Climate-driven warming, deoxygenation, and desertification in large marine ecosystems

Abstract

This study explores Large Marine Ecosystems (LME) impacts caused by climate-induced changes in sea surface temperature (SST), surface dissolved oxygen concentrations (O₂), and surface phytoplankton concentrations (CHL). It spans pre-industrial (1850–1900) to future (2015–2099) epochs under Shared Socioeconomic Pathways (SSPs) medium (SSP-2.45) and high (SSP-5.85) CO₂ emission scenarios. Across the 66 LMEs, we observed consistent warming, deoxygenation, and desertification, with more pronounced changes in SSP-5.85. SST trends (°C/decade) varied from 0.04 to 0.29 (SSP-2.45) and 0.12 to 0.63 (SSP-5.85), resulting in net increases from >3 °C (SSP-2.45) to >4.5 °C (SSP-5.85). O₂ exhibited trends (μmol/kg/decade) of −0.04 to −1.97 (SSP-2.45), with substantial declines in SSP-5.85 (−0.86 to −3.93), and significant net decreases (μmol/kg) of >−18 (SSP-2.45) and >−25 (SSP-5.85). CHL showed significant decreases (kg/m³) up to −0.31 (SSP-2.45) and −0.36 (SSP-5.85), with negative trends (kg/m³/decade) up to −0.0097 (SSP-2.45) and −0.0159 (SSP-5.85), except the Black Sea and Antarctica which exhibited positive trends. Climate indices reveal that LMEs experiencing the least impacts across all indicators occur in the East Siberian Sea, Faroe Plateau, Central Arctic, and Gulf of Mexico, in both scenarios. However, under the SSP-2.45 scenario, additional the Laptev Sea, Insular Pacific-Hawaiian also experienced lower impacts. In SSP-5.85, reduced impacts are observed in the South Brazil Shelf, East Brazil Shelf, Agulhas Current, West Central Australian Shelf, and Canadian High Arctic-North Greenland. Conversely, the most impacted LMEs, including the Barents Sea, Norwegian Sea, Oyashio Current, West Bering Sea, and the Aleutian Islands are affected in both scenarios. Additionally, the Pacific Central-American Coastal region, the Gulf of Alaska, Benguela Current, and the Sea of Japan are affected in the SSP-2.45 scenario. Only the Scotian Shelf experienced high impacts in SSP-5.85. Antarctica exhibited low impacts in both scenarios but substantial increases in SST, O₂, and CHL.