From: PO2::"roesslep@TCPLINK.NREL.GOV" 27-APR-1995 15:37:30.63 To: Multiple recipients of list DIATOM-L CC: Subj: summary - diatom numbers and primary production Thanks to everyone who responded to my query about current estimates for the number of extant diatom species and their contribution to global primary production. A number of people suggested that a summary of the results be posted, so here it is. First, my own condensation of the responses: Regarding the number of species: The estimates ranged from 12,000 to over a million! Obviously, the huge number of morphological variations in diatoms makes this number a hard one to predict. Note the manuscript in press by Mann and Droop (below) that attempts to address this question. Regarding primary production: Many people still use the Werner (1977) reference (see below), suggesting that diatoms are responsible for 20-25% of the total global primary production. Several estimates were quite a bit higher than this (up to 70%), but there were not any references provided to back up these numbers. I did a bit of investigating, and came up with a value of approximately 23%. To calculate this value, I used data from an article that appeared in this week's Science (vol 268, pp. 375-379) on the silica balance in the oceans, which stated that diatoms are responsible for the fixation of up to 25.8 x 10E15 g C per year, which is 43% of the total global ocean primary production (estimated to be up to 60 x 10E15 g C per year). I coupled this number to a recent estimate for global terrestrial net primary production of 53.2 x 10E15 g C per year [see Nature 363, pp. 234-240 (1993)] as shown below: 25.8 for diatoms / (60 for oceans + 53.2 for terrestrial)= 22.8% I suppose that this number could change a bit if one were to take into account freshwater habitats, but I doubt that it would change it by much. So, as we've known all along, diatoms are a pretty darn important component of this world that we live in! Now for the individual replies: ---------------------------------------------------------------------- 1) Regarding the number of species, the real answer "is nobody knows". My current guess is on the order of 100,000, but I wouldn't be greatly surprised to see that estimate grossly exceeded in my lifetime. 2) Fraction of total production is also a qualified guess. Mine would be on the order of 35%. One must suspect that this number is changing fairly rapidly because of decreased terrestrial and increased nearitic oceanic production during the "Anthropocene". It would be interesting if you would post the answers you get. ***************************************************************** Eugene Stoermer, University of Michigan Internet e-mail address: stoermer@umich.edu Voice Phone: 313-764-5238 Fax: 313-747-2748 ***************************************************************** ---------------------------------------------------------------------- Margaret (Harper) is at a conference in Woods Hole at present but she might well have suggested you look up VanLandingham's many volumes of diatom spp to see how many there are. John Harper ---------------------------------------------------------------------- Dear Paul Roessler I'm sorry to hear about your crash. My colleague David Mann sent you a message, I believe, with our estimate of the number of diatom species. However, he is away this week, and will not be able to resend his message until next week. Our estimate for the total number of extant diatom species is 200,000. This estimate is in press, and is based on extrapolation from our studies of variation and interbreeding in some pennate genera. References: Mann, D.G. and Droop, S.J.M. (in press). Biodiversity, biogeography and conservation of diatoms. Hydrobiologia. Droop, S.J.M. (1994). Morphological variation in Diploneis smithii and D. fusca (Bacillariophyceae). Archiv fur Protistenkunde 144: 249-270. Mann, D.G. (1989). The species concept in diatoms: evidence for morphologically distinct, sympatric gamodemes in four epipelic species. Pl. Syst. Evol. 164: 215-237. I hope this is of some use; failing that, send a message to mann@rbge.org.uk next week for more information. Cheers Stephen ********************************************************************** Stephen J.M. Droop Royal Botanic Garden, Edinburgh EH3 5LR, UK Tel.: +44 31 552 7171; Fax: +44 31 552 0382 stephen@rbge.org.uk ********************************************************************** ---------------------------------------------------------------------- Dear Paul, These have been recurring questions during my 20-year career as an applied diatomist. I'd be interested in the responses you receive, particularly if they're not posted to DIATOM-L. I'm a regional biologist for the USGS National Water Quality Assessment (NAWQA) Program and advocate/protocol author for benthic algae in the Program. In time, NAWQA will provide considerable information about the occurrence and distribution of diatoms (and other algal taxa) in the US. A colleague of mine in Montana (Loren Bahls) has reported over 6,000 diatom species from Montana alone. I would assume that folks like Pat Kociolek (Cal Academy/SF), Ed Theriot (Philadelphia Academy), and Gene Stoermer (UM/Ann Arbor) would be in a better position to answer your questions, but my understanding of the current paradigm is (1) maybe 30,000-50,000 species and (2) about 70% of global primary production. I could be way off on both accounts. I'm located in Lakewood, ca. 5 miles from you (Bldg 25, Denver Federal Center), and can be reached at 23-5950 ext. 216. What are your interests in diatoms? Give me a call if you're interested in what NAWQA is doing. Stephen Stephen D. Porter, Regional Biologist, CR, Lakewood, CO ---------------------------------------------------------------------- Paul, here is a re-send of my former message with some more info: One of the references for info on this would be Werner, D. (editor) 1977, The Biology of Diatoms. Botanical Monographs 13, U. of California Press, Berkeley. Another is Simpson and Volcani (eds) 1981, Silicon and siliceous structures in biological systems. Springer-Verlag, NY. ---------- Forwarded message ---------- Paul, I think that the entire Diatom-List would be interested in hearing anything you might find out from this query. (Certainly I would) I have been interested in these two questions myself. I have seen it written that there exists over one million species of diatom, but then in questioning folks, it seems that many of these are probably the same species, and there aren't nearly so many different types. I don't know. I know that I have identified over 400 species from cores in a single location, that I know do not reflect many of the living species (mesohaline Chesapeake Bay). I have also seen that diatoms contribute anywhere from 25-50% of the world's primary productivity. I just saw the 25% recently, but can't remember the reference off the top of my head. I believe that 25-30% is more widely accepted (I can find a reference or two with these numbers if you want). I heard 50% at a seminar, but when I asked the speaker about it, he wasn't sure about the number. I would like to hear what you find out! Thanks, and best wishes, Sherri Cooper Chesapeake Biological Lab Solomons, MD 20688 ---------------------------------------------------------------------- Dear Paul, We discussed this at the beginning of: Gordon, R. & R. W. Drum (1994). The chemical basis of diatom morphogenesis. Int. Rev. Cytol. 150, 243-372, 421-422. Dick Gordon ---------------------------------------------------------------------- Paul I've got some old information on your two questions. According to Werner (1977) about 12000 bona fide species have been described. Diatoms probably contribute about 20-25% of the world's net primary production. In freshwater systems, diatoms yield from 20-50% of all the productivity of certain lakes (Siver 1977), thus diatom productivity is as important as the boreal forest or the grasslands (Werner 1977). I would be very interested in other responses to your question. Perhaps you can put the responses together and send them out as you did your question. Best to you. Michael Stewart (Michael_Stewart@nps.gov) Siver, P.A. 1977. Comparison of attached diatom communities on natural and artificial substrates. J. Phycol. 13:402-406. Werner, D. ed. 1977. The Biology of Diatoms. Botanical Monographs. Vol. 13. Univ. of California Press. 498 pp. ---------------------------------------------------------------------- Dear Paul: I should be very interested in seeing a summary of the responses that you get since I've seen estimates of diatom species numbers of the order of millions! Course, it depends how you define a species...and this is a big problem with diatoms. Regards, Mike. PS. Diatoms are not my field.... :} ********************************************************************* Michael D. Guiry Phone: +353-91-750410 Dept of Botany Fax: +353-91-750502 University College, Galway E-Mail: mike.guiry@ucg.ie The National University of Ireland Galway, Ireland ********************************************************************* ----------------------------------------------------------------------