Gemeinfreies Foto / Public Domain
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Coral polyps are very sensitive creatures that are exposed to a variety of threats in different seas.
Not only do traditional predators such as crown-of-thorns starfish, triggerfish, parrotfish, butterflyfish, snail species such as Drupella and Coralliophila, and some sea urchins like to eat coral polyps, but tropical storms, El Niño, and the continuous acidification of the oceans also take a heavy toll on coral polyps.
Coral polyps are able to survive water temperatures of over 32°Celsius in the Arabian Sea, as these corals have entered into a symbiotic relationship with highly heat-resistant zooxanthellae (Symbiodinium thermophilum).
Even in the icy cold regions of Antarctica, corals thrive, for example soft corals such as Gersemia antarctica
These soft corals can withstand water temperatures of up to 11.5°Celsius!
All in all, these small polyps are very tough, even on a global scale!
The colonial soft coral Gersemia antarctica is a sediment feeder in the soft sediment communities of McMurdo Sound in Antarctica.
This feeding strategy involves a coordinated bending of the entire colony toward the substrate and has not been described in soft corals before.
Gersemia antarctica colonies attach themselves with their basal disc to scallop shells or small stones and clay, forming a suitable “substrate anchorage” for the fine mud and low current conditions.
Colonies of this tree-like soft coral bend over the fine sediment floor, lie flat on it, then rotate 360° and roll on their trunks, catching and consuming organic detritus material on the sediment surface with their polyp-containing branches.
The colonies were capable of considerable hydrostatic expansion, with the colony height increasing from 35 to 275 cm within 16 hours!
Analyses of the intestinal contents indicate a mixed diet comprising benthic diatoms, foraminifera, and particulate organic matter (sedimented phytoplankton, so-called “green carpets,” and microzooplankton).
Soft corals move periodically like “caterpillars,” presumably to exploit undisturbed sediments.
In fact, they retreat from the substrate almost immediately when they encounter previously grazed sediments.
This feeding strategy has probably evolved to supplement the capture of planktonic prey and is of particular importance in Antarctica and possibly also in the deep sea.
From an extended ventral position, the colonies eventually free themselves from the sediment by a series of contractions in the basal region.
Once the corals are free, the colonies inflate their hydrostatic skeleton and stretch their distal part away from their original location.
By expelling water and contracting, the entire colony moves forward like an insect.
After relocation, the colonies repeat this novel detritus-feeding process.
Nature has always equipped its creatures with unique feeding and survival strategies, and Gersemia antarctica is one of these special creatures.
Synonyms:
Eunephthya antarctica (Kükenthal, 1902) · unaccepted > superseded combination
Paraspongodes antarctica Kükenthal, 1902 · unaccepted > superseded combination (original combination)
Not only do traditional predators such as crown-of-thorns starfish, triggerfish, parrotfish, butterflyfish, snail species such as Drupella and Coralliophila, and some sea urchins like to eat coral polyps, but tropical storms, El Niño, and the continuous acidification of the oceans also take a heavy toll on coral polyps.
Coral polyps are able to survive water temperatures of over 32°Celsius in the Arabian Sea, as these corals have entered into a symbiotic relationship with highly heat-resistant zooxanthellae (Symbiodinium thermophilum).
Even in the icy cold regions of Antarctica, corals thrive, for example soft corals such as Gersemia antarctica
These soft corals can withstand water temperatures of up to 11.5°Celsius!
All in all, these small polyps are very tough, even on a global scale!
The colonial soft coral Gersemia antarctica is a sediment feeder in the soft sediment communities of McMurdo Sound in Antarctica.
This feeding strategy involves a coordinated bending of the entire colony toward the substrate and has not been described in soft corals before.
Gersemia antarctica colonies attach themselves with their basal disc to scallop shells or small stones and clay, forming a suitable “substrate anchorage” for the fine mud and low current conditions.
Colonies of this tree-like soft coral bend over the fine sediment floor, lie flat on it, then rotate 360° and roll on their trunks, catching and consuming organic detritus material on the sediment surface with their polyp-containing branches.
The colonies were capable of considerable hydrostatic expansion, with the colony height increasing from 35 to 275 cm within 16 hours!
Analyses of the intestinal contents indicate a mixed diet comprising benthic diatoms, foraminifera, and particulate organic matter (sedimented phytoplankton, so-called “green carpets,” and microzooplankton).
Soft corals move periodically like “caterpillars,” presumably to exploit undisturbed sediments.
In fact, they retreat from the substrate almost immediately when they encounter previously grazed sediments.
This feeding strategy has probably evolved to supplement the capture of planktonic prey and is of particular importance in Antarctica and possibly also in the deep sea.
From an extended ventral position, the colonies eventually free themselves from the sediment by a series of contractions in the basal region.
Once the corals are free, the colonies inflate their hydrostatic skeleton and stretch their distal part away from their original location.
By expelling water and contracting, the entire colony moves forward like an insect.
After relocation, the colonies repeat this novel detritus-feeding process.
Nature has always equipped its creatures with unique feeding and survival strategies, and Gersemia antarctica is one of these special creatures.
Synonyms:
Eunephthya antarctica (Kükenthal, 1902) · unaccepted > superseded combination
Paraspongodes antarctica Kükenthal, 1902 · unaccepted > superseded combination (original combination)
