scholarly journals Polychaeta Diversity in the Continental Shelf Off the Orinoco River Delta, Venezuela

10.5772/24965 ◽  
2011 ◽  
Author(s):  
David Bone ◽  
Carmen Teresa ◽  
Iliana Chollett
Keyword(s):  
Continental Shelf ◽  
River Delta ◽  
Orinoco River

Hemoglobin variants, hematological parameters andβ-globin gene cluster haplotypes in an isolated Amerindian group from the Orinoco River Delta

2008 ◽  
Vol 35 (2) ◽  
pp. 250-255 ◽  
Author(s):  
Anabel Arends ◽  
Marycarmen Chacín ◽  
Martha Bravo-Urquiola ◽  
Tibisay Arends De O ◽  
Maritza Álvarez ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Hematological Parameters ◽  
Globin Gene ◽  
River Delta ◽  
Orinoco River ◽  
Globin Gene Cluster ◽  
Hemoglobin Variants

Aquatic vegetation of the Orinoco River Delta (Venezuela). An overview

Hydrobiologia ◽  
1996 ◽  
Vol 340 (1-3) ◽  
pp. 109-113 ◽  
Author(s):  
Giuseppe Colonnello Bertoli
Keyword(s):  
Aquatic Vegetation ◽  
River Delta ◽  
Orinoco River

Mercury and methylmercury along a transect from the Lena river estuary across the Laptev Sea Shelf

2020 ◽  
Author(s):  
Van Liem Nguyen ◽  
Birgit Wild ◽  
Örjan Gustafsson ◽  
Igor Semiletov ◽  
Oleg Dudarev ◽  
...  
Keyword(s):  
Organic Matter ◽  
Continental Shelf ◽  
Arctic Ocean ◽  
River Delta ◽  
The Arctic ◽  
Laptev Sea ◽  
Terrestrial Organic Matter ◽  
Lena River ◽  
The Arctic Ocean ◽  
The Laptev Sea

<p>Widespread accelerated permafrost thawing is predicted for this century and beyond. This threatens to remobilize the large amounts of Mercury (Hg) currently ‘locked’ in Arctic permafrost soils to the Arctic Ocean and thus potentially lead to severe consequences for human and wildlife health. Future risks of Arctic Hg in a warmer climate are, however, poorly understood. One crucial knowledge gap to fill is the fate of Hg once it enters the marine environment on the continental shelves. Arctic rivers are already today suggested to be the main source of Hg into the Arctic Ocean, with dissolved and particulate organic matter (DOM and POM, respectively) identified as important vectors for the land to sea transport.</p><p>In this study, we have investigated total Hg (HgT) and monomethylmercury (MeHg) concentrations in surface sediments from the East Siberian Arctic Shelf (ESAS) along a transect from the Lena river delta to the Laptev Sea continental slope. The ESAS is the world’s largest continental shelf and receives large amounts of organic carbon by the great Arctic Russian rivers (e.g., Lena, Indigirka and Kolyma), remobilized from continuous and discontinuous permafrost regions in the river catchments, and from coastal erosion. Data on HgT and MeHg levels in ESAS sediments is however limited. Here, we observed concentrations of Hg ranging from 30 to 96 ng Hg g<sup>-1</sup> d.w. of HgT, and 0.03 to 9.5 ng Hg g<sup>-1</sup> d.w. of MeHg. Similar concentrations of HgT were observed close to the river delta (54 ± 19 ng Hg g<sup>-1</sup> d.w.), where >95 % of the organic matter is of terrestrial origin, and the other section of the transect (42 ± 7 ng Hg g<sup>-1</sup> d.w.) where the terrestrial organic matter is diluted with carbon from marine sources. In contrast, we observed higher concentrations of MeHg close to the river delta (0.72 ± 0.71 ng Hg g<sup>-1</sup> d.w. as MeHg) than further out on the continental shelf (0.031 ± 0.71 ng Hg g<sup>-1</sup> d.w. as MeHg). We also observed a positive correlation between the MeHg:Hg ratio and previously characterized molecular markers of terrestrial organic matter (Bröder et al. Biogeosciences (2016) & Nature Com. (2018)). We thus suggest riverine inputs, rather than in situ MeHg formation, to explain observed MeHg trends.</p>

Cover Fire emissions from the Orinoco river delta

1997 ◽  
Vol 18 (5) ◽  
pp. 1007-1008
Author(s):  
C. Balladares ◽  
R. Lazo ◽  
A. M. Martinez
Keyword(s):  
River Delta ◽  
Fire Emissions ◽  
Orinoco River

scholarly journals Seasonal Distribution of Nutrients and Primary Productivity on the Eastern Continental Shelf of Venezuela as Influenced by the Orinoco River

2016 ◽  
Author(s):  
JAIME BONILLA ◽  
William James Senior
Keyword(s):  
Continental Shelf ◽  
Primary Productivity ◽  
Coastal Upwelling ◽  
Nutrient Status ◽  
Dry Season ◽  
Wet Season ◽  
Orinoco River ◽  
Carbon 14 ◽  
Low Salinity ◽  
The Caribbean

Nitrogenous nutrients, dissolved silicate, and salinity were measured in surface waters and shallowhydrocasts along similar cruise tracks during the spring (dry season) and fall (wet season) of 1988. Bothcruises transected the eastern Caribbean, transited the Gulf of Paria, ran parallel to the Orinoco Deltaand into the main channel of the Orinoco River. Trends in primary productivity were also measuredby daily carbon 14 incubations. In both seasons, samples covered the range from highly oligotrophicand transparent to highly productive and rich in biogenic and abiogenic particulate matter. Most of theOrinoco outflow appears to turn N to NW and remains in shallow waters off Venezuela andsurrounding Trinidad, permitting benthic regeneration of river-borne nutrients. However, the role ofthe Orinoco and associated low-salinity coastal waters in fertilizing large areas of the easternCaribbean basin, as suggested by satellite imagery, can be approximated crudely from the nutrientcomposition at Boca de Dragon, which is representative of the nutrient status of these waters as theyflow into deeper Caribbean waters. Additional nutrients may be supplied to the area primarily fromAmazon-derived water entering the Caribbean Basin further north, with some coastal upwelling alongthe continental shelf in the dry season.

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