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Titel |
Benthic communities in the deep Mediterranean Sea: exploring microbial and meiofaunal patterns in slope and basin ecosystems |
VerfasserIn |
K. Sevastou, N. Lampadariou, P. N. Polymenakou, A. Tselepides |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 10, no. 7 ; Nr. 10, no. 7 (2013-07-18), S.4861-4878 |
Datensatznummer |
250018349
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Publikation (Nr.) |
copernicus.org/bg-10-4861-2013.pdf |
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Zusammenfassung |
The long-held perception of the deep sea consisting of monotonous slopes and
uniform oceanic basins has over the decades given way to the idea of a
complex system with wide habitat heterogeneity. Under the prism of a highly
diverse environment, a large dataset was used to describe and compare spatial
patterns of the dominant small-size components of deep-sea benthos, metazoan
meiofauna and microbes, from Mediterranean basins and slopes. A grid of 73
stations sampled at five geographical areas along the central-eastern
Mediterranean Basin (central Mediterranean, northern Aegean Sea, Cretan Sea,
Libyan Sea, eastern Levantine) spanning over 4 km in depth revealed a high
diversity, irrespective of the benthic group or level of taxonomic analysis.
A common decreasing bathymetric trend was detected for meiobenthic abundance,
major taxa diversity and nematode genera richness, but no differences were
found between the two habitats (basin vs slope). In contrast, microbial
richness is significantly higher at the basin ecosystem and tends to increase
with depth. Multivariate analyses (β- and δ-diversity and
ordination analysis) complemented these results and underlined the high
within-habitat variability of benthic communities. Meiofaunal communities in
particular were found to change gradually and vary more towards the abyss. On
the other hand, microbial communities were highly variable, even among
samples of the same area, habitat and bathymetry. A significant proportion of
the variation of benthic communities and their descriptors was explained by
depth and proxies of food availability (sedimentary pigments and organic
content), but the combination of predictor variables and the strength of the
relationship varied depending on the data set used (based on type of habitat,
benthic component, taxonomic level). This, along with the observed high
within-habitat variability suggests that other factors, which tend to vary at
local scale (hydrodynamics, substrate structure, geochemistry, food quality,
etc.), may also relate to the observed benthic patterns. Overall, the results
presented here suggest that differences in small-size benthos between the
basin and slope habitats are neither strong nor consistent; it appears that
within-habitat variability is high, differences among depth ranges are
important and further investigation of possible environmental drivers of
benthic patterns is needed. |
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