Seasonal effects of temperature and salinity on the partial pressure of CO2 in seawater

Nature ◽  
1982 ◽  
Vol 300 (5892) ◽  
pp. 511-513 ◽  
Author(s):  
R. F. Weiss ◽  
R. A. Jahnke ◽  
C. D. Keeling
Keyword(s):  
Partial Pressure ◽  
Seasonal Effects ◽  
Partial Pressure Of Co2 ◽  
Effects Of Temperature

Seasonal variation of surface water CO2 partial pressure in the Southland Current, east of New Zealand

1999 ◽  
Vol 50 (5) ◽  
pp. 375 ◽  
Author(s):  
Kim I. Currie ◽  
Keith A. Hunter
Keyword(s):  
Biological Activity ◽  
New Zealand ◽  
Surface Water ◽  
Partial Pressure ◽  
Surface Waters ◽  
Sea Surface ◽  
Mixing Processes ◽  
Co2 Partial Pressure ◽  
Partial Pressure Of Co2 ◽  
Effects Of Temperature

The partial pressure of CO2 in the surface waters (pCO2sw) of the Southland Front east of New Zealand was determined over one annual cycle in 1992/93. Associated parameters of temperature, salinity and nutrients were also measured. Both the modified subtropical waters of the Southland Current and the cooler subantarctic surface waters were undersaturated with CO2 with respect to the atmosphere. The maximum ΔpCO2 of –150 µatm was measured in April 1993. A simple model taking into account the effects of temperature, biological activity and air–sea exchange applied to subantarctic surface water indicated that at different times of the year changes in sea surface temperature, biological activity and mixing processes are the dominant controls of pCO2sw .

scholarly journals A Simple and Accurate Approach for Determining the VFA Concentration in Anaerobic Digestion Liquors, Relying on Two Titration Points and an External Inorganic Carbon Analysis

2021 ◽  
Vol 5 (2) ◽  
pp. 15
Author(s):  
Paz Nativ ◽  
Yonatan Gräber ◽  
Yaron Aviezer ◽  
Ori Lahav
Keyword(s):  
Partial Pressure ◽  
Volatile Fatty Acids ◽  
Inorganic Carbon ◽  
Strong Acid ◽  
Direct Analysis ◽  
Anaerobic Digesters ◽  
Acid Titration ◽  
Partial Pressure Of Co2 ◽  
Ph Range

A new analytic approach is presented for determining the total volatile fatty acids (VFAT) concentration in anaerobic digesters. The approach relies on external determination of the inorganic carbon concentration (CT) in the analyzed solution, along with two strong-acid titration points. The CT concentration can be determined by either a direct analysis (e.g., by using a TOC device) or by estimating it from the recorded partial pressure of CO2(g) in the biogas (often a routine analysis in anaerobic digesters). The titration is carried out to pH 5.25 and then to pH 4.25. The two titration results are plugged into an alkalinity-mass-based equation and then the two terms are subtracted from each other to yield an equation in which VFAT is the sole unknown (since CT is known and the effect of the total orthophosphate and ammonia concentrations is shown to be small at this pH range). The development of the algorithm and its verification on four anaerobic reactor liquors is presented, on both the raw water and on acetic acid-spiked samples. The results show the method to be both accurate (up to 2.5% of the expected value for VFAT/Alkalinity >0.2) and repetitive when the total orthophosphate and ammonia concentrations are known, and fairly accurate (±5% for VFAT >5 mM) when these are completely neglected. PHREEQC-assisted computation of CT from the knowledge of the partial pressure of CO2(g) in the biogas (and pH, EC and temperature in the liquor) resulted in a very good estimation of the CT value (±3%), indicating that this technique is adequate for the purpose of determining VFAT for alarming operators in case of process deterioration and imminent failure.

scholarly journals Hurricane Arthur and its effect on the short-term variability of pCO<sub>2</sub> on the Scotian Shelf, NW Atlantic

2017 ◽  
Author(s):  
Jonathan Lemay ◽  
Helmuth Thomas ◽  
Susanne E. Craig ◽  
William J. Burt ◽  
Katja Fennel ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Carbon Cycling ◽  
Dissolved Inorganic Carbon ◽  
High Temporal Resolution ◽  
Co2 Uptake ◽  
Surface Mixed Layer ◽  
Scotian Shelf ◽  
Short Term ◽  
Partial Pressure Of Co2 ◽  
Short Term Variability

Abstract. The understanding of seasonal variability of carbon cycling on the Scotian Shelf, NW Atlantic Ocean, has improved in recent years, however, very little information is available regarding its short-term variability. In order to shed light on this aspect of carbon cycling on the Scotian Shelf we investigate the effects of Hurricane Arthur, which passed the region on July 5th 2014. The hurricane caused a substantial decline in the surface water partial pressure of CO2 (pCO2), even though the Scotian Shelf possesses CO2 rich deep waters. High temporal resolution data of moored autonomous instruments demonstrate that there is a distinct layer of relatively cold water with low dissolved inorganic carbon (DIC) slightly above the thermocline, presumably due to a sustained population of phytoplankton. Strong storm-related wind mixing caused this cold intermediate layer with high phytoplankton biomass to be entrained into the surface mixed layer. At the surface, phytoplankton begin to grow more rapidly due to increased light. The combination of growth and mixing of low DIC water led to a short-term reduction in partial pressure of CO2 until wind speeds relaxed and allowed for the restratification of the upper water column. These Hurricane-related processes caused a (net-) CO2 uptake by the Scotian Shelf region that is comparable to the spring bloom, thus exerting a major impact on the annual CO2 flux budget.

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