Published 22 May 2015
Tags: chemistry, methods
The California Current Acidification Network (C-CAN) is a collaboration dedicated to advancing understanding of ocean acidification (OA) and its effects on biological resources of the U.S. West Coast. C-CAN first convened in 2010 in response to a growing realization that declines in shellfish hatchery production corresponded to coastal upwelling of low pH waters. The initial workshop brought together leading shellfish industry representatives, coastal managers, researchers, Sea Grant programs, and Integrated Ocean Observing Systems to increase collective understanding of OA effects on the nearshore environment. C-CAN has since expanded to include other ocean-dependent industries, environmental advocacy groups, regulatory agencies, and tribal groups.
The overarching goal of C-CAN is to coordinate and standardize OA measurement and data collection practices, ensuring data accessibility, utility, and application. C-CAN provides shared guidelines and support for participating groups in implementation of high quality, compatible monitoring programs. C-CAN also facilitates application of the network’s data in developing tools that examine the causes of ecosystem impacts and predict future changes in ocean chemistry and biological communities. Finally, C-CAN communicates its findings to address management concerns about defining the ecological effects of OA for development of mitigation and adaptation strategies. Given the complexity of this emerging issue, and recognizing that advancing knowledge will require a concerted community effort, C-CAN is committed to serve as the region’s source of reliable, vetted scientific information on ocean acidification.
Continue reading ‘Best Practices for autonomous measurement of seawater pH with the Honeywell Durafet pH sensor’
The wintertime spatial distribution of carbonate parameters in outer estuarine and coastal waters around Ireland is described from total alkalinity (TA) and dissolved inorganic carbon (DIC) data collected between 2010 and 2013. Due to predominantly limestone bedrock of their river catchments, the River Shannon and Barrow, Nore and Suir River system export high concentrations (>3800 μmol kg−1) of TA to their estuarine and inshore coastal waters where estuarine alkalinity decreases with increasing salinity. TA is lower in rivers with a non-calcareous bedrock, with positively correlated alkalinity-salinity relationships in both the Lee and Foyle outer estuaries. Winter pCO2 in the Shannon, Barrow/Nore/Suir and Lee estuaries is supersaturated relative to atmospheric CO2, while pCO2 in the outer Liffey estuary is slightly lower than atmospheric CO2 in three consecutive winters, indicative of a CO2 sink. Winter pCO2 is close to atmospheric equilibrium along the western shelf and through the centre of the Irish Sea, while it is a CO2 sink across the North Channel. While aragonite was supersaturated in most Irish waters, it was close to undersaturation in both the Lee estuary, attributed to its low alkalinity freshwater source, and Barrow/Nore/Suir estuary related to the flux of high concentrations of DIC from this river system. The seasonal impacts on inorganic carbon chemistry was also investigated by comparing winter and summer data collected between 2009 and 2013 along two transects in western coastal waters and along the western shelf edge. DIC was ~60 μmol kg−1 lower in summer relative to winter in the coastal transects and 39 μmol kg−1 lower along the shelf edge, accompanied by depleted nutrients and supersaturation of dissolved oxygen during summer, indicative of primary production. TA was generally higher in summer relative to winter corresponding with a decrease in nitrate, indicating that primary production dominated the TA distribution over calcification. An exception to this was at two stations along the shelf edge where TA was lower in summer relative to winter (51 μmol kg−1) and coincides with high reflectance in satellite images from a coccolithophore bloom at the time of sampling. While pCO2 was close to atmospheric equilibrium along the shelf edge during winter, this area was a CO2 sink during summer, apart from the stations where calcification was likely occurring resulting in elevated CO2 relative to atmospheric concentrations.
Continue reading ‘The inorganic carbon chemistry in coastal and shelf waters around Ireland’
Published 22 May 2015
HARPSWELL, Maine — The town is looking for state assistance to study how to protect a resource embedded in Harpswell’s heritage.
Harpswell’s 4,000 acres of intertidal mud flats have long supported the soft-shell clam industry, which has consistently reported some of the highest landings in Maine. Recent environmental shifts, however, have reduced an industry that used to support more than 50 full-time harvesters to a handful of 10 to 15 people who supplement their income with other part-time jobs. (…)
The town is asking the Maine Coastal Program for a $44,000 grant to help support projects studying how local ocean acidification and a disease called neoplasia affect clam populations. Preliminary survey work by Resource Access International, the town’s marine consultant, showed that while some of Harpswell’s clam flats have healthy levels of acidity, others read “well below optimal levels” for larval clam survival.
Continue reading ‘Harpswell seeks funding to study clam decline’
Published 22 May 2015
Photo by John Lok (ST)
Congress must invest in research to combat acidic seawater conditions.
OVER the past several years, it has become apparent that Pacific Ocean and Puget Sound waters are becoming more acidic and that increased acidity can be lethal to Pacific oysters. New data are becoming available that indicate that other species are also threatened. Salmon, Dungeness crab and razor clams are iconic Pacific Northwest species, supporting robust commercial and recreational harvests — all three are threatened by ocean acidification. But we don’t know enough yet about the severity or the immediacy of the threat to these species to develop an appropriate response.
Let’s go back to the basics: Carbon-dioxide emissions, along with urban and rural runoff, are causing seawater to become more acidic, damaging the basic building blocks of life needed by oysters, clams and other sea creatures. The impacts of this phenomenon, known as “ocean acidification,” are being felt all over the world, but nowhere more than right here in the Pacific Northwest.
Continue reading ‘Fund the race to save marine life from souring seas’
Ongoing ocean acidification (OA), caused by continuous anthropogenic CO2 emissions, seems to decrease the concentrations of dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) in the surface oceans. This might have consequences for future climate due to changes in formation and growth of atmospheric sulfate aerosols formed from DMS. However, the effect of OA on dimethylsulfoxide (DMSO), another intermediate of the DMS pathway and a potential precursor of oceanic methane, is unknown. Therefore, we investigated the effect of OA on the DMSO concentrations in a mesocosm study conducted in a Norwegian fjord in spring 2011. Dissolved and particulate DMSO concentrations (DMSOd/p) decreased with pH during the course of the experiment. Temperature correlated inversely with DMSOd concentrations during the first week of the experiment, reflecting the influence of temperature dependent biological activities on DMSOd pathways. Furthermore, DMSOd increased with the cell abundance of heterotrophic bacteria, cryptophytes, and the cyanobacterium Synechococcus sp. Nitrate availability influenced the distribution of cryptophytes and Synechococcus sp. in the same way as DMSOd indicating again a possible link between these phytoplankton taxa and DMSOd. We conclude that ongoing OA may lead to decreasing DMSO concentrations in the surface ocean which, in turn, might affect the oceanic distributions of DMS and methane.
Continue reading ‘Environmental control of dimethylsulfoxide (DMSO) cycling under ocean acidification’
Seasonal variability of the aragonite saturation state (ΩAR) in the upper (50 m and 100 m depths) North Pacific Ocean (NPO) was investigated using multiple linear regression (MLR). The MLR algorithm derived from a high-quality carbon dataset accurately predicted the ΩAR of evaluation datasets (three time-series stations and P02 section) with acceptable uncertainty (<0.1 ΩAR). The algorithm was combined with seasonal climatology data, and the estimated ΩAR varied in the range of 0.4–0.6 in the mid-latitude western NPO, with the largest variation found for the tropical eastern NPO. These marked variations were largely controlled by seasonal changes in vertical mixing and thermocline depth, both of which determine the degree of entrainment of CO2-rich corrosive waters from deeper depths. Our MLR-based subsurface ΩAR climatology is complementary to surface climatology based on pCO2 measurements.
Continue reading ‘Seasonal variations in the aragonite saturation state in the upper open-ocean waters of the North Pacific Ocean’
Ocean acidification, the result of increased dissolution of carbon dioxide (CO2) in seawater, is a leading subject of current research. The effects of acidification on non-calcifying macroalgae are, however, still unclear. The current study reports two 1-month studies using two different macroalgae, the red alga Palmaria palmata (Rhodophyta) and the kelp Saccharina latissima (Phaeophyta), exposed to control (pHNBS = ∼8.04) and increased (pHNBS = ∼7.82) levels of CO2-induced seawater acidification. The impacts of both increased acidification and time of exposure on net primary production (NPP), respiration (R), dimethylsulphoniopropionate (DMSP) concentrations, and algal growth have been assessed. In P. palmata, although NPP significantly increased during the testing period, it significantly decreased with acidification, whereas R showed a significant decrease with acidification only. S. latissima significantly increased NPP with acidification but not with time, and significantly increased R with both acidification and time, suggesting a concomitant increase in gross primary production. The DMSP concentrations of both species remained unchanged by either acidification or through time during the experimental period. In contrast, algal growth differed markedly between the two experiments, in that P. palmata showed very little growth throughout the experiment, while S. latissima showed substantial growth during the course of the study, with the latter showing a significant difference between the acidified and control treatments. These two experiments suggest that the study species used here were resistant to a short-term exposure to ocean acidification, with some of the differences seen between species possibly linked to different nutrient concentrations between the experiments.
Continue reading ‘Two intertidal, non-calcifying macroalgae (Palmaria palmata and Saccharina latissima) show complex and variable responses to short-term CO2 acidification’