Globale Taxonomie-Initiative – Nationale Kontaktstelle Deutschland

Photo: Jan Borgsted / Flickr

Scientists discovered at the edge of the Western Antarctic Peninsular (WAP) in a basin called Palmers Deep a reproductive population of the king crab species Neolithodes yaldwyni in February 2011. Never before have these animals been recorded on the Western Antarctic continental shelf and scientists have assumed low water temperatures to be a limitating factor for their prevalence. If these assumptions are true the continues increase observed in water temperature due to climate change in these areas could by time facilitate the settlement of these crabs. Considering the warming rate of the water around Palmers Deep this could happen within the next 10-20 years.

N. yaldwyni, a predator with a broad food pallette, cracks its prey with its mouthparts and therefore belongs to the group of durophagous predators. It feed among others off Echinodermata. In search for food the crabs sift sediments using their chelipeds and thereby leave characteristic traces in the surface of the ocean bed. Through their foraging habits they have great impact on the ecosystem and are therefore perceived as ecosystem engineers. Research has shown, that the presence of the crabs correlates with loss of magafauna and echinodermata biodiversity and generally changes the structure of the megabenthos. If as a result of climate change N. yaldwyni establishes populations on the Antarctic continental shelf, this could have detrimental effect on existing ecosystem there.

This Survey uses images and samples collected by a submarine vehicle along a transect of 3,3 km lengths and 1419-600 m depth. The crab species N. yaldwyni was identified by taxonomists using among others genetic information, which was then compared to information of genetic databases (Genbank and Barcode of Life). This process enabled the distinction of N. yaldwyni from closely relate dspecies such as N. brodiei, N. asperrimus and N. duhameli. In order to determine the ecological impact of the animals further taxonomic Surveys of the habitat was necessary. The information about foraging and other habits can also be ascribed to the work of taxonomists.

Resources:

• Smith Craig R (2011), A large population of king crabs in Palmer Deep on the west Antarctic Peninsula shelf and potential invasive impacts, Proceedings of the Royal Society, September 8, 2011
• Essay Spiegel online, Der Antarktis droht die Königskrabben - Invasion  (German language)