Temporal Change of Dissolved Inorganic Carbon in the Subsurface Water at Station KNOT (44°N, 155°E) in the Western North Pacific Subpolar Region

2005 ◽  
Vol 61 (1) ◽  
pp. 129-139 ◽  
Author(s):  
Masahide Wakita ◽  
Shuichi Watanabe ◽  
Yutaka W. Watanabe ◽  
Tsuneo Ono ◽  
Nobuo Tsurushima ◽  
...  
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Inorganic Carbon ◽  
Temporal Change ◽  
Dissolved Inorganic Carbon ◽  
Subsurface Water

scholarly journals Decadal change of dissolved inorganic carbon in the subarctic western North Pacific Ocean

Tellus B ◽  
2010 ◽  
Vol 62 (5) ◽  
pp. 608-620 ◽  
Author(s):  
M. Wakita ◽  
S. Watanabe ◽  
A. Murata ◽  
N. Tsurushima ◽  
M. Honda
Keyword(s):  
Pacific Ocean ◽  
North Pacific ◽  
Western North Pacific ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
North Pacific Ocean ◽  
Decadal Change ◽  
Western North Pacific Ocean

scholarly journals North Pacific dissolved inorganic carbon variations related to the Pacific Decadal Oscillation

2014 ◽  
Vol 41 (3) ◽  
pp. 1005-1011 ◽  
Author(s):  
Sayaka Yasunaka ◽  
Yukihiro Nojiri ◽  
Shin-ichiro Nakaoka ◽  
Tsuneo Ono ◽  
Hitoshi Mukai ◽  
...  
Keyword(s):  
Pacific Decadal Oscillation ◽  
North Pacific ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
The Pacific

scholarly journals A Survey on the Relationship between Ocean Subsurface Temperature and Tropical Cyclone over the Western North Pacific

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Difu Sun ◽  
Junqiang Song ◽  
Kaijun Ren ◽  
Xiaoyong Li ◽  
Guangjie Wang
Keyword(s):  
Tropical Cyclone ◽  
Water Temperature ◽  
Negative Correlation ◽  
North Pacific ◽  
Western North Pacific ◽  
Vertical Wind Shear ◽  
Longwave Radiation ◽  
Subsurface Water ◽  
Subsurface Temperature ◽  
The Relationship

The relationship between ocean subsurface temperature and tropical cyclone (TC) over the western North Pacific (WNP) is studied based on the TC best-track data and global reanalysis data during the period of 1948–2012. Here the TC frequency (TCF), lifespan, and genesis position of TCs are analysed. A distinctive negative correlation between subsurface water temperature and TCF is observed, especially the TCF in the southeastern quadrant of the WNP (0–15°N, 150–180°E). According to the detrended subsurface temperature anomalies of the 125 m depth layer in the main TC genesis area (0–30°N, 100–180°E), we selected the subsurface cold and warm years. During the subsurface cold years, TCs tend to have a longer mean lifespan and a more southeastern genesis position than the subsurface warm years in general. To further investigate the causes of this characteristic, the TC genesis potential indexes (GPI) are used to analyse the contributions of environmental factors to TC activities. The results indicate that the negative correlation between subsurface water temperature and TCF is mainly caused by the variation of TCF in the southeastern quadrant of the WNP, where the oceanic and atmospheric environments are related to ocean subsurface conditions. Specifically, compared with the subsurface warm years, there are larger relative vorticity, higher relative humidity, smaller vertical wind shear, weaker net longwave radiation, and higher ocean mixed layer temperature in the southeastern quadrant during cold years, which are all favorable for genesis and development of TC.

scholarly journals Vertically migrating phytoplankton drive seasonal formation of subsurface negative preformed nitrate anomalies in the subtropical North Pacific and North Atlantic

2018 ◽  
Author(s):  
Robert T. Letscher ◽  
Tracy A. Villareal
Keyword(s):  
Organic Matter ◽  
Mixed Layer ◽  
North Atlantic ◽  
North Pacific ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Euphotic Zone ◽  
The North ◽  
Station Aloha ◽  
Biological Nitrogen

Abstract. Summertime drawdown of dissolved inorganic carbon in the absence of measurable nutrients from the mixed layer and subsurface negative preformed nitrate (preNO3) anomalies observed for the ocean's subtropical gyres are two biogeochemical phenomena that have thus far eluded complete description. Many processes are thought to contribute including biological nitrogen fixation, lateral nutrient transport, carbon overconsumption or non-Redfield C : N : P organic matter cycling, heterotrophic nutrient uptake, and the actions of vertically migrating phytoplankton. Here we investigate the seasonal formation rates and potential contributing mechanisms for negative preformed nitrate anomalies (oxygen consumption without stoichiometric nitrate release) in the subsurface and positive preformed nitrate anomalies (oxygen production without stoichiometric nitrate drawdown) in the euphotic zone at the subtropical ocean time series stations ALOHA in the North Pacific and BATS in the North Atlantic. Non-Redfield −O2 : N stoichiometry for dissolved organic matter (DOM) remineralization is found to account for up to ~ 15 mmol N m−2 yr−1 of negative preNO3 anomaly formation at both stations. Residual negative preNO3 anomalies in excess of that which can be accounted for by non-Redfield DOM cycling are found to accumulate at a rate of ~ 32–46 mmol N m−2 yr−1 at station ALOHA and ~ 46–87 mmol N m−2 yr−1 at the BATS station. These negative anomaly formation rates are in approximate balance with positive preNO3 anomaly formation rates from the euphotic zone located immediately above the nutricline in the water column. Cycling of transparent exopolymer particles (TEP) and heterotrophic nitrate uptake can contribute to the formation of these preNO3 anomalies, however a significant fraction, estimated at ~ 50–95 %, is unexplained by the sum of these processes. Vertically migrating phytoplankton possess the necessary nutrient acquisition strategy and biogeochemical signature to quantitatively explain both the residual negative and positive preNO3 anomalies as well as the mixed layer dissolved inorganic carbon drawdown at stations ALOHA and BATS. TEP production by the model Rhizosolenia mat system could provide accelerated vertical transport of TEP as well as link the three processes together. Phytoplankton vertical migrators, although rare and easily overlooked, may play a large role in subtropical ocean nutrient cycling and the biological pump.

Time-series observation of dissolved inorganic carbon and nutrients in the northwestern North Pacific

2007 ◽  
Vol 63 (6) ◽  
pp. 967-982 ◽  
Author(s):  
Hajime Kawakami ◽  
Makio C. Honda ◽  
Masahide Wakita ◽  
Shuichi Watanabe
Keyword(s):  
Time Series ◽  
North Pacific ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon

scholarly journals How significant is submarine groundwater discharge and its associated dissolved inorganic carbon in a river-dominated shelf system-the northern South China Sea?

2011 ◽  
Vol 8 (6) ◽  
pp. 12381-12422 ◽  
Author(s):  
Q. Liu ◽  
M. Dai ◽  
W. Chen ◽  
C.-A. Huh ◽  
G. Wang ◽  
...  
Keyword(s):  
Submarine Groundwater Discharge ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Northern South China Sea ◽  
River Plume ◽  
Subsurface Water ◽  
Pearl River ◽  
New Production ◽  
Submarine Groundwater ◽  
The Pearl River

Abstract. In order to assess the role of submarine groundwater discharge (SGD) and its impact on the carbonate system on the northern South China Sea (NSCS) shelf, we measured seawater concentrations of four radium isotopes 223,224,226,228Ra along with carbon dioxide parameters in June–July, 2008. Complementary groundwater sampling was conducted in coastal areas in December 2008 and October 2010 to constrain the groundwater end-members. The distribution of Ra isotopes in the NSCS was largely controlled by the Pearl River plume and coastal upwelling. Long-lived Ra isotopes (228Ra and 226Ra) were enriched in the river plume but low in the offshore surface water and subsurface water/upwelling zone. In contrast, short-lived Ra isotopes (224Ra and 223Ra) were elevated in the subsurface water/upwelling zone as well as the river plume but depleted in the offshore surface water. In order to quantify SGD, we adopted two independent mathematical approaches. Using a three end-member mixing model with total alkalinity (TAlk) and Ra isotopes, we derived a SGD flux into the NSCS shelf of 2.3–3.7 ×108 m3 d−1. Our second approach involved a simple mass balance of 228Ra and 226Ra and resulted in a first order but consistent SGD rate estimate of 2.8–4.5 × 108 m3 d−1. These fluxes were equivalent to 13–25 % of the Pearl River discharge, but the source of the SGD is mostly recirculated seawater. Despite the relatively small SGD volume flow compared to the river, the associated material fluxes were substantial given the elevated concentrations of dissolved inorganic solutes. In this case, dissolved inorganic carbon (DIC) flux through SGD was 266–520 × 109 mol yr−1, which was ~44–73 % of the riverine DIC export flux. Given our estimates of the groundwater-derived phosphate flux, SGD may be responsible for new production on the shelf up to 3–6 mmol C m−2 d−1. This rate of new production would at most consume 18 % of the DIC contribution delivered by SGD. Hence, SGD may play an important role in the carbon balance over the NSCS shelf.

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