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Les foraminifères benthiques de la marge portugaise : impact des apports organiques sur la densité, la biodiversité et la composition des faunes
| Content Provider | Semantic Scholar |
|---|---|
| Author | Phipps, Mark |
| Copyright Year | 2012 |
| Abstract | Live (Rose Bengal stained) foraminifera were analysed at 8 stations along a latitudinal bathymetric transect (282-4987 m) across the Portuguese margin open slope. A succession of foraminiferal assemblaghes occurs with increasing depth, related to the decrease of trophic level. Standing stocks, species richness and diversity decrease more rapidly with depth for calcareous than for agglutinated taxa. Calcareous taxa are generally restricted to the uppermost cm in mesotrophic and oligotrophic sites. Agglutinated taxa have low diversity at the most shallow, eutrophic station due to competition with calcareous foraminifera and very shallow oxygen penetration. At greater depths, their diversity and ALD10 increase in response to deeper oxygen penetration and macrofaunal bioturbation. At the deepest, oligotrophic environments, where their diversity is low, agglutinated taxa are again restricted to shallow microhabitats. Another 7 stations from ~1000 m water depth were sampled along a longitudinal transect consisting of open slope and canyon environments. Total foraminiferal standing stocks, dominated by intermediate and deep infaunal species, are much higher in canyon stations than on the open slope, related to the elevated CPE concentrations within the canyons. Low oxygen conditions decrease foraminiferal diversity on the Nazare canyon terrace by inhibiting many shallow infaunal taxa and increasing the dominance of intermediate and deep infaunal species. Temporal variability appears to be much greater in canyon environments, where both sedimentary disturbance and organic supplies are maximal, compared to the relatively stable open slope environment. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://tel.archives-ouvertes.fr/tel-00993121/document |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
