Deep-Sea Biodiversity in the Mediterranean Sea: The Known, the Unknown, and the Unknowable

Type Article
Date 2010-08
Language English
Author(s) Danovaro Roberto1, Batista Company Joan2, Corinaldesi Cinzia1, D'Onghia Gianfranco3, Galil Bella4, Gambi Cristina1, Gooday Andrew J.5, Lampadariou Nikolaos6, Luna Gian Marco1, Morigi Caterina7, Olu KarineORCID8, Polymenakou Paraskevi6, Ramirez-Llodra Eva2, Sabbatini Anna1, Sarda Francesc2, Sibuet Myriam9, Tselepides Anastasios10
Affiliation(s) 1 : Univ Politecn Marche, Dipartimento Sci Mare, Ancona, Italy.
2 : CSIC, Inst Ciencias Mar, Barcelona, Spain.
3 : Univ Bari, Dept Anim & Environm Biol, Bari, Italy.
4 : Natl Inst Oceanog, IL-31080 Haifa, Israel.
5 : Natl Oceanog Ctr, Southampton, Hants, England.
6 : Hellen Ctr Marine Res, Iraklion, Greece.
7 : Geol Survey Denmark & Greenland, Stratig Dept, Copenhagen, Denmark.
8 : IFREMER, Ctr Brest, Dept Etude Ecosyst Profonds, Plouzane, France.
9 : Inst Oceanog, Paris, France.
10 : Univ Piraeus, Dept Maritime Studies, Piraeus, France.
Source Plos One (1932-6203) (Public Library Science), 2010-08 , Vol. 5 , N. 8 , P. -
DOI 10.1371/journal.pone.0011832
WOS© Times Cited 221
Abstract Deep-sea ecosystems represent the largest biome of the global biosphere, but knowledge of their biodiversity is still scant. The Mediterranean basin has been proposed as a hot spot of terrestrial and coastal marine biodiversity but has been supposed to be impoverished of deep-sea species richness. We summarized all available information on benthic biodiversity (Prokaryotes, Foraminifera, Meiofauna, Macrofauna, and Megafauna) in different deep-sea ecosystems of the Mediterranean Sea (200 to more than 4,000 m depth), including open slopes, deep basins, canyons, cold seeps, seamounts, deep-water corals and deep-hypersaline anoxic basins and analyzed overall longitudinal and bathymetric patterns. We show that in contrast to what was expected from the sharp decrease in organic carbon fluxes and reduced faunal abundance, the deep-sea biodiversity of both the eastern and the western basins of the Mediterranean Sea is similarly high. All of the biodiversity components, except Bacteria and Archaea, displayed a decreasing pattern with increasing water depth, but to a different extent for each component. Unlike patterns observed for faunal abundance, highest negative values of the slopes of the biodiversity patterns were observed for Meiofauna, followed by Macrofauna and Megafauna. Comparison of the biodiversity associated with open slopes, deep basins, canyons, and deep-water corals showed that the deep basins were the least diverse. Rarefaction curves allowed us to estimate the expected number of species for each benthic component in different bathymetric ranges. A large fraction of exclusive species was associated with each specific habitat or ecosystem. Thus, each deep-sea ecosystem contributes significantly to overall biodiversity. From theoretical extrapolations we estimate that the overall deep-sea Mediterranean biodiversity (excluding prokaryotes) reaches approximately 2805 species of which about 66% is still undiscovered. Among the biotic components investigated (Prokaryotes excluded), most of the unknown species are within the phylum Nematoda, followed by Foraminifera, but an important fraction of macrofaunal and megafaunal species also remains unknown. Data reported here provide new insights into the patterns of biodiversity in the deep-sea Mediterranean and new clues for future investigations aimed at identifying the factors controlling and threatening deep-sea biodiversity.
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Danovaro Roberto, Batista Company Joan, Corinaldesi Cinzia, D'Onghia Gianfranco, Galil Bella, Gambi Cristina, Gooday Andrew J., Lampadariou Nikolaos, Luna Gian Marco, Morigi Caterina, Olu Karine, Polymenakou Paraskevi, Ramirez-Llodra Eva, Sabbatini Anna, Sarda Francesc, Sibuet Myriam, Tselepides Anastasios (2010). Deep-Sea Biodiversity in the Mediterranean Sea: The Known, the Unknown, and the Unknowable. Plos One, 5(8), -. Publisher's official version : https://doi.org/10.1371/journal.pone.0011832 , Open Access version : https://archimer.ifremer.fr/doc/00011/12206/