scholarly journals Review of Baldry et al. "Estimating total alkalinity for coastal ocean acidification monitoring at regional to continental scales in Australian coastal waters"

2017 ◽  
Author(s):  
Chris Hunt
Keyword(s):  
Ocean Acidification ◽  
Coastal Waters ◽  
Coastal Ocean ◽  
Total Alkalinity

scholarly journals Concomitant ocean acidification and increasing total alkalinity at a coastal site in the NW Mediterranean Sea (2007-2015)

2016 ◽  
Author(s):  
Lydia Kapsenberg ◽  
Samir Alliouane ◽  
Frédéric Gazeau ◽  
Laure Mousseau ◽  
Jean-Pierre Gattuso
Keyword(s):  
Ocean Acidification ◽  
Mediterranean Sea ◽  
Dissolved Inorganic Carbon ◽  
Coastal Ocean ◽  
Total Alkalinity ◽  
Global Ocean ◽  
Coastal Zones ◽  
Carbonate Chemistry ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea

Abstract. Monitoring of global ocean change is necessary in coastal zones due to their physical and biological complexity. Here, we document changes in coastal carbonate chemistry at the coastal time-series station, Point B, in the NW Mediterranean Sea from 2007 through 2015 at 1 and 50 m. The rate of surface ocean acidification (−0.0028 ± 0.0003 units pHT yr−1) was faster-than-expected based on atmospheric carbon dioxide forcing alone. Changes in carbonate chemistry were predominantly driven by an increase in total dissolved inorganic carbon (CT, +2.97 ± 0.20 μmol kg−1 yr−1), > 50 % of which was buffered by a synchronous increase in total alkalinity (AT, +2.08 ± 0.19 μmol kg−1 yr−1). The increase in AT was unrelated to salinity and its cause remains to be identified. Interestingly, concurrent increases in AT and CT were most rapid from May to July. Changes at 50 m were slower compared to 1 m. It seems therefore likely that changes in coastal AT cycling via a shallow coastal process gave rise to these observations. This study exemplifies the importance of understanding coastal ocean acidification through localized biogeochemical cycling that extends beyond simple air-sea gas exchange dynamics, in order to make relevant predictions about future coastal ocean change and ecosystem function.

scholarly journals Estimating total alkalinity for coastal ocean acidification monitoring at regional to continental scales in Australian coastal waters

2017 ◽  
Author(s):  
Kimberlee Baldry ◽  
Nick Hardman-Mountford ◽  
Jim Greenwood
Keyword(s):  
Coral Reef ◽  
Linear Regression ◽  
Ocean Acidification ◽  
Multiple Linear Regression ◽  
Chlorophyll A ◽  
Coastal Waters ◽  
World Ocean ◽  
Total Alkalinity ◽  
Estimation Methods ◽  
Coastal Regions

Abstract. Owing to a lack of resources, tools, and knowledge, the natural variability and distribution of Total Alkalinity (TA) has been poorly characterised in coastal waters globally, yet variability is known to be high in coastal regions due to the complex interactions of oceanographic, biotic, and terrestrially-influenced processes. This is a particularly challenging task for the vast Australian coastline, however, it is also this vastness that demands attention in the face of ocean acidification (OA). Australian coastal waters have high biodiversity and endemism, and are home to large areas of coral reef, including the Great Barrier Reef, the largest coral reef system in the world. Ocean acidification threatens calcifying marine organisms by hindering calcification rates, threatening the structural integrity of coral reefs and other ecosystems. Tracking the progression of OA in different coastal regions requires accurate knowledge of the variability in TA. Thus, estimation methods that can capture this variability at synoptic scales are needed. Multiple linear regression is a promising approach in this regard. Here, we compare a range of both simple and multiple linear regression models to the estimation of coastal TA from a range of variables, including salinity, temperature, chlorophyll-a concentration and nitrate concentration. We find that regionally parameterised models capture local variability better than more general coastal or open ocean parameterised models. The strongest contribution to model improvement came through incorporating temperature as an input variable as well as salinity. Further improvements were achieved through the incorporation of either nitrate or chlorophyll-a, with the combination of temperature, salinity, and nitrate constituting the minimum model in most cases. These results provide an approach that can be applied to satellite Earth observation and autonomous in situ platforms to improve synoptic scale estimation of TA in coastal waters.

scholarly journals Persistent spatial structuring of coastal ocean acidification in the California Current System

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
F. Chan ◽  
J. A. Barth ◽  
C. A. Blanchette ◽  
R. H. Byrne ◽  
F. Chavez ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Current System ◽  
California Current ◽  
Coastal Ocean ◽  
California Current System ◽  
Spatial Structuring

scholarly journals Ocean Acidification 2.0: Managing our Changing Coastal Ocean Chemistry

BioScience ◽  
2014 ◽  
Vol 64 (7) ◽  
pp. 581-592 ◽  
Author(s):  
Aaron L. Strong ◽  
Kristy J. Kroeker ◽  
Lida T. Teneva ◽  
Lindley A. Mease ◽  
Ryan P. Kelly
Keyword(s):  
Ocean Acidification ◽  
Coastal Ocean ◽  
Ocean Chemistry

scholarly journals Carbon cycling in the North American coastal ocean: A synthesis

2018 ◽  
Author(s):  
Katja Fennel ◽  
Simone Alin ◽  
Leticia Barbero ◽  
Wiley Evans ◽  
Timotheé Bourgeois ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
North American ◽  
Inorganic Carbon ◽  
Co2 Flux ◽  
Carbon Fluxes ◽  
Coastal Ocean ◽  
Open Ocean ◽  
The Arctic ◽  
The North ◽  
Anthropogenic Carbon

Abstract. A quantification of carbon fluxes in the coastal ocean and across its boundaries, specifically the air-sea, land-to-coastal-ocean and coastal-to-open-ocean interfaces, is important for assessing the current state and projecting future trends in ocean carbon uptake and coastal ocean acidification, but is currently a missing component of global carbon budgeting. This synthesis reviews recent progress in characterizing these carbon fluxes with focus on the North American coastal ocean. Several observing networks and high-resolution regional models are now available. Recent efforts have focused primarily on quantifying net air-sea exchange of carbon dioxide (CO2). Some studies have estimated other key fluxes, such as the exchange of organic and inorganic carbon between shelves and the open ocean. Available estimates of air-sea CO2 flux, informed by more than a decade of observations, indicate that the North American margins act as a net sink for atmospheric CO2. This net uptake is driven primarily by the high-latitude regions. The estimated magnitude of the net flux is 160 ± 80 Tg C/y for the North American Exclusive Economic Zone, a number that is not well constrained. The increasing concentration of inorganic carbon in coastal and open-ocean waters leads to ocean acidification. As a result conditions favouring dissolution of calcium carbonate occur regularly in subsurface coastal waters in the Arctic, which are naturally prone to low pH, and the North Pacific, where upwelling of deep, carbon-rich waters has intensified and, in combination with the uptake of anthropogenic carbon, leads to low seawater pH and aragonite saturation states during the upwelling season. Expanded monitoring and extension of existing model capabilities are required to provide more reliable coastal carbon budgets, projections of future states of the coastal ocean, and quantification of anthropogenic carbon contributions.

scholarly journals Ocean acidification from 1997 to 2011 in the subarctic western North Pacific Ocean

2013 ◽  
Vol 10 (5) ◽  
pp. 8283-8311 ◽  
Author(s):  
M. Wakita ◽  
S. Watanabe ◽  
M. Honda ◽  
A. Nagano ◽  
K. Kimoto ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Mixed Layer ◽  
North Pacific ◽  
Dissolved Inorganic Carbon ◽  
North Pacific Ocean ◽  
Total Alkalinity ◽  
Co2 Uptake ◽  
The North ◽  
Western Subarctic Gyre ◽  
Calcite Saturation

Abstract. Rising atmospheric CO2 contents have led to greater CO2 uptake by the oceans, lowering both pH due to increasing hydrogen ions and CaCO3 saturation states due to declining carbonate ion (CO32−). Here, we used previously compiled data sets and new data collected in 2010 and 2011 to investigate ocean acidification of the North Pacific western subarctic gyre. In winter, the western subarctic gyre is a source of CO2 to the atmosphere because of convective mixing of deep waters rich in dissolved inorganic carbon (DIC). We calculated pH in winter mixed layer from DIC and total alkalinity (TA), and found that it decreased at the rate of −0.001 ± 0.0004 yr−1 from 1997 to 2011. This decrease rate is slower than that expected under condition of seawater/atmosphere equilibration, and it is also slower than the rate in the subtropical regions (−0.002 yr−1). The slow rate is caused by a reduction of CO2 emission in winter due to an increase in TA. Below the mixed layer, the calcite saturation horizon (~185 m depth) shoaled at the rate of 2.9 ± 0.9 m yr−1 as the result of the declining CO32− concentration (−0.03 ± 0.01 μmol k−1yr−1). Between 200 m and 300 m depth, pH decline during the study period (−0.0051 ± 0.0010 yr−1) was larger than ever reported in the open North Pacific. This enhanced acidification rate below the calcite saturation horizon reflected not only the uptake of anthropogenic CO2 but also the increase in the decomposition of organic matter evaluated from the increase in AOU, which suggests that the dissolution of CaCO3 particles increased.

Ocean alkalinity enhancement as a tool to mitigate ocean acidification and facilitate CO2 uptake from the atmosphere

2021 ◽  
Author(s):  
Jakob Rønning ◽  
Carolin Löscher
Keyword(s):  
Ocean Acidification ◽  
Total Alkalinity ◽  
Small Scale ◽  
Marine Biodiversity ◽  
Steady Increase ◽  
Co2 Uptake ◽  
Seawater Ph ◽  
Mineral Additions ◽  
Primary Producer ◽  
Negative Emission Technologies

<p>Anthropogenic global warming over the last century has led to a steady increase of CO<sub>2</sub> in the atmosphere. One of the consequences of increasing CO<sub>2</sub> concentrations is ocean acidification, a phenomenon problematic to marine biodiversity and biogeochemistry. The ocean reservoir takes up 25% of CO<sub>2</sub> from the atmosphere both chemically and biologically. This potential can be made use of to promote CO<sub>2 </sub>uptake from the atmosphere while mitigating ocean acidification and protecting biodiversity using negative emission technologies associated with the ocean. We have investigated the potential of various alkaline minerals to stabilize seawater pH overtime on a small scale. Those alkaline minerals were predicted to be appropriate for ocean alkalinity enhancement and can offer a toolset to mitigate CO<sub>2</sub> from the atmosphere. Specifically, we have examined how chalk, calcite, dolomite, limestone, and olivine affects seawater pH and total alkalinity (TA) on timescales of several months. Thereby, we could identify two promising minerals, dolomite and olivine, and develop a strategy for mineral additions to buffer the seawater pH. Importantly, the often proposed had an unexpected opposite impact and massively lowered the seawater pH over a timescale of 100 days. The identified advantageous minerals will inform our experiments on primary producer cultures and natural consortia.</p>

scholarly journals Ocean acidification and high irradiance stimulate the photo-physiological fitness, growth and carbon production of the Antarctic cryptophyte <i>Geminigera cryophila</i>

2019 ◽  
Vol 16 (15) ◽  
pp. 2997-3008 ◽  
Author(s):  
Scarlett Trimborn ◽  
Silke Thoms ◽  
Pascal Karitter ◽  
Kai Bischof
Keyword(s):  
Ocean Acidification ◽  
Coastal Waters ◽  
High Irradiance ◽  
High Pco2 ◽  
Experimental Conditions ◽  
Phytoplankton Assemblages ◽  
Beneficial Effects ◽  
Carbon Production ◽  
Geminigera Cryophila ◽  
The Antarctic

Abstract. Ecophysiological studies on Antarctic cryptophytes to assess whether climatic changes such as ocean acidification and enhanced stratification affect their growth in Antarctic coastal waters in the future are lacking so far. This is the first study that investigates the combined effects of the increasing availability of pCO2 (400 and 1000 µatm) and irradiance (20, 200 and 500 µmol photons m−2 s−1) on growth, elemental composition and photophysiology of the Antarctic cryptophyte Geminigera cryophila. Under ambient pCO2, this species was characterized by a pronounced sensitivity to increasing irradiance with complete growth inhibition at the highest light intensity. Interestingly, when grown under high pCO2 this negative light effect vanished, and it reached the highest rates of growth and particulate organic carbon production at the highest irradiance compared to the other tested experimental conditions. Our results for G. cryophila reveal beneficial effects of ocean acidification in conjunction with enhanced irradiance on growth and photosynthesis. Hence, cryptophytes such as G. cryophila may be potential winners of climate change, potentially thriving better in more stratified and acidic coastal waters and contributing in higher abundance to future phytoplankton assemblages of coastal Antarctic waters.

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