| Summary: | Thesis (Ph.D.) - Florida Institute of Technology, 2016 The emission of greenhouse gases into the atmosphere over the last century has increased atmospheric and oceanic temperatures, and has led to a decrease in oceanic pH. The increased ocean temperatures and reduced pH have been detrimental to marine life. In addition, Florida’s watersheds have suffered from decades of disrupted hydrology and diverted runoff, which has increased nutrients and changed coastal carbonate chemistry. Although the adult stages of many marine species are capable of tolerating fluctuations in environmental conditions (i.e., elevated pCO₂ tolerances to such conditions improve. and temperature), marine larvae that hatch in coastal habitats may not have the ability to detect, respond to, or even tolerate such conditions. This study examined the response of the Florida stone crab, Menippe mercenaria, as a model for coastal crustaceans, to determine the impacts of elevated temperature and ocean acidification (OA) on embryonic development and hatching success. The study determined the impacts of simultaneous exposure to both elevated temperature and OA on stone crab survival, larval growth, larval condition, and larval morphology throughout development. The study also examined whether changes in environmental conditions affected the ability of larvae to orient vertically. More specifically, the geotactic swimming behavior of larval stone crabs was tested to determine if elevated temperature and pCO₂ impacted geotaxis orientation, and if geotactic responses change throughout larval development. The impacts of OA on stone crab embryonic development and hatching success was determined by maintaining ovigerous females in conditions that mimicked present-day (pCO₂ ~ 360 ppm, pH = 8.1) and future carbonate conditions (pCO₂ ~ 1500 ppm, pH = 7.5). To determine the effects of simultaneous exposure of stone-crab larvae to elevated temperature and pCO₂, larvae were raised in a fully crossed experiment with two treatments, temperature, and pCO₂, each ...
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