Shell Condition and Survival of Puget Sound Pteropods Are Impaired by Ocean Acidification Conditions

We tested whether the thecosome pteropod Limacina helicina from Puget Sound, an urbanized estuary in the northwest continental US, experiences shell dissolution and altered mortality rates when exposed to the high CO2, low aragonite saturation state (Ωa) conditions that occur in Puget Sound and the northeast Pacific Ocean. Five, week-long experiments were conducted in which we incubated pteropods collected from Puget Sound in four carbon chemistry conditions: current summer surface (∼460–500 µatm CO2, Ωa≈1.59), current deep water or surface conditions during upwelling (∼760 and ∼1600–1700 µatm CO2, Ωa≈1.17 and 0.56), and future deep water or surface conditions during upwelling (∼2800–3400 µatm CO2, Ωa≈0.28). We measured shell condition using a scoring regime of five shell characteristics that capture different aspects of shell dissolution. We characterized carbon chemistry conditions in statistical analyses with Ωa, and conducted analyses considering Ωa both as a continuous dataset and as discrete treatments. Shell dissolution increased linearly as aragonite saturation state decreased. Discrete treatment comparisons indicate that shell dissolution was greater in undersaturated treatments compared to oversaturated treatments. Survival increased linearly with aragonite saturation state, though discrete treatment comparisons indicated that survival was similar in all but the lowest saturation state treatment. These results indicate that, under starvation conditions, pteropod survival may not be greatly affected by current and expected near-future aragonite saturation state in the NE Pacific, but shell dissolution may. Given that subsurface waters in Puget Sound’s main basin are undersaturated with respect to aragonite in the winter and can be undersaturated in the summer, the condition and persistence of the species in this estuary warrants further study

Elevated carbon dioxide alters neural signaling and anti-predator behaviors in ocean phase coho salmon (Oncorhynchus kisutch)

Elevated levels of CO2 have been shown to disrupt numerous neurological sensory systems in marine fish. This is of concern as Pacific salmon rely heavily on an important neurosensory system for survival, the olfactory system. In this study, we investigated the effects of elevated CO2 on a salmon olfactory driven behavior, as well as changes in neural signaling and gene expression within the peripheral and central olfactory system. Juvenile coho salmon were exposed to three different levels of CO2 for two weeks. These included a current CO2 level with a pH of 7.8, a medium CO2 level with a pH of 7.5, and a high CO2 level with a pH of 7.2. Our study found that juvenile coho salmon exposed to increasing levels of CO2 ceased avoiding an alarm odor compared to the controls. Furthermore, exposure to the high level of CO2 did not alter odorant induced signaling in the olfactory rosettes but did induce significant changes in signaling within the olfactory bulbs. RNA-seq analysis revealed significant changes in expression of genes involved in neuronal signaling and signal modulation within the olfactory bulbs from coho exposed to the high CO2 level compared to control coho. Our results indicate that coho salmon exposed to elevated CO2 can experience significant behavioral impairments that are potentially driven by alteration in higher-order neural signal processing within the olfactory bulbs. Supported by Washington Sea Grant, the Washington Ocean Acidification Center, and NIEHS Superfund ES-004696

Understanding, characterizing, and communicating responses to ocean acidification : challenges and uncertainties

Author Posting. © The Oceanography Society, 2015. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 28, no. 2 (2015): 30-39, doi:10.5670/oceanog.2015.29.Over the past decade, ocean acidification (OA) has emerged as a major concern in ocean science. The field of OA is based on certainties—uptake of carbon dioxide into the global ocean alters its carbon chemistry, and many marine organisms, especially calcifiers, are sensitive to this change. However, the field must accommodate uncertainties about the seriousness of these impacts as it synthesizes and draws conclusions from multiple disciplines. There is pressure from stakeholders to expeditiously inform society about the extent to which OA will impact marine ecosystems and the people who depend on them. Ultimately, decisions about actions related to OA require evaluating risks about the likelihood and magnitude of these impacts. As the scientific literature accumulates, some of the uncertainty related to single-species sensitivity to OA is diminishing. Difficulties remain in scaling laboratory results to species and ecosystem responses in nature, though modeling exercises provide useful insight. As recognition of OA grows, scientists’ ability to communicate the certainties and uncertainties of our knowledge on OA is crucial for interaction with decision makers. In this regard, there are a number of valuable practices that can be drawn from other fields, especially the global climate change community. A generally accepted set of best practices that scientists follow in their discussions of uncertainty would be helpful for the community engaged in ocean acidification.NOAA Ocean Acidification Program and National Marine Fisheries Service (DSB, MP), NSF-supported Center for Climate and Energy Decision Making (SCD), and NASA Ocean Biology and Biogeochemistry Program (SS)

The challenges of detecting and attributing ocean acidification impacts on marine ecosystems

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Doo, S. S., Kealoha, A., Andersson, A., Cohen, A. L., Hicks, T. L., Johnson, Z., I., Long, M. H., McElhany, P., Mollica, N., Shamberger, K. E. F., Silbiger, N. J., Takeshita, Y., & Busch, D. S. The challenges of detecting and attributing ocean acidification impacts on marine ecosystems. ICES Journal of Marine Science, 77(7-8), (2020): 2411-2422, https://doi.org/10.1093/icesjms/fsaa094.A substantial body of research now exists demonstrating sensitivities of marine organisms to ocean acidification (OA) in laboratory settings. However, corresponding in situ observations of marine species or ecosystem changes that can be unequivocally attributed to anthropogenic OA are limited. Challenges remain in detecting and attributing OA effects in nature, in part because multiple environmental changes are co-occurring with OA, all of which have the potential to influence marine ecosystem responses. Furthermore, the change in ocean pH since the industrial revolution is small relative to the natural variability within many systems, making it difficult to detect, and in some cases, has yet to cross physiological thresholds. The small number of studies that clearly document OA impacts in nature cannot be interpreted as a lack of larger-scale attributable impacts at the present time or in the future but highlights the need for innovative research approaches and analyses. We summarize the general findings in four relatively well-studied marine groups (seagrasses, pteropods, oysters, and coral reefs) and integrate overarching themes to highlight the challenges involved in detecting and attributing the effects of OA in natural environments. We then discuss four potential strategies to better evaluate and attribute OA impacts on species and ecosystems. First, we highlight the need for work quantifying the anthropogenic input of CO2 in coastal and open-ocean waters to understand how this increase in CO2 interacts with other physical and chemical factors to drive organismal conditions. Second, understanding OA-induced changes in population-level demography, potentially increased sensitivities in certain life stages, and how these effects scale to ecosystem-level processes (e.g. community metabolism) will improve our ability to attribute impacts to OA among co-varying parameters. Third, there is a great need to understand the potential modulation of OA impacts through the interplay of ecology and evolution (eco–evo dynamics). Lastly, further research efforts designed to detect, quantify, and project the effects of OA on marine organisms and ecosystems utilizing a comparative approach with long-term data sets will also provide critical information for informing the management of marine ecosystems.SSD was funded by NSF OCE (grant # 1415268). DSB and PM were supported by the NOAA Ocean Acidification Program and Northwest Fisheries Science Center, MHL was supported by NSF OCE (grant # 1633951), ZIJ was supported by NSF OCE (grant # 1416665) and DOE EERE (grant #DE-EE008518), NJS was supported by NSF OCE (grant # 1924281), ALC was supported by NSF OCE (grant # 1737311), and AA was supported by NSF OCE (grant # 1416518). KEFS, AK, and TLH were supported by Texas A&M University. This is CSUN Marine Biology contribution (# 306)

Climate Science Special Report: Fourth National Climate Assessment (NCA4), Volume I

New observations and new research have increased our understanding of past, current, and future climate change since the Third U.S. National Climate Assessment (NCA3) was published in May 2014. This Climate Science Special Report (CSSR) is designed to capture that new information and build on the existing body of science in order to summarize the current state of knowledge and provide the scientific foundation for the Fourth National Climate Assessment (NCA4)

Ecological roles for corticosterone in birds: season, stages, habitat, and perturbations

Thesis (Ph. D.)--University of Washington, 2006.Glucocorticoid hormones have multiple purposes. At low levels, they function to maintain basic energy and salt balance. At high levels, they are key hormones in the emergency response to noxious stimuli. In the short term, glucocorticoids help the individual cope with a given challenge. Chronic exposure to high glucocorticoid levels can be detrimental to health and may increase mortality. In this dissertation, I explore how corticosterone (CORT) is modulated with life stage, season, habitat, and perturbations in song birds.In rufous-collared sparrows (Zonotrichia capensis costaricensis), I studied the effects of season, breeding, and molt on baseline CORT levels and the CORT response to stress. Month explained most of the variation in the CORT data, with higher CORT levels occurring in the spring. Breeding individuals had a higher HPA axis response to stress than non-breeding individuals, most likely to favor self-maintenance over a current reproductive attempt. Unlike past research, we found that CORT levels did not change or were higher in molting birds.I measured CORT levels, body condition, behavior, and hematocrit in song wrens (Cyphorhinus phaeocephalus) along a rainfall-induced habitat gradient. Birds living in drier habitat had lower body condition and were more likely to have an abnormally low hematocrit score. The relationship between rainfall and baseline CORT was not significant, but birds with the highest baseline CORT levels lived at the dry edge of the range. Birds in better body condition and with lower baseline CORT levels were captured more quickly. Our results indicate that physiology and behavior can change with an environmental gradient.To better understand the consequences of living in a disturbed environment, I studied the effects of repeated, acute pulses of CORT on the HPA axis and body condition in captive, wild Gambel's white-crowned sparrow (Zonotrichia leucophrys gambelii). CORT-treated birds had higher endogenous baseline CORT levels and failed to increase CORT levels with exposure to stress. Body mass, flight muscle, and food intake all declined with CORT treatment. CORT-treated birds expressed migratory restlessness but delayed the onset of molt. We conclude that frequent, acute CORT administration can create a chronic stress phenotype

Using mineralogy and higher-level taxonomy as indicators of species sensitivity to pH: A case-study of Puget Sound

Information on ecosystem sensitivity to global change can help guide management decisions. Here, we characterize the sensitivity of the Puget Sound ecosystem to ocean acidification by estimating, at a number of taxonomic levels, the direct sensitivity of its species. We compare sensitivity estimates based on species mineralogy and on published literature from laboratory experiments and field studies. We generated information on the former by building a database of species in Puget Sound with mineralogy estimates for all CaCO3-forming species. For the latter, we relied on a recently developed database and meta-analysis on temperate species responses to increased CO2. In general, species sensitivity estimates based on the published literature suggest that calcifying species are more sensitive to increased CO2 than non-calcifying species. However, this generalization is incomplete, as non-calcifying species also show direct sensitivity to high CO2 conditions. We did not find a strong link between mineral solubility and the sensitivity of species survival to changes in carbonate chemistry, suggesting that, at coarse scales, mineralogy plays a lesser role to other physiological sensitivities. Summarizing species sensitivity at the family level resulted in higher sensitivity scalar scores than at the class level, suggesting that grouping results at the class level may overestimate species sensitivity. This result raises caution about the use of broad generalizations on species response to ocean acidification, particularly when developing summary information for specific locations. While we have much to learn about species response to ocean acidification and how to generalize ecosystem response, this study on Puget Sound suggests that detailed information on species performance under elevated carbon dioxide conditions, summarized at the lowest taxonomic level possible, is more valuable than information on species mineralogy

Reference curve.

<p>Reference curve for the survival response of a generic functional group to pH conditions.</p

Scores summarizing response to increased CO₂.

<p>(a) Directional, (b) evidence, and (c) agreement scores and (d) relative survival scalar for each functional group, ordered by relative survival scalar values.</p