MEDIA FOR THE CULTURE OF OCEANIC ULTRAPHYTOPLANKTON^1,2

TLDR

The authors developed a seawater‑based medium (K) to culture fastidious oceanic ultraphytoplankton across at least seven algal classes. The medium contains selenium, nitrate, ammonium, enhanced chelation, and moderate buffering, and was tested on 200 clones (186 grew reliably) and a synthetic counterpart on 40 difficult clones (27 grew well). Although neither medium satisfies all nutritional needs, they are effective for most oceanic clones and support isolation and culture establishment of new phytoplankton.

Abstract

ABSTRACT 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 seawater‐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 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.