Characterizing the vulnerability of intertidal organisms in Olympic National Park to ocean acidification

Abstract

Ocean acidification (OA) will have a predominately negative impact on marine animals sensitive to changes in carbonate chemistry. Coastal upwelling regions, such as the Northwest coast of North America, are likely among the first ecosystems to experience the effects of OA as these areas already experience high pH variability and naturally low pH extremes. Over the past decade, pH off the Olympic coast of Washington has declined an order of magnitude faster than predicted by accepted conservative climate change models. Resource managers are concerned about the potential loss of intertidal biodiversity likely to accompany OA, but as of yet, there are little pH sensitivity data available for the vast majority of taxa found on the Olympic coast. The intertidal zone of Olympic National Park is particularly understudied due to its remote wilderness setting, habitat complexity, and exceptional biodiversity. Recently developed methodological approaches address these challenges in determining organism vulnerability by utilizing experimental evidence and expert opinion. Here, we use such an approach to determine intertidal organism sensitivity to pH for over 700 marine invertebrate and algal species found on the Olympic coast. Our results reinforce OA vulnerability paradigms for intertidal taxa that build structures from calcium carbonate, but also introduce knowledge gaps for many understudied species. We furthermore use our assessment to identify how rocky intertidal communities at four long-term monitoring sites on the Olympic coast could be affected by OA given their community composition. the park's general management plan (NPS, 2007). The 65-mile coastline is a UNESCO Biosphere Reserve and World Heritage Site that hosts one of the most biodiverse assemblages of marine invertebrates and seaweeds along the west coast of North America (Schoch et al., 2006). The intertidal zone is comprised of rocky reefs, sandy beaches, and cobble boulder fields and is valued regionally and nationally for its ecological, economic, and cultural significance. The loss of species in the intertidal zone that rely on a particular pH threshold or the availability of CO 3 2− could fundamentally alter one or all of these interests (Cooley et al., 2009;Lynn et al., 2013) and have resounding reverberations for marine food webs (Gaylord et al., 2015). Over the past decade, ocean pH off the Olympic coast has declined an order of magnitude faster than predicted by accepted conservative climate change models (Feely et al., 2004;Wootton and Pfister, 2012) and has impacted marine aquaculture in the region (Barton et al., 2015). These observations spurred the Governor of Washington to form a Blue Ribbon Panel on Ocean Acidification. The panel's report (Washington Department of Ecology, 2012) recommended expanded pH monitoring and an assessment of marine resource sensitivity to OA. Although OA-associated impacts are documented for several cosmopolitan species, a major limitation for resource managers is determining how those impacts will be experience...

Seasonality and Life History Complexity Determine Vulnerability of Dungeness Crab to Multiple Climate Stressors

“…It confers high productivity to the region and its fisheries, but also high vulnerability to low pH and DO (Checkley & Barth, 2009). The incorporation of seasonality should, therefore, improve vulnerability assessments for species in seasonal seas (Jones et al., 2018; Spencer et al., 2019). The regional model used to project the ocean conditions continues to experience seasonality in the projected ocean conditions in the future (2100), but despite an increase in the projected winds in the CMIP5 projections, the future upwelling intensity does not change much due to compensation from increased stratification (Howard et al., 2020; Siedlecki et al., 2021).…”

A decade-long cruise time series (2008–2018) of physical and biogeochemical conditions in the southern Salish Sea, North America

“…The data product can also inform biological assessments. Many regional species have inferred or known sensitivity to ocean acidification parameters (pCO 2 , partial pressure of CO 2 ; pH; and ) (Busch and McElhany, 2016;Jones et al, 2018). The early part of this time series was used to delineate the range of physical and biogeochemical conditions encountered by species of ecological or economic importance in the region (Reum et al, 2014(Reum et al, , 2016.…”

Understanding and Advancing Natural Resource Management in the Context of Changing Ocean Conditions

“…Research suggests that even small changes in ocean conditions can have large ramifications for fisheries and aquaculture productivity, marine and coastal habitats, cultural heritage, and human health and wellbeing (Mauger et al 2015). Within the California Current Ecosystem, models indicate that 11 of 34 functional groups have a consistent negative relationship with ocean acidification (OA) conditions (Busch and McElhany 2016) and of the 697 intertidal species found within the Olympic National Park on the Washington State coastline, 80% may be vulnerable, as estimated by exposure and sensitivity, to OA (Jones, Passow, and Fradkin 2018). Puget Sound, an estuarine fjord in Washington State, has known vulnerabilities to low pH (Feely et al 2010;Bianucci et al 2018;Evans et al 2019) which are expected to become more severe over time (Fassbender et al 2018;Khangaonkar et al 2018).…”