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Large-scale distribution and activity of prokaryotes in deep-sea surface sediments of the Mediterranean Sea and the adjacent Atlantic Ocean.

Giovannelli D, Molari M, d'Errico G, Baldrighi E, Pala C, Manini E - PLoS ONE (2013)

Bottom Line: Prokaryotic abundance and biomass did not vary significantly across the Mediterranean Sea; however, there were depth-related trends in all areas.Overall, our data suggest that deeper areas of the Mediterranean Sea share more similar communities with each other than with shallower sites.Freshness and quality of sedimentary organic matter were identified through Generalized Additive Model analysis as the major factors for describing the variation in the prokaryotic community structure and activity in the surface deep-sea sediments.

View Article: PubMed Central - PubMed

Affiliation: Institute for Marine Science - ISMAR, National Research Council of Italy - CNR, Ancona, Italy.

ABSTRACT
The deep-sea represents a substantial portion of the biosphere and has a major influence on carbon cycling and global biogeochemistry. Benthic deep-sea prokaryotes have crucial roles in this ecosystem, with their recycling of organic matter from the photic zone. Despite this, little is known about the large-scale distribution of prokaryotes in the surface deep-sea sediments. To assess the influence of environmental and trophic variables on the large-scale distribution of prokaryotes, we investigated the prokaryotic assemblage composition (Bacteria to Archaea and Euryarchaeota to Crenarchaeota ratio) and activity in the surface deep-sea sediments of the Mediterranean Sea and the adjacent North Atlantic Ocean. Prokaryotic abundance and biomass did not vary significantly across the Mediterranean Sea; however, there were depth-related trends in all areas. The abundance of prokaryotes was positively correlated with the sedimentary concentration of protein, an indicator of the quality and bioavailability of organic matter. Moving eastwards, the Bacteria contribution to the total prokaryotes decreased, which appears to be linked to the more oligotrophic conditions of the Eastern Mediterranean basins. Despite the increased importance of Archaea, the contributions of Crenarchaeota Marine Group I to the total pool was relatively constant across the investigated stations, with the exception of Matapan-Vavilov Deep, in which Euryarchaeota Marine Group II dominated. Overall, our data suggest that deeper areas of the Mediterranean Sea share more similar communities with each other than with shallower sites. Freshness and quality of sedimentary organic matter were identified through Generalized Additive Model analysis as the major factors for describing the variation in the prokaryotic community structure and activity in the surface deep-sea sediments. Longitude was also important in explaining the observed variability, which suggests that the overlying water masses might have a critical role in shaping the benthic communities.

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Measured variables across the sampling areas and sampling depths.Left axes, barplots; right axes, dot plots. (a, b) Biopolymeric carbon (BPC) and chloroplastic pigment equivalent (CPE) according to area (a) and depth (b). (c, d) Total prokaryotic counts (TPN) and prokaryotic biomass (PBM) according to area (c) and depth (d). (e, f) Bacteria to Archaea ratio (BAR) and Euryarchaeota to Crenarchaeota ratio (ECR) according to area (e) and depth (f). (g, h) Heterotrophic production (HCP) and cell specific activity (HCP x cell) calculated on the active cell according to area (g) and depth (h). (j, k) Prokaryotic turnover time and Protein turnover time according to area (j) and depth (k). Means and standard deviations are reported. N, North stations; W, West stations; C, Central stations; E, East stations.
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pone-0072996-g003: Measured variables across the sampling areas and sampling depths.Left axes, barplots; right axes, dot plots. (a, b) Biopolymeric carbon (BPC) and chloroplastic pigment equivalent (CPE) according to area (a) and depth (b). (c, d) Total prokaryotic counts (TPN) and prokaryotic biomass (PBM) according to area (c) and depth (d). (e, f) Bacteria to Archaea ratio (BAR) and Euryarchaeota to Crenarchaeota ratio (ECR) according to area (e) and depth (f). (g, h) Heterotrophic production (HCP) and cell specific activity (HCP x cell) calculated on the active cell according to area (g) and depth (h). (j, k) Prokaryotic turnover time and Protein turnover time according to area (j) and depth (k). Means and standard deviations are reported. N, North stations; W, West stations; C, Central stations; E, East stations.

Mentions: The BPC content of the surface sediment and the CPE are plotted over the sampling area in Figure 2a, b, with the reported averages for area and depth in Figure 3a, b, respectively. On average, the West and Central Mediterranean accounted for the higher amounts of BPC in sediment (1.16 ±0.48 and 1.03 ±0.35 mgC g-1, respectively), with the BPC quantity evenly distributed across the depths (Figure 3b). CHO was the dominant category in organic matter, constituting, on average, 50% of the total organic matter, with PRT following with an average contribution of 37% (Table 2). The CPE followed a similar trend, with higher values in the West and Central Mediterranean (3.75 ±2.05 and 2.21 ±2.25 µg g-1, respectively), while showing a higher variability along the depth transects, with average values higher at 2,000 m (3.46 ±2.61 µg g-1; Figure 3b). The CPE showed good correlation with surface primary production (SPP; Pearson moment correlation, n = 69, r = 0.51, p <0.05).


Large-scale distribution and activity of prokaryotes in deep-sea surface sediments of the Mediterranean Sea and the adjacent Atlantic Ocean.

Giovannelli D, Molari M, d'Errico G, Baldrighi E, Pala C, Manini E - PLoS ONE (2013)

Measured variables across the sampling areas and sampling depths.Left axes, barplots; right axes, dot plots. (a, b) Biopolymeric carbon (BPC) and chloroplastic pigment equivalent (CPE) according to area (a) and depth (b). (c, d) Total prokaryotic counts (TPN) and prokaryotic biomass (PBM) according to area (c) and depth (d). (e, f) Bacteria to Archaea ratio (BAR) and Euryarchaeota to Crenarchaeota ratio (ECR) according to area (e) and depth (f). (g, h) Heterotrophic production (HCP) and cell specific activity (HCP x cell) calculated on the active cell according to area (g) and depth (h). (j, k) Prokaryotic turnover time and Protein turnover time according to area (j) and depth (k). Means and standard deviations are reported. N, North stations; W, West stations; C, Central stations; E, East stations.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3755984&req=5

pone-0072996-g003: Measured variables across the sampling areas and sampling depths.Left axes, barplots; right axes, dot plots. (a, b) Biopolymeric carbon (BPC) and chloroplastic pigment equivalent (CPE) according to area (a) and depth (b). (c, d) Total prokaryotic counts (TPN) and prokaryotic biomass (PBM) according to area (c) and depth (d). (e, f) Bacteria to Archaea ratio (BAR) and Euryarchaeota to Crenarchaeota ratio (ECR) according to area (e) and depth (f). (g, h) Heterotrophic production (HCP) and cell specific activity (HCP x cell) calculated on the active cell according to area (g) and depth (h). (j, k) Prokaryotic turnover time and Protein turnover time according to area (j) and depth (k). Means and standard deviations are reported. N, North stations; W, West stations; C, Central stations; E, East stations.
Mentions: The BPC content of the surface sediment and the CPE are plotted over the sampling area in Figure 2a, b, with the reported averages for area and depth in Figure 3a, b, respectively. On average, the West and Central Mediterranean accounted for the higher amounts of BPC in sediment (1.16 ±0.48 and 1.03 ±0.35 mgC g-1, respectively), with the BPC quantity evenly distributed across the depths (Figure 3b). CHO was the dominant category in organic matter, constituting, on average, 50% of the total organic matter, with PRT following with an average contribution of 37% (Table 2). The CPE followed a similar trend, with higher values in the West and Central Mediterranean (3.75 ±2.05 and 2.21 ±2.25 µg g-1, respectively), while showing a higher variability along the depth transects, with average values higher at 2,000 m (3.46 ±2.61 µg g-1; Figure 3b). The CPE showed good correlation with surface primary production (SPP; Pearson moment correlation, n = 69, r = 0.51, p <0.05).

Bottom Line: Prokaryotic abundance and biomass did not vary significantly across the Mediterranean Sea; however, there were depth-related trends in all areas.Overall, our data suggest that deeper areas of the Mediterranean Sea share more similar communities with each other than with shallower sites.Freshness and quality of sedimentary organic matter were identified through Generalized Additive Model analysis as the major factors for describing the variation in the prokaryotic community structure and activity in the surface deep-sea sediments.

View Article: PubMed Central - PubMed

Affiliation: Institute for Marine Science - ISMAR, National Research Council of Italy - CNR, Ancona, Italy.

ABSTRACT
The deep-sea represents a substantial portion of the biosphere and has a major influence on carbon cycling and global biogeochemistry. Benthic deep-sea prokaryotes have crucial roles in this ecosystem, with their recycling of organic matter from the photic zone. Despite this, little is known about the large-scale distribution of prokaryotes in the surface deep-sea sediments. To assess the influence of environmental and trophic variables on the large-scale distribution of prokaryotes, we investigated the prokaryotic assemblage composition (Bacteria to Archaea and Euryarchaeota to Crenarchaeota ratio) and activity in the surface deep-sea sediments of the Mediterranean Sea and the adjacent North Atlantic Ocean. Prokaryotic abundance and biomass did not vary significantly across the Mediterranean Sea; however, there were depth-related trends in all areas. The abundance of prokaryotes was positively correlated with the sedimentary concentration of protein, an indicator of the quality and bioavailability of organic matter. Moving eastwards, the Bacteria contribution to the total prokaryotes decreased, which appears to be linked to the more oligotrophic conditions of the Eastern Mediterranean basins. Despite the increased importance of Archaea, the contributions of Crenarchaeota Marine Group I to the total pool was relatively constant across the investigated stations, with the exception of Matapan-Vavilov Deep, in which Euryarchaeota Marine Group II dominated. Overall, our data suggest that deeper areas of the Mediterranean Sea share more similar communities with each other than with shallower sites. Freshness and quality of sedimentary organic matter were identified through Generalized Additive Model analysis as the major factors for describing the variation in the prokaryotic community structure and activity in the surface deep-sea sediments. Longitude was also important in explaining the observed variability, which suggests that the overlying water masses might have a critical role in shaping the benthic communities.

Show MeSH
Related in: MedlinePlus