Even though the Red Sea is characterized by unique oceanographic conditions, only few studies have addressed the ecology of its deep-sea benthos. This work discusses some traits of the Saudi deep waters of the Red Sea between 23°N and 28°N. Macrobenthic samples were collected using a box corer (0.1m2 surface area) from 59 stations at depths ranging between 220m and 1678 m. The stations were categorized into four depth zones (≤500 m, 501–750 m, 751–1000m and>1000 m) and two latitudinal areas (northern and central) for data analysis. A total of 186 species have been identified including polychaetes (135), crustaceans (27), molluscs (18), echinoderms (3), echiuroid (1), sipunculoid (1), and oligochaete (1). While 114 species were present in only 1–3 stations, only 30 species were found to be widely distributed, being recorded in all depth zones from northern and central areas. The trophic structure analysis indicated high functional diversity with the presence of seven feeding levels represented mainly by surface deposit feeders, facultative detritivores, and benthic carnivores. In general, the density and biomass of the deep sea macrobenthic community studied herein are lower than those reported in other seas with similar depth zones. This is most likely due to the particular environmental factors of the Red Sea, represented mainly by its oligotrophic nature, high temperature, high salinity, and low food availability in the form of organic matter. It is worth noting that some ecological parameters considered showed a general decreasing pattern (density: 10–1666 ind. m−2; biomass: 0.02 – 10.98 gm−2; species richness S: 1–59; Shannon-Wiener diversity index H': 0 – 5.1) in relation with the increasing depth in northern and central areas. The bathymetric trends of the macrobenthic communities were also demonstrated with findings of multivariate analyses. The distribution of benthic communities at all depth zones appeared to be controlled by the availability of organic matter and abiotic factors such as temperature and salinity. Pronounced latitudinal and longitudinal trends in the macrobenthic communities are not evident, most likely due to the limited latitudinal and longitudinal variation of the sampling stations of this study. No spatial variations were found with the feeding types, species evenness index, and species dominance index. Considering the scarcity of published data on the deep benthic community from the Red Sea, this study provides some useful baseline information on this topic and contributes to decrease the knowledge gap on the diversity of macrobenthic communities in this region.

Macrobenthic community structure in the deep waters of the Red Sea

Salvatore Giacobbe
Penultimo
Membro del Collaboration Group
;
2018-01-01

Abstract

Even though the Red Sea is characterized by unique oceanographic conditions, only few studies have addressed the ecology of its deep-sea benthos. This work discusses some traits of the Saudi deep waters of the Red Sea between 23°N and 28°N. Macrobenthic samples were collected using a box corer (0.1m2 surface area) from 59 stations at depths ranging between 220m and 1678 m. The stations were categorized into four depth zones (≤500 m, 501–750 m, 751–1000m and>1000 m) and two latitudinal areas (northern and central) for data analysis. A total of 186 species have been identified including polychaetes (135), crustaceans (27), molluscs (18), echinoderms (3), echiuroid (1), sipunculoid (1), and oligochaete (1). While 114 species were present in only 1–3 stations, only 30 species were found to be widely distributed, being recorded in all depth zones from northern and central areas. The trophic structure analysis indicated high functional diversity with the presence of seven feeding levels represented mainly by surface deposit feeders, facultative detritivores, and benthic carnivores. In general, the density and biomass of the deep sea macrobenthic community studied herein are lower than those reported in other seas with similar depth zones. This is most likely due to the particular environmental factors of the Red Sea, represented mainly by its oligotrophic nature, high temperature, high salinity, and low food availability in the form of organic matter. It is worth noting that some ecological parameters considered showed a general decreasing pattern (density: 10–1666 ind. m−2; biomass: 0.02 – 10.98 gm−2; species richness S: 1–59; Shannon-Wiener diversity index H': 0 – 5.1) in relation with the increasing depth in northern and central areas. The bathymetric trends of the macrobenthic communities were also demonstrated with findings of multivariate analyses. The distribution of benthic communities at all depth zones appeared to be controlled by the availability of organic matter and abiotic factors such as temperature and salinity. Pronounced latitudinal and longitudinal trends in the macrobenthic communities are not evident, most likely due to the limited latitudinal and longitudinal variation of the sampling stations of this study. No spatial variations were found with the feeding types, species evenness index, and species dominance index. Considering the scarcity of published data on the deep benthic community from the Red Sea, this study provides some useful baseline information on this topic and contributes to decrease the knowledge gap on the diversity of macrobenthic communities in this region.
2018
File in questo prodotto:
File Dimensione Formato  
127 Joydas et al 2018 Red Sea.pdf

solo utenti autorizzati

Descrizione: documento unico
Tipologia: Versione Editoriale (PDF)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 860.17 kB
Formato Adobe PDF
860.17 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/3131340
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 4
  • ???jsp.display-item.citation.isi??? 3
social impact