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San Jose State University

Master's Theses

2022

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The Shallow Benthic Invertebrate Recovery From The End-Cretaceous Mass Extinction Across The Gulf Coastal Plain, Ronan B. Beltracchi May 2022

The Shallow Benthic Invertebrate Recovery From The End-Cretaceous Mass Extinction Across The Gulf Coastal Plain, Ronan B. Beltracchi

Master's Theses

The Gulf Coastal Plain, in the southeastern United States, contains several sites with well-preserved fossil assemblages from the Cretaceous- Paleogene boundary (K/Pg). Changes in benthic macroinvertebrate assemblages after mass extinction events commonly include reduction in body size of surviving organisms and preferential survival based on ecospace occupation. This study examines patterns of functional ecology and body size change in mollusk fossils from bulk samples collected throughout the post-extinction recovery interval at a well-studied boundary site from Darting Minnow Creek in Brazos, Texas USA and a recently described K/Pg boundary section on the Ouachita River in Malvern, Arkansas USA. The proportional …


Research Handling Effects On Stress Hormones, Blood Parameters, And Heart Rate In Juvenile Northern Elephant Seals (Mirounga Angustirostris), Lauren A. Cooley Jan 2022

Research Handling Effects On Stress Hormones, Blood Parameters, And Heart Rate In Juvenile Northern Elephant Seals (Mirounga Angustirostris), Lauren A. Cooley

Master's Theses

Wildlife researchers must balance the need to safely capture and handle their study animals to sample tissues, collect morphological measurements, and attach dataloggers while simultaneously ensuring their results are not confounded by stress artifacts caused by handling. To determine the physiological effects of research activities including chemical immobilization, transport, instrumentation with biologgers, and overnight holding on a model marine mammal species, I collected hormone, blood chemistry, hematology, and heart rate data from 19 juvenile northern elephant seals (Mirounga angustirostris) throughout a translocation experiment. Across my six sampling timepoints, cortisol and aldosterone data revealed a moderate hormonal stress response to handling …