Geyer Bank

Color bathymetric map of Geyer Bank
Geyer Bank is a pear-shaped feature with two distinct domes

Bottom Depth Range: 105-670 feet (32-204 meters)

Geyer Bank is approximately 23 km (14 mi) east southeast of Bright Bank, and 52 km (32 mi) east southeast of East Flower Garden Bank. The bank is pear-shaped with two distinct domes and sits atop an active salt diaper on the upper continental slope.

The surface of the north dome is relative rough, with a series of concentric ridges as well as a few pinnacles, the tallest of which peaks at 32 m (105 ft) under water. The surface of the south dome is 58–62 m ( 190-203 ft) under water, but has much less relief than the north dome. The bank supports a coral community, as well as mesophotic coral habitats including black corals, gorgonians, fish, sponges, algae and invertebrates.

A variety of colorful tropical fishes swim around a section of reef covered in orange fire coral
The crest of Geyer Bank is home to a variety of corals, sponges and tropical fish species

Recent observations have documented a sargassum bloom on the reef crest. Divers have also documented enormous numbers of Reef Butterflyfish (Chaetodon sedentarius) at specific times of year.

A forest of leafy algae covers most of the bottom in a section of reef. A pair of butterflyfish swim in a small gap in the algae.
A sargassum bloom at Geyer Bank

The coral community on the reef crest is made up of at least four species of reef-building coral, as well as an invasive species, Tubastraea coccinea. Sanctuary research staff conducted a Tubastraea removal exercise with NASA divers in 2006, and removed 46 colonies of the invasive coral. 

An angelfish and a squirrelfish swim past a rocky outcropping covered in clusters of invasive orange cup coral
Invasive Orange Cup Coral is quite visible on outcroppings at Geyer Bank

Geyer Bank is also thought to be the first known site for spawning aggregations of Marbled Grouper (Dermatolepis inermis), a rare species. This aggregation may be under considerable threat from fishing pressure.

In addition, a shipping lane cuts across the top of the bank. Unfortunately, this makes it a convenient place to drop anchor, impacting the resources. A large tanker was recently anchored on top of the feature just outside of the shipping lane.

Geyer Bank, named after Texas A&M University geophysicist Richard A. Geyer, is a designated Habitat Area of Particular Concern (HAPC).

Red brittle stars intertwined among the branches of a bright orange gorgonian.
Brittle stars intertwined with colorful gorgonians in deep habitat at Geyer Bank