scholarly journals Spatiotemporal variability and long-term trends of ocean acidification in the California Current System

2013 ◽  
Vol 10 (1) ◽  
pp. 193-216 ◽  
Author(s):  
C. Hauri ◽  
N. Gruber ◽  
M. Vogt ◽  
S. C. Doney ◽  
R. A. Feely ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Current System ◽  
California Current ◽  
Spatiotemporal Variability ◽  
The Arctic ◽  
Saturation State ◽  
Aragonite Saturation ◽  
Large Variability ◽  
California Current System ◽  
Ipcc Sres

Abstract. Due to seasonal upwelling, the upper ocean waters of the California Current System (CCS) have a naturally low pH and aragonite saturation state (Ωarag), making this region particularly prone to the effects of ocean acidification. Here, we use the Regional Oceanic Modeling System (ROMS) to conduct preindustrial and transient (1995–2050) simulations of ocean biogeochemistry in the CCS. The transient simulations were forced with increasing atmospheric pCO2 and increasing oceanic dissolved inorganic carbon concentrations at the lateral boundaries, as projected by the NCAR CSM 1.4 model for the IPCC SRES A2 scenario. Our results show a large seasonal variability in pH (range of ~ 0.14) and Ωarag (~ 0.2) for the nearshore areas (50 km from shore). This variability is created by the interplay of physical and biogeochemical processes. Despite this large variability, we find that present-day pH and Ωarag have already moved outside of their simulated preindustrial variability envelopes (defined by ±1 temporal standard deviation) due to the rapidly increasing concentrations of atmospheric CO2. The nearshore surface pH of the northern and central CCS are simulated to move outside of their present-day variability envelopes by the mid-2040s and late 2030s, respectively. This transition may occur even earlier for nearshore surface Ωarag, which is projected to depart from its present-day variability envelope by the early- to mid-2030s. The aragonite saturation horizon of the central CCS is projected to shoal into the upper 75 m within the next 25 yr, causing near-permanent undersaturation in subsurface waters. Due to the model's overestimation of Ωarag, this transition may occur even earlier than simulated by the model. Overall, our study shows that the CCS joins the Arctic and Southern oceans as one of only a few known ocean regions presently approaching the dual threshold of widespread and near-permanent undersaturation with respect to aragonite and a departure from its variability envelope. In these regions, organisms may be forced to rapidly adjust to conditions that are both inherently chemically challenging and also substantially different from past conditions.

scholarly journals Spatiotemporal variability and long-term trends of ocean acidification in the California Current System

2012 ◽  
Vol 9 (8) ◽  
pp. 10371-10428 ◽  
Author(s):  
C. Hauri ◽  
N. Gruber ◽  
M. Vogt ◽  
S. C. Doney ◽  
R. A. Feely ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Current System ◽  
California Current ◽  
Spatiotemporal Variability ◽  
The Arctic ◽  
Saturation State ◽  
Aragonite Saturation ◽  
Large Variability ◽  
California Current System ◽  
Ipcc Sres

Abstract. Due to seasonal upwelling, the upper ocean waters of the California Current System (CCS) have a naturally low pH and aragonite saturation state (Ωarag), making this region particularly prone to the effects of ocean acidification. Here, we use the Regional Oceanic Modeling System (ROMS) to conduct preindustrial and transient (1995–2050) simulations of ocean biogeochemistry in the CCS. The transient simulations were forced with increasing atmospheric pCO2 as projected by the NCAR CSM 1.4 model run under either the IPCC SRES A2 or B1 scenarios. Using ROMS, we investigate the timing of transition decades during which pH and Ωarag depart from their modeled preindustrial (1750) and present-day (2011) variability envelopes. We report these transition decades by noting the midpoint of the ten-year transition periods. In addition, we also analyze the timing of near permanent aragonite undersaturation in the upper 100 m of the water column. Our results show that an interplay of physical and biogeochemical processes create large seasonal variability in pH (∼ 0.14) and Ωarag (∼ 0.2). Despite this large variability, we find that present-day pH and Ωarag have already moved out of their preindustrial variability envelopes due to the rapidly increasing concentrations of atmospheric CO2. The simulations following the A2 emissions scenario suggest that nearshore surface pH of the northern and central CCS will move out of their present-day variability envelopes by 2045 and 2037, respectively. However, surface Ωarag of the northern and central CCS subregions are projected to depart from their present-day variability envelopes sooner, by 2030 and 2035, respectively. By 2025, the aragonite saturation horizon of the central CCS is projected to shoal into the upper 75 m for the duration of the annual cycle, causing near permanent undersaturation in subsurface waters. Overall, our study shows that the CCS joins the Arctic and Southern Oceans as one of only a few known ocean regions presently approaching this dual threshold of undersaturation with respect to aragonite and a departure from its variability envelope. In these regions, organisms may be forced to rapidly adjust to conditions that are both inherently chemically challenging and also substantially different from prior conditions.

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 Impact of aragonite saturation state changes on migratory pteropods

2011 ◽  
Vol 279 (1729) ◽  
pp. 732-738 ◽  
Author(s):  
Steeve Comeau ◽  
Jean-Pierre Gattuso ◽  
Anne-Marin Nisumaa ◽  
James Orr
Keyword(s):  
Critical Role ◽  
The Arctic ◽  
Depth Range ◽  
High Latitudes ◽  
Empirical Relationships ◽  
Saturation State ◽  
Aragonite Saturation ◽  
Ecological Changes ◽  
State Changes ◽  
Ipcc Sres

Thecosome pteropods play a key role in the food web of various marine ecosystems and they calcify, secreting the unstable CaCO 3 mineral aragonite to form their shell material. Here, we have estimated the effect of ocean acidification on pteropod calcification by exploiting empirical relationships between their gross calcification rates (CaCO 3 precipitation) and aragonite saturation state Ω a , combined with model projections of future Ω a . These were corrected for modern model-data bias and taken over the depth range where pteropods are observed to migrate vertically. Results indicate large reductions in gross calcification at temperate and high latitudes. Over much of the Arctic, the pteropod Limacina helicina will become unable to precipitate CaCO 3 by the end of the century under the IPCC SRES A2 scenario. These results emphasize concerns over the future of shelled pteropods, particularly L. helicina in high latitudes. Shell-less L. helicina are not known to have ever existed nor would we expect them to survive. Declines of pteropod populations could drive dramatic ecological changes in the various pelagic ecosystems in which they play a critical role.

scholarly journals Skillful multiyear predictions of ocean acidification in the California Current System

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Riley X. Brady ◽  
Nicole S. Lovenduski ◽  
Stephen G. Yeager ◽  
Matthew C. Long ◽  
Keith Lindsay
Keyword(s):  
Ocean Acidification ◽  
Current System ◽  
California Current ◽  
California Current System

scholarly journals Locating gaps in the California Current System ocean acidification monitoring network

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042093620
Author(s):  
Rae Taylor-Burns ◽  
Courtney Cochran ◽  
Kelly Ferron ◽  
Madison Harris ◽  
Courtney Thomas ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
West Coast ◽  
Current System ◽  
Local Level ◽  
Regional Scale ◽  
California Current ◽  
Monitoring Network ◽  
Ecological Impacts ◽  
The West ◽  
California Current System

Ocean acidification is a global issue with particular regional significance in the California Current System, where social, economic, and ecological impacts are already occurring. Although ocean acidification is a concern that unifies the entire West Coast region, managing for this phenomenon at a regional scale is complex and further complicated by the large scale and dynamic nature of the region. Currently, data collection relevant to ocean acidification on the West Coast is piecemeal, and cannot capture the primary sources of variability in ocean acidification through time and across the region, hindering collaboration among regional managers. We developed a tool to analyze gaps in the West Coast ocean acidification monitoring network. We describe this tool and discuss how it can enable scientists and marine managers in the California Current System to fill information gaps and better understand and thus respond to ocean acidification through the implementation of management solutions at the local level.

scholarly journals Including high-frequency variability in coastal ocean acidification projections

2015 ◽  
Vol 12 (19) ◽  
pp. 5853-5870 ◽  
Author(s):  
Y. Takeshita ◽  
C. A. Frieder ◽  
T. R. Martz ◽  
J. R. Ballard ◽  
R. A. Feely ◽  
...  
Keyword(s):  
Time Series ◽  
Ocean Acidification ◽  
Surf Zone ◽  
Current System ◽  
Sensor Data ◽  
High Temporal Resolution ◽  
Saturation State ◽  
Study Region ◽  
California Current System ◽  
Anthropogenic Carbon

Abstract. Assessing the impacts of anthropogenic ocean acidification requires knowledge of present-day and future environmental conditions. Here, we present a simple model for upwelling margins that projects anthropogenic acidification trajectories by combining high-temporal-resolution sensor data, hydrographic surveys for source water characterization, empirical relationships of the CO2 system, and the atmospheric CO2 record. This model characterizes CO2 variability on timescales ranging from hours (e.g., tidal) to months (e.g., seasonal), bridging a critical knowledge gap in ocean acidification research. The amount of anthropogenic carbon in a given water mass is dependent on the age; therefore a density–age relationship was derived for the study region and then combined with the 2013 Intergovernmental Panel on Climate Change CO2 emission scenarios to add density-dependent anthropogenic carbon to the sensor time series. The model was applied to time series from autonomous pH sensors deployed in the surf zone, kelp forest, submarine canyon edge, and shelf break in the upper 100 m of the Southern California Bight. All habitats were within 5 km of one another, and exhibited unique, habitat-specific CO2 variability signatures and acidification trajectories, demonstrating the importance of making projections in the context of habitat-specific CO2 signatures. In general, both the mean and range of pCO2 increase in the future, with the greatest increase in both magnitude and range occurring in the deeper habitats due to reduced buffering capacity. On the other hand, the saturation state of aragonite (ΩAr) decreased in both magnitude and range. This approach can be applied to the entire California Current System, and upwelling margins in general, where sensor and complementary hydrographic data are available.

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