Contribution of phytoliths to total biogenic silica volumes in the tropical rivers of Malaysia and associated implications for the marine biogeochemical cycle

Abstract. This article presents data regarding the Si biogeochemical cycle during two oceanographic cruises conducted in the tropical South Pacific (BIOSOPE and OUTPACE cruises) in 2005 and 2015. It involves the first Si stock measurements in this understudied region, encompassing various oceanic systems from New Caledonia to the Chilean upwelling between 8 and 34∘ S. Some of the lowest levels of biogenic silica standing stocks ever measured were found in this area, notably in the southern Pacific gyre, where Chlorophyll a concentrations are the most depleted worldwide. Integrated biogenic silica stocks are as low as 1.08±0.95 mmol m−2 and are the lowest stocks measured in the South Pacific. Size-fractionated biogenic silica concentrations revealed a non-negligible contribution of the pico-sized fraction (<2–3 µm) to biogenic silica standing stocks, representing 26%±12% of total biogenic silica during the OUTPACE cruise and 11%±9% during the BIOSOPE cruise. These results indicate significant accumulation in this size class, which was undocumented for 2005, but has since then been related to Si uptake by Synechococcus cells. Si uptake measurements carried out during BIOSOPE confirmed biological Si uptake by this size fraction. We further present diatoms community structure associated with the stock measurements for a global overview of the Si cycle in the tropical South Pacific.

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Lake sedimentary biogenic silica from diatoms constitutes a significant global sink for aluminium

Nature Communications ◽

10.1038/s41467-019-12828-9 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 2

Author(s):

Dong Liu ◽

Peng Yuan ◽

Qian Tian ◽

Hongchang Liu ◽

Liangliang Deng ◽

...

Keyword(s):

Biogenic Silica ◽

Biogeochemical Cycle ◽

Biochemical Processes ◽

Al Content ◽

High Al Content ◽

Global Oceans

Abstract Diatoms play an important role in marine biogeochemical cycle of aluminum (Al), as dissolved Al is taken up by diatoms to build their siliceous frustules and is involved in the sedimentation of diatomaceous biogenic silica (BSi). The Al incorporation in BSi facilitates decreasing the dissolution of marine BSi and thus substantially influences the biochemical processes driven by diatoms, such as CO2 sequestration. However, the role of lake BSi in the terrestrial biochemical Al cycle has not been explored, though lakes represent the second-largest sink for BSi. By identifying the previously unexplored high Al/Si atomic ratios (up to 0.052) in lake BSi, here we show lake BSi is a large terrestrial Al pool due to its high Al content, and lake sedimentary BSi constitutes a significant global sink for Al, which is on the same magnitude as the Al sink in global oceans.

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Silicon cycle in the Tropical South Pacific: evidence for an active pico-sized siliceous plankton

10.5194/bg-2018-149 ◽

2018 ◽

Cited By ~ 1

Author(s):

Karine Leblanc ◽

Véronique Cornet ◽

Peggy Rimmelin-Maury ◽

Olivier Grosso ◽

Sandra Hélias-Nunige ◽

...

Keyword(s):

Chlorophyll A ◽

Biogenic Silica ◽

New Caledonia ◽

South Pacific ◽

Tropical Pacific ◽

Biogeochemical Cycle ◽

Silicon Cycle ◽

Standing Stocks ◽

Negligible Contribution

Abstract. This article presents data regarding the Si biogeochemical cycle during two oceanographic cruises conducted in the Southern Tropical Pacific (BIOSOPE and OUTPACE cruises) in 2005 and 2015. It involves the first Si stock measurements in this understudied region, encompassing various oceanic systems from New Caledonia to the Chilean upwelling between 8 and 34° S. Some of the lowest levels of biogenic silica standing stocks ever measured were found in this area, notably in the Southern Pacific Gyre, where Chlorophyll a concentrations are most depleted worldwide. Integrated biogenic silica stocks are as low as 1.08 ± 0.95 mmol m−2, and are the lowest stocks measured in the Southern Pacific. Size-fractionated biogenic silica concentrations revealed a non-negligible contribution of the pico-sized fraction (

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