scholarly journals Acidification-vulnerable carbonate system of the East Sea (Japan Sea)

2019 ◽  
Author(s):  
Taehee Na ◽  
Jeomshik Hwang ◽  
Soyun Kim ◽  
Seonghee Jeong ◽  
TaeKeun Rho ◽  
...  
Keyword(s):  
Deep Water ◽  
Dissolved Inorganic Carbon ◽  
Japan Sea ◽  
South Atlantic ◽  
East Sea ◽  
Ulleung Basin ◽  
Total Alkalinity ◽  
The South ◽  
Carbonate System ◽  
Deep Waters

Abstract. The East Sea (Japan Sea) has its own deep overturning circulation, but this operates over a much shorter timescale than that in the open ocean. This allows the East Sea to be used as a natural laboratory in which to investigate potential future changes in the oceanic system. Dissolved inorganic carbon (DIC) and total alkalinity (TA) were measured in 2014 and 2017 to investigate the characteristics and temporal variability of the carbonate system of the East Sea. When the East Sea was compared with a site in the South Atlantic that has similar apparent oxygen utilization (AOU) values, it was also found to have similar DIC content of the deep waters. However, the TA levels in the East Sea were much lower than those recorded in the South Atlantic. Consequently, the DIC / TA ratio of the deep waters of the East Sea was high and similar to that in the North Pacific, which leaves the deep waters of the East Sea vulnerable to acidification by CO2 input. High export production of organic matter, together with low rates of CaCO3 export, are responsible for this high DIC / TA ratio. In the Ulleung Basin, in the southwest of the East Sea, the DIC and AOU of the deep waters increased between 1999 and 2014. pH decrease of the deep waters and shoaling of the carbonate saturation horizons was faster than that recorded in the oceans. Both slowed deep-water ventilation, and the intrusion of anthropogenic CO2 contributed to the acidification of the East Sea. However, a clear increase in DIC from the Japan Basin to the Ulleung Basin, accompanied by a commensurate increase in AOU, was observed in 2014, whereas the meridional gradient was absent in 1999. This observation appears to reflect recent changes in deep-water ventilation, such as the re-initiation of deep-water formation. The East Sea is extremely vulnerable to acidification and should be seen as a special case of ocean acidification rather than an example of how the oceans will respond to a slowdown in ventilation in the future.

scholarly journals Acidification and Deoxygenation of the Northwestern Japan/East Sea

2021 ◽  
Vol 9 (9) ◽  
pp. 953
Author(s):  
Pavel Tishchenko ◽  
Vyacheslav Lobanov ◽  
Dmitry Kaplunenko ◽  
Sergey Sagalaev ◽  
Petr Tishchenko
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Empirical Relationship ◽  
Peter The Great Bay ◽  
Japan Sea ◽  
East Sea ◽  
Total Alkalinity ◽  
Nutrient Concentrations ◽  
Northwestern Part ◽  
Rate Of Increase ◽  
Japan Sea Proper Water

Seasonal hypoxia in the bottom waters of the Peter the Great Bay (PGB) of the Japan/East Sea (JES) occurs in summer. Using the empirical relationship between dissolved oxygen (DO) and pH obtained for hypoxic conditions and available historical DO data, acidification rates were estimated. Carefully sampled time-series observations from the northwestern part of the JES, carried out from 1999 to 2014 along the 132°20′ E and 134°00′ E longitudes, were chosen to determine the interannual variability of the sea’s hydrochemical parameters (DO, pH, and TA—the total alkalinity phosphates, nitrate, and silicates). To limit the effects of seasonal and spatial variability, only data obtained in the warm period were used. Additionally, all data from depths shallower than 500 m were discarded because they are affected by high natural variability, mostly due to strong mesoscale dynamic structures. Our results demonstrated that the pH and DO concentrations measured in the Upper Japan Sea Proper Water (750 m), Lower Japan Sea Proper Water (1250, 1750, 2250 m), and Bottom Water (3000 m) have been decreasing in recent years. On the other hand, calculated normalized dissolved inorganic carbon (NDIC), CO2 partial pressure (pCO2), and measured nutrient concentrations have been increasing. Maximum rates of acidification and deoxygenation are occurring at around 750 m. The annual rate of increase of pCO2 in the water exceeds the atmospheric rate more than 2-fold at a depth of 750 m. The observed variability of the hydrochemical properties can be explained by the combination of the slowdown ventilation of the vertical water column and eutrophication. However, the results obtained here are valid for the subpolar region of the JES, not for the whole sea. The synchronization of the deoxygenation of the open part of the JES and PGB has been found.

scholarly journals Distributions of the carbonate system properties, anthropogenic CO<sub>2</sub>, and acidification during the 2008 BOUM cruise (Mediterranean Sea)

2012 ◽  
Vol 9 (3) ◽  
pp. 2709-2753 ◽  
Author(s):  
F. Touratier ◽  
V. Guglielmi ◽  
C. Goyet ◽  
L. Prieur ◽  
M. Pujo-Pay ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Dissolved Inorganic Carbon ◽  
Marine Ecosystem ◽  
Total Alkalinity ◽  
Carbonate System ◽  
Simple Method ◽  
Deep Waters ◽  
History Of ◽  
The Mediterranean ◽  
System Properties

Abstract. We relate here the distributions of two carbonate system key properties (total alkalinity, AT; and total dissolved inorganic carbon, CT) measured along a section in the Mediterranean Sea, going from Marseille (France) to the south of the Cyprus Island, during the 2008 BOUM cruise. The three main objectives of the present study are (1) to draw and comment on the distributions of AT and CT in the light of others properties like salinity, temperature, and dissolved oxygen, (2) to estimate the distribution of the anthropogenic CO2 (CANT) in the intermediate and the deep waters, and (3) to calculate the resulting variation of pH (acidification) since the beginning of the industrial era. Since the calculation of CANT is always an intense subject of debate, we apply two radically different approaches to estimate CANT: the very simple method TrOCA and the MIX approach, the latter being more precise but also more difficult to apply. A clear picture for the AT and the CT distributions is obtained: the mean concentration of AT is higher in the oriental basin while that of CT is higher in the occidental basin of the Mediterranean Sea, fully coherent with the previous published works. Despite of the two very different approaches we use here (TrOCA and MIX), the estimated distributions of CANT are very similar. These distributions show that the minimum of CANT encountered during the BOUM cruise is higher than 46.3 μmol kg−1 (TrOCA) or 48.8 μmol kg−1(MIX). All Mediterranean water masses (even the deepest) appear to be highly contaminated by CANT, as a result of the very intense advective processes that characterize the recent history of the Mediterranean circulation. As a consequence, unprecedented levels of acidification are reached with an estimated decrease of pH since the pre-industrial era of −0.148 to −0.061 pH unit, which places the Mediterranean Sea as one of the most acidified world marine ecosystem.

New Deep Water Frontiers in the South Atlantic Equatorial Margins

2013 ◽  
Author(s):  
Marcio Rocha Mello ◽  
Tikae Takaki ◽  
Carlos Alberto Fontes ◽  
Webster Mohriak ◽  
Silvana Maria Barbanti ◽  
...  
Keyword(s):  
Deep Water ◽  
South Atlantic ◽  
The South

Organic and inorganic whole system metabolism in two acidified coastal systems in Ireland

2020 ◽  
Author(s):  
Maria Teresa Guerra ◽  
Carlos Rocha
Keyword(s):  
Ocean Acidification ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
Carbonate System ◽  
Net Community Production ◽  
Coastal Acidification ◽  
Autumn And Winter ◽  
System Metabolism ◽  
Internal Buffer ◽  
Community Production

&lt;p&gt;Organic and inorganic whole system metabolism for two Irish coastal areas were compared to evaluate carbonate system resilience to acidification. The two systems are characterized by contrasting watershed input types and composition. Kinvara Bay is fed by Submarine Groundwater Discharge (SGD) derived from a karstic catchment while Killary Harbour is fed by river discharge draining a siliciclastic catchment. Freshwater sources to sea have distinct Total Alkalinity (TA) and Dissolved Inorganic Carbon (DIC) concentrations, higher and lower than the open ocean, respectively, but both evidence seasonally variable low pH, ranging from 6.20 to 7.50. Retention of TA and DIC was calculated for the two areas using LOICZ methodology. In Kinvara bay, annually averaged retention of DIC was greater than for TA (5 &amp;#215; 10&lt;sup&gt;4&lt;/sup&gt; and 1.5 &amp;#215; 10&lt;sup&gt;5&lt;/sup&gt; mol d&lt;sup&gt;-1&lt;/sup&gt;), suggesting the system is acidifying further. Conversely, Killary Harbour shows negative TA and DIC retention, with DIC:TA &lt;1, suggesting an internal buffer against ocean acidification is operating.&lt;/p&gt;&lt;p&gt;Net Community Production (NCP) was calculated for both systems using Dissolved Oxygen data. Subsequently, we estimated Net Community Calcification (NCC) from the ratio between TA and DIC. NCP was always positive in Killary Harbour with an average of 318 mmol O&lt;sub&gt;2&lt;/sub&gt; m&lt;sup&gt;-2 &lt;/sup&gt;d&lt;sup&gt;-1&lt;/sup&gt; (equivalent to 89 mol C m&lt;sup&gt;-2&lt;/sup&gt; y&lt;sup&gt;-1&lt;/sup&gt;). However, Kinvara Bay shows relatively lower positive NCP in spring and summer (average of 46 mmol O&lt;sub&gt;2&lt;/sub&gt; m&lt;sup&gt;-2&lt;/sup&gt; d&lt;sup&gt;-1&lt;/sup&gt;), but negative NCP in autumn and winter. Therefore, Kinvara Bay&amp;#8217;s Total Organic Carbon (TOC) production was low, at ~21 g m&lt;sup&gt;-2&lt;/sup&gt; y&lt;sup&gt;-1&lt;/sup&gt; and not enough to overcome acidification driven by the SGD source composition. These results emphasize the complexity of interactions between the drivers of coastal acidification rate, affecting our ability to accurately assess the resilience of the carbonate system in these areas to ocean acidification pressure in the future.&lt;/p&gt;

Timing of trap formation in the southwestern margin of the Ulleung Basin, East Sea (Japan Sea) and implications for hydrocarbon accumulations

2004 ◽  
Vol 8 (4) ◽  
pp. 369-380 ◽  
Author(s):  
Gwang Hoon Lee ◽  
Booyong Kim ◽  
Sung Jin Chang ◽  
Sik Huh ◽  
Han-Joon Kim
Keyword(s):  
Japan Sea ◽  
East Sea ◽  
Ulleung Basin ◽  
Trap Formation ◽  
Southwestern Margin
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