Spatio-temporal variability and diversity of water column prokaryotic communities in the eastern North Atlantic

Abstract

This work describes the microbial community structure in the water column at the Porcupine Abyssal Plain in the eastern North Atlantic. Restriction fragment length polymorphism analysis was carried out on clone libraries constructed from samples collected at 100 m, 1000 m, 3000 m, 10 m above bottom and sediment contact water during July 1997 and March 1998. Simpson (1/D) and Shannon (H') diversity indices revealed temporal and spatial variations in the community structure and complexity. Higher diversity was observed in the samples collected from 100 m (H'=3.22), 1000 m (H'=3.48) and 10 m above bottom (H'=3.18) during July 1997 compared with the corresponding samples during March 1998. Changes in diversity may be associated with a seasonal flux in particulate organic matter. This could promote the proliferation of a selection of taxa that are adapted to rapidly responding to a large influx of organic matter. Sequencing of clones representing 20 operational taxonomic units revealed a diverse population of Bacteria and Archaea. The most numerous clone operational taxonomic units were from the alpha and gamma subdivisions of the Proteobacteria and the group I marine Crenarchaeota. A number of sequences were phylogenetically grouped in clades with no culture representatives such as the SAR116, SAR86, SAR406 and SAR324 groups. Most of the sequences identified were found to be more closely related to other 16S rDNA clones recovered from the marine environment rather than cultured species.

Hydrography shapes bacterial biogeography of the deep Arctic Ocean

“…The Deltaproteobacteria were dominated by the SAR324 cluster , another typical deep water cluster earlier reported from the Arctic (Bano and Hollibaugh, 2002) but also from the Antarctic (Lopez-Garcia et al, 2001) and North Atlantic (Gonzalez et al, 2000). The SAR406 cluster, previously detected in various oceanic provinces (Gordon and Giovannoni, 1996;Gallagher et al, 2004;Pham et al, 2008), as well as the Chloroflexi SAR202 cluster , described as abundant and ubiquitous in meso-and bathypelagic waters Bano and Hollibaugh, 2002;Morris et al, 2004;Varela et al, 2008a), were other abundant clusters of the dark ocean.…”

Seasonal and Spatial Variation of Bacterial Community Structure in River-Mouth Areas of Gokasho Bay, Japan

“…Previous reports have described seasonal variation in bacterial community structure in estuarine seawater, but have discussed the variation in relation to primary productivity or nutrient supply 13,15,20,27) . The CCA analysis undertaken for this study indicated that water temperature is a major environmental factor associated with the seasonal variation in community structure, but POC and nitrite plus nitrate concentrations were associated with vertical variation in the stratified season (Table 3).…”

Spatio-temporal diversity of free-living and particle-attached prokaryotes in the tropical lagoon of Ahe atoll (Tuamotu Archipelago) and its surrounding oceanic waters

“…This pelagic archaeal clade has been identified from surface waters of different marine areas and seems to be dominant here. Furthermore, MG-II members have been also found associated with tropical corals (Massana et al, 1997(Massana et al, , 2000Delong et al, 1999;Gallagher et al, 2004) and blooms have been observed in surface water of Monterey Bay and of the North Sea during summer (Pernthaler et al, 2002;Delong, 2003). Sequences of uncultured Archaea have been originally classified according to their geographic location.…”