The ecological consequences of nutrient enrichment in mangroves

Mangrove forests are among the most productive ecosystems on earth, despite featuring trees that can grow in nutrient poor, highly saline environments with anoxic soils. Anthropogenic inputs of both nitrogen (N) and phosphorus (P) have increased due to agricultural, aquacultural, and urban runoff into coastal mangrove ecosystems. Further, mangrove ecosystems are increasingly impacted by changing global pressures, like climate warming and sea level rise (SLR), which can exacerbate the effects of nutrient pollution. We summarize the existing literature on nutrient enrichment influences on mangrove growth, reproduction, and mortality. We also review the impacts of excess nutrients on soil respiration, microbial communities and decomposition within mangrove ecosystems. Based on this literature, we identify three emergent implications of nutrient enrichment for mangroves: 1) resilience to extreme climatic events and SLR, 2) mangrove range expansion, and 3) carbon storage capacity. Lastly, we explore key gaps in the literature while offering future research suggestions to address them. We argue that understanding and addressing the impact of nutrient enrichment on mangrove ecosystems is crucial to protect their ability to mitigate and adapt to the challenges of climate change.