Assessing the chemical landscape of the Galápagos Marine Reserve

The Galápagos Archipelago is at the forefront of the Anthropocene, facing intensifying pressures from its growing human footprint and accelerated global connectivity. Despite this, little is currently known of its chemical landscape. This review critically examines the drivers, sources, distribution and fate of oil, plastics, pesticides, persistent organic pollutants and heavy metals in the Galápagos Marine Reserve, identifying pollutant hotspots and evaluating rapid assessment methods and sentinel species that could aid regional monitoring. The cumulative influence of the Galápagos' equatorial position amongst major (and seasonally variable) atmospheric and oceanic circulation patterns, along with its distinctive geophysical and environmental conditions, such as extreme UV radiation and precipitation, likely exacerbates the archipelagos susceptibility to chemicals from both local and continental inputs. Point and diffuse sources identified include wastewater/effluent discharge, agricultural run-off, mismanaged waste, recreational boating, commercial shipping and industrial fishing. Limited spatiotemporal monitoring has hindered the identification of pollution hotspots, except for harbours as aggregates for maritime activities and urban run-off, and eastern-facing coastlines exposed to the Humboldt Current as plastic accumulation zones. Furthermore, the remote nature and vital protected status of the Galápagos National Park has constrained comprehensive assessment of chemical toxicity and its impacts on marine species across the reserve, with studies primarily restricted to Galápagos pinnipeds. Thus, there is currently insufficient knowledge to determine the extent to which the widespread but sporadic presence of chemical contaminants threatens the resilience and adaptive capacity of Galápagos' complex ecosystems, unique biodiversity and interconnected environmental processes. Future efforts are recommended to strengthen environmental monitoring and chemical risk assessment through the utilisation of rapid assessment tools and regional sentinel species, enhancing fundamental understanding of the chemical landscape in this global conservation Hope Spot, as well as the wider implications of the Anthropocene on diverse, dynamic and remote island ecosystems.