Photosymbiotic corals inhabit depths 0–170 + m and form the foundation of coral reef ecosystems by creating complex habitats with their calcium carbonate skeletons. While well studied in shallow waters, almost nothing is known about their basic biology & ecology at depths > 60 m. Here, we report on the first measurements of skeletal density and coral calcification rates from Leptoseris spp. growing at depths of 70–111 m in Hawaii. These corals have very thin, nonporous, skeletons that are considerably denser (2.7 g ­cm−3) than most shallow water corals. Their calcification rates (0.042–0.085 g c­ m−2 ­yr−1) are the lowest ever reported for a photosymbiotic scleractinian coral and ~ 20–40 times lower than the dominant shallow water corals in Hawaii. Given their colony geometry, calcification rate and tissue biomass productivity (per unit area) are tightly coupled, and a constant calcification rate leads to an increasing radial extension rate with colony size. These growth parameter relationships contrast sharply with hemispheroidal colonies in shallow water. Despite their extremely low calcification rates, these corals are very productive at increasing planar area over time, which is consistent with their phototrophic strategy at depth.

Depth range
70- 111 m

Mesophotic “mentions”
1 x (total of 6441 words)

Classification
* Presents original data
* Focused on 'mesophotic' depth range
* Focused on 'mesophotic coral ecosystem'

Fields
Ecology
Physiology

Focusgroups
Scleractinia (Hard Corals)

Locations
USA - Hawaii

Platforms
Land-based