Spatial and temporal carbonate chemistry variability on coral reefs is influenced by a combination of seawater hydrodynamics, geomorphology, and biogeochemical processes, though their relative influence varies by site. It is often assumed that the water column above most reefs is well-mixed with small to no gradients outside of the benthic boundary layer. However, few studies to date have explored the processes and properties controlling these multi-dimensional gradients. Here, we investigated the lateral, vertical, and temporal variability of seawater carbonate chemistry on a Bermudan rim reef using a combination of spatial seawater chemistry surveys and autonomous in situ sensors. Instruments were deployed at Hog Reef measuring current flow, seawater temperature, salinity, pH_T, pCO₂, dissolved oxygen (DO), and total alkalinity (TA) on the benthos, and temperature, salinity, DO, and pCO₂ at the surface. Water samples from spatial surveys were collected from surface and bottom depths at 13 stations covering ∼3 km² across 4 days. High frequency temporal variability in carbonate chemistry was driven by a combination of diel light and mixed semi-diurnal tidal cycles on the reef. Daytime gradients in DO between the surface and the benthos suggested significant water column production contributing to distinct diel trends in pH_T, pCO₂, and DO, but not TA. We hypothesize these differences reflect the differential effect of biogeochemical processes important in both the water column and benthos (organic carbon production/respiration) vs. processes mainly occurring on the benthos (calcium carbonate production/dissolution). Locally at Hog Reef, the relative magnitude of the diel variability of organic carbon production/respiration was 1.4–4.6 times larger than that of calcium carbonate production/dissolution, though estimates of net organic carbon production and calcification based on inshore-offshore chemical gradients revealed net heterotrophy (−118 ± 51 mmol m^–2 day^–1) and net calcification (150 ± 37 mmol CaCO₃ m^–2 day^–1). These results reflect the important roles of time and space in assessing reef biogeochemical processes. The spatial variability in carbonate chemistry parameters was larger laterally than vertically and was generally observed in conjunction with depth gradients, but varied between sampling events, depending on time of day and modifications due to current flow.

珊瑚礁的时空碳酸盐化学变化是受海水流体动力学，地貌学和生物地球化学过程综合影响的，尽管它们的相对影响因地点而异。通常认为，在大多数礁石上方的水柱充分混合，底栖边界层以外的梯度很小甚至没有梯度。但是，迄今为止，很少有研究探索控制这些多维梯度的过程和属性。在这里，我们结合空间海水化学调查和自主研究，调查了百慕大边缘礁上海水碳酸盐化学的横向，垂直和时间变化。原位传感器。在猪礁部署了仪器，用于测量电流，海水温度，盐度，pH _T，p底栖动物的CO ₂，溶解氧（DO）和总碱度（TA）以及温度，盐度，DO和p表面的CO ₂。来自空间调查的水样在4天的约3 km ²内从13个站的地表和底部深度采集。碳酸盐化学过程中的高频时间变化是由礁石上的diel光和混合的半日潮汐循环共同驱动的。表面和底栖生物之间的溶解氧在白天的梯度表明，水柱的产生显着，导致pH _T的明显diel趋势，pCO ₂和DO，但不包括TA。我们假设这些差异反映了在水柱和底栖生物中重要的生物地球化学过程（有机碳产生/呼吸作用）与主要在底栖生物中发生的过程（碳酸钙产生/溶解）的差异作用。在猪礁的本地，有机碳生产/呼吸的狄尔变异性的相对大小是碳酸钙生产/溶解的狄尔变异性的相对大小的1.4-4.6倍，尽管根据近岸-近海化学梯度估算的净有机碳产量和钙化显示净异养（−118±51 mmol m ^–2天^–1）和净钙化（150±37 mmol CaCO ₃ m ^–2天^–1）。这些结果反映了时间和空间在评估礁石生物地球化学过程中的重要作用。碳酸盐化学参数的空间变异性在横向上大于垂直方向，通常与深度梯度一起观察到，但在采样事件之间变化，这取决于一天中的时间和电流的变化。