Rachel Carson’s Silent Spring (1962) is rightly recognised as a seminal text, the first to draw meaningful critical attention onto the devastating effects of the widespread use of pesticides and insecticides on land-based wildlife, and on human health. Less well known is what the text has to say about the destruction of marine environments. This paper argues that Silent Spring is prescient in suggesting that the effects of damage to marine biodiversity may ultimately prove even more detrimental to our ecosystems than the damage to land biodiversity. What Silent Springhas to say about threats to marine biodiversity has hitherto been overlooked in previous critiques of Carson’s text. In this paper, I will show how Carson reminds us in Silent Spring that oceans are the ultimate receptacle for the cocktail of insecticides and pesticides that run off land into freshwater systems and to the sea. She calls for further research into the unknown effects of these forms of marine pollution, and she documents several examples that had recently become visible: the destruction of marine fish and bird species who depend in their food chain on land-based species eradicated by insecticides or pesticides; and the grave loss of marine bird, fish and crustacean populations as a direct result of the spraying of insecticide onto salt marshes, and the indirect effect of the discharge of pesticides into rivers and estuaries. The paper will show how this work in Silent Spring echoes her work in her ‘Sea Trilogy’ (1941-1955). Ultimately, this paper serves as a reminder that the gravity of threats to marine biodiversity were anticipated by Carson in one of the seminal texts of the modern ecological movement.