Accession Number : ADA609478


Title :   Population Dynamics and Diversity of Synechococcus on the New England Shelf


Descriptive Note : Doctoral thesis


Corporate Author : MASSACHUSETTS INST OF TECH WOODS HOLE MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING


Personal Author(s) : Hunter-Cevera, Kristen


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a609478.pdf


Report Date : Sep 2014


Pagination or Media Count : 206


Abstract : Synechococcus is a ubiquitous marine primary producer. Our understanding of the factors that determine its abundance has been limited by available observational tools, which have not been able to resolve population dynamics at timescales that match response times of cells (hours-days). Development of an automated flow cytometer (FlowCytobot) has enabled hourly observation of Synechococcus at the Martha s Vineyard Coastal Observatory (MVCO) since 2003. In order to ascribe changes in cell abundances to either growth or loss processes, information on division rate is needed. I refined a matrix population model that relates diel changes in the distribution of cell volume to division rate and demonstrated that it provides accurate estimates of daily division rate for both cultured and natural populations. Application of the model to the 11-year MVCO time series reveals that division rate is temperature limited during winter and spring, but light limited during fall. Inferred loss rates closely follow division rate in magnitude over the entire seasonal cycle, suggesting that losses are mainly generated by biological processes. While Synechococcus cell abundance, division rate, and loss rate demonstrate striking seasonal patterns, there are also significant shorter timescale variations and important multi-year trends that may be linked to climate. Interpretation of population dynamic patterns is complicated by the diversity found within marine Synechococcus, which is partitioned into 20 genetically distinct clades. Each clade may represent an ecotype, with a distinct ecological niche. To understand how diversity may affect population dynamics, I assessed the diversity at MVCO over annual cycles with culture-independent and dependent approaches. The population at MVCO is diverse, but dominated by clade I representatives throughout the year. Other clades were only found during summer and fall. High through-put sequencing of a diversity marker allowed a more quantitative inve


Descriptors :   *BACTERIA , *CELL DIVISION , *CONTINENTAL SHELVES , *PHYTOPLANKTON , CELLS(BIOLOGY) , CLIMATE , CULTURES(BIOLOGY) , DEOXYRIBONUCLEIC ACIDS , DILUTION , DYNAMICS , ECOLOGY , FLOW , GRAZING , HISTOGRAMS , MODELS , OBSERVATION , PATTERNS , SAMPLING , SEASONAL VARIATIONS , TIME SERIES ANALYSIS


Subject Categories : Biology
      Ecology
      Microbiology
      Biological Oceanography
      Physical and Dynamic Oceanography


Distribution Statement : APPROVED FOR PUBLIC RELEASE