Dear All,
How many grams (weight) is recommended for Planktonic foraminifera Analysis?. The samples are from Ocean Drilling Cores.
Thank You
Dear Maqsood,
Should you precise how many grams of what? (planktonic foraminifera or sediment?)
It really depends on the type of analysis you want to run, e.g.,
- 8 mg of planktonic forams is usually enough for d14C,
- For accurate counting of assemblages, 300 specimens (at least) are needed,
Best,
Johan
Dear Maqsood,
It's depend of many factors. Just prepare around 100 g of sediments.
Armel
It very much depends where your sample is from. If you have an ooze you'll find many foraminifera in your sample. If it is a clayey sample with very low carbonate content you need to sieve more. A few ml. of marine sediments is usually enough. Weight may be a bit difficult to advise as this depends on wet/dry weight. You may want to start with half of the sample if it is an ODP (= valuable) sample and then see how that works out!
Frank Peeters Thank you for your suggestion. I tried a sample of about 50 g that gave me a good result.
Samples from IODP are usually given in the range of 10cc for foraminifera and 5cc for nannoplankton. I usually use half of the 10cc and save the rest in case of need and/or for eventual nannoplankton analyses. Then I weight the dry sediment before washing and the single fractions after washing. Then you split your fractionto have around 300 specimens and you count the single species relative abundances (and you count the number of splits as well). If you need to have foraminifera x gram of sediments, you consider sediment weight and split numbers.
Silvia Spezzaferri Thank you so much for your valuable information.
Dear Maqsood, if you are asking samples from ODP cores, better check the preliminary reports, available online. I'm sure, the report will have CaCO3 data. As Frank wrote, higher the CaCO3, lesser is the sediment you require to get sufficient planktic foraminifera. In fact, if you are only interested in census count, ~10 g of dry sediment containing 4-5% CaCO3 should provide you enough specimens. Of course, you also have to have an idea about the biogenic content of the samples. Again the preliminary reports can help you a lot.
Perhaps the following work may be useful to you:
https://core.ac.uk/download/pdf/27215242.pdf
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