DIATOMS AND OYSTERS
by J. Bartholomew
From our good friend, J. Bartholomew, we have interesting news. Together with Dr. Hopkins, he is now engaged in oyster research at Biloxi, Miss. It seems that this bivalve delicacy is on the way out,or at least rapidly decreasing in numbers at this locality which is economically, as well as gastronomically, a great loss to the citizenry at large. It may be possible that polution by waste water from Freeport Sulphur Co. is the cause of the oyster demise; however, it may also be possible that there are other causes, hence, this research project.
One reason for which this project is most interesting to microscopists is the fact that young oysters find their main food supply in plankton of which diatoms are the most prominent inhabitants. One may almost say no diatoms , no oysters. Some curious observations have been made in this respect. Mr. Bartholomew reports that the Menhaden (a surface feeding fish of the herring family) is quite a consumer of diatoms. He writes as follows: "You will probably be astonished to know that a 200 millimeter beaker of Menhaden intestines will frequently yield, after cleaning 25 millimeter of diatoms. Years ago, I thought I was a collector but my hat is off to the Menhaden."
"It is possible to set up an oyster control under laboratory conditions, feed him for 24 hours in natural seawater rich in plankton, take him out at the end of the period, scrub him, sterilize him and put him into filtered sea water and let him deficate for 24 hours and then make complete diatom studies of what has actually passed through his intestines. These angles of course fascinate me. Of the 60 odd genera and perhaps 100 species, common in townet-takes and the studies of the mud bottom, darned if the little brat does not confine himself almost wholly to Melosira, several species Cosciusdiscus, goodness knows how many varied species and Navicula - virtually all the strictly linears he rejects and even among the Navicula will only pick the nearly oval shapes. Also in studying sizes, if the Cosciusdiscus, for instance, will average a hundred to one hundred and fifty microns in natural sea water, the little skunk will ingest nothing beyond 50 or 60 microns. We are now ready to set up pure cultures in Miguel solution and grow the genera and species that the oysters accept. We will then treat the cultures in various percentages of bleedwater to see how it affects the growth of the diatoms themselves!
Mr. Bartholomew is inviting our diatom interested readers to cooperate with him in this project, particularly the taxonomitical assistance would be helpful.If you feel you can be of help, kindly contact J. E. Nielsen, 5517 Drexel Ave., Chicago 37.