Abstract
The microflora in 58 supralittoral rockpools in the archipelago outside the Biological Station, Espegrend was studied during shorter periods of summer-autumn 1962 and spring-summer 1963.
Water samples from the pools were centrifuged and the sedimented microflora was studied in a live condition with a microscope. The salinity in each sample was determined. Data on depth and area of the pools are presented.
The pools were classifiEd according to the rockpool system of Levander (1900), with some modifications.
Of the pools, 44% had a predominant marine influence and 32% a predominant limnetic influence. The rest of the pools (24%) showed transitions between these two groups, due to variations in the marine influence the two years. Only 10% of the limnetic pools could be classified as rainwater pools.
Chlorophyceans were recorded once or more in 48 pools while dinophyceans and euglenaphyceans were recorded in 40 and 29 pools respectively. The wide distribution of chlorophyceans and dinophyceans was mainly due to the prevalence of single species, Brachiomonas submarina and Oxyrrhis marina respectively.
Few of the microflora species showed preference for one pool type only. Roughly, the microflora could be divided into a euhaline, limnetic, and mixohaline category.
The microflora in the Espegrend pools was compared with records from other areas, mainly the Baltic. Species found in the Espegrend pools with their main distribution in salinities higher than 5‰ seem not to inhabit rockpools in the Baltic area.