oysters and the climate crisis The climate crisis raises significant concerns for oyster farmers who, according to Wellfleet farmer Jake Puffer, tend not to plan for the unknown, but rather address the conditions in front of them. Ten years ago, Wellfleet farmers put out oyster hats to catch spat in early July. This year, because of earlier warm temperatures, they were placed in mid-June. It is unclear how shifts like this will impact cultivation. The oceans act as a carbon sink, absorbing roughly a quarter of anthropogenic carbon dioxide released since the Industrial Revolution, and leading to the acidification of seawater. The ocean’s dropping pH and dissolved oxygen levels adversely impact the formation of calcium carbonate, the primary material of an oyster shell, making it difficult for oyster larvae to survive long enough to become spat. In the United States, because of ocean currents, these effects were first observed in the Pacific Northwest, but acidification is a global phenomenon and a concern for farmers throughout the world. Interestingly, fossil records indicate that oysters have not evolved much in the last two hundred million years, having perfected themselves during a period of high ocean acidification: oysters evolved so that their shells, which had once been wholly aragonite, developed into a calcite material, the same as oysters today. 10 The reason young oysters are so vulnerable is because their shells still start as aragonite before transitioning to calcium carbonate. Hatcheries, working with marine researchers, are adapting their practices to reduce the impacts on larvae, allowing them to survive to the calcium carbonate stage of shell development. Oysters are biological machines that filter seawater. Unlike fish farmers, oyster farmers do not need to feed their stock. Oysters sustain themselves on what occurs naturally in their environment. An adult oyster can filter up to 190 litres of seawater per day in a cycle that includes nutrient consumption, waste processing and nutrient removal. The result is a cleaner, healthier water column less likely to spawn algal blooms and hypoxic dead zones unable to support life. Left to their own devices, oysters build reefs such as the one Champlain experienced as he attempted to sail into Port aux Huîtres – generations of spat attach to older oysters below. When wild oyster populations collapsed in the late 1800s from the combined impacts of pollution and overharvesting, the environmental benefits of the reefs were lost as well. Reefs can serve as breakwaters and calm the wave energy that erodes estuaries, while at the same time providing habitat for millions of species other than oysters. Efforts such as the Billion Oyster Project in New York City to restore wild oyster reefs are partially funded by the federal government as disaster prevention measures. conclusion In the age of sea-level rise, the waterscape of oystering, whether a small Wellfleet farm or reefs being built by restoration projects, is an increasingly essential element of resilient coastal communities. We are rediscovering the delicious, nutrient-dense oyster at a critical moment in human history where we need to focus our energy and resources on developing sources of protein and other nutrients that do not contribute to the climate crisis. 11 While the full scope of the impacts of the climate crisis are far from certain, it is clear that working with nature, rather than at odds with it, will be key to the survival of many species, including our own. *
Chesapeake Bay Foundation Sediment-filtering capacity of the oyster
Rosie Cohen
The Billion Oyster Restoration project, building oyster reefs as erosion mitigation in New York harbour.
JAMES MOSES is an architect practicing in western Massachusetts. Despite having been raised in Eastern Massachusetts, he did not eat a raw oyster until he was in his mid-twenties… in central Texas. He’s eaten many dozens in the ensuing years, perhaps none better than the Normandy-grown oysters ( Crassostrea gigas ) he ate in the shadow of the Maisons La Roche et Jeanneret.
10 Martino, Dan. The Oyster Book . Agate Publishing, 2024, p.23 11 Because oysters have only a nervous system, lacking a brain, they are not considered sentient. Some vegans will allow them as a component of their diets.
34 on site review 49 :: shorelines
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