Large benthic foraminifera (LBF) are an important component of low-light, mesophotic tropical marine environments, including coral ecosystems. LBF occur from nearshore, shallow coastal environments experiencing high-terrestrial runoff to the deep-shelf edge in transparent, oceanic waters. Here, I compare the LBF in both these low-light habitats. In both reef-associated and interreef environments, species show differing tolerance to both light intensity and terrestrial influx. In interreef environments, LBF can alter the benthic environment from muddy to coarse carbonate grains. Their depth distribution is truncated by seasonal variability in water transparency, particularly for the deepest-living species. This is because shallower-dwelling species are more likely to experience suitable environmental conditions throughout the year and can position themselves in microhabitats experiencing higher light irradiance during periods of low light intensity, thus managing to maintain their symbionts. In contrast, deep-living species are less flexible because light intensity in deep water is ubiquitously low; consequently, deep-dwelling LBF live predominantly on or very close to the water-seafloor interface. In coastal environments, zonation or habitat fractionating, i.e., the differentiation of assemblages on the reef slope, increases from nearshore to offshore reefs, primarily due to species-specific differences in tolerance to nutrients.

Mesophotic “mentions”
17 x (total of 4042 words)

Classification
* Focused on 'mesophotic coral ecosystem'

Fields
Biodiversity
Disturbances
Ecology

Focusgroups
Protists (non-Symbiodiniaceae)

Locations
Australia - Great Barrier Reef

Platforms
Land-based