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Summer 2017 Updates

posted Aug 4, 2017, 7:39 AM by Stephen Gosnell   [ updated Sep 7, 2017, 1:36 PM ]
This summer we've been collaborating with the River Project​ and Billion Oyster Project on a study focused on how the presence of predators impacts biodeposition in oysters. Oysters feed by filtering plankton from the water, which is important to improving water quality. Biodeposition also connects pelagic (water) and benthic (sediment) systems as oysters produce biodeposits (poop, to put it scientifically). These biodeposits may act as fertilizer and increase the rates at which sediment microbes contribute to denitrification, or the removal of available nitrogen to the air. Denitrification is an important ecosystem service provided by coastal habitats, as excess nitrogen in aquatic systems can lead to algal blooms and resulting low oxygen conditions that can harm other living things. This is especially true in NY due to the high amounts of nitrogen our waters. 

We know from past studies that oysters grow less when they are near predators, so we assume predators impact their feeding. Changes in oyster feeding could include how much they filter from the water or how they use what they filter, and either of these changes mig
ht impact biodeposition quantity and quality and eventually influence denitrification rates. This summer we're exploring this issue by seeing how previous exposure to predators (oyster drills) interacts with immediate exposure to the predators to influence biodeposition by oysters. Preliminary results indicate oysters biodeposit more in the presence of predators. We plan to continue this work to quantify impacts of predators on oyster filtration rates and denitrification in adjacent sediments to better understand how these species interactions might influence ecosystem services.

Preliminary analysis indicates that predator presence and previous exposure to predators both increase biodepostion rates.