Methane (CH₄) and nitrous oxide (N₂O) dynamics in coastal coral reef areas are poorly understood. We measured dissolved carbon dioxide (CO₂) and CH₄ (with δ¹³C-CO₂ and δ¹³C-CH₄ isotope fractions) and N₂O in the Great Barrier Reef (GBR) to determine spatial distributions and emissions. CO₂ (379–589 μatm) was oversaturated due to calcification and riverine sources, as indicated by depleted δ¹³C-CO₂ values. CH₄ (1.5–13.5 nM) was also oversaturated from nearshore biogenic sources indicated by depleted δ¹³C-CH₄ and probable offshore aerobic production. N₂O (5.5–6.6 nM) was generally undersaturated, with uptake highest near the coast. Daily CO₂ emissions were 5826 ± 1191 tonnes, with CO₂ equivalent (_eq) N₂O uptake (191 ± 44 tonnes) offsetting 3.3% of CO₂ or 89% of CH_4eq (214 ± 45 tonnes) emissions based on 20-year global warming potentials. The GBR was a slight CO₂ and CH₄ source and N₂O sink during our study. However, further work is required to constrain diurnal, seasonal, and spatial dynamics.

中文翻译：

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通过高分辨率采样和同位素分析揭示大堡礁中 CO2、CH4 和 N2O 的空间分布

对沿海珊瑚礁地区的甲烷 (CH ₄ ) 和一氧化二氮 (N ₂ O) 动态知之甚少。我们测量了大堡礁 (GBR) 中溶解的二氧化碳 (CO ₂ ) 和 CH ₄（具有 δ ¹³ C-CO ₂和 δ ¹³ C-CH ₄同位素分数）和 N ₂ O，以确定空间分布和排放。CO ₂ (379–589 μatm) 由于钙化和河流源而过饱和，如耗尽的 δ ¹³ C-CO ₂值所示。CH ₄ (1.5–13.5 nM) 也从近岸生物源中过饱和，由耗尽的 δ¹³ C-CH ₄和可能的海上需氧生产。N ₂ O (5.5–6.6 nM) 通常不饱和，在海岸附近吸收最高。每日 CO ₂排放量为 5826 ± 1191 吨，其中 CO ₂当量 ( _eq ) N ₂ O 吸收量 (191 ± 44 吨) 抵消了 CO _{2 的}3.3%或 CH _{4 eq} (214 ± 45 吨) 排放量的89%，基于 20 -年全球变暖潜势。在我们的研究中，GBR 是轻微的 CO ₂和 CH ₄源以及 N ₂ O 汇。然而，需要进一步的工作来限制昼夜、季节性和空间动态。