Pacific oysters, are an integral part of Puget Sound's ecology, economy, and culture. Of the nearly 25 million pounds of bivalves farmed in Washington in 2013, one-third were Pacific oysters (Crassostrea gigas). (NOAA Washington Shellfish Initiative).
Oyster reefs create fish habitat, stabilize shorelines, and improve water quality and clarity by filter feeding. Excluding harvesting, yearly economic value of these ecosystem services is estimated between $5,500 and $99,000 per hectare.
Currently, the economic, social, and environmental benefits provided by C. gigas are endangered by climate change.
Ocean acidification and rising ocean temperatures are two of the most critical dimensions of changing climate in marine ecosystems. When the ocean absorbs atmospheric carbon dioxide, the gas reacts with water to form carbonic acid and bicarbonate, lowering pH. Increased production of bicarbonate also results in dissolution of calcium carbonate. It is the latter that affects shell formation for marine calcifiers like C. gigas. Larval oysters and spat (newly-settled oysters) have poorly formed shells, low survivorship, and developmental delays in acidified conditions. Adult oysters face shell degradation and compromised reproductive function. Additionally, warmer conditions lead to increased energy demand by C. gigas and greater indicators of oxidative stress.
In this class, we will first discuss the phenomenon of ocean acidification, focusing on how natural features of estuarine systems like those found in Puget Sound can exaggerate climate change impacts. We will then engage in hands-on activity to understand how Pacific oysters are impacted by ocean acidification at different life stages. Finally, we'll explore how the field of genetics can be used to ensure oysters will thrive in future oceans.
Introduction to ocean acidification: https://www.youtube.com/watch?v=6SMWGV-DBnk
Introduction to oyster genetics and climate change resilience: https://www.youtube.com/watch?v=WP8J0-90VoM