old and can therefore be used, on its own or in association with other fossils, to accurately date rocks.

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Nummulites gizehensis

 

I mentioned Nummulites gizehensis is a member of the Foraminifera in my second blog and showed a picture of the pyramids at Gizeh that are constructed from rocks that contain this species. The genus Nummulites is a member of a group called the "Larger Foraminifera" that build multichambered shells up to 15cm in size despite being a single celled amoeba. The chambers like the ones shown above can only be seen by breaking the shells apart or making specially oriented thin sections of the rocks they are found in. Sometimes symbiotic green algae also lived in the chambers, providing products of photosynthesis to the amoebe while using the shell as protection. N. gizehensis lived during the Middle Eocene epoch about 37-48 million years ago, in shallow marine conditions and can be used as a marker to show the age of rocks that contain them, particularly in the oil region of the Middle East.

 

Finally a big thank you to my former colleagues Jeremy, Susanne and Clive who originally wrote about three of these beautiful microfossil species of the day.



Giles Miller

Giles Miller

Member since: Apr 21, 2010

This is Giles Miller's Curator of Micropalaeontology blog. I make the Museum micropalaeontology collections available to visitors from all over the world, publish articles on the collections, give public talks and occasionally make collections myself.

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