Diversity indices require you to be able to count and identify individual species.

Dear Michael,

Thank you so much,

I agree that diversity indices are required to count the species diversity of a location/region, but when we consider optical data set it deals with pixel representation in synoptic scale. So, there my doubt is raising about indices calculation!, the satellite data-set does not deal with species representation, but it does have values in each pixel for different wavelengths.

regards,

Mona Sundar

If you can identify different wavelengths in each pixel, I don't see why you could not use the index, just realize that it is modified and not comparable to traditional studies. The modified index could be used to compare different areas captured by the same methodology, but I suspect it would give different results from a net sample processed the traditional way.

Dear Michael,  It is clearly understood that I have to modify the index with the same methodology to make it applicable with the optical data sets, I will work on it. If it does not match with the results reported in the traditional method, then, I have to think more about it and try to compare how far is the difference between the indices for the optical data with respect to the results from traditional methods. Many thanks for the suggestions.

Mona.

Hello Malcolm, Converting the satellite data to ordinal numbers, I think it can be achieved when we group them into different classes, but as you said comparing them to diversity is the critical point. Thank you, Mona.

Hi Mona, I think you need know first how "patchy" is the area that you are studying looking at the literature. If you find that your area is more heterogeneous than the size of your pixel, then you will have problems to justify your diversity analysis. But if your area is very homogeneous and typically phytoplankton assemblages are bigger than the size of your pixel, then the Shannon index can be useful. Read section 2.4 here:   https://www.researchgate.net/publication/283902063_Seasonal_changes_of_the_microplankton_community_along_a_tropical_estuary   And see if an nMDS is a good idea for working with your six variables. Good luck!

Article Seasonal changes of the microplankton community along a trop...

Hi Seguro, This seems to be a very useful information. I have already made some inferences based on available literature's on the phytoplankton diversity of the study region. It is very convincing to look into your second point, my study region is with phytoplankton functional groups, that are mostly homogeneous and the patch is bigger than the size of the pixel, I think I can rely on Shannon indices to check the results. The literature attached is a very good reference. Many thanks, Mona.