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C:N:P Molar Ratios, Sources and 14C Dating of Surficial Sediments from the NW Slope of Cuba.

de la Lanza Espino G, Soto LA - PLoS ONE (2015)

Bottom Line: C:P fluctuated from 7.7 to 14.1 in the surficial sediment layer.The bulk organic δ13Corg and δ15N values confirmed pelagic organic sources, and the 14C dating revealed that the sediments were deposited during the Holocene (1000-5000 yr BP).We suggest that the hydrodynamic conditions in the Straits influence vertical and advective fluxes of particulate organic material trapped in the mixed-layer, which reduces the particulate matter flux to the seabed.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Biología, UNAM México D.F., México.

ABSTRACT
The surficial sediments recovered from 12 sites located near the channel axis of the Florida Straits and the lower slope off NW Cuba were analyzed for total organic carbon (TOC), nitrogen (TN), phosphorus (TP), elemental C:N:P ratios, C and N isotopic values, and 14C dating. The depth profiles of TOC, TN, and TP (0-18 cm) displayed a downcore trend and a significant variation. The TOC values were low (0.15 to 0.62%; 66 to 516 µmol g(-1)). Sites near the island's lower slope had lower TOC average concentrations (158-333 µmol g(-1)) than those closer to the channel axis (averaging 341-516 µmol g(-1); p <0.05). The TN concentrations near the lower slope attained 0.11% (80 µmol g(-1)), whereas, towards the channel axis, they decreased to 0.07% (55 µmol g(-1); p<0.05). The C:N ratios ranged from 1.9 to 10.2. The mean molar C:N ratio (5.4) indicated a marine hemipelagic deposition. The TP was lower at sites near the lower slope (38.4 to 50.0 µmol gv; 0.12% to 0.16%) than those near the channel axis (50.0 to 66 µmol g(-1); 0.15 to 0.21%). C:P fluctuated from 7.7 to 14.1 in the surficial sediment layer. The bulk organic δ13Corg and δ15N values confirmed pelagic organic sources, and the 14C dating revealed that the sediments were deposited during the Holocene (1000-5000 yr BP). We suggest that the hydrodynamic conditions in the Straits influence vertical and advective fluxes of particulate organic material trapped in the mixed-layer, which reduces the particulate matter flux to the seabed.

No MeSH data available.


Related in: MedlinePlus

TOC:TP ratios.Correlation of the TOC:TP ratios in subcores from six sites of Block III on the NW slope of Cuba, Southern Florida Straits.
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pone.0125562.g005: TOC:TP ratios.Correlation of the TOC:TP ratios in subcores from six sites of Block III on the NW slope of Cuba, Southern Florida Straits.

Mentions: The individual correlations of TP and TOC obtained for each Block were not significant, with the exception of Block III (R2 = 0.56). In this particular case, the intercept on the TP axis was 31 μmol g-1, which corresponded to the inorganic phosphorus (IP) calculated through the subtraction recommended by Calvert [7] (Fig 5). In general, IP predominated in all the surficial sediments of the three Blocks.


C:N:P Molar Ratios, Sources and 14C Dating of Surficial Sediments from the NW Slope of Cuba.

de la Lanza Espino G, Soto LA - PLoS ONE (2015)

TOC:TP ratios.Correlation of the TOC:TP ratios in subcores from six sites of Block III on the NW slope of Cuba, Southern Florida Straits.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4482514&req=5

pone.0125562.g005: TOC:TP ratios.Correlation of the TOC:TP ratios in subcores from six sites of Block III on the NW slope of Cuba, Southern Florida Straits.
Mentions: The individual correlations of TP and TOC obtained for each Block were not significant, with the exception of Block III (R2 = 0.56). In this particular case, the intercept on the TP axis was 31 μmol g-1, which corresponded to the inorganic phosphorus (IP) calculated through the subtraction recommended by Calvert [7] (Fig 5). In general, IP predominated in all the surficial sediments of the three Blocks.

Bottom Line: C:P fluctuated from 7.7 to 14.1 in the surficial sediment layer.The bulk organic δ13Corg and δ15N values confirmed pelagic organic sources, and the 14C dating revealed that the sediments were deposited during the Holocene (1000-5000 yr BP).We suggest that the hydrodynamic conditions in the Straits influence vertical and advective fluxes of particulate organic material trapped in the mixed-layer, which reduces the particulate matter flux to the seabed.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Biología, UNAM México D.F., México.

ABSTRACT
The surficial sediments recovered from 12 sites located near the channel axis of the Florida Straits and the lower slope off NW Cuba were analyzed for total organic carbon (TOC), nitrogen (TN), phosphorus (TP), elemental C:N:P ratios, C and N isotopic values, and 14C dating. The depth profiles of TOC, TN, and TP (0-18 cm) displayed a downcore trend and a significant variation. The TOC values were low (0.15 to 0.62%; 66 to 516 µmol g(-1)). Sites near the island's lower slope had lower TOC average concentrations (158-333 µmol g(-1)) than those closer to the channel axis (averaging 341-516 µmol g(-1); p <0.05). The TN concentrations near the lower slope attained 0.11% (80 µmol g(-1)), whereas, towards the channel axis, they decreased to 0.07% (55 µmol g(-1); p<0.05). The C:N ratios ranged from 1.9 to 10.2. The mean molar C:N ratio (5.4) indicated a marine hemipelagic deposition. The TP was lower at sites near the lower slope (38.4 to 50.0 µmol gv; 0.12% to 0.16%) than those near the channel axis (50.0 to 66 µmol g(-1); 0.15 to 0.21%). C:P fluctuated from 7.7 to 14.1 in the surficial sediment layer. The bulk organic δ13Corg and δ15N values confirmed pelagic organic sources, and the 14C dating revealed that the sediments were deposited during the Holocene (1000-5000 yr BP). We suggest that the hydrodynamic conditions in the Straits influence vertical and advective fluxes of particulate organic material trapped in the mixed-layer, which reduces the particulate matter flux to the seabed.

No MeSH data available.


Related in: MedlinePlus