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Impacts of Hurricanes on Phytoplankton Blooms in the Chincoteague Bay Trudee Jaeger, Department of Biology, York College Introduction Due to the climate.

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Presentation on theme: "Impacts of Hurricanes on Phytoplankton Blooms in the Chincoteague Bay Trudee Jaeger, Department of Biology, York College Introduction Due to the climate."— Presentation transcript:

1 Impacts of Hurricanes on Phytoplankton Blooms in the Chincoteague Bay Trudee Jaeger, Department of Biology, York College Introduction Due to the climate change, scientists have predicated increased levels of hurricane intensity. Hurricanes are destructive to the environment with their torrential rainfall and high-velocity winds. These conditions can significantly impact phytoplankton communities. Phytoplankton are single-celled organisms which photosynthesize in the ocean. They are the start of the food chain and require plenty of both light and nutrients in order to grow. Often, however, light and nutrients are found in different locations in the water column. During the passing of a hurricane, the water column of the bay can mix. This mixing will cause colder, nutrient- rich water on the bottom to be mixed with the warmer nutrient-poor water on top. If the water column restratifies, this can give phytoplankton excess light and nutrients, causing a bloom. Review of Literature They noted that phytoplankton response depended on both the conditions of the storm and the water column beforehand (Wetz and Paerl, 2008). The damage to the ecosystem of Pamlico Sound was also much more severe when multiple storms passed in a short period of time (Wetz and Paerl, 2008). During the passage of a hurricane, salinity dropped within the bay. The more significant the drop of salinity levels, the larger the noted response of a phytoplankton bloom. They even found a large phytoplankton bloom after a seemingly small hurricane (Wetz and Paerl, 2008). Despite this knowledge, there has been minimal research in the relationship between phytoplankton dynamics with the types and magnitudes of storms (Wetz and Paerl, 2008). These findings have not been measured in bays as small as the Chincoteague Bay (of Maryland and Virginia). Water stratification is the vertical distribution in water density, dividing the water column. Light levels are highest at the surface. Nutrient levels increase with depth. Preliminary Research Salinity: As the hurricanes pass the Chincoteague Bay, salinity levels plummet from freshwater rainfall and run-off. Temperature: Temperature decreased and then rose again, especially after hurricanes Bonnie and Charley. This may indicate the storms caused mixing of the water column then the water re-stratified, giving phytoplankton access to both excess nutrients and light. Chlorophyll: Chlorophyll levels spiked roughly two weeks following hurricane activity which shows the occurrence of a phytoplankton bloom. Nutrient Data Figure 1. Temperature, salinity and chlorophyll levels of the Chincoteague Bay, Bishopsville Prong. Measured roughly one month prior and post Hurricanes Bonnie, Charley and Alex, Proposed Hypothesis Proposed Methods Establish a sampling location at Northern, Southern and central regions of the bay. Observe both the top and bottom layers of the water column. Automated observations of temperature, salinity and chlorophyll levels with YSI 6600 data loggers every 15 minutes. Optical nitrate analyzer - Satlantic SUNA V2 nitrate sensor. Will be on buoy, sampling continuously to increase sampling frequency for nutrients. Sampling to be taken for 10 years Take a sampling point in Virginia, which has not been historically sampled Proposed Results Figure 5. Proposed measurement of chlorophyll levels in the Chincoteague Bay after a hurricane under differing pre-hurricane stratification conditions. An unpaired t-test indicated a significant difference (*) between values (p<0.05). Phytoplankton levels are expected to significantly increase if the water column is stratified prior to the storm. When the storm passes, mixing occurs which allows phytoplankton to be exposed to higher levels of light and nutrients causing a larger bloom. Figure 6. Proposed impact of the number of hurricanes passing in a month on subsequent chlorophyll levels in the Chincoteague Bay A linear regression showed a significant relationship between number of storms and chlorophyll levels (p<0.05). Phytoplankton blooms are expected to increase if there are more hurricanes per month as repeated mixing and runoff result in continued inputs of nutrients to the system. Importance Phytoplankton are the start of the food web. When a storm impacts them, the entire bay ecosystem can be affected. Phytoplankton blooms can cause toxicity and hypoxia which would destroy bay life and greatly impact local fisheries. Works Cited Hughes, C. (2009). Difficulties in separating hurricane induced effects from natural benthic succession: Hurricane isabel, a case study from eastern virginia, usa. Estuarine, Coastal and Shelf Science, 85(3), Retrieved from cdn.com/S Wetz, M. and Paerl, H. (2008). Estuarine phytoplankton responses to hurricanes and tropical storms with different characteristics (trajectory, rainfall, winds). Estuaries and Coasts, 31(2), Retrieved from Acknowledgements I would like to thank Dr. Jessica Nolan for her endless support and guidance, and extend my gratitude to Joshua Brennan and Emily Springer for statistical advice. Wetz and Paerl (2008) studied the short-term impacts of five hurricanes, both small and large in scale, in Pamlico Sound, North Carolina. Figure 2. Original sampling location (Bishopsville Prong) with proposed Northern, Southern and central sampling locations of the Chincoteague Bay. Figure 3. YSI 6600 data logger. Figure 4. Satlantic SUNA V2 nitrate sensor. Bishopsville Prong Northern Location Central Location Southern Location earth.google.com/


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