Lithogenic fluxes in the Bay of Bengal measured by sediment traps

Ramaswamy, V.; Kumar, Brijesh; Parthiban, G.; Ittekkot, V.; Nair, R.R.

doi:10.1016/s0967-0637(96)00117-3

Cited by 36 publications

(10 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Their density decreases from 2.72 to 1.4 g cm −3 during hydration (Osipov, 2012), whereas hydration hardly affects the density of illite, which decreases from 2.75 to 2.72 g cm −3 . At our trap sites, illite and quartz dominate lithogenic matter (Ramaswamy et al, , 1997. Since the density of quartz is 2.65 g cm −3 , we assumed a density of 2.70 ± 0.05 g cm −3 for lithogenic matter at our trap sites.…”

Section: Sinking Speedmentioning

confidence: 99%

The ballast effect of lithogenic matter and its influences on the carbon fluxes in the Indian Ocean

Rixen

Gaye²,

Emeis

et al. 2019

Biogeosciences

View full text Add to dashboard Cite

Data obtained from long-term sediment trap experiments in the Indian Ocean in conjunction with satellite observations illustrate the influence of primary production and the ballast effect on organic carbon flux into the deep sea. They suggest that primary production is the main control on the spatial variability of organic carbon fluxes at most of our study sites in the Indian Ocean, except at sites influenced by river discharges. At these sites the spatial variability of organic carbon flux is influenced by lithogenic matter content. To quantify the impact of lithogenic matter on the organic carbon flux, the densities of the main ballast minerals, their flux rates and seawater properties were used to calculate sinking speeds of material intercepted by sediment traps. Sinking speeds in combination with satellite-derived export production rates allowed us to compute organic carbon fluxes. Flux calculations imply that lithogenic matter ballast increases organic carbon fluxes at all sampling sites in the Indian Ocean by enhancing sinking speeds and reducing the time of organic matter respiration in the water column. We calculated that lithogenic matter content in aggregates and pellets enhances organic carbon flux rates on average by 45 % and by up to 62 % at trap locations in the river-influenced regions of the Indian Ocean. Such a strong lithogenic matter ballast effect explains the fact that organic carbon fluxes are higher in the low-productive southern Java Sea compared to the high-productive western Arabian Sea. It also implies that land use changes and the associated enhanced transport of lithogenic matter from land into the ocean may significantly affect the CO 2 uptake of the organic carbon pump in the receiving ocean areas.

show abstract

Section: Sinking Speedmentioning

confidence: 99%

The ballast effect of lithogenic matter and its influences on the carbon fluxes in the Indian Ocean

Rixen

Gaye²,

Emeis

et al. 2019

Biogeosciences

View full text Add to dashboard Cite

show abstract

“…The kaolinite percentages in general are higher compared to those from the Ganges -Brahmaputra river sediments (Segall & Kuehl 1992) as the Ayeyarwady sediments are derived mostly from tropical regions, whereas in the Ganges -Brahmaputra river sediments they are mostly derived from the Himalayas and are dominated by physical weathering (Mallik 1976;Ramaswamy et al 1997). The kaolinite percentages in general are higher compared to those from the Ganges -Brahmaputra river sediments (Segall & Kuehl 1992) as the Ayeyarwady sediments are derived mostly from tropical regions, whereas in the Ganges -Brahmaputra river sediments they are mostly derived from the Himalayas and are dominated by physical weathering (Mallik 1976;Ramaswamy et al 1997).…”

Section: Clay-size Mineralogymentioning

confidence: 99%

Chapter 17 The Myanmar continental shelf

Ramaswamy

Rao

2014

Memoirs

Self Cite

View full text Add to dashboard Cite

The Myanmar (Burma) coastline is about 2280 km long, with the continental shelf covering an area of approximately 230 000 km 2 . The Myanmar coastline may be divided into the northern Rakhine (Arakan) coast, the central Ayeyarwady coast and the southern Tanintharyi (Tenasserim) coast. The Rakhine coast lies adjacent to the Bay of Bengal, while the Ayeyarwady and Tanintharyi coast faces the Andaman Sea. The continental shelf of Myanmar receives sediments from some of the largest rivers in the world like the Ayeyarwady (Irrawaddy), the Salween (Thanlwin) and the Ganges-Brahmaputra rivers. The Myanmar shelf is characterized by a seasonal reversal of monsoon winds and coastal currents, periodic tropical cyclones and storm surges, meso-to macrotidal conditions, and neotectonic activity. The most prominent bathymetric feature on the Ayeyarwady continental shelf is the 120 km-wide Martaban Depression, at the centre of which is located the Martaban Canyon. Most of the suspended sediment discharge of the Ayeyarwady is transported eastwards by coastal and tidal currents, and trapped in the Gulf of Martaban, resulting in the formation of an extensive mud belt covering an area of more than 45 000 km 2 . Because of these features, the Myanmar shelf ranks amongst the most globally important continental shelves in the world but remains inadequately studied owing to its inaccessibility.

show abstract

“…At our trap sites quarz and the clay mineral illite mostly compose lithogenic matter Ramaswamy et al, 1997) and the density of these two minerals is 2.72 g cm -3…”

Section: Density Of the Bulk Components 10mentioning

confidence: 87%

The Ballast Effect in the Indian Ocean

Rixen

Gaye

Emeis

et al. 2017

Preprint

View full text Add to dashboard Cite

Abstract. In this study, data obtained from a sediment trap experiments off South Java are analyzed and compared to satellite-derived information on primary production and data collected by deep-moored sediment traps in the Arabian Sea 10 and the Bay of Bengal. The aim was to study the relative importance of primary production and the ballast effect on the organic carbon export and the CO 2 uptake of the biological carbon pumps. Therefore, data obtained from sediment trap experiments carried out in other ocean basins were also integrated into the data analysis and a four-box model was developed. Our data showed that the organic carbon flux in the highly-productive upwelling system in the Arabian Sea was similar to those in the low productive system off South Java. Off South Java as in other river-influenced regions, lithogenic 15 matter supplied from land mainly controls the organic carbon flux via its ballast effect in sinking particles, whereas carbonate produced by marine organisms appears to be the main ballast material in the high productive regions. Since the carbonate flux tends to increase with an increasing export production, it is difficult to quantify the relative importance of productivity and the ballast effect on the organic carbon flux into the deep sea. However, the export of organic matter into the deep sea represents a loss of nutrients for the pelagic ecosystems, which needs to be balanced by mode water nutrient 20 supply into the seasonal thermocline to sustain the productivity of the pelagic system. The amount of preformed nutrients utilized during the formation of the exported organic matter strongly influences the impact of the ballast effect on the CO 2 uptake of the organic carbon pump. Accordingly, this is stronger at higher latitudes where preformed nutrients are formed than at lower latitudes where the euphotic zone is nutrient depleted. Nevertheless, the ballast effect enhances the export of organic matter into the deep sea and favors the sedimentation of organic matter in river-influenced regions. Since globally > 25 80% of organic carbon burial occurs in river-dominated systems, the lithogenic ballast is assumed to play an important role in the Earth's climate system on geological time scales.

show abstract

Lithogenic fluxes in the Bay of Bengal measured by sediment traps

Cited by 36 publications

References 27 publications

The ballast effect of lithogenic matter and its influences on the carbon fluxes in the Indian Ocean

The ballast effect of lithogenic matter and its influences on the carbon fluxes in the Indian Ocean

Chapter 17 The Myanmar continental shelf

The Ballast Effect in the Indian Ocean

Contact Info

Product

Resources

About