Mangroves sustain high soil accretion and carbon sequestration rates, yet it is still unknown if they can keep pace with increasing sea level rise (SLR) across a wider range of coastal geomorphic settings. Because accretion rates are controlled by mineral sediment inputs and organic matter accumulation, it is paramount to assess the relative contribution of root productivity to soil formation. Here, we evaluated root biomass, production, and turnover in three mangrove ecotypes to evaluate the role of soil nutrient limitation, stressors, and hydroperiod in controlling root dynamics in San Andres Island (SAI), a karstic oceanic island in the Caribbean Sea. Root production was modulated by soil stress conditions and not by nutrient availability as it has been reported for other karstic environments. The lowest root biomass allocation, and both production and turnover of fine roots were measured under low flooding duration, and low salinity (<20 PSU) and sulfide concentrations (0.84 ± 0.4 mM). Yet, when soil stress conditions increased during high flooding duration (6207 h y–1) and low oxygen conditions (Eh), root tissues reached the highest biomass and production values, including a relative fast turnover of fine roots (<2 mm; 0.75 y–1). Our results follow the predictions of the plant root longevity cost-benefit hypothesis where plants maintain roots only until the efficiency of resource acquisition is maximized by water and nutrient acquisition. Because of the importance of groundwater in controlling porewater salinity and mangrove root productivity in karstic oceanic islands such as SAI, water use and coastal development should be regulated in the short term to avoid the loss of mangrove area and concomitant ecosystem services.

中文翻译：

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水周期和盐度相互作用控制加勒比海岩溶海洋岛屿的红树林根系动力学（哥伦比亚圣安德烈斯）

红树林维持着较高的土壤吸积率和碳固存率，但它们是否能跟上更广泛的沿海地貌环境中不断上升的海平面上升 (SLR) 的步伐仍是未知数。由于沉积速率受矿物沉积物输入和有机物质积累控制，因此评估根系生产力对土壤形成的相对贡献至关重要。在这里，我们评估了三种红树林生态型的根生物量、产量和周转率，以评估土壤养分限制、压力源和水周期在控制加勒比海岩溶海洋岛屿圣安德烈斯岛 (SAI) 根系动态方面的作用。根系生产受土壤压力条件的调节，而不是受其他岩溶环境报道的养分有效性调节。最低的根生物量分配，在低水淹持续时间、低盐度 (<20 PSU) 和硫化物浓度 (0.84 ± 0.4 mM) 下测量细根的产量和周转率。然而，当在高水淹持续时间 (6207 hy-1) 和低氧条件 (Eh) 期间土壤压力条件增加时，根组织达到最高的生物量和生产值，包括细根的相对快速周转（<2 mm；0.75 y –1)。我们的结果遵循植物根系寿命成本效益假设的预测，即植物只维持根系，直到通过水和养分获取最大化资源获取效率。由于地下水在控制岩溶海洋岛屿（如 SAI）的孔隙水盐度和红树林根系生产力方面的重要性，