Hypoxia, a condition of low oxygen levels, is a growing problem in coastal waters, with severe consequences for marine life, including death and ecosystem disruption. The study by Raquel Vaquer-Sunyer and Carlos M. Duarte highlights that the conventional threshold of 2 mg O₂/liter for hypoxia is too low for many marine species, as it falls below the sublethal and lethal oxygen thresholds for half of the tested species. This suggests that the current understanding of hypoxia impacts on marine biodiversity is underestimated. The research analyzed experimental data from 872 studies involving 206 species of benthic organisms, revealing a wide range of oxygen thresholds for lethal and sublethal responses. Median lethal oxygen concentrations (LC₅₀) ranged from 8.6 mg O₂/liter for the most sensitive species to 0.085 mg O₂/liter for others. Median sublethal concentrations (SLC₅₀) ranged from 10.2 mg O₂/liter to 0.085 mg O₂/liter. Median lethal times (LT₅₀) varied significantly, with some species surviving for over 32 weeks under hypoxia. The study found that different taxa have varying oxygen thresholds, with crustaceans being the most sensitive and molluscs the most tolerant. Fish and crustaceans, which are highly mobile, showed higher thresholds, allowing them to avoid hypoxic waters. However, many species, including fish and crustaceans, experience significant mortality before reaching the 2 mg O₂/liter threshold. The conventional 2 mg O₂/liter threshold is inadequate for conserving marine biodiversity, as it fails to account for the wide variability in oxygen thresholds among species. The study suggests that a higher threshold, such as 4.6 mg O₂/liter, could better protect marine life, as it would avoid catastrophic mortality for most species. The findings emphasize the need for revised hypoxia thresholds to better manage and conserve coastal ecosystems. The study also highlights the limitations of laboratory experiments in predicting field conditions, as oxygen levels in the field fluctuate and are influenced by various factors. Despite these limitations, laboratory experiments provide a conservative estimate of oxygen thresholds, which should be considered when setting management targets to protect marine biodiversity. The results underscore the urgent need for revised hypoxia thresholds to address the growing threat of hypoxia to coastal ecosystems.Hypoxia, a condition of low oxygen levels, is a growing problem in coastal waters, with severe consequences for marine life, including death and ecosystem disruption. The study by Raquel Vaquer-Sunyer and Carlos M. Duarte highlights that the conventional threshold of 2 mg O₂/liter for hypoxia is too low for many marine species, as it falls below the sublethal and lethal oxygen thresholds for half of the tested species. This suggests that the current understanding of hypoxia impacts on marine biodiversity is underestimated. The research analyzed experimental data from 872 studies involving 206 species of benthic organisms, revealing a wide range of oxygen thresholds for lethal and sublethal responses. Median lethal oxygen concentrations (LC₅₀) ranged from 8.6 mg O₂/liter for the most sensitive species to 0.085 mg O₂/liter for others. Median sublethal concentrations (SLC₅₀) ranged from 10.2 mg O₂/liter to 0.085 mg O₂/liter. Median lethal times (LT₅₀) varied significantly, with some species surviving for over 32 weeks under hypoxia. The study found that different taxa have varying oxygen thresholds, with crustaceans being the most sensitive and molluscs the most tolerant. Fish and crustaceans, which are highly mobile, showed higher thresholds, allowing them to avoid hypoxic waters. However, many species, including fish and crustaceans, experience significant mortality before reaching the 2 mg O₂/liter threshold. The conventional 2 mg O₂/liter threshold is inadequate for conserving marine biodiversity, as it fails to account for the wide variability in oxygen thresholds among species. The study suggests that a higher threshold, such as 4.6 mg O₂/liter, could better protect marine life, as it would avoid catastrophic mortality for most species. The findings emphasize the need for revised hypoxia thresholds to better manage and conserve coastal ecosystems. The study also highlights the limitations of laboratory experiments in predicting field conditions, as oxygen levels in the field fluctuate and are influenced by various factors. Despite these limitations, laboratory experiments provide a conservative estimate of oxygen thresholds, which should be considered when setting management targets to protect marine biodiversity. The results underscore the urgent need for revised hypoxia thresholds to address the growing threat of hypoxia to coastal ecosystems.