Department of Marine Ecology/Faculty of Biology and Chemistry, Universität Bremen, Bremen, Germany.
Departamento de Biología/Facultad de Ciencias Naturales y Exactas/Grupo de Investigación en Ecología de Arrecifes Coralinos, Universidad del Valle, Cali, Valle del Cauca, Colombia.
PeerJ. 2023 Jan 26;11:e14586. doi: 10.7717/peerj.14586. eCollection 2023.
Dissolved oxygen concentration (DO) is one of the main factors limiting benthic species distribution. Due to ocean warming and eutrophication, the ocean is deoxygenating. In the Eastern Tropical Pacific (ETP), deep waters with low DO (<1 mg L) may reach coral reefs, because upwelling will likely intensify due to climate change. To understand oxygen variability and its effects on corals, we characterize the Spatio-temporal changes of DO in coral reefs of Gorgona Island and calculate the critical oxygen tension ( ) to identify the DO concentration that could represent a hypoxic condition for , one of the main reef-building species in the ETP. The mean (±SD) DO concentration in the coral reefs of Gorgona Island was 4.6 ± 0.89 mg L. Low DO conditions were due to upwelling, but hypoxia (<3.71 mg L, defined as a DO value 1 SD lower than the Mean) down to 3.0 mg O L sporadically occurred at 10 m depth. The of was 3.7 mg L and lies close to the hypoxic condition recorded on coral reefs during the upwelling season at 10 m depth. At Gorgona Island oxygen conditions lower than 2.3 mg L occur at >20 m depth and coincide with the deepest bathymetric distribution of scattered colonies of . Because DO concentrations in coral reefs of Gorgona Island were comparably low to other coral reefs in the Eastern Tropical Pacific, and the hypoxic threshold of was close to the minimum DO record on reefs, hypoxic events could represent a threat if conditions that promote eutrophication (and consequently hypoxia) increase.
溶解氧浓度（DO）是限制底栖物种分布的主要因素之一。由于海洋变暖与富营养化，海洋正在脱氧。在东热带太平洋（ETP），低 DO（<1mg/L）的深水可能会到达珊瑚礁，因为气候变化可能会加剧上升流。为了了解氧气的变化及其对珊瑚的影响，我们描述了戈尔戈纳岛珊瑚礁的时空 DO 变化，并计算了临界氧张力（ ），以确定 DO 浓度，该浓度可能代表东热带太平洋的主要造礁物种之一—— 的低氧条件。戈尔戈纳岛珊瑚礁的平均（±SD）DO 浓度为 4.6±0.89mg/L。低 DO 条件是由于上升流造成的，但在 10 米深处，偶尔会出现低氧（<3.71mg/L，定义为比平均值低 1 SD 的 DO 值），持续时间较短。 为 3.7mg/L，接近上升流季节在 10 米深处记录的珊瑚礁低氧条件。在戈尔戈纳岛，氧气浓度低于 2.3mg/L 出现在>20 米深处，与分散的 散生群体的最深水深分布一致。由于戈尔戈纳岛珊瑚礁的 DO 浓度与东热带太平洋其他珊瑚礁相当低，并且 接近珊瑚礁上记录的最低 DO 值，因此如果促进富营养化（进而导致低氧）的条件增加，低氧事件可能会构成威胁。
