Anthropogenic and Climatic Contributions to Observed Carbon System Trends in the Northeast Pacific

Franco, Ana C.; Ianson, Debby; Ross, Tetjana; Hamme, Roberta C.; Monahan, Adam H.; Christian, James R.; Davelaar, Marty; Johnson, William K.; Miller, Lisa A.; Robert, Marie; Tortell, Philippe D.

doi:10.1029/2020gb006829

Cited by 27 publications

(18 citation statements)

References 80 publications

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“…Trends are closer to the atmospheric trend in this region (2.12 atm yr -1 ), meaning any change in the carbon sink due to anthropogenic climate change will require long observation time series to detect, as the signal is small relative to internal variability McKinley et al, 2016;Resplandy et al, 2015;Adrienne J. Sutton et al, 2019). We report trends in pCO 2 that are similar to those observed at time series sites along Fisheries and Ocean Canada Line P stations (this study: P4 = 1.30.1 atm yr -1 ; P12 = 1.60.1 atm yr -1 ; comparable to Franco et al (2021): P4 = 1.01.4 atm yr -1 ; P12 = 1.50.6 atm yr -1 ). Alaskan Gyre, west coast upwelling zone; Figure 8a).…”

Section: Air-sea Pco 2 Trendssupporting

confidence: 69%

High-resolution Neural Network Demonstrates Strong CO2 Source-Sink Juxtaposition in the Coastal Zone

Duke,

Hamme,

Ianson

et al. 2024

Preprint

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Coastal oceans may play an important role in regulating the concentration of carbon dioxide in the atmosphere. Quantification of carbon fluxes at this highly dynamic land-ocean interface will aid in monitoring, reporting, and verification for marine carbon dioxide removal. Here, we use a two-step neural network approach to generate basin-wide estimates from sparse observational data in the coastal Northeast Pacific Ocean at an unprecedented spatial resolution of 1/12° with coverage in the nearshore (0 - 25 km offshore). We compiled partial pressure of carbon dioxide (pCO2) observations as well as a range of predictor variables including satellite-based and physical oceanographic reanalysis products. With the predictor variables representing processes affecting pCO2, we created non-linear relationships to interpolate observations from 1998-2019. Compared to in situ shipboard and mooring observations, our coastal pCO2 product captures broad spatial patterns and seasonal cycle variability well. A sensitivity analysis identifies that the parameters responsible for the neural network’s ability to capture regional pCO2 variability agrees with mechanistic processes. Using wind speed and atmospheric CO2, we calculated air-sea CO2 fluxes. We report an anticorrelation between net annual air-sea CO2 flux and air-sea CO2 flux seasonal amplitude and suggest the relationship is driven by regional processes. We show the inclusion of nearshore net outgassing fluxes lowers the overall regional net flux. Overall, our results suggest that the region is a net sink (-0.7 mol m-2 yr-1) for atmospheric CO2 with trends indicating increasing oceanic uptake due to strong connectivity to subsurface waters.

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Section: Air-sea Pco 2 Trendssupporting

confidence: 69%

High-resolution Neural Network Demonstrates Strong CO2 Source-Sink Juxtaposition in the Coastal Zone

Duke,

Hamme,

Ianson

et al. 2024

Preprint

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“…These best practices are a first attempt at combining several common approaches into a standard methodology for varied ocean time-series data. However, these best practices must evolve along with the evolving state of the data sets and the techniques used in trend analysis, particularly related to different linear regression models (e.g., Franco et al, 2021) and gap-filling techniques (e.g., Vance et al, 2022) able to create continuous time series that can be analyzed using statistical-based signal processing approaches. We recommend these best practices be revisited and updated by a formalized community of practice on a regular basis.…”

Section: Introductionmentioning

confidence: 99%

Advancing best practices for assessing trends of ocean acidification time series

Sutton

Battisti²,

Carter³

et al. 2022

Front. Mar. Sci.

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Assessing the status of ocean acidification across ocean and coastal waters requires standardized procedures at all levels of data collection, dissemination, and analysis. Standardized procedures for assuring quality and accessibility of ocean carbonate chemistry data are largely established, but a common set of best practices for ocean acidification trend analysis is needed to enable global time series comparisons, establish accurate records of change, and communicate the current status of ocean acidification within and outside the scientific community. Here we expand upon several published trend analysis techniques and package them into a set of best practices for assessing trends of ocean acidification time series. These best practices are best suited for time series capable of characterizing seasonal variability, typically those with sub-seasonal (ideally monthly or more frequent) data collection. Given ocean carbonate chemistry time series tend to be sparse and discontinuous, additional research is necessary to further advance these best practices to better address uncharacterized variability that can result from data discontinuities. This package of best practices and the associated open-source software for computing and reporting trends is aimed at helping expand the community of practice in ocean acidification trend analysis. A broad community of practice testing these and new techniques across different data sets will result in improvements and expansion of these best practices in the future.

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“…Physiologically, the metabolic oxygen demand of aerobic organisms rises with increasing temperature (Pörtner & Knust, 2007), such that deoxygenation has greater impacts on organismal growth and survival under high temperature conditions (Deutsch et al, 2015; Deutsch et al, 2020). At the same time, higher temperature favors oxygen loss by decreasing seawater oxygen solubility and increasing stratification, which limits the ventilation rate of thermocline water masses (Franco et al, 2021; Kwon et al, 2016; Ono et al, 2001; Sasano et al, 2018). Among all oceanic regions, the Northeast Pacific exhibits one of the most rapid apparent rates of deoxygenation (Keeling et al, 2010; Schmidtko et al, 2017), with large oxygen decreases projected for intermediate depths over the coming decades (Long et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Impact of warming and deoxygenation on the habitat distribution of Pacific halibut in the Northeast Pacific

Franco

Kim

Frenzel

et al. 2022

Fisheries Oceanography

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Ocean warming and deoxygenation are already modifying the habitats of many aerobic organisms. Benthic habitat in the Northeast Pacific is sensitive to deoxygenation, as low oxygen concentrations occur naturally in continental shelf bottom waters.Here, we examine the potential impacts of deoxygenation and ocean warming on the habitat distribution of Pacific halibut (Hippoglossus stenolepis), one of the most commercially important groundfish in North America. We combine fisheries-independent Pacific halibut survey data (1998-2020) with oceanographic measurements and a regional ocean circulation model to investigate current and future (end of 21st century) influences of deoxygenation and warming on optimal Pacific halibut habitat. We use the observations and model output to derive a metabolic index of Pacific halibutspecific suitable habitat. Our results show high Pacific halibut counts in regions where the metabolic index is greatest and demonstrate that interannual variability in Pacific halibut abundance is coherent with the Pacific Decadal Oscillation. Working with model projections, we examine potential future changes in suitable Pacific halibut habitat by the end of the century under a high carbon dioxide emissions scenario. These projections indicate that suitable Pacific halibut habitat may largely disappear off the coast of Washington state, retreating approximately 5 latitude northward. In bottom waters along coastal British Columbia and Alaska continental shelf, Pacific halibut habitat is projected to decrease by about 50%. Such habitat changes may potentially drive a northward shift in Pacific halibut, with significant implications for commercial fisheries.

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Anthropogenic and Climatic Contributions to Observed Carbon System Trends in the Northeast Pacific

Cited by 27 publications

References 80 publications

High-resolution Neural Network Demonstrates Strong CO2 Source-Sink Juxtaposition in the Coastal Zone

High-resolution Neural Network Demonstrates Strong CO2 Source-Sink Juxtaposition in the Coastal Zone

Advancing best practices for assessing trends of ocean acidification time series

Impact of warming and deoxygenation on the habitat distribution of Pacific halibut in the Northeast Pacific

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