Pteropods provide look into ocean acidification

A scientist with the Southern California Coastal Research Center who studies pteropods – key forage for a variety of fish including juvenile salmon, sole and pollock – says they are being affected by ocean acidification in the Beaufort Sea and Western Gulf of Alaska.

Nina Bednarsek discussed the findings of her research team during a recent presentation at the annual Alaska Marine Science Symposium.

Due to their extreme sensitivity, these tiny ocean snails serve as a kind of canary in the coal mine, an excellent ocean acidification indicator, with the potential to provide insight into changes in the ecosystem integrity, which is essential to effective fisheries and marine resource management, she noted. Bednarsek and fellow researchers developed baseline information on several species – including species distribution and incidence of shell dissolution and their coupling with ocean acidification parameters –during several trips to the Gulf of Alaska, Bering Sea and Beaufort Sea between 2014 and 2017. The results, she said, demonstrate the biological vulnerability to ocean acidification across different high latitudinal environments.

Continue reading ‘Pteropods provide look into ocean acidification’

Analysis finds oceans have become less ‘acidic’ with rising CO2, challenging the ‘acidification’ narrative

A modest long-term (1800s-present) declining trend in ocean pH values predominantly occurred prior to 1930, or before anthropogenic CO2 emissions began rising precipitously. Since 1930, seawater pH trends have risen slightly, meaning sharply rising CO2 has been coincident with less, not more, ocean “acidification”.

Is “acidification” occurring too rapidly for species to adapt?
Scientists (Wei et al., 2015) estimate that the ocean’s global mean surface pH may have declined (i.e., become less alkaline and thus more “acidic”) by -0.07 to -0.08 in the last 200 years — from ~8.12 during pre-industrial times to 8.04 to 8.05 today.

It is commonly claimed that this long-term decline in pH, or “acidification”, is occurring far too rapidly for the oceanic biosphere to adapt. Consequently, there are alarmist claims that the pH changes in the last few hundred years are so extreme they will lead to a mass extinction event.

Continue reading ‘Analysis finds oceans have become less ‘acidic’ with rising CO2, challenging the ‘acidification’ narrative’

Integrating ocean acidification into coastal benthic ecology

Thursday, February 14, 2019 – 11:00am – 12:00pm

Event Location Schmidt Conference Center

Speaker: Alex Lowe, Smithsonian Environmental Research Center

Pre-registration Required No

Description: Ocean acidification from rising atmospheric CO2 poses serious threats to coastal ecosystem services. Seawater pH can impact physiological processes of many aquatic organisms, including valuable aquaculture species like Pacific oysters. Yet increasingly, researchers are finding that local ecological processes may be altering some of these global trends.

Ecologists have started to realize that that not only does pH affect organisms, but that organisms also affect pH. This discovery is changing the way we view coastal ecosystems. Understanding 1) how environmental factors or ecological processes drive variation in seawater pH; 2) whether this results in spatial variation of long-term ocean acidification; and 3) the effects of this pH variation on coastal organisms are critical research needs for climate change adaptation and management of important natural resources.

In this talk, Alex Lowe will discuss research that explores these questions at different scales in the Salish Sea, Washington, where scientists found that biological processes were the key driver of pH variation at daily, seasonal and decadal scales. In this system, seawater pH changed with phytoplankton and suspended detritus composition, seagrass cover and, to a lesser extent, temperature and salinity. Using experiments with native and aquaculture oysters as examples, Lowe will discuss the potential for integrating observations of carbonate chemistry into coastal ecological studies.

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How will sea life adapt to climate change? Grunion might show us clues, says new CSU Long Beach study

AP Photo/Gary Florin, Cabrillo Marine Aquarium

Grunion, the little fish that come to shore to spawn along Southern California beaches, may hold clues as to how sea life will adapt to the effects of climate change on the ocean, according to a new study from California State University, Long Beach.

Researcher Darren Johnson conducted a series of experiments with grunion caught in Seal Beach. He found some families of grunion seemed better able to adapt to ocean acidification.

Grunion — unique little fish found only in Southern California and down south in Baja — mate on the sand when the waves wash them to shore. Grunion running season attracts droves of people who show up at beaches in the dark of night to wait and watch, some ready with buckets to collect the fish to eat when catching is allowed.

Continue reading ‘How will sea life adapt to climate change? Grunion might show us clues, says new CSU Long Beach study’

A low-cost long-term model of coastal observatories of global change

The identification and quantification of global change, including climate change, requires long time series of key variables. In this work, the fundamentals and operation of low-cost long-term coastal observatories are described, and preliminary data are shown. The vision is to offer a scientific platform of physicochemical data for at least the next 100 years, what requires establishing sustainable strategies, training human resources, strong institutional support, and long-term funding sources. The network formally operates since 2013 and has generated more than 6 million data points, continuously growing, of which >1.5 million data points are permanently stored and available through a public access web platform. The strategies and methodologies are described and, in the Mazatlan observatory, data recovery and basic statistics of eight environmental variables are presented. During 2015, an extreme El Niño year, marine temperatures increased from the bay to the middle Urias coastal lagoon, were higher than atmospheric temperatures, and showed the impact of a thermal power plant. In surface waters of Mazatlan bay, hypoxic periods were also observed. It is expected that results will foster the development of other projects, and will be useful to the scientific community and decision makers, for a better management of coastal ecosystems worldwide.

Continue reading ‘A low-cost long-term model of coastal observatories of global change’

The influence of CO2 seeps to coastal environments of Shikine Island in Japan as indicated by geochemistry analyses of seafloor sediments

Recently, two shallow CO2 seeps were described in Ashitsuki and Mikama Bay (Shikine Island, Japan). These sites were deemed to have potentials for studying the impacts of ocean acidification. Here, we report geochemistry analyses of seawater and seafloor sediments collected from the shallow coasts on and around the two CO2 seeps. Seawater analyses indicated that shallow waters in the area share similar acidic characteristics (e.g. Avg. pH = ca. 7.1), supporting the result of a previous study. Next, the sediments from all sampling loci also share similar properties (Avg. Fe: Si = 0.043; Avg. organic content = 1.26%; Avg. relative Si content = 75.25%). However, sediments from Matsugashitamiyabi hot spring, which is located near the Ashitsuki seep, showed high Fe: Si ratio (1.250) when compared to other loci. This is most likely a local phenomenon, where iron accumulates in the sediment by the precipitation of rust produced through the mixing of FeS from the hot spring and carbonated seawater of the nearby CO2 seeps. We also compared seawater (e.g. Avg. pH = 8.3) and sediments (Avg. Fe: Si = 0.126; Avg. organic content = 2.06%; Avg. Si = 69.06%) of Hidaka Port in central Wakayama (as a standard sample of coastal surface water environment), to the Shikine Island samples excluding the Matsugashitamiyabi hot spring samples. The differences in characteristics (i.e. lower seawater pH and lower Avg. Fe: Si ratio of the latter) were probably caused by CO2 seep influence, and indicate that the influence of the hot spring water to the sediment of both CO2 seeps was minimal, or probably none. Accordingly, these seep sites are useful for future studies on the effects of ocean acidification on sea floor sediment composition, and its implication to biodiversity and the ecosystem.

Continue reading ‘The influence of CO2 seeps to coastal environments of Shikine Island in Japan as indicated by geochemistry analyses of seafloor sediments’

Variations in the summer oceanic pCO2 and carbon sink in Prydz Bay using the self-organizing map analysis approach

This study applies a neural network technique to produce maps of oceanic surface pCO2 in Prydz Bay in the Southern Ocean on a weekly 0.1∘ longitude × 0.1∘ latitude grid based on in situ measurements obtained during the 31st CHINARE cruise from February to early March 2015. This study area was divided into three regions, namely, the “open-ocean” region, “sea-ice” region and “shelf” region. The distribution of oceanic pCO2 was mainly affected by physical processes in the open-ocean region, where mixing and upwelling were the main controls. In the sea-ice region, oceanic pCO2 changed sharply due to the strong change in seasonal ice. In the shelf region, biological factors were the main control. The weekly oceanic pCO2 was estimated using a self-organizing map (SOM) with four proxy parameters (sea surface temperature, chlorophyll a concentration, mixed Layer Depth and sea surface salinity) to overcome the complex relationship between the biogeochemical and physical conditions in the Prydz Bay region. The reconstructed oceanic pCO2 data coincide well with the in situ pCO2 data from SOCAT, with a root mean square error of 22.14 µatm. Prydz Bay was mainly a strong CO2 sink in February 2015, with a monthly averaged uptake of 23.57±6.36 TgC. The oceanic CO2 sink is pronounced in the shelf region due to its low oceanic pCO2 values and peak biological production.

Continue reading ‘Variations in the summer oceanic pCO2 and carbon sink in Prydz Bay using the self-organizing map analysis approach’

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Ocean acidification in the IPCC AR5 WG II

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