growth rate consequences of coloniality in a harmful phytoplankter增长率phytoplankter coloniality在有害的后果.pdfVIP

Growth Rate Consequences of Coloniality in a Harmful Phytoplankter 1 1 2 Alan E. Wilson *, RajReni B. Kaul , Orlando Sarnelle 1 Department of Fisheries and Allied Aquacultures, Auburn University, Auburn, Alabama, United States of America, 2 Department of Fisheries and Wildlife, Michigan State University, East Lansing, Michigan, United States of America Abstract Background: Allometric studies have shown that individual growth rate is inversely related to body size across a broad spectrum of organisms that vary greatly in size. Fewer studies have documented such patterns within species. No data exist directly documenting the influence of colony size on growth rate for microscopic, colonial organisms. Methodology/Principal Findings: To determine if similar negative relationships between growth rate and size hold for colonial organisms, we developed a technique for measuring the growth of individual colonies of a bloom-forming, toxic cyanobacterium, Microcystis aeruginosa using microscopy and digital image analysis. For five out of six genotypes of M. aeruginosa isolated from lakes in Michigan and Alabama, we found significant negative relationships between colony size and growth rate. We found large intraspecific variation in both the slope of these relationships and in the growth rate of colonies at a standard size. In addition, growth rate estimates for individual colonies were generally consistent with population growth rates measured using standard batch culture. Conclusions/Significance: Given that colony size varies widely within populations, our results imply that natural populations of colonial phytoplankton exist as a mosaic of individuals with widely varying ecological attributes (since size