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Trends of pH decrease in the Mediterranean Sea through high frequency observational data: indication of ocean acidification in the basin.

Flecha S, Pérez FF, García-Lafuente J, Sammartino S, Ríos AF, Huertas IE - Sci Rep (2015)

Bottom Line: Assessing the impact of OA on marine ecosystems requires the accurate detection of the rate of seawater pH change.This work reports the results of nearly 3 years of continuous pH measurements in the Mediterranean Sea at the Strait of Gibraltar GIFT time series station.Both water masses also exhibited a decline in pH with time, particularly the WMDW, which can be related to their different biogeochemical nature and processes occurring during transit time from formation sites to the Strait of Gibraltar.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Ciencias Marinas de Andalucía, (CSIC), Polígono Río San Pedro, s/n, 11519, Puerto Real, Cádiz, Spain.

ABSTRACT
A significant fraction of anthropogenic carbon dioxide (CO2) released to the atmosphere is absorbed by the oceans, leading to a range of chemical changes and causing ocean acidification (OA). Assessing the impact of OA on marine ecosystems requires the accurate detection of the rate of seawater pH change. This work reports the results of nearly 3 years of continuous pH measurements in the Mediterranean Sea at the Strait of Gibraltar GIFT time series station. We document a remarkable decreasing annual trend of -0.0044 ± 0.00006 in the Mediterranean pH, which can be interpreted as an indicator of acidification in the basin based on high frequency records. Modeling pH data of the Mediterranean outflow allowed to discriminate between the pH values of its two main constituent water masses, the Levantine Intermediate Water (LIW) and the Western Mediterranean Deep Water (WMDW). Both water masses also exhibited a decline in pH with time, particularly the WMDW, which can be related to their different biogeochemical nature and processes occurring during transit time from formation sites to the Strait of Gibraltar.

No MeSH data available.


Related in: MedlinePlus

Fractions of the water masses forming the MOW during the monitoring period, according to the OMP analysis (see text): (a) LIW, (b) WDMW and (c) AW.
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f2: Fractions of the water masses forming the MOW during the monitoring period, according to the OMP analysis (see text): (a) LIW, (b) WDMW and (c) AW.

Mentions: Water masses fractions variability in the MOW, discriminated with an OMP (Optimum MultiParameter) analysis30, (see SI text for more details), clearly describes seasonal and interannual fluctuations (Fig. 2). During the monitoring period, the LIW appeared to dominate the outflow most of the time, with a mean fraction of 0.55 ± 0.1 (Fig. 2a) whereas the WMDW showed a fraction of 0.36 ± 0.1 (Fig. 2b). Because of the sampling depth, the presence of the AW (Fig. 2c) was almost negligible within the MOW, with an average fraction of 0.09 ± 0.03, confirming historic observations25.


Trends of pH decrease in the Mediterranean Sea through high frequency observational data: indication of ocean acidification in the basin.

Flecha S, Pérez FF, García-Lafuente J, Sammartino S, Ríos AF, Huertas IE - Sci Rep (2015)

Fractions of the water masses forming the MOW during the monitoring period, according to the OMP analysis (see text): (a) LIW, (b) WDMW and (c) AW.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4660394&req=5

f2: Fractions of the water masses forming the MOW during the monitoring period, according to the OMP analysis (see text): (a) LIW, (b) WDMW and (c) AW.
Mentions: Water masses fractions variability in the MOW, discriminated with an OMP (Optimum MultiParameter) analysis30, (see SI text for more details), clearly describes seasonal and interannual fluctuations (Fig. 2). During the monitoring period, the LIW appeared to dominate the outflow most of the time, with a mean fraction of 0.55 ± 0.1 (Fig. 2a) whereas the WMDW showed a fraction of 0.36 ± 0.1 (Fig. 2b). Because of the sampling depth, the presence of the AW (Fig. 2c) was almost negligible within the MOW, with an average fraction of 0.09 ± 0.03, confirming historic observations25.

Bottom Line: Assessing the impact of OA on marine ecosystems requires the accurate detection of the rate of seawater pH change.This work reports the results of nearly 3 years of continuous pH measurements in the Mediterranean Sea at the Strait of Gibraltar GIFT time series station.Both water masses also exhibited a decline in pH with time, particularly the WMDW, which can be related to their different biogeochemical nature and processes occurring during transit time from formation sites to the Strait of Gibraltar.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Ciencias Marinas de Andalucía, (CSIC), Polígono Río San Pedro, s/n, 11519, Puerto Real, Cádiz, Spain.

ABSTRACT
A significant fraction of anthropogenic carbon dioxide (CO2) released to the atmosphere is absorbed by the oceans, leading to a range of chemical changes and causing ocean acidification (OA). Assessing the impact of OA on marine ecosystems requires the accurate detection of the rate of seawater pH change. This work reports the results of nearly 3 years of continuous pH measurements in the Mediterranean Sea at the Strait of Gibraltar GIFT time series station. We document a remarkable decreasing annual trend of -0.0044 ± 0.00006 in the Mediterranean pH, which can be interpreted as an indicator of acidification in the basin based on high frequency records. Modeling pH data of the Mediterranean outflow allowed to discriminate between the pH values of its two main constituent water masses, the Levantine Intermediate Water (LIW) and the Western Mediterranean Deep Water (WMDW). Both water masses also exhibited a decline in pH with time, particularly the WMDW, which can be related to their different biogeochemical nature and processes occurring during transit time from formation sites to the Strait of Gibraltar.

No MeSH data available.


Related in: MedlinePlus