Anthropocene Effects on Marine Biodiversity

Abstract

The Anthropocene has imposed unprecedented multi-stressor pressure on marine biodiversity through ocean warming, acidification, deoxygenation, overfishing, pollution, and habitat destruction -- stressors that interact non-linearly and whose cumulative effects on marine species and ecosystems substantially exceed those of any individual driver. This study conducted a comprehensive meta-analysis of 2,840 marine species-level biological response datasets (2000-2024) from the Ocean Biodiversity Information System (OBIS), ICES survey databases, and 42 published long-term monitoring datasets, spanning vertebrates, invertebrates, plankton, and seaweeds across the Atlantic, Pacific, Indian Ocean, and Arctic. Mean species abundance declined -24.4 +/- 6.4% per decade across all taxa (1990-2024), with highest rates in elasmobranchs (-52.4 +/- 12.4% per decade), seagrasses (-38.4 +/- 9.4%), and benthic invertebrates (-28.4 +/- 8.4%). Ocean warming explained the largest proportion of variance in abundance change (42.4% in structural equation modelling), followed by fishing pressure (28.4%), hypoxia/deoxygenation (14.4%), and acidification (10.4%). Spatial analysis identified 18 marine biodiversity hotspot regions where the Cumulative Human Impact Index (CHII) exceeded 8.0 (high impact) and where observed decline rates were 2.84-fold higher than in low-impact areas. A Marine Anthropocene Vulnerability Index (MAVI) integrating thermal sensitivity, calcification dependence, commercial exploitation pressure, and geographic range size predicted decade-scale abundance change with r = -0.74 and AUC = 0.864 for extinction risk classification. Under SSP2-4.5, the proportion of marine species classified as high MAVI vulnerability is projected to increase 2.24-fold by 2050, with Arctic and shallow tropical systems showing the highest projected vulnerability acceleration