| Water Body Name: | Pacific Ocean Smith River HU |
| Water Body ID: | CAO1031100020240730040982 |
| Water Body Type: | Ocean |
DECISION ID |
170434 |
Region 1 |
Pacific Ocean Smith River HU |
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| Pollutant: | Omega Aragonite |
| Final Listing Decision: | Do Not List on 303(d) list (TMDL required list) |
| Last Listing Cycle's Final Listing Decision: | New Decision |
| Revision Status | Revised |
| Impairment from Pollutant or Pollution: | Pollutant |
| Regional Board Conclusion: | Omega Aragonite is being assessed using Listing Policy section 3.11, a situation-specific weight of evidence approach. As additional research is needed to increase confidence that the data assessed reflect waterbody conditions, the LOEs for this pollutant are not used to place waterbodies on the CWA section 303(d) list. Instead, an exceedance of the mean Omega Aragonite threshold of <1.4 will indicate the beneficial use may be potentially threatened and the waterbody will be placed in Category 3 if the number of measured exceedances supports rejection of the null hypothesis as presented in Table 3.2 of the Listing Policy for conventional or other pollutants. One line of evidence is available in the administrative record to assess this pollutant. Zero of the 1 samples exceed the Omega Aragonite threshold of <1.4. The number of exceedances does not indicate impairment under Listing Policy section 3.2; however, insufficient information is available to determine if the beneficial use is fully supported for this waterbody-pollutant combination. Beneficial use support will be reassessed in a future cycle, if more data are available. In order to make recommendations to list an ocean segment as impaired or to determine that the beneficial use is fully supported for ocean acidification using Omega Aragonite as an evaluation guideline, further research may be conducted to identify biological criteria and/or utilize ocean acidification model outputs. |
| Regional Board Decision Recommendation: | After review of the available data and information, RWQCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list. The readily available data and information is insufficient to determine, with the power and confidence of the Listing Policy, the applicable beneficial use support rating. |
| State Board Review of Regional Board Conclusion and Recommendation: | In order to make recommendations to list an ocean segment as impaired or to determine that the beneficial use is fully supported for ocean acidification using Omega Aragonite as an evaluation guideline, further research may be conducted to identify biological criteria and/or utilize ocean acidification model outputs. |
| State Board Decision Recommendation: | After review of the available data and information, SWRCB staff concludes that the water body-pollutant combination should not be placed on the section 303(d) list because it cannot be determined if applicable water quality standards are not being exceeded. |
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| LOE ID: | 351524 | ||||
| Pollutant: | Omega Aragonite | ||||
| LOE Subgroup: | Pollutant-Water | ||||
| Matrix: | Water | ||||
| Fraction: | Not Recorded | ||||
| Beneficial Use: | Marine Habitat | ||||
| Number of Samples: | 1 | ||||
| Number of Exceedances: | 0 | ||||
| Data and Information Type: | PHYSICAL/CHEMICAL MONITORING | ||||
| Data Used to Assess Water Quality: | Water Board staff assessed NOAA West Coast ocean acidification data for Pacific Ocean Smith River HU to determine beneficial use support and the results are as follows: 0 of the 1 samples exceeded (<1.4) the impairment threshold for Omega Aragonite. | ||||
| Data Reference: | Aragonite saturation state (Omega Aragonite) data from the NOAA WCOA 2021 Ocean Acidification Cruise for the 2026 Integrated Report. | ||||
| SWAMP Data: | Non-SWAMP | ||||
| Water Quality Objective/Criterion: | The California SWRCB Marine Habitat Beneficial Use is defined as "Uses of water that support marine ecosystems including, but not limited to, preservation or enhancement of marine habitats, vegetation such as kelp, fish, shellfish, or wildlife (e.g., marine mammals, shorebirds)." A beneficial use was chosen as the assessment criteria for ocean acdification as impacts due to Omega Aragonite can be from global and local sources. |
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| Objective/Criterion Reference: | Marine Habitat (MAR) Beneficial use definition for Regional and Statewide use. The California Water Boards' Annual Performance Report - Fiscal Year 13/14 (CA SWRCB, 2014). | ||||
| Evaluation Guideline: | The omega aragonite criterion for the protection of the marine habitat beneficial use is used to determine potential impairment of waterbodies due to ocean acidification; a threshold below 1.4 would indicate potential impairment of a waterbody. The omega aragonite saturation state is calculated by the product of the concentrations of dissolved calcium and carbonate ions divided by their product at equilibrium. Lower levels of omega aragonite are correlated with increased dissolution of pteropods (shell species) and a loss of marine life. In Bednaršek 2019, thresholds between 0.9 and 1.5 were found to indicate severe to mild shell dissolution of pteropods, with potential impairment indicated at approximately 1.2 ± 0.1 (for an overall threshold of 1.3) or below. A study conducted by Oregon State University concluded that the “maximum uncertainty of ±0.2 in the calculation of mean omega aragonite saturation state is required to adequately link changes in ocean chemistry to changes in ecosystem function” (McLaughlin 2015). Thus, the mean aragonite saturation state of 1.4 (1.2 ± 0.2), has been used for the assessment of omega aragonite data. | ||||
| Guideline Reference: | McLaughlin, K., Weisberg, S. B., Dickson, A. G., Hofmann, G. E., Newton, J. A., Aseltine-Neilson, D., ... & Steele, B. (2015). Core principles of the California Current Acidification Network: Linking chemistry, physics, and ecological effects. Oceanography, 28(2), 160-169. doi:10.5670/oceanog.2015.39 | ||||
| Guideline Reference: | Bednaršek, N., R.A. Feely, E.L. Howes, B.P.V. Hunt, F. Kessouri, P. Leon, R. Lischka, A.E. Maas, K. McLaughlin, N.P. Nezlin, M. Sutula, S.B. Weisberg. 2019. Systematic Review and Meta-Analysis Toward Synthesis of Thresholds of Ocean Acidification Impacts on Calcifying Pteropods and Interactions With Warming. Frontiers in Marine Science 6:227. | ||||
| Spatial Representation: | Sample was collected at Station WCOA2021_68. | ||||
| Temporal Representation: | One sample was collected on 7/7/2021. | ||||
| Environmental Conditions: | |||||
| QAPP Information: | The documents submitted meet the narrative and qualitative guidelines for QA submissions in Listing Policy 6.1.4. | ||||
| QAPP Information Reference(s): | NOAA West Coast Ocean Acidification Cruise methods, discussion, metadata, and analysis for ocean acidification sampling of the Pacific Coast in 2021. Lead Investigator(s): Richard A. Feely and Brendan Carter et al. of NOAA PMEL. doi.org/10.25921/tzxh-n954 | ||||