Seagrass as a stabilizing environment for benthic foraminifera living in anthropogenically impacted coastal areas

Abstract

In tropical regions, seagrass meadows provide a unique habitat for benthic foraminifera, both serving as important ecosystem engineers and sensitive indicators of coastal marine ecosystems. However, their interactions remain poorly understood, particularly in the context of anthropogenic pressures and climate change. This study investigates benthic foraminiferal assemblages associated with the tropical seagrass Halophila stipulacea in the Gulf of Aqaba-Eilat (GoA) as a model system to monitor natural and anthropogenic changes. Sampling was conducted during 11 campaigns (January 2020–April 2021) at two sites: South Coast (SC), a pristine shoreline, and North Coast (NC), an urbanized area. At each site, samples were collected from three distinct environments: seagrass leaves (L), sediments within meadows (SIM), and sediments outside meadows (SOM).

Throughout all of the sampling period, we found higher abundance and diversity of benthic foraminifera in sediments within H. stipulacea meadows (SIM) compared with sediments outside meadows (SOM). These results demonstrate that H. stipulacea creates a favorable environment for benthic foraminifera compared to adjacent bare sediments. Notably, the occurrence of certain foraminiferal species in the GoA is directly linked to the presence of seagrass. The leaves also serve as nurseries for juvenile Amphistegina, a key cosmopolitan symbiont-bearing genus. Additionally, the seagrass meadows appear to mitigate anthropogenic impacts, maintaining “healthy” foraminiferal assemblages even in the urbanized northern region of the GoA (NC). These findings highlight the ecological importance of seagrass meadows for benthic foraminifera and emphasize their susceptibility to anthropogenic stressors.