Global change, including rising temperatures and acidification, threatens corals globally. Although bleaching events reveal fine-scale patterns of resilience, traits enabling persistence under global change remain elusive. We conducted a 95-d controlled-laboratory experiment investigating how duration of exposure to warming (~28, 31°C), acidification (pCO2 ~ 343 [present day], ~663 [end of century], ~3109 [extreme] μatm), and their combination influences physiology of reef-building corals (Siderastrea siderea, Pseudodiploria strigosa) from two reef zones on the Belize Mesoamerican Barrier Reef System. Every 30 d, net calcification rate, host protein and carbohydrate, chlorophyll a, and symbiont density were quantified for the same coral individual to characterize acclimation potential under global change. Coral physiologies of the two species were differentially affected by stressors and exposure duration was found to modulate these responses. Siderastrea siderea exhibited resistance to end of century pCO2 and temperature stress, but calcification was negatively affected by extreme pCO2. However, S. siderea calcification rates remained positive after 95 d of extreme pCO2 conditions, suggesting acclimation. In contrast, P. strigosa was more negatively influenced by elevated temperatures, which reduced most physiological parameters. An exception was nearshore P. strigosa, which maintained calcification rates under elevated temperature, suggesting local adaptation to the warmer environment of their natal reef zone. This work highlights how tracking coral physiology across various exposure durations can capture acclimatory responses to global change stressors.
Continue reading ‘Exposure duration modulates the response of Caribbean corals to global change stressors’Archive Page 235
Exposure duration modulates the response of Caribbean corals to global change stressors
Published 7 July 2021 Science ClosedTags: abundance, biological response, BRcommunity, calcification, community composition, corals, laboratory, multiple factors, North Atlantic, photosynthesis, physiology, protists, temperature
Ocean acidification amplifies multi-stressor impacts on global marine invertebrate fisheries
Published 7 July 2021 Science ClosedTags: abundance, biological response, crustaceans, fisheries, globalmodeling, individualmodeling, modeling, mollusks, otherprocess, physiology
Elevated atmospheric carbon dioxide (CO2) is causing global ocean changes and drives changes in organism physiology, life-history traits, and population dynamics of natural marine resources. However, our knowledge of the mechanisms and consequences of ocean acidification (OA) – in combination with other climatic drivers (i.e., warming, deoxygenation) – on organisms and downstream effects on marine fisheries is limited. Here, we explored how the direct effects of multiple changes in ocean conditions on organism aerobic performance scales up to spatial impacts on fisheries catch of 210 commercially exploited marine invertebrates, known to be susceptible to OA. Under the highest CO2 trajectory, we show that global fisheries catch potential declines by as much as 12% by the year 2100 relative to present, of which 3.4% was attributed to OA. Moreover, OA effects are exacerbated in regions with greater changes in pH (e.g., West Arctic basin), but are reduced in tropical areas where the effects of ocean warming and deoxygenation are more pronounced (e.g., Indo-Pacific). Our results enhance our knowledge on multi-stressor effects on marine resources and how they can be scaled from physiology to population dynamics. Furthermore, it underscores variability of responses to OA and identifies vulnerable regions and species.
Continue reading ‘Ocean acidification amplifies multi-stressor impacts on global marine invertebrate fisheries’Cod is a keystone species in marine ecosystems. It shapes the conditions for a large number of other species in the sea and is also of great importance both economically and culturally. However, the Swedish Atlantic cod stocks are on the verge of collapse with serious population declines observed in the Baltic Sea and on the Swedish west coast. Will the already weakened stocks meet another challenge; climate change?
Research based on the latest climate models shows that the temperature will rise and lead to local heat waves. Ocean acidification will increase, and salinity will reduce in the Baltic Sea and part of the west coast. Together, these climate effects will dramatically alter the marine environment around Sweden.
Climate effects cause physiological stress
Each of these changes can cause physiological stress in marine organisms. In order to better understand the anticipated fate of cod in a changing climate, this project aims to investigate how Atlantic cod (Gadus morhua) from coastal populations in the Baltic Sea and the North Sea respond to the cumulative effects of climate change factors such as reduced salinity (freshening), reduced pH (ocean acidification) and increased temperature (warming events).
Continue reading ‘Fish in a changing climate – can cod cope?’Ocean acidification and direct interactions affect coral, macroalga, and sponge growth in the Florida Keys
Published 6 July 2021 Science ClosedTags: algae, biological response, BRcommunity, calcification, corals, laboratory, morphology, North Atlantic, porifera
Coral reef community composition, function, and resilience have been altered by natural and anthropogenic stressors. Future anthropogenic ocean and coastal acidification (together termed “acidification”) may exacerbate this reef degradation. Accurately predicting reef resilience requires an understanding of not only direct impacts of acidification on marine organisms but also indirect effects on species interactions that influence community composition and reef ecosystem functions. In this 28-day experiment, we assessed the effect of acidification on coral–algal, coral–sponge, and algal–sponge interactions. We quantified growth of corals (Siderastrea radians), fleshy macroalgae (Dictyota spp.), and sponges (Pione lampa) that were exposed to local summer ambient (603 μatm) or elevated (1105 μatm) pCO2 seawater. These species are common to hard-bottom communities, including shallow reefs, in the Florida Keys. Each individual was maintained in isolation or paired with another organism. Coral growth (net calcification) was similar across seawater pCO2 and interaction treatments. Fleshy macroalgae had increased biomass when paired with a sponge but lost biomass when growing in isolation or paired with coral. Sponges grew more volumetrically in the elevated seawater pCO2 treatment (i.e., under acidification conditions). Although these results are limited in temporal and spatial scales due to the experimental design, they do lend support to the hypothesis that acidification may facilitate a shift towards increased sponge and macroalgae abundance by directly benefiting sponge growth which in turn may provide more dissolved inorganic nitrogen to macroalgae in the Florida Keys.
Continue reading ‘Ocean acidification and direct interactions affect coral, macroalga, and sponge growth in the Florida Keys’Ocean acidification may mitigate negative effects of warming on carbon burial potential in subtidal unvegetated estuarine sediments
Published 6 July 2021 Science ClosedTags: biological response, laboratory, mitigation, multiple factors, primary production, sediment
Estuarine sediments make an important contribution to the global carbon cycle, but we do not know how this will change under a future climate, which is expected to have lower pH oceans and frequent high-temperature days. Six combinations of warming and partial pressures of CO2 (pCO2) were chosen to investigate the combined and individual effects of short-term pressures on the diel metabolic response of shallow unvegetated sediments ex-situ. Whereas warming significantly increased respiration, making sediments more heterotrophic, high-pCO2 increased net primary productivity, resulting in less heterotrophic sediments. As a result, warming decreased the carbon burial potential of estuarine sediments and high-pCO2 had the opposite effect. High-pCO2 mitigates the negative effects of warming on benthic metabolism under the combined scenario, with carbon burial similar to that expected under high-pCO2 conditions alone. Climate scenarios also changed the diurnal pCO2 variation, with ranges increasing by 33% with warming, and almost doubling under high-pCO2 conditions. An additive response in pCO2 variability was observed under the combined scenario, increasing to 2.3× the current diel-pCO2 range, highlighting the reduced buffering capacity of the water associated with a high CO2 climate. Future carbon burial and export under increased frequencies of unseasonably warm days projected for mid and end of century (30% and 50% of days-per-year, respectively) were estimated with and without ocean acidification. By 2100, warming alone could decrease annual estuarine sediment burial potential by 25%. However, ocean acidification could mitigate the negative effects of more frequent high-temperature days and increase carbon burial potential over current conditions by ~18%.
Continue reading ‘Ocean acidification may mitigate negative effects of warming on carbon burial potential in subtidal unvegetated estuarine sediments’Inorganic carbon fluxes and perturbations by ocean acidification estimated using a data-constrained, process-based model of coral physiology
Published 6 July 2021 Science ClosedTags: biological response, calcification, corals, individualmodeling, laboratory, modeling, photosynthesis
Recognition that ocean acidification (OA) alters calcification rates in many tropical corals and photosynthetic processes in some has motivated research into coral’s carbon processing systems. Here, a multi-compartment coral model is used to assess inorganic carbon fluxes, accounting for carbon uptake, photosynthesis, transport across and between coral tissue and calcification. The increased complexity of this model is enabled by incorporating recent measurements of carbonic anhydrase activity and dissolved inorganic carbon (DIC) related photosynthetic parameters, allowing the model to respond to changes in external inorganic carbon chemistry. The model reproduced measured gross photosynthesis, calcification rates and calcifying fluid pH from Orbicella faveolata at current oceanic conditions. Model simulations representing OA conditions showed an increase in net photosynthesis and modest decreases in calcification which fall within trends seen in experimental data. Photosynthesis increased due to higher diffusive influx of CO2 into the oral tissue layers, increasing DIC where symbiotic algae reside. The model suggests that decreases in calcification result from increased fluxes of CO2 into the calcifying fluid from the aboral tissue layer and the bulk seawater, lowering its pH and reducing the aragonite saturation state. However, modeled pH drops in the calcifying fluid exceed those observed, pointing to the need for additional empirical constraints on DIC fluxes associated with calcification and coelenteron transport.
Continue reading ‘Inorganic carbon fluxes and perturbations by ocean acidification estimated using a data-constrained, process-based model of coral physiology’Anaerobic microbial respiration as a link between 2 carbonate platform drowning and Ocean Anoxic Events
Published 6 July 2021 Science ClosedTags: chemistry, globalmodeling, modeling
The deposition of carbonate rocks is closely tied to Earth’s climate and ocean chemistry. Healthy carbonate platforms produce sediment at a rate that usually keeps up with accommodation changes due to tectonic subsidence and sea level rise. In contrast, platform ‘drowning’ during Ocean Anoxic Events (OAEs) has long been considered a physical expression of biogeochemical changes that reduce shallow-water sedimentation rates. Identifying the exact mechanism(s) that contribute to platform drowning are critical for understanding the nature and duration of environmental disruptions during these events.
Here we present a new model for long-term platform drowning based on changing oceanic gradients in alkalinity and carbonate saturation states. Well-oxygenated oceans are characterized by steep gradients in saturation state with high rates of carbonate ‘over-production’ in the surface ocean and dissolution in the deep ocean. Under reducing conditions, anaerobic microbial metabolisms act to reduce these gradients so that there is less overproduction in the surface ocean which may manifest locally as slower accumulation rates in tropical shallow-water settings. Simple box models show that this is a quasi-steady state process that lasts as long for as long an anoxic condition persist, effectively coupling the timescales of carbonate sedimentation and redox changes. We posit that redox-based changes in ocean gradients act alongside other kill mechanisms to produce the diversity of platform drowning patterns observed in the rock record both in Meseozoic OAEs and for older hyperthermal events.
Continue reading ‘Anaerobic microbial respiration as a link between 2 carbonate platform drowning and Ocean Anoxic Events’Starts the scientific campaign to analyze the ocean circulation and acidification of the North Atlantic
Published 6 July 2021 Web sites and blogs Closed
This Wednesday a team of researchers from the Marine Research Center of the University of Vigo departed from Reykjavik on board the Sarmiento de Gamboa to start the first oceanographic campaign of the BOCATS2 project (Biennial observation of carbon, acidification, transport and sedimentation in the North Atlantic). This study comprises two subprojects, one focused on the characterization of the water column (physical and chemical properties) and the other on the characterization of the sediments to interpret the properties and dynamics of the water masses in the past, which would involve the last tens of thousands of years. This second part is coordinated by CIM-UVigo researchers Guillermo Francés, from the Geological and Biogeochemical Oceanography Group, and Gabriel Rosón, from the Physical Oceanography Group. It supposes a continuation of a first study carried out in 2016 (BOCATS) and has as main objective “to continue with the observational monitoring (recent and past) of the ocean circulation and ocean acidification in the North Atlantic”. The information they will obtain is “essential to advance in the accurate detection of anthropogenic impact and to improve the projections of the adjusted climate models that underpin the IPCC reports for the North Atlantic subpolar gyre (SPNA), a region known for its strong influence on the European climate”, as Guillermo Francés highlights.
On board after six days in confinement
This expedition is no stranger to the special circumstances of the covid-19 pandemic. The scientific team, formed by UVigo researchers Irene Alejo, Marta Pérez Arlucea, Miguel Ángel Nombela and Guillermo Francés, the student of Marine Sciences Mª Fernanda Copete, the technician Susa Álvarez, a researcher of the ICM-CSIC of Barcelona and a student of the Royal Holloway University, were forced to carry out a 6-day quarantine upon arrival in Iceland before being able to board the Sarmiento de Gamboa. Finally, this Tuesday they were able to board the oceanographic vessel, which left Vigo on May 28th with another scientific team that developed, in these weeks, studies framed within another subproject of BOCATS2. After a day on board to prepare last minute issues, yesterday Wednesday the ship left the port of Reykjavik. And as Guillermo Francés explains, the study coordinated by the CIM is part of a larger project, coordinated by the Institute of Marine Research (IIM, CSIC), and funded with 342,430 euros, of which 124,630 correspond to the subproject of the University of Vigo, under the Generation of Knowledge 2019 program of the Ministry of Science and Innovation. The overall objective is to study the millennial and submillennial variability of deep currents through the channels that cross the Reykjanes Ridge (Bight and Charlie-Gibbs fracture zones), southwest of Iceland. These two fracture zones, especially the CGFZ, constitute the main deepwater communication routes between the western and eastern North Atlantic basins, and their hydrography is rather unknown, both at present and in the past when they were under other global climatic conditions. BOCATS2 also intends to continue with the estimation of carbonate and organic carbon flux to sediments, along the lines of the preceding project, essential aspects related to the production, accumulation and preservation of these compounds (carbon cycling, acidification, etc.).
Towards the Bight Fracture Zone
The team aboard the Sarmiento de Gamboa will focus its work on the Bight Fracture Zone, a large transforming ridge that cuts the Reykjanes Ridge and is one of the main pathways for deep water masses between the eastern and western basins of the North Atlantic”. The other ond, he adds, “is the Charlie-Gibbs Fracture Zone”. The scientific plan for the coming weeks comprises two phases. On the one hand, “the acoustic characterization of the seabed with multi-beam and parametric echo sounders in order to obtain a detailed mapping, the internal structure of the first meters of the sedimentary filling, and the most suitable choice of the sampling points”. The second part of the work will consist of obtaining surface sediment samples using a box- corer type dredge”, to then carry out “the sedimentary registry by means of gravity sieve sampling”. Both operations will be carried out at four different points along the fracture zone, “two to the west of the ridge and two to the east”. The team will return to the port of Vigo in mid-July, but this oceanographic campaign will be followed by a second one in 2023, which will complete the project.
Climate change increases susceptibility to grazers in a foundation seaweed
Published 5 July 2021 Science ClosedTags: algae, biological response, laboratory, mollusks, morphology, multiple factors, North Atlantic, performance, physiology, salinity, temperature
Climate change leads to multiple effects caused by simultaneous shifts in several physical factors which will interact with species and ecosystems in complex ways. In marine systems the effects of climate change include altered salinity, increased temperature, and elevated pCO2 which are currently affecting and will continue to affect marine species and ecosystems. Seaweeds are primary producers and foundation species in coastal ecosystems, which are particularly vulnerable to climate change. The brown seaweed Fucus vesiculosus (bladderwrack) is an important foundation species in nearshore ecosystems throughout its natural range in the North Atlantic Ocean and the Baltic Sea. This study investigates how individual and interactive effects of temperature, salinity, and pCO2 affect F. vesiculosus, using a fully crossed experimental design. We assessed the effects on F. vesiculosus in terms of growth, biochemical composition (phlorotannin content, C:N ratio, and ∂13C), and susceptibility to the specialized grazer Littorina obtusata. We observed that elevated pCO2 had a positive effect on seaweed growth in ambient temperature, but not in elevated temperature, while growth increased in low salinity at ambient but not high temperature, regardless of pCO2-level. In parallel to the statistically significant, but relatively small, positive effects on F. vesiculosus growth, we found that the seaweeds became much more susceptible to grazing in elevated pCO2 and reduced salinity, regardless of temperature. Furthermore, the ability of the seaweeds to induce chemical defenses (phlorotannins) was strongly reduced by all the climate stressors. Seaweeds exposed to ambient conditions more than doubled their phlorotannin content in the presence of grazers, while seaweeds exposed to any single or combined stress conditions showed only minor increases in phlorotannin content, or none at all. Despite the minor positive effects on seaweed growth, the results of this study imply that climate change can strongly affect the ability of fucoid seaweeds to induce chemical defenses and increase their susceptibility to grazers. This will likely lead to widespread consequences under future climate conditions, considering the important role of F. vesiculosus and other fucoids in many coastal ecosystems.
Continue reading ‘Climate change increases susceptibility to grazers in a foundation seaweed’Measuring coastal acidification using in situ sensors in the National Estuary Program
Published 5 July 2021 Newsletters and reports ClosedEstuaries and coastal areas are highly vulnerable to the impacts of acidification on shellfish, coral reefs, fisheries, and the commercial and recreational industries that they support. Yet, little is known about the extent of this vulnerability and the estuary-specific drivers that contribute to acidification, such as nutrient enrichment from stormwater, agriculture and wastewater discharges, upwelling of CO2 -rich seawater, elevated atmospheric CO2 from urban and agricultural activities, benthic and marsh-driven processes, and alkalinity and carbon content of freshwater flows. Comprehensive, high resolution monitoring data are needed at varying spatial and temporal scales to provide actionable information tailored to each estuary. Because carbonate chemistry in the coastal environment can be affected by nutrient dynamics, understanding how nutrient inputs exacerbate acidification impacts is essential for the formulation of estuary-specific actions.
EPA supports coastal acidification monitoring and research in various ways (Table 1). The purpose of this report is to share EPA’s approach to long-term coastal acidification monitoring in which it initiated the use of autonomous monitoring sensors for dissolved carbon dioxide (pCO2) and pH deployed in situ in estuaries across the country through EPA’s National Estuary Programs (NEP) and their partners. This approach captures the high-resolution data that are needed to understand variability associated with acidification and ultimately to inform trends and mitigation and adaptation strategies for these vulnerable systems. This report details the plans and experiences of ten NEPs geographically distributed around the U.S. coast and their partners in conducting this monitoring over the last four years (2015–2019). The report illustrates the monitoring goals, deployment methods, data analysis, costs, preliminary results, and the role of partnerships in their successes. The preliminary results have already improved our understanding of baseline carbonate chemistry conditions in these estuaries, the factors affecting spatial and temporal variability, and the drivers responsible for changes in pCO2 and associated acidification. The sensors are successfully capturing seasonal variability and finer temporal trends that provide information on diel variability, physical processes (e.g., weather, tides), and biological activity which cannot be captured with discrete sampling alone. The preliminary data indicate that there are regional differences in the drivers of acidification, particularly the influence of upwelling events vs. land-based freshwater sources. Several of these NEPs have calculated aragonite saturation state, an indicator of conditions in which mollusk shells begin to dissolve and have identified certain vulnerable conditions for shellfish and other economically-important species in their estuaries.
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Continue reading ‘Measuring coastal acidification using in situ sensors in the National Estuary Program’Climate change, the science – 5.3 – ocean acidification (text & video)
Published 5 July 2021 Presentations ClosedA series of videos on Climate Change by Professor Tim Lenton of the University of Exeter.
PLAYLIST: https://tinyurl.com/Climate-Change-Sc…
See playlist description for topic headings.
Continue reading ‘Climate change, the science – 5.3 – ocean acidification (text & video)’Technical note: stability of tris pH buffer in artificial seawater stored in bags
Published 2 July 2021 Science ClosedTags: laboratory, methods
Equimolal tris (2-amino-2-hydroxymethyl-propane-1,3-diol) buffer in artificial seawater is a well characterized and commonly used standard for oceanographic pH measurements. We evaluated the stability of tris pH when stored in purportedly gas-impermeable bags across a variety of experimental conditions, including bag type and storage in air vs. seawater over 300 d. Bench-top spectrophotometric pH analysis revealed that the pH of tris stored in bags decreased at a rate of 0.0058±0.0011 yr−1 (mean slope ±95 % confidence interval of slope). The upper and lower bounds of expected pH change at t=365 d, calculated using the averages and confidence intervals of slope and intercept of measured pH change vs. time data, were −0.0042 and −0.0076 from initial pH. Analyses of total dissolved inorganic carbon confirmed that a combination of CO2 infiltration and/or microbial respiration led to the observed decrease in pH. Eliminating the change in pH of bagged tris remains a goal, yet the rate of pH change is lower than many processes of interest and demonstrates the potential of bagged tris for sensor calibration and validation of autonomous in situ pH measurements.
Continue reading ‘Technical note: stability of tris pH buffer in artificial seawater stored in bags’Selection experiments in the sea: what can experimental evolution tell us about how marine life will respond to climate change?
Published 2 July 2021 Science ClosedTags: adaptation, algae, biological response, corals, crustaceans, echinoderms, molecular biology, mollusks, mortality, otherprocess, physiology, phytoplankton, prokaryotes, reproduction, review
Rapid evolution may provide a buffer against extinction risk for some species threatened by climate change; however, the capacity to evolve rapidly enough to keep pace with changing environments is unknown for most taxa. The ecosystem-level consequences of climate adaptation are likely to be the largest in marine ecosystems, where short-lived phytoplankton with large effective population sizes make up the bulk of primary production. However, there are substantial challenges to predicting climate-driven evolution in marine systems, including multiple simultaneous axes of change and considerable heterogeneity in rates of change, as well as the biphasic life cycles of many marine metazoans, which expose different life stages to disparate sources of selection. A critical tool for addressing these challenges is experimental evolution, where populations of organisms are directly exposed to controlled sources of selection to test evolutionary responses. We review the use of experimental evolution to test the capacity to adapt to climate change stressors in marine species. The application of experimental evolution in this context has grown dramatically in the past decade, shedding light on the capacity for evolution, associated trade-offs, and the genetic architecture of stress-tolerance traits. Our goal is to highlight the utility of this approach for investigating potential responses to climate change and point a way forward for future studies.
Continue reading ‘Selection experiments in the sea: what can experimental evolution tell us about how marine life will respond to climate change?’Microbiome response differs among selected lines of Sydney rock oysters to ocean warming and acidification
Published 2 July 2021 Science ClosedTags: biological response, BRcommunity, community composition, laboratory, molecular biology, mollusks, multiple factors, otherprocess, prokaryotes, South Pacific, temperature
Oyster microbiomes are integral to healthy function and can be altered by climate change conditions. Genetic variation among oysters is known to influence the response of oysters to climate change and may ameliorate any adverse effects on oyster microbiome, however, this remains unstudied. Nine full-sibling selected breeding lines of the Sydney rock oyster (Saccostrea glomerata) were exposed to predicted warming (ambient = 24°C, elevated = 28°C) and ocean acidification (ambient pCO2 = 400, elevated pCO2 = 1000 µatm) for four weeks. The haemolymph bacterial microbiome was characterised using 16S rRNA (V3-V4) gene sequencing and varied among oyster lines in the control (ambient pCO2, 24°C) treatment. Microbiomes were also altered by climate change dependent on oyster lines. Bacterial α-diversity increased in response to elevated pCO2 in two selected lines, while bacterial β-diversity was significantly altered by combinations of elevated pCO2 and temperature in four selected lines. Climate change treatments caused shifts in the abundance of multiple Amplicon Sequence Variants (ASVs) driving change in the microbiome of some selected lines. We show that oyster genetic background may influence the Sydney rock oyster haemolymph microbiome under climate change and that future assisted evolution breeding programs to enhance resilience should consider the oyster microbiome.
Continue reading ‘Microbiome response differs among selected lines of Sydney rock oysters to ocean warming and acidification’Tidal mixing of estuarine and coastal waters in the Western English Channel controls spatial and temporal variability in seawater CO2
Published 2 July 2021 Science ClosedTags: chemistry, field, modeling, North Atlantic, regionalmodeling
Surface ocean CO2 measurements are used to compute the oceanic air–sea CO2 flux. The CO2 flux component from rivers and estuaries is uncertain. Estuarine and coastal water carbon dioxide (CO2) observations are relatively few compared to observations in the open ocean. The contribution of these regions to the global air–sea CO2 flux remains uncertain due to systematic under-sampling. Existing high-quality CO2 instrumentation predominantly utilise showerhead and percolating style equilibrators optimised for open ocean observations. The intervals between measurements made with such instrumentation make it difficult to resolve the fine-scale spatial variability of surface water CO2 at timescales relevant to the high frequency variability in estuarine and coastal environments. Here we present a novel dataset with unprecedented frequency and spatial resolution transects made at the Western Channel Observatory in the south west of the UK from June to September 2016, using a fast response seawater CO2 system. Novel observations were made along the estuarine–coastal continuum at different stages of the tide and reveal distinct spatial patterns in the surface water CO2 fugacity (fCO2) at different stages of the tidal cycle. Changes in salinity and fCO2 were closely correlated at all stages of the tidal cycle and suggest that the mixing of oceanic and riverine end members determines the variations in fCO2. The observations demonstrate the complex dynamics determining spatial and temporal patterns of salinity and fCO2 in the region. Spatial variations in observed surface salinity were used to validate the output of a regional high resolution hydrodynamic model. The model enables a novel estimate of the air–sea CO2 flux in the estuarine–coastal zone. Air–sea CO2 flux variability in the estuarine–coastal boundary region is dominated by the state of the tide because of strong CO2 outgassing from the river plume. The observations and model output demonstrate that undersampling the complex tidal and mixing processes characteristic of estuarine and coastal environment bias quantification of air-sea CO2 fluxes in coastal waters. The results provide a mechanism to support critical national and regional policy implementation by reducing uncertainty in carbon budgets.
Continue reading ‘Tidal mixing of estuarine and coastal waters in the Western English Channel controls spatial and temporal variability in seawater CO2’NOAA Science Camp webinar: what’s up with carbon? the 5 W’s of ocean acidification
Published 2 July 2021 Events ClosedDate: Tuesday, July 6, 2021
Time: 10:00 am Pacific time / 9 am Alaska time
Webinar
Register for the GoToWebinar event.
The webinar will last about 60 minutes with moderated questions and answers throughout. This webinar will be recorded and posted afterward with English captions and Spanish subtitles. (Grades 6-8 but all ages will enjoy).
NOAA Science Camp summer activities
NOAA Science Camp is hosting two weeks with interactive webinars, aimed at students in grades 6–8 (but of interest to all ages!). We feature NOAA scientists, educators, and partners to explore NOAA’s work on climate change and marine mammals. Learn about current research. Connect to what’s going on in your communities. Join us to ask questions to our presenters and learn more about weather, oceanography, marine life, fisheries and more!
The 2021 NOAA Science Camp is coordinated by NOAA’s Alaska Fisheries Science Center, NOAA’s Northwest Fisheries Science Center, and Washington Sea Grant. The webinars are modeled on the NOAA Live! webinars coordinated by Woods Hole Sea Grant and the NOAA Regional Collaboration Network. Contact Lisa.Hiruki-Raring@noaa.gov with any questions.
Continue reading ‘NOAA Science Camp webinar: what’s up with carbon? the 5 W’s of ocean acidification’In a flash: how bioluminescent organisms signal ocean acidification
Published 2 July 2021 Web sites and blogs ClosedOcean acidification is on the rise as our seas soak up rising atmospheric carbon dioxide levels. Although the increase in the last 200 years over the industrial age has been modest, the change is noticeable. A recent presentation at the annual Society for Integrative and Comparative Biology conference showed that when the ocean is more acid, bioluminescence is brighter.
The presentation highlighted work by researchers from the University of Hawaii, who mimicked the anticipated rise in ocean acidity to investigate its effect on secretory bioluminescence, as Science News reports. After extracting the bioluminescence chemicals from various marine organisms, the light reaction generated in the increased acidity was up to 15% brighter, according to the presentation abstract. This suggests ocean acidification could have a major effect on light generation in a host of bioluminescent ocean organisms and seriously affect the marine sensory environment.
Ocean Life and Bioluminescence
Bioluminescence is a way of life for millions of sea creatures who generate their own light sources to feed, mate and escape predators in the gloomy depths. Some organisms, such as the dinoflagellates that create red tides, make the light internally. But for others, the process is external or secretory. Because it requires a chemical reaction, bioluminescence is often governed by surrounding acidity. For secretory bioluminescence, it’s the pH of the surrounding seawater that is important.
Continue reading ‘In a flash: how bioluminescent organisms signal ocean acidification’The ocean has a serious case of heartburn. Is relief on the way?
Published 2 July 2021 Web sites and blogs 1 CommentThe Earth’s atmosphere contains more carbon dioxide (CO2) than at any time in the last 20 million years, researchers say. The levels would be even higher if it weren’t for the ocean, which slurps up carbon emissions and stores roughly 60 times more carbon than the atmosphere. But high carbon levels in the ocean are causing the pH of seawater to drop and ocean acidity to rise. This phenomenon, known as ocean acidification, has given our top ally in the fight against climate change a serious case of heartburn.
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Fortunately, the weathering of rocks on land produces alkalinity, which has an “antacid” effect once it washes into the ocean. Researchers estimate there is currently the equivalent of 200 billion antacid tablets in the global ocean. Alkalinity also plays a critical role in helping the ocean store carbon. But there’s a problem: alkalization of the ocean from the natural geological cycle is slow, sometimes taking hundreds of thousands of years to occur.
Adam Subhas, a marine chemist at WHOI, wants to speed up the process. He is investigating the viability of an ocean intervention-based process known as ocean alkalinity enhancement, which he loosely describes as adding “Tums” to the ocean.
Continue reading ‘The ocean has a serious case of heartburn. Is relief on the way?’Transplanted bleaching-resistant coral retain their resistance to heat
Published 2 July 2021 Web sites and blogs Closed
Katie Barott of the University of Pennsylvania’s School of Arts & Sciences led a study to see if climate-change resistant corals could grow on battered reefs after transplantation. Her team took corals that survived a severe bleaching event and transplanted them to a new reef where they retained their resilient qualities.
This is excellent news because the looming threat of the climate crisis, acidification, and warming oceans hangs heavy on the world’s coral reefs. Most of them are struggling to adapt to the increasingly inhospitable waters.
Scientists are concerned that corals will fall victim to global warming very soon because mass bleaching events occur more frequently. This new study’s findings offer hope that hardy corals could be the saviors, restoring ruined reefs in the future. Barott and colleagues believe this strategy can buy corals more time as the world battles climate change.
Coral bleaching occurs when the ocean warms to higher-than-normal temperatures, prompting corals to expel the algae they contain, which is their food source. Without sustenance, the coral turns white and eventually dies. The phenomenon has plagued Australia’s Great Barrier Reef and Hawaii’s reefs in recent years.
Continue reading ‘Transplanted bleaching-resistant coral retain their resistance to heat’
