Field surveys of Funauki Bay, Iriomote-jima: Internal waves and mesophotic coral ecosystems

During November 2016 and March 2017 we conducted field surveys of Funauki Bay, Iriomote-jima. The main focus of this work is to understand the environmental drivers of mesophotic coral ecosystem (MCE) distributions in and around the bay. In collaboration with Professor James Leichter of Scripps Institution of Oceanography, we have been making long-term observations of internal wave dynamics, which requires regular trips to maintain instrument deployments and to recover precious data.

We have been testing a new drop camera system to document MCE distributions. Inside Funauki Bay, extensive Leptoseris sp. beds exist in the 30-60 m depth range. Ongoing analyses are expected to identify the primary nutrient sources for these corals using stable isotope and radiocarbon analyses of seawater and coral tissue samples.

This work was supported by JSPS KAKENHI Grant Number JP15F15904 and the Sumitomo Foundation.

Figure 1: Extensive Leptoseris sp. beds inside Funauki Bay at 30-60m depth (photo 45 m).

Figure 2: Dr Wyatt deploying the drop camera in less than ideal weather in Funauki Bay.

Figure 3: Long evenings of filtering to measure spatial patterns in particulate organic matter isotopes.