These pages describe relatively simple and reliable methods for the culture of marine phytoplankton species useful for feeding marine invertebrates. The methods suffice for the most fastidious algae now routinely cultivable, and simplifications indicated for less demanding species are easily made; for example, omission of silicate for plants other than diatoms. Certain modifications of techniques, ancillary methods, and precautions will be treated briefly because questions often arise concerning them, but documentation will be minimal and hopefully restricted to publications readily available.

Culture of Phytoplankton for Feeding Marine Invertebrates

Communities of microscopic plant life, or phytoplankton, dominate the Earth's aquatic ecosystems. This important new book by Colin Reynolds covers the adaptations, physiology and population dynamics of phytoplankton communities in lakes and rivers and oceans. It provides basic information on composition, morphology and physiology of the main phyletic groups represented in marine and freshwater systems and in addition reviews recent advances in community ecology, developing an appreciation of assembly processes, co-existence and competition, disturbance and diversity. Although focussed on one group of organisms, the book develops many concepts relevant to ecology in the broadest sense, and as such will appeal to graduate students and researchers in ecology, limnology and oceanography.

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The Ecology of Phytoplankton

A medium (K) developed for culturing fastidious oceanic phytoplankton has been tested using recently isolated ultraphytoplankton clones representing at least seven different algal classes. The medium was designed to satisfy as completely as possible the nutritional requirements of this diverse group of phytoplankters. Important aspects are the addition of selenium, the inclusion of both nitrate and ammonium, an increased level of chelation and a moderate level of pH buffering. The sea water-based version of this medium has been tested on 200 clones of which 186 grew reliably. A synthetic counterpart (AK) was tested on 40 of the more difficult clones and 27 grew well; 13 grew not at all. While neither medium meets the exacting nutritional needs of all the ultraphytoplankton forms tested, they are excellent for most oceanic clones and are very successful for the isolation and establishment in culture of new oceanic phytoplankton clones.

Media for the culture of oceanic ultraphytoplankton

TIic Culture Collection of Algac at The University of Texas (Ul EX) at Austin was formerly located at Indiana University, Bloomington. In the summer of 1976 when the writer joined ihc faculty of the Department of Botany at The University of Texas, plans were formtilated for moving ihe Collection. With the cooperatioti of the National Science Foundation atid the Administrations of Indiana University and The University of Texas at Austin, the move was made duritig 1976-77 without atiy interruption of service to the scientific community. The Utiiversiiy of Texas has (lrovided and equipped physical facilities for the maintenance and o{>etation of the Collection. The contitiued support of the Collection as a natiotial researcli resource by the National Science Foundation is gratefully acknowledged. The Fottndation provides ihe tnajor fttiancial supjjon fur the actual oi>eration of the Collection, but funds received frotn the sale of ctiltutes are mainlairivd in a special account for partial support of Collection needs such as postage, supplies, secretarial help» etc.

The culture collevtion of algae at the university of texas ataustin 123

Publisher Summary This chapter focuses on the isolation and purification of Cyanobacteria. Cyanobacterial populations recognized in their natural habitat should be sampled with sterile instruments and placed in sterile containers to ensure the origin of eventual isolates. If funds permit, commercial sterile disposable scalpels, pipets, and plastic tubes are very convenient for this purpose. Only small quantities (a pea-size equivalent generally being ample) are required from habitats where macroscopic growth is visible. Sampling of endosymbiotic cyanobacteria from coralloid nodules of Cycadaceae or the stems of Gunnera can be performed as described for soil and rock-borne cyanobacteria, but other host-cyanobacteria associations might require more special treatments. To isolate cyanobacteria from lakes and ponds in which cyanobacterial growth is not visible with the eye (or even after examination with a portable microscope) it is advisable to take larger samples: 250- to 500-ml sterile screw-cap centrifuge pots, filled almost completely with sampling water, are convenient containers for transport and allow immediate concentration (by centrifugation) on arrival in the laboratory, the sampling volume generally being sufficient to isolate cyanobacteria present even in only low numbers. The origin of many cyanobacteria currently in culture is poorly characterized because little more is known about their habitat than that they were derived from a soil sample, freshwater, or marine environment, which is rather restricted information (although better than source unknown, another not uncommon description).

Isolation and purification of cyanobacteria.

The development of artificial media for marine algae.

Only the Woods Hole strain of Gyrodinium cohnii has grown to high densities (4 million cells/ml) in 7 days in a chemically defined medium. The other strains were slow-growing, and preferred seawater media enriched with organics. The Woods Hole strain, at the onset, required histidine, but was trained to grow on ammonia (no histidine strain). The no-histidine strain of G. cohnii utilized NH4, several amino acids and amines, did not utilize nitrates as N-sources. Though NH4 supported continued growth, addition of histidine and betaine resulted in higher densities. Glucose, glycerol, and acetate were the best carbon sources; the combination of 2 or 3 C-sources yielded better growth than any singly. 
G. cohnii is euryhaline and withstood high concentrations of Tris buffer, but was sensitive to temperatures below 20° C. Biotin was needed. Thiamine is probably synthesized but at a low rate: absence of thiamine resulted in indefinite continued slow growth; the addition of thiamine gave dense, rapidly dividing cultures. 
G. cohnii may perhaps serve for assay of thiamine and biotin in seawater.

L. Provasoli

Papers

The development of artificial media for marine algae.

Nutrition of the American strain of Gyrodinium cohnii.