Organic Carbon Concentrations in High- and Low-Productivity Areas of the Sulu Sea

Ferrera, Charissa M.; Jacinto, Gil S.; Chen, Chen‐Tung Arthur; Lui, Hon-Kit

doi:10.3390/su10061867

Cited by 4 publications

(3 citation statements)

References 62 publications

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“…3). This finding is in agreement with the widely acknowledged conclusion that the maximum sinking POC turnover usually occurs in the mesopelagic zone (Martin et al 1987), but is usually uniform in the general dark ocean such as in the water columns of the NE Pacific Ocean (Druffel et al 1998), the Arctic Ocean (Griffith et al 2012), the Sulu Sea (Ferrera et al 2018), the Eastern Fram Strait (Engel et al 2019), and so on. The attenuation coefficients of the vertical profiles of microbial community respiration proxy are significantly lower (0.16-0.23) than the corresponding coefficients of the vertical POC profiles (0.35-0.38, Table 3), indicating high levels of microbial community respiration at the corresponding depths.…”

Section: Poc Turnover In the Pelagic Realm: Insight From Microbial Co...supporting

confidence: 92%

High variability in organic carbon sources and microbial activities in the hadopelagic waters

Zhao

Dang

et al. 2023

Limnology & Oceanography

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Hadal sediments are recognized as organic carbon depocenters with intensified microbial activity compared to adjacent abyssal sites due to focusing of relatively labile organic materials. However, the sources and turnover of hadopelagic organic carbon and its linkages to microbial activities have not been studied. We present the first synergic research on particulate organic carbon, dark carbon fixation, and size‐fractionated microbial community respiration proxy over the Atacama Trench. The results demonstrate that all parameters attenuate rapidly from surface to mesopelagic water (~ 1000 m). Progressing deeper, values remain relatively stable throughout bathypelagic (~ 4000 m) and abyssopelagic (~ 6000 m) waters. However, in the hadopelagic zone (> 6000 m), highly variable values indicate dynamic organic carbon sources and microbial activities in the deepest trench. On average, 71% of the microbial community respiration proxy is attributable to particle‐associated communities, indicating importance of particles for microbial metabolism. No apparent relationship was observed between the microbial community respiration proxy and microbial 16S rRNA gene abundance below the epipelagic depth, indicating variable supply and quality of organic carbon likely constrained heterotrophic activities rather than microbial abundances in the deep ocean. The depth‐integrated dark carbon fixation (> 1000 m) accounts for 11.5% ± 7.6% of the surface net primary production, of which 2.9% ± 0.4% is from hadopelagic depth. Dark carbon fixation is thus an important in situ organic carbon source for hadal life. This study suggests that high variability in organic carbon sources and microbial activities in the hadopelagic trench cannot be simply extrapolated from findings in the shallower dark ocean (e.g., 1000–6000 m).

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Section: Poc Turnover In the Pelagic Realm: Insight From Microbial Co...supporting

confidence: 92%

High variability in organic carbon sources and microbial activities in the hadopelagic waters

Zhao

Dang

et al. 2023

Limnology & Oceanography

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“…Figure 1 shows the DOM cross-sections in the Atlantic and Pacific Oceans, mainly based on the data of Hansell et al [15]. Coastal oceans receive DOM from land and may have a DOM concentration as high as 100µM [16,17]. The open ocean surface water generally has a concentration just above 70µM, which gradually decreases to between 40 and 50µM in the deep Pacific and Atlantic Oceans.…”

Section: International Journal Of Environmental Sciences and Natural Resourcesmentioning

confidence: 99%

The Much Overrated Microbial Carbon Pump in the Oceans

Chen

2021

IJESNR

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The oceans cover 70.8% of the globe's surface and absorb 26.6% of the CO 2 released by human activities in 2019 [1]. As CO 2 is the major greenhouse gas, the more the oceans absorb it, and the longer the oceans keep it, the slower the Earth warms. It is thus of paramount importance in understanding the air-sea exchange of CO 2 and the carbon cycle in the oceans.The oceans exchange 90GtC CO 2 with the atmosphere with net absorption of 2.5GtC anthropogenic CO 2 in 2019 [1]. Once CO 2 enters the surface ocean, it is traditionally considered to be transported downward by two major pathways, or the so-called "pumps." The physical or solubility pump works mainly by sinking the cold, CO 2 -rich seawater in the polar and subpolar regions, thus storing CO 2 in the deep oceans for hundreds of years. Figure 1 shows, schematically, the sinking of major deep and bottom waters: the North Atlantic Deep Water (NADW) in the polar North Atlantic Ocean, the Antarctic Bottom Water (AABW) in the Antarctic region, the Antarctic Intermediate Water (AAIW) in the sub-Antarctic region, and the North Pacific Intermediate Water (NPIW) in the subpolar North Pacific Ocean.

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“…Recent investigation demonstrates that, in riverine export, 41% of terrestrially derived DOC is delivered to the coastal ocean, 21% is buried in sediment, and the remaining 38% is returned to the atmosphere through outgassing from inland waters [13,14]. DOC in river water has a close impact on the dynamic of the aquatic biogeochemical cycle, light penetration, transportation of trace metals, secondary production, and the flow of nitrogen [15][16][17][18][19]. It is also considered to increase the solubility of some organic pollutants in water [20].…”

Section: Introductionmentioning

confidence: 99%

Export of Dissolved Organic Carbon from the Source Region of Yangtze River in the Tibetan Plateau

You

Sillanpää

et al. 2022

Sustainability

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The carbon release and transport in rivers are expected to increase in a warming climate with enhanced melting. We present a continuous dataset of DOC in the river, precipitation, and groundwater, including air temperature, discharge, and precipitation in the source region of the Yangtze River (SRYR). Our study shows that the average concentrations of DOC in the three end-members are characterized as the sequence of groundwater > precipitation > river, which is related to the water volume, cycle period, and river flow speed. The seasonality of DOC in the river is observed as the obvious bimodal structure at Tuotuohe (TTH) and Zhimenda (ZMD) gauging stations. The highest concentration appears in July (2.4 mg L−1 at TTH and 2.1 mg L−1 at ZMD) and the secondary high value (2.2 mg L−1 at TTH 1.9 mg L−1 at ZMD) emerges from August to September. It is estimated that 459 and 6751 tons of DOC are transported by the river at TTH and ZMD, respectively. Although the wet deposition flux of DOC is nearly ten times higher than the river flux, riverine DOC still primarily originates from soil erosion of the basin rather than precipitation settlement. Riverine DOC fluxes are positively correlated with discharge, suggesting DOC fluxes are likely to increase in the future. Our findings highlight that permafrost degradation and glacier retreat have a great effect on DOC concentration in rivers and may become increasingly important for regional biogeochemical cycles.

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Organic Carbon Concentrations in High- and Low-Productivity Areas of the Sulu Sea

Cited by 4 publications

References 62 publications

High variability in organic carbon sources and microbial activities in the hadopelagic waters

High variability in organic carbon sources and microbial activities in the hadopelagic waters

The Much Overrated Microbial Carbon Pump in the Oceans

Export of Dissolved Organic Carbon from the Source Region of Yangtze River in the Tibetan Plateau

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