Transient Carbonate Chemistry in the Expanded Kuroshio Region

Lui, Hon-Kit; Chen, Chen‐Tung Arthur; Hou, Wei-Ping; Yu, Shujie; Chan, Jui-Wen; Bai, Yan; He, Xianqiang

doi:10.1007/978-981-15-4886-4_16

Cited by 4 publications

(5 citation statements)

References 36 publications

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“…Second, oxygen acts as a co-substrate and a rate-limiting factor as the biodegradation mechanisms require the presence of molecular oxygen to initiate the enzymatic attack of PAH rings . The dissolved oxygen of the Kuroshio water is significantly higher than that of the northern SCS (Figure S7), and a previous study has confirmed that Kuroshio intrusion increases the level of dissolved oxygen . Third, the nutrient is another rate-limiting factor for PAHs’ biodegradation as microorganisms require various nutrients like nitrogen, phosphorous, potassium, and iron for metabolism and growth .…”

Section: Resultsmentioning

confidence: 91%

“…48 The dissolved oxygen of the Kuroshio water is significantly higher than that of the northern SCS (Figure S7), and a previous study has confirmed that Kuroshio intrusion increases the level of dissolved oxygen. 49 Third, the nutrient is another ratelimiting factor for PAHs' biodegradation as microorganisms require various nutrients like nitrogen, phosphorous, potassium, and iron for metabolism and growth. 50 The open area of SCS is characterized by nutrient deficiency in its surface water and low primary productivity.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Enhanced Sinks of Polycyclic Aromatic Hydrocarbons Due to Kuroshio Intrusion: Implications on Biogeochemical Processes in the Ocean-Dominated Marginal Seas

Zheng

Wang

et al. 2021

Environ. Sci. Technol.

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The biogeochemical processes of polycyclic aromatic hydrocarbons (PAHs) in the South China Sea (SCS) are influenced by the exchanges of water masses, energies, and materials between this marginal sea and the Pacific Ocean. To investigate the impact of oceanic water intrusion on semivolatile compounds, we collected seawater samples in the Western Pacific, northern, and central SCS in 2017 and analyzed for dissolved PAHs. PAH concentrations in the water columns of the Pacific Ocean and SCS were 1.7–11 and 1.1–7.3 ng L–1, respectively, showing spatial distinctions in terms of the composition and source characteristics. A common depletion for three-ring PAHs was found in the northern SCS by comparing the modeling results of conservative mixing by Kuroshio intrusion. Kuroshio water increased the levels of temperature, dissolved oxygen, and nutrients when intruding into the northern SCS and was likely to enhance the bioavailability of PAHs and stimulate their biodegradation process. In the water column, the most effective layer under the Kuroshio intrusion impact is different for three- and four-ring PAHs, where the three-ring PAHs’ depletion was most significant at the surface; however, for four-ring PAHs, that was at the deep chlorophyll maximum layer. This study highlighted the effect of ocean currents on PAHs for their water-column processes both from physical and biogeochemical perspectives.

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Section: Resultsmentioning

confidence: 91%

Section: ■ Materials and Methodsmentioning

confidence: 99%

Enhanced Sinks of Polycyclic Aromatic Hydrocarbons Due to Kuroshio Intrusion: Implications on Biogeochemical Processes in the Ocean-Dominated Marginal Seas

Zheng

Wang

et al. 2021

Environ. Sci. Technol.

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“…11a). It is lower than the rate of f CO 2 increase (4 µatm yr −1 ) for the period of 1999-2003 (Tseng et al, 2007), while it is higher than the rate of pCO 2 increase for the period of 1998-2006 (0.8 µatm yr −1 ) at Station SEATS (Lui et al, 2020). The differences between their rates and ours exist because (a) our rate is a spatial average in summer and their rates are based on data collected in spring, summer, fall, and winter at a basin station and (b) the period to derive our rate is much longer than theirs.…”

Section: Reconstruction Validation and Uncertainty Quantificationmentioning

confidence: 71%

“…The samples of total alkalinity and dissolved inorganic carbon were collected and measured following the same procedure in Guo et al (2015). The calculation of pCO 2 was made using the program of Lewis and Wallace (1998), in which the apparent dissociation constants for carbonic acid of Mehrbach et al (1973) refit by Dickson and Millero (1987) and the dissociation constant for bisulfate ion from Dickson (1990) were employed. Another sea surface pCO 2 dataset calculated in the same way at Station SEATS in the summer of 2000, 2001, 2004, and 2006 was compiled from Lui et al (2020).…”

Section: Observed Data In the Scsmentioning

confidence: 99%

“…The differences between their rates and ours exist because (a) our rate is a spatial average in summer and their rates are based on data collected in spring, summer, fall, and winter at a basin station and (b) the period to derive our rate is much longer than theirs. Using the summer data in Lui et al (2020), the rate we estimated from the year 2000, which is the beginning year of our data, to the year 2006 at Station SEATS is 2.5 ± 1.0 µatm yr −1 . Although the period of 2000-2006 is much shorter than our period of 2000-2017, the summer rate at Station SEATS is almost the same as our rate based on the reconstructed data over the SCS.…”

Section: Reconstruction Validation and Uncertainty Quantificationmentioning

confidence: 99%

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Feasibility of reconstructing the summer basin-scale sea surface partial pressure of carbon dioxide from sparse in situ observations over the South China Sea

Wang

Shen

Chen

et al. 2021

Earth Syst. Sci. Data

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Abstract. Sea surface partial pressure of CO2 (pCO2) data with a high spatiotemporal resolution are important in studying the global carbon cycle and assessing the oceanic carbon uptake. However, the observed sea surface pCO2 data are usually limited in spatial and temporal coverage, especially in marginal seas. This study provides an approach to reconstruct the complete sea surface pCO2 field in the South China Sea (SCS) with a grid resolution of 0.5∘×0.5∘ over the period of 2000–2017 using both remote-sensing-derived pCO2 and observed underway pCO2, among which the gridded underway pCO2 data in 2004, 2005, and 2006 are presented for the first time. Empirical orthogonal functions (EOFs) were computed from the remote-sensing-derived pCO2. Then, a multilinear regression was applied to the observed pCO2 as the response variable with the EOFs as the explanatory variables. EOF1 explains the general spatial pattern of pCO2 in the SCS. EOF2 shows the pattern influenced by the Pearl River plume on the northern shelf and slope. EOF3 is consistent with the pattern influenced by coastal upwelling along the northern coast of the SCS. When pCO2 observations cover a sufficiently large area, the reconstructed fields successfully display a pattern of relatively high pCO2 in the mid and southern basin. The rate of sea surface pCO2 increase in the SCS is 2.4±0.8 µatm yr−1 based on the spatial average of the reconstructed pCO2 over the period of 2000–2017. This is consistent with the temporal trends at Station SEATS (SouthEast Asia Time-series Study; 18∘ N, 116∘ E) in the northern basin of the SCS and at Station ALOHA (A Long-Term Oligotrophic Habitat Assessment; 22∘45′ N, 158∘ W) in the North Pacific. We validated our reconstruction with a leave-one-out cross-validation approach, which yields the root-mean-square error (RMSE) in the range of 2.4–5.2 µatm, smaller than the spatial standard deviation of our reconstructed data and much smaller than the spatial standard deviation of the observed underway data. The RMSE between the reconstructed summer pCO2 and the observed underway pCO2 is no larger than 31.7 µatm, in contrast to (a) the RMSE from 12.8 to 89.0 µatm between the remote-sensing-derived pCO2 and the underway data and (b) the RMSE from 32.6 to 44.5 µatm between the neural-network-produced pCO2 and the underway data. The difference between the reconstructed pCO2 and those calculated from observations at Station SEATS is in the range from −7 to 10 µatm. These comparison results indicate the reliability of our reconstruction method and output. All the data for this paper are openly and freely available at PANGAEA under the link https://doi.org/10.1594/PANGAEA.921210 (Wang et al., 2020).

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Anthropogenic Stresses in Coral Reefs and Adjacent Ecosystems of the East China Sea

Takeuchi

2023

Coral Reefs of the World

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Transient Carbonate Chemistry in the Expanded Kuroshio Region

Cited by 4 publications

References 36 publications

Enhanced Sinks of Polycyclic Aromatic Hydrocarbons Due to Kuroshio Intrusion: Implications on Biogeochemical Processes in the Ocean-Dominated Marginal Seas

Enhanced Sinks of Polycyclic Aromatic Hydrocarbons Due to Kuroshio Intrusion: Implications on Biogeochemical Processes in the Ocean-Dominated Marginal Seas

Feasibility of reconstructing the summer basin-scale sea surface partial pressure of carbon dioxide from sparse in situ observations over the South China Sea

Anthropogenic Stresses in Coral Reefs and Adjacent Ecosystems of the East China Sea

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