Exploring mesophotic coral reef boundaries using environmental DNA metabarcoding
In: Environmental DNA. John Wiley & Sons: Hoboken. ISSN 2637-4943; e-ISSN 2637-4943, meer
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| Author keywords |
biomonitoring | eDNA | marine biodiversity | mesophotic ecosystem | metazoan assemblages |
| Abstract |
Mesophotic coral reefs are deep tropical reefs (40–160 m) characterized by light attenuation that are renowned for their unique biodiversity and ecological significance. They have long been proposed to supplement shallow reefs and serve as refugia for shallow-water species in the face of ocean warming. Nevertheless, these deep reefs are still severely understudied compared to shallow reefs, mainly due to the technical challenges inherent to deep water environments. Here, we utilized environmental DNA (eDNA) metabarcoding to provide high-resolution spatial biodiversity profiling and evaluate changes in the community structure across the steep depth gradient in the Gulf of Aqaba, Red Sea. eDNA was extracted from water samples spanning from shallow reefs to mesophotic depths and beyond (10 to 200 m), utilizing a metabarcoding pipeline focusing on metazoan assemblages. We show that community structure differs significantly across depth, particularly between the shallow reef and lower mesophotic. Specifically, we show that depth proved to be more influential than site in shaping the respective community structures, regardless of the statutory status and protection level of the sites. We thus provide quantitative evidence to support the current mesophotic classification as defined by abiotic factors. We further provide support for effective species overlap between the upper mesophotic and shallow depth communities, asserting the potential for effective bathymetric range shifts in response to warming. This study highlights the potential of eDNA metabarcoding as a practical tool for mesophotic reefs and deep-sea monitoring. |
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