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Diversity and distribution patterns in high southern latitude sponges.

Downey RV, Griffiths HJ, Linse K, Janussen D - PLoS ONE (2012)

Bottom Line: Nineteen distinct sponge distribution patterns were found, ranging from regional endemics to cosmopolitan species.A single, distinct Antarctic demosponge fauna is found to encompass all areas within the Polar Front, and the sub-Antarctic regions of the Kerguelen Plateau and Macquarie Island.We conclude that the biogeographic and species distribution patterns observed are largely driven by the Antarctic Circumpolar Current and the timing of past continent connectivity.

View Article: PubMed Central - PubMed

Affiliation: British Antarctic Survey, Natural Environmental Research Council, Cambridge, United Kingdom.

ABSTRACT
Sponges play a key role in Antarctic marine benthic community structure and dynamics and are often a dominant component of many Southern Ocean benthic communities. Understanding the drivers of sponge distribution in Antarctica enables us to understand many of general benthic biodiversity patterns in the region. The sponges of the Antarctic and neighbouring oceanographic regions were assessed for species richness and biogeographic patterns using over 8,800 distribution records. Species-rich regions include the Antarctic Peninsula, South Shetland Islands, South Georgia, Eastern Weddell Sea, Kerguelen Plateau, Falkland Islands and north New Zealand. Sampling intensity varied greatly within the study area, with sampling hotspots found at the Antarctic Peninsula, South Georgia, north New Zealand and Tierra del Fuego, with limited sampling in the Bellingshausen and Amundsen seas in the Southern Ocean. In contrast to previous studies we found that eurybathy and circumpolar distributions are important but not dominant characteristics in Antarctic sponges. Overall Antarctic sponge species endemism is ∼43%, with a higher level for the class Hexactinellida (68%). Endemism levels are lower than previous estimates, but still indicate the importance of the Polar Front in isolating the Southern Ocean fauna. Nineteen distinct sponge distribution patterns were found, ranging from regional endemics to cosmopolitan species. A single, distinct Antarctic demosponge fauna is found to encompass all areas within the Polar Front, and the sub-Antarctic regions of the Kerguelen Plateau and Macquarie Island. Biogeographical analyses indicate stronger faunal links between Antarctica and South America, with little evidence of links between Antarctica and South Africa, Southern Australia or New Zealand. We conclude that the biogeographic and species distribution patterns observed are largely driven by the Antarctic Circumpolar Current and the timing of past continent connectivity.

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Depth ranges of each sponge family within their respective class.Hexactinellida (a), Demospongiae (b), and Calcarea (c) in the Southern Ocean. Brackets after family name indicate firstly the number of genera within that family, and secondly, number of species within that family.
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pone-0041672-g007: Depth ranges of each sponge family within their respective class.Hexactinellida (a), Demospongiae (b), and Calcarea (c) in the Southern Ocean. Brackets after family name indicate firstly the number of genera within that family, and secondly, number of species within that family.

Mentions: In order to explore the nature of eurybathy in SO sponges, we analysed maximum and minimum depth as well as the depth range at which each species was found (Figs. 6a–d, 7a–c), as well as defining their presence on the shelf, slope and abyss in order to determine eurybathy. Thirty-six percent of all recorded sponge species were found to have small ranges (0–100 m). Twenty-nine percent of all species had depth ranges over 500 m, with only 15% having depth ranges that were greater than 1000 m. Eight percent of all sponges were found to be shallow species, having a maximum recorded depth that is less than 100 m. Sixty-four percent of species were restricted to the shelf, and 25% of species were found to be distributed in more than one zone (shelf, slope or abyss), with the majority of these found at both shelf and continental slope locations.


Diversity and distribution patterns in high southern latitude sponges.

Downey RV, Griffiths HJ, Linse K, Janussen D - PLoS ONE (2012)

Depth ranges of each sponge family within their respective class.Hexactinellida (a), Demospongiae (b), and Calcarea (c) in the Southern Ocean. Brackets after family name indicate firstly the number of genera within that family, and secondly, number of species within that family.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3404021&req=5

pone-0041672-g007: Depth ranges of each sponge family within their respective class.Hexactinellida (a), Demospongiae (b), and Calcarea (c) in the Southern Ocean. Brackets after family name indicate firstly the number of genera within that family, and secondly, number of species within that family.
Mentions: In order to explore the nature of eurybathy in SO sponges, we analysed maximum and minimum depth as well as the depth range at which each species was found (Figs. 6a–d, 7a–c), as well as defining their presence on the shelf, slope and abyss in order to determine eurybathy. Thirty-six percent of all recorded sponge species were found to have small ranges (0–100 m). Twenty-nine percent of all species had depth ranges over 500 m, with only 15% having depth ranges that were greater than 1000 m. Eight percent of all sponges were found to be shallow species, having a maximum recorded depth that is less than 100 m. Sixty-four percent of species were restricted to the shelf, and 25% of species were found to be distributed in more than one zone (shelf, slope or abyss), with the majority of these found at both shelf and continental slope locations.

Bottom Line: Nineteen distinct sponge distribution patterns were found, ranging from regional endemics to cosmopolitan species.A single, distinct Antarctic demosponge fauna is found to encompass all areas within the Polar Front, and the sub-Antarctic regions of the Kerguelen Plateau and Macquarie Island.We conclude that the biogeographic and species distribution patterns observed are largely driven by the Antarctic Circumpolar Current and the timing of past continent connectivity.

View Article: PubMed Central - PubMed

Affiliation: British Antarctic Survey, Natural Environmental Research Council, Cambridge, United Kingdom.

ABSTRACT
Sponges play a key role in Antarctic marine benthic community structure and dynamics and are often a dominant component of many Southern Ocean benthic communities. Understanding the drivers of sponge distribution in Antarctica enables us to understand many of general benthic biodiversity patterns in the region. The sponges of the Antarctic and neighbouring oceanographic regions were assessed for species richness and biogeographic patterns using over 8,800 distribution records. Species-rich regions include the Antarctic Peninsula, South Shetland Islands, South Georgia, Eastern Weddell Sea, Kerguelen Plateau, Falkland Islands and north New Zealand. Sampling intensity varied greatly within the study area, with sampling hotspots found at the Antarctic Peninsula, South Georgia, north New Zealand and Tierra del Fuego, with limited sampling in the Bellingshausen and Amundsen seas in the Southern Ocean. In contrast to previous studies we found that eurybathy and circumpolar distributions are important but not dominant characteristics in Antarctic sponges. Overall Antarctic sponge species endemism is ∼43%, with a higher level for the class Hexactinellida (68%). Endemism levels are lower than previous estimates, but still indicate the importance of the Polar Front in isolating the Southern Ocean fauna. Nineteen distinct sponge distribution patterns were found, ranging from regional endemics to cosmopolitan species. A single, distinct Antarctic demosponge fauna is found to encompass all areas within the Polar Front, and the sub-Antarctic regions of the Kerguelen Plateau and Macquarie Island. Biogeographical analyses indicate stronger faunal links between Antarctica and South America, with little evidence of links between Antarctica and South Africa, Southern Australia or New Zealand. We conclude that the biogeographic and species distribution patterns observed are largely driven by the Antarctic Circumpolar Current and the timing of past continent connectivity.

Show MeSH
Related in: MedlinePlus