Dataset and code: Experimental evidence for transgenerational effects of environmental heavy metals in a long-lived seabird

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Abstract of the study: Marine ecosystems are experiencing unprecedented selective pressures from increasing pollution due to human activities. As top predators, seabirds are particularly exposed to these pressures. While the impacts of contaminants and low food quality on adult seabirds are well documented, far less is known about potential transgenerational effects. Yet, filling this gap is crucial, as early-life development can have pervasive consequences on individual fitness and population dynamics. Using a unique experimental setting, we fed breeding Common gulls (Larus canus) with either fish originating from polluted or clean habitats during the egg-laying period. Fish caught from the polluted habitat were confirmed to contain higher levels of a cocktail of non-essential trace elements and a lower energy content compared to fish from the clean habitat. Our results show that even short-term exposure to environmentally relevant levels of pollution has measurable transgenerational consequences on morphological and physiological traits of chicks. Precisely, they had smaller head-bill lengths and tended to exhibit lower hatchling mass when parents were fed fish from the polluted habitat. Moreover, these chicks showed an impaired corticosterone secretion and disruption of the relationship between growth and corticosterone compared to chicks from parents fed with fish from the clean habitat. Altogether, our study provides one of the first experimental evidence that environmentally relevant exposure to polluted food during breeding can generate negative transgenerational effects in seabirds. Our findings highlight an overlooked pathway through which human-driven environmental changes may alter early-life development and, consequently, population dynamics in a world of rapidly changing marine ecosystems.