The effect of temperature on the biology of two cladocerans.
Temperature dependent growth, respiration, and energy budgets were measured for two temperate and arctic zone zooplanktors. A mechanistic formulation for enzyme kinetics was applied to predict the effects of temperature on whole organisms. Embryo development rates as a function of temperature, the t...
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| Format: | Thesis |
| Language: | English |
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1997
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| Online Access: | https://hdl.handle.net/2027.42/130619 http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqm&rft_dat=xri:pqdiss:9732214 |
| Summary: | Temperature dependent growth, respiration, and energy budgets were measured for two temperate and arctic zone zooplanktors. A mechanistic formulation for enzyme kinetics was applied to predict the effects of temperature on whole organisms. Embryo development rates as a function of temperature, the thermal cues for hatching of dormant or resting eggs, and respiration rates as a function of temperatures and animal size, were measured for Bythotrephes cederstroemi. The complete life cycle of Bythotrephes was observed to have two distinct morphological series. Post embryonic development was documented for parthenogenically produced and sexually produced offspring. A useful temperature dependent model for birth rate calculations in field work was developed based on observable morphological traits of embryos. Temperature and photoperiod are environmental cues that are known to affect the time and success in hatching of diapausing eggs in many species. An increase in temperature above the storage temperature (4$\sp\circ$C) was found to increase the success of hatching Bythotrephes diapausing eggs; however, all temperature treatments had an equivalent effect on success, implying that the cue is discrete and occurs close to 4$\sp\circ$C. Respiration rates for Bythotrephes cederstroemi were measured over a broad range of temperatures. The data was fit to the model f($\sp\circ$K) W$\rm\sp{b}$ where f($\sp\circ$K) is a mechanistic relationship for enzyme activity as a function of temperature. The enzyme kinetic model better described the biological observations of respiration as a function of temperature than standard empirical models. Energy flow in the arctic Daphnia middendorffiana as a function of temperature was investigated by measuring the processes of ingestion, assimilation, respiration, and growth. The scope for growth and reproduction was determined and compared with the temperate zone species Daphnia pulex. A difference was observed in the arctic species compared to the temperate zone species in both temperature ... |
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