Lobsters and acidic seas: can shellfish help neutralise one of the greatest threats to the ocean?

A lobster in St George, Maine. The crustacean is a tricky test subject, disliking warm seawater and ‘unfortunately, they eat each other.’ Photograph: D Grill/Tetra

For many in the US region of New England, the lobster roll is synonymous with summertime. Loaded into a toasted bun, chunks of the sweet meat are served hot and soaked in butter, or chilled and slathered in mayonnaise with celery and herbs.

The only thing more debated than the recipe is the price: the once-humble roll now routinely fetches $30 (£22), or even $50, in a sign of the changing times – and seas.