Enhanced particle fluxes in Bay of Bengal induced by injection of fresh water

Ittekkot, V.; Nair, R.R.; Honjo, Susumu; Ramaswamy, V.; Bartsch, Michelle R.; Manganini, Steven J.; Desai, B. N.

doi:10.1038/351385a0

Cited by 210 publications

(78 citation statements)

References 15 publications

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“…3). The increase of Al fluxes with depth has been observed in previous sediment trap experiments (e.g., Ittekkot et al, 1991;Noriki et al, 1995).…”

Section: Total Mass and Al Fluxessupporting

confidence: 54%

“…In the North Pacific, source materials of the terrigenous component in sediment have been presumed by comparing sediment with the crust in surrounding regions based on the mineralogy (Griffin et al, 1968; lithogenic materials supplied to the surface of the ocean (Honjo, 1982;Ittekkot et al, 1991;Biscaye and Anderson, 1994;Otosaka and Noriki, 2000), as well as biogenic materials such as opal and carbonate (Noriki and Tsunogai, 1986;Honjo and Manganini, 1993) and pollutants (Fowler et al, 1983;Knap et al, 1986). Because settling particles contain morphological and chemical signals of material sources and subsequent transformation processes, time-series observations by sediment trap is a useful tool to elucidate transport processes of materials in the water column.…”

Section: Introductionmentioning

confidence: 99%

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La/Yb and Th/Sc in settling particles: Vertical and horizontal transport of lithogenic material in the western North Pacific

2004

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In order to understand the origins and transport processes of lithogenic aluminosilicate in the western North Pacific, time-series sediment traps were deployed at Stn. KNOT at 44∞N 155∞E (water depth: 5320 m). Annual mean content of aluminum (Al) which is a proxy of lithogenic material in settling particles was 0.38% at 1 km depth, 0.78% at 3 km depth and 1.14% at 5 km depth, respectively. Mass fluxes were corrected by 230 Th and 231 Pa activities in particles and seawater. Annual mean corrected Al fluxes at 1, 3 and 5 km depths were calculated to 0.45, 0.46 and 0.33 g/m 2 /year, respectively. Lanthanum/ytterbium (La/Yb) and thorium/scandium (Th/Sc) ratios were used as proxies for estimating the origin of lithogenic aluminosilicate in settling particles. Both La/Yb and Th/Sc ratios in settling particles increased with depth, and the seasonal variation was the smallest at 5 km depth. It was considered that variations of La/Yb and Th/Sc ratios in settling particles reflected the change of source material of lithogenic aluminosilicates. Origins of lithogenic materials in the settling particles were summarized using two end-members, loess from central Asian continent (AL) and basalts from the Kurile-Kamchatka Islands (KK). Contributions of end-members in settling particles were estimated from the La/Yb and Th/Sc ratios. The contribution of KK particles in lithogenic materials was calculated to be 84% at 1 km depth, and 61% at 3 and 5 km depths, respectively. Although the KK material was the dominant constituent of the terrigenous component in settling particles at Stn. KNOT, the KK flux decreased with depth. On the other hand, the AL flux increased with depth and the significant increase of the AL flux was presumably due to the lateral import of AL particles to the deep layer at Stn. KNOT. From these results we conclude that the distribution of lithogenic materials recorded in sediments in the western North Pacific are influenced by the northward transport of AL within the deep layer.

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“…3). The increase of Al fluxes with depth has been observed in previous sediment trap experiments (e.g., Ittekkot et al, 1991;Noriki et al, 1995).…”

Section: Total Mass and Al Fluxessupporting

confidence: 54%

Section: Introductionmentioning

confidence: 99%

La/Yb and Th/Sc in settling particles: Vertical and horizontal transport of lithogenic material in the western North Pacific

2004

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“…Another puzzle is that the average annual fluxes into the deep are comparable both in AS and BOB. However, lithogenic fluxes are more in the Bay and increase in fluxes are associated with increase in river discharge (Ittekkot et al, 1991;Ramaswamy and Nair, 1994). It may be that biogenic matter is more rapidly scavenged along with those of terrigeneous origin and ballast the material resulting in faster sedimentation to the deep (Ittekkot et al, 1992;Kumar et al, 1998).…”

Section: Discussionmentioning

confidence: 99%

Biogeochemistry of the Bay of Bengal: physical, chemical and primary productivity characteristics of the central and western Bay of Bengal during summer monsoon 2001

Madhupratap

Gauns

Ramaiah

et al. 2003

Deep Sea Research Part II: Topical Studies in Oceanography

275

141

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“…The above may be summarized by noting that nutrients from land, which may be transported by rivers or submarine groundwater discharge, or may be atmospheric fallout, markedly affect estuaries and continental shelves (Ittekkot et al, 1991;Cole and Caraco, 2001;Neubauer and Anderson, 2003;Clark et al, 2004;Thomas et al, 2004;Gazeau et al, 2005;Hales et al, 2008;Jiang et al, 2013;Lauerwald et al, 2012). Consequently, estuaries and proximal continental shelves typically sustain high biological productivity (Walsh et al, 1981;Wollast, 1993Wollast, , 1998Cai, 2003), which may draw down CO 2 .…”

Section: C-t a Chen Et Al: Air-sea Exchanges Of Co 2 In The Worldmentioning

confidence: 99%

Air–sea exchanges of CO<sub>2</sub> in the world's coastal seas

et al. 2013

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Abstract. The air-sea exchanges of CO 2 in the world's 165 estuaries and 87 continental shelves are evaluated. Generally and in all seasons, upper estuaries with salinities of less than two are strong sources of CO 2 (39 ± 56 mol C m −2 yr −1 , positive flux indicates that the water is losing CO 2 to the atmosphere); mid-estuaries with salinities of between 2 and 25 are moderate sources (17.5 ± 34 mol C m −2 yr −1 ) and lower estuaries with salinities of more than 25 are weak sources . Mixing with low-pCO 2 shelf waters, water temperature, residence time and the complexity of the biogeochemistry are major factors that govern the pCO 2 in estuaries, but wind speed, seldom discussed, is critical to controlling the air-water exchanges of CO 2 . The total annual release of CO 2 from the world's estuaries is now estimated to be 0.10 Pg C yr −1 , which is much lower than published values mainly because of the contribution of a considerable amount of heretofore unpublished or new data from Asia and the Arctic. The Asian data, although indicating high pCO 2 , are low in sea-to-air fluxes because of low wind speeds. Previously determined flux values rely heavily on data from Europe and North America, where pCO 2 is lower but wind speeds are much higher, such that the CO 2 fluxes are higher than in Asia. Newly emerged CO 2 flux data in the Arctic reveal that estuaries there mostly absorb rather than release CO 2 .Most continental shelves, and especially those at high latitude, are undersaturated in terms of CO 2 and absorb CO 2 from the atmosphere in all seasons. Shelves between 0 and 23.5 • S are on average a weak source and have a small flux per unit area of CO 2 to the atmosphere. Water temperature, the spreading of river plumes, upwelling, and biological production seem to be the main factors in determining pCO 2 in the shelves. Wind speed, again, is critical because at high latitudes, the winds tend to be strong. Since the surface water pCO 2 values are low, the air-to-sea fluxes are high in regions above 50 • N and below 50 • S. At low latitudes, the winds tend to be weak, so the sea-to-air CO 2 flux is small. Overall, the world's continental shelves absorb 0.4 Pg C yr −1 from the atmosphere.

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Enhanced particle fluxes in Bay of Bengal induced by injection of fresh water

Cited by 210 publications

References 15 publications

La/Yb and Th/Sc in settling particles: Vertical and horizontal transport of lithogenic material in the western North Pacific

La/Yb and Th/Sc in settling particles: Vertical and horizontal transport of lithogenic material in the western North Pacific

Biogeochemistry of the Bay of Bengal: physical, chemical and primary productivity characteristics of the central and western Bay of Bengal during summer monsoon 2001

Air–sea exchanges of CO<sub>2</sub> in the world's coastal seas

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Enhanced particle fluxes in Bay of Bengal induced by injection of fresh water

Cited by 210 publications

References 15 publications

La/Yb and Th/Sc in settling particles: Vertical and horizontal transport of lithogenic material in the western North Pacific

La/Yb and Th/Sc in settling particles: Vertical and horizontal transport of lithogenic material in the western North Pacific

Biogeochemistry of the Bay of Bengal: physical, chemical and primary productivity characteristics of the central and western Bay of Bengal during summer monsoon 2001

Air–sea exchanges of CO&lt;sub&gt;2&lt;/sub&gt; in the world's coastal seas

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Air–sea exchanges of CO<sub>2</sub> in the world's coastal seas