Why are there so many species in deep-sea sediments?

Gage, John

doi:10.1016/s0022-0981(96)02638-x

Cited by 125 publications

(68 citation statements)

References 142 publications

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“…More than 30 evolutionary and ecological hypotheses have been proposed to explain this gradient of species diversity (Hawkins & Diniz-Filho 2002, Arita 2005). In the marine realm, similar parabolic patterns have also been reported along bathymetric gradients for fish (Powell et al 2003) and macro-and megafaunal invertebrate groups (polychaetes, cumaceans and bivalves) from the northwestern Atlantic (Gage & Tyler 1991, Gage 1996.…”

Section: Introductionsupporting

confidence: 65%

Distribution of megabenthic gastropods along environmental gradients: the mid-domain effect and beyond

Carranza¹,

Colwell²,

Rangel³

2008

Mar. Ecol. Prog. Ser.

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We analysed the distribution patterns of megabenthic species of marine molluscs from the Uruguayan shelf in relation to 3 interacting gradients, namely depth, salinity and temperature of sea bottom waters. Our results were generated from a data set comprising the complete list of megabenthic gastropods (adult shell length > 50 mm; 22 species) from a study area that encompassed latitudes from 34 to 39°south, between 4 and 800 m depth. Multiple regressions were used to evaluate the contribution of 3 classes of explanatory variables to gastropod richness at sampling points along the gradients: (1) geometric constraints on the distribution of species' tolerance ranges for environmental variables (the mid-domain effect, MDE), (2) the species-area effect driven by the spatial extent of scaled environmental variables, and (3) the environmental variables themselves. In addition, we explored multivariate explanations for the bathymetric pattern of gastropod species richness, incorporating depth-based area, temperature, salinity and geometric constraints as predictor variables. Examination of Moran's I for regression residuals confirmed that results were not biased by spatial autocorrelation. Overall, the environmental variables per se were the most important contributors to the observed patterns. However, a significant signature of the MDE was revealed, by the entry of geometric constraints into nearly all models. In contrast, the species-area effect was less important. These results suggest that: (1) MDE may operate in any kind of bounded gradient, (2) both stochastic and deterministic processes are responsible for the pattern observed, and (3) the relative contribution of the MDE to the patterns is dependent on the gradient considered and the way in which species richness is measured. KEY WORDS: Mid-domain effect · Species richness · Continental shelf · Gastropods · UruguayResale or republication not permitted without written consent of the publisher

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Section: Introductionsupporting

confidence: 65%

Distribution of megabenthic gastropods along environmental gradients: the mid-domain effect and beyond

Carranza¹,

Colwell²,

Rangel³

2008

Mar. Ecol. Prog. Ser.

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“…The importance of such 'habitat islands' for deep-sea fauna has been confirmed by Gage (1996), who states that they attract aggregations of species, including many specialist taxa that are very rare in the background community.…”

Section: Biodiversitymentioning

confidence: 91%

Microhabitat type determines the composition of nematode communities associated with sediment-clogged cold-water coral framework in the Porcupine Seabight (NE Atlantic)

Raes

Vanreusel

2006

Deep Sea Research Part I: Oceanographic Research Papers

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The nematofauna associated with a cold-water coral degradation zone in the Porcupine Seabight (NE Atlantic) was investigated. This is the first comprehensive study of nematodes associated with cold-water corals. This research mainly aimed to investigate the influence of microhabitat type on nematode community structure. Three distinct microhabitats for nematodes were distinguished: dead coral fragments, glass sponge skeletons and the underlying sediment. The nematode assemblages associated with these three microhabitats were significantly different from each other. Coral and sponge substrata lie relatively unprotected on the seafloor and are consequently more subjected to strong currents than the underlying sediment. As a result, both large biogenic substrata were characterized by higher abundances of taxa that are less vulnerable and more adapted to physical disturbance, whereas the underlying sediment yielded more slender, sedimentdwelling taxa. Typically epifaunal taxa, such as Epsilonematidae and Draconematidae, were especially abundant on dead coral fragments, where they are thought to feed on the microbial biofilm which covers the coral surface. Several epifaunal genera showed significant preferences for this microhabitat, and Epsilonema (Epsilonematidae) was dominant here. Sponge skeletons are thought to act as efficient sediment traps, resulting in a lower abundance of epifaunal taxa compared to coral fragments. The underlying sediment was dominated by taxa typical for slope sediments. The considerable degree of overlap between the communities of each microhabitat is attributed to sediment infill between the coral branches and sponge spicules. It is assumed that the nematofauna associated with large biogenic substrata is composed of a typical sedimentdwelling background community, supplemented with taxa adapted to an epifaunal life strategy. The extent to which these taxa contribute to the community depends on the type of the substratum. Selective deposit feeders were dominant on sponge skeletons and in the underlying sediment, whereas coral fragments were dominated by epistratum feeders. The presence of a microbial biofilm on the coral fragments is proposed as an explanation for the significant preference of epistratum feeders for this microhabitat. Densities in the underlying sediment were low in comparison with other studies, but biodiversity was higher here than on the coral and sponge fragments, a difference which is attributed to lower disturbance. Nevertheless, the large biogenic substrata provide a microhabitat for rare, epifaunal taxa, and fragments of both substrata within the sediment increase habitat complexity and hence biodiversity. r

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“…In both cases, new habitats create opportunities for benthic organisms to colonise. In the comparatively stable and low energy environment of the deep sea, such patches persist much longer and can potentially be used by a broader spectrum of organisms than in hydrodynamically more energetic shallow-water environments (Thistle 1981, Gage 1996, Snelgrove & Smith 2002.…”

Section: Introductionmentioning

confidence: 99%

Active colonisation of disturbed sediments by deep-sea nematodes: evidence for the patch mosaic model

Gallucci¹,

Moens²,

Vanreusel³

et al. 2008

Mar. Ecol. Prog. Ser.

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An on-board experiment was performed during a research cruise to investigate the ability of deep-sea nematode species to actively colonise defaunated sediments. Small cylinders of 500 µm wire mesh filled with defaunated sediment were inserted into microcosms containing sediment with indigenous meiofauna collected from 1300 m depth in the Arctic Ocean. The defaunated sediments were either enriched with the diatom Thalassiosira weissflogii, or remained unenriched. Samples from the defaunated sediment were taken after 9 and 17 d. As controls, microcosms with sediment containing the indigenous meiofauna but without an internal cylinder were also sampled at each time interval. Nematodes colonised both enriched and unenriched sediments with abundances of up to 20% of the controls. Irrespective of the time of sampling, abundance and number of species were significantly higher in the enriched treatment, suggesting that the presence of food enhances colonisation and resilience. Nematode assemblages in the defaunated sediments were species-rich and differed from the controls. The majority of colonising species were rare or undetectable in the controls, suggesting that episodic disturbances may be necessary for their persistence in deep sea sediments. Colonisation was in part determined by species characteristics such as size and motility. At the same time, a large number of different species colonised the empty cylinders, resulting in poor similarity in community composition between replicates, particularly between samples enriched with diatoms. Our results indicate a poor predictability of community composition of recently disturbed sediments despite highly reproducible abundance and diversity patterns and lends experimental support to the existence of a spatio-temporal mosaic that emerges from highly localised colonisation patterns.

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Why are there so many species in deep-sea sediments?

Cited by 125 publications

References 142 publications

Distribution of megabenthic gastropods along environmental gradients: the mid-domain effect and beyond

Distribution of megabenthic gastropods along environmental gradients: the mid-domain effect and beyond

Microhabitat type determines the composition of nematode communities associated with sediment-clogged cold-water coral framework in the Porcupine Seabight (NE Atlantic)

Active colonisation of disturbed sediments by deep-sea nematodes: evidence for the patch mosaic model

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