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AN ECOLOGICAL BASIS FOR EXTRACELLULAR CARBONIC ANHYDRASE IN MARINE UNICELLULAR ALGAE
Author(s) -
Hobson Louis A.,
Hanson Christine E.,
Holeton Claire
Publication year - 2001
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1046/j.1529-8817.2001.00112.x
Subject(s) - biology , algae , diatom , algal bloom , carbonic anhydrase , bloom , phytoplankton , botany , nutrient , ecology , autotroph , enzyme , bacteria , biochemistry , genetics
Extracellular carbonic anhydrase (CA e ) is expressed by many, but not all, autotrophic species of aquatic unicellular protists. We measured CA e activities in unicellular marine algae characteristic of either high nutrient spring, fall, and winter blooms or low nutrient summer populations to provide ecological/evolutionary information about the enzyme. Highest activities occurred in spring bloom and opportunistic diatoms exposed to long photoperiods (16 h) when pH was highest and CO 2 was lowest. Lower activities were recorded for a fall‐bloom diatom exposed to the long photoperiod, and lowest values were found under all culture conditions for one diatom and a number of flagellated species typical of summer low nutrient environments. Other potential sources of variance in measurements of CA e activity were examined. Maximum activities of CA e were recorded for the diatom, Skeletonema costatum (Greville) Cleve, during late exponential phase of growth and within 8 h of the beginning of the photoperiod. We concluded that ecological factors are important in determining CA e activities in marine unicellular protists. Potential functions of CA e in the metabolism of marine unicellular algae are discussed.