Increasing temperature and CO2 concentration are among the most important factors affecting marine ecosystems under climate change. We investigated the morphological, biochemical, and physiological trait responses of seedlings of the tropical seagrass Enhalus acoroides under experimental conditions. Trait responses were greater under temperature effects than increasing CO2 concentration. Seedlings under rising temperatures showed enhanced leaf growth, lower leaf nutrient content, and stimulated down-regulating mechanisms in terms of photo-physiology. Increasing CO2 concentrations did not show any significant effects independently. There was a significant interaction for some of the trait responses considered, such as leaf number and carbon content in the roots, and trends of higher starch concentrations in the leaves and lower rETRmax under combined enriched CO2 and high temperature, even though none of these interactions were synergistic. Understanding the single and interactive trait responses of seagrass seedlings to increasing temperature and CO2 concentration is of importance to determine the relative responses of early life stages of seagrasses, which may differ from adult plants, in order to form a more holistic view of seagrass ecosystem health under climate change.
Continue reading ‘Rising temperature is a more important driver than increasing carbon dioxide concentrations in the trait responses of Enhalus acoroides seedlings’Archive Page 238
Rising temperature is a more important driver than increasing carbon dioxide concentrations in the trait responses of Enhalus acoroides seedlings
Published 21 June 2021 Science ClosedTags: biological response, growth, laboratory, multiple factors, phanerogams, photosynthesis, physiology, temperature
Will Bay fish feel the bite from ocean acidification? ‘Hooked on OA’ series shares latest science
Published 21 June 2021 Web sites and blogs ClosedOcean waters are becoming more acidic — but how does that affect the Chesapeake Bay? And what does it mean for fish and the people fishing for them?
The ‘Hooked on Ocean Acidification’ webinars answered these questions for mid-Atlantic Anglers in March and April. The four webinars walked through recent research about acidification in coastal waters and out in the open ocean. The webinars were hosted by the Mid-Atlantic Coastal Acidification Network, in collaboration with other mid-Atlantic partners.
In the mid-Atlantic, there are many pieces in the puzzle of acidification
Globally, the oceans absorb carbon dioxide from the atmosphere — and since the industrial revolution, human activities are adding carbon dioxide to the atmosphere 10 times faster than the earth has experienced in the last 50 million years. As the ocean absorbs carbon dioxide, the water becomes more acidic. This effect is known as ocean acidification.
But the effects of acidification aren’t uniform across all water, and the mid-Atlantic region gets its ocean water from several sources, explained Grace Saba, an assistant professor at Rutgers University. The mid-Atlantic continental shelf gets currents of cold water, which can be more acidic, and also warmer, less acidic water from the Gulf stream.
Continue reading ‘Will Bay fish feel the bite from ocean acidification? ‘Hooked on OA’ series shares latest science’Combined effects of seawater acidification and benzo(a)pyrene on the physiological performance of the marine bloom-forming diatom Skeletonema costatum
Published 18 June 2021 Science ClosedTags: biological response, growth, laboratory, multiple factors, photosynthesis, physiology, phytoplankton, toxicants
Highlights
- Skeletonema costatum was tolerant to low and moderate benzo(a)pyrene concentrations.
- The high benzo(a)pyrene concentration remarkably inhibited growth and photosynthesis.
- Negative effects of ocean acidification were detected at the high benzo(a)pyrene level.
Abstract
The combined effects of polycyclic aromatic hydrocarbons and seawater acidification are poorly understood. Hence, we exposed the bloom-forming diatom Skeletonema costatum to four concentrations (0, 0.1, 1 and 10 μg L-1) of benzo(a)pyrene and two pCO2 levels (400 and 1000 μatm) to investigate its physiological performance. The growth and photosynthesis of S. costatum were tolerant to low and moderate benzo(a)pyrene concentrations regardless of the pCO2 level. However, the highest benzo(a)pyrene concentration had remarkably adverse effects on most parameters, decreasing the growth rate by 69%. Seawater acidification increased the sensitivity to high light stress, as shown by the lower relative maximum electron transport rate and light saturation point at the highest benzo(a)pyrene concentration. Our results suggested that benzo(a)pyrene could be detrimental to diatoms at a habitat-relevant level, and seawater acidification might further decrease its light tolerance, which would have important ramifications for the community structure and primary production in coastal waters.
Continue reading ‘Combined effects of seawater acidification and benzo(a)pyrene on the physiological performance of the marine bloom-forming diatom Skeletonema costatum’Physiology, niche characteristics and extreme events: current and future habitat suitability of a rhodolith-forming species in the Southwestern Atlantic
Published 18 June 2021 Science ClosedTags: algae, biological response, individualmodeling, laboratory, modeling, mortality, multiple factors, nutrients, performance, photosynthesis, physiology, policy, reproduction, South Atlantic, temperature
Highlights
- Global climate change and local stressors are the main threats to reef-building organisms and habitats they build, such as rhodolith beds.
- Through an experimental essay and ecological niche modelling, we were able to determine the environmental factors that determine the distribution and affect the physiology of an important rhodolith-forming species in the southwestern Atlantic.
- Our results raise the possibility of some rhodolith-forming species being resilient to future environmental change based on our current understanding of their distributions, a perspective that will need to be further explored by future studies.
- This information is helpful in informing policies for the conservation of priority areas, aiding the preservation of marine biodiversity in the South Atlantic.
Abstract
Given the ecological and biogeochemical importance of rhodolith beds, it is necessary to investigate how future environmental conditions will affect these organisms. We investigated the impacts of increased nutrient concentrations, acidification, and marine heatwaves on the performance of the rhodolith-forming species Lithothamnion crispatum in a short-term experiment, including the recovery of individuals after stressor removal. Furthermore, we developed an ecological niche model to establish which environmental conditions determine its current distribution along the Brazilian coast and to project responses to future climate scenarios. Although L. crispatum suffered a reduction in photosynthetic performance when exposed to stressors, they returned to pre-experiment values following the return of individuals to control conditions. The model showed that the most important variables in explaining the current distribution of L. crispatum on the Brazilian coast were maximum nitrate and temperature. In future ocean conditions, the model predicted a range expansion of habitat suitability for this species of approximately 58.5% under RCP 8.5. Physiological responses to experimental future environmental conditions corroborated model predictions of the expansion of this species’ habitat suitability in the future. This study, therefore, demonstrates the benefits of applying combined approaches to examine potential species responses to climate-change drivers from multiple angles.
Continue reading ‘Physiology, niche characteristics and extreme events: current and future habitat suitability of a rhodolith-forming species in the Southwestern Atlantic’Date: 30 Jun 2021
Time: 6:00 pm – 8:00 pm
Location: Level 4, 50 Kitchener Street, Auckland CBD
Registration is essential
Description
As the oceans warm, what’s happening to the marine species beneath the waves?
Join us at an upcoming alumni lecture at the University’s Auckland premises on the evening of Wednesday 30 June.
Hear about some of our latest research from award-winning marine biologist Dr Christopher Cornwall.
Fresh from his Prime Minister’s MacDiarmid Emerging Scientist Prize, he’ll share what we’re learning about how the world’s coral reefs, marine algae and the species that depend on them will respond to ocean acidification.
There’s good news – thanks to the adapabilty of organisims – but still challenges ahead. Whether you have a background in the sciences or just enjoy catching up on the latest research, hear the full story during this deep dive into the big blue sea.
There’ll also be the opportunity to catch up with fellow graduates during the event over light refreshments.
There is no charge for this event, but places are limited.
Please register via the button above at your earliest convenience to ensure you don’t miss out.
For more information contact: Heidi Stedman
Continue reading ‘Alumni lecture in Auckland: Coral reefs and climate change’Event Type: Webinars and Virtual Events
Title: Sharing science in and around the Bering Sea
When: 22 June 2021
Where: Online: 10:00-11:00 am AKDT, 2:00-3:00 pm EDT
More information: Link to Webinar Webpage
Summary
The Bering Sea is experiencing many changes. Loss of sea ice and record high ocean and air temperatures continue to impact wildlife and all aspects of life for coastal communities. Through the Bering Region Ocean Update project, the Alaska Ocean Observing System works to increase regional data sharing among federal, state, community and private sector partners. Join us for an overview of the Winter 2020/2021 Bering Science report which is a resource to state, federal, community and university partners to share recent observations from in and around the Bering Sea with community members and other scientists and management agencies. This year’s report includes sections on storms, erosion, fish, crab, ocean acidification, plankton, HABs, marine mammals, marine debris and seabirds. The discussion will also provide updates on scientific research taking place during summer 2021 in the Bering Sea region.
Please follow the link above to register.
Speakers
- Rick Thoman, ACCAP at the University of Alaska Fairbanks
- Katie Howard, Alaska Department of Fish and Game
- Bob Foy or Maggie Mooney-Seus – NOAA Alaska Fisheries Science Center
NOAA spearheads North American collaboration
Vulnerable coastal areas now have a tool to assess the status and impacts of ocean acidification (OA). NOAA and collaborators have compiled data about OA conditions for the entire continental shelves of North America, from Alaska to Mexico in the west and from Canada to the Caribbean in the east.
Acidified water can harm fish, oysters, clams, sea urchins, shallow water corals, and deep-sea corals, among other living organisms.
Ocean acidification results from the ocean’s absorption of carbon dioxide (CO2) from the atmosphere and increases the acidity of seawater. Although this process helps reduce levels of CO2 in the atmosphere and thus slows down global climate change, it comes at a cost to aquatic ecosystems and local fisheries. Acidified water can harm fish, oysters, clams, sea urchins, shallow water corals, and deep-sea corals, among other living organisms.
The Coastal Ocean Data Analysis Product for North America (CODAP-NA) fills a gap for information about the water column that can indicate acidification. Prior to now, no such data products existed for the coastal ocean where most of the OA-susceptible commercial and recreational fisheries and aquaculture industries are located. Previous OA products have mostly been focused on the open ocean, although the majority of the fisheries yield is located in the coastal ocean.
Continue reading ‘Ocean acidification data for coasts’Asteroid impact in Earth’s past caused brief bloom of algae and substantial ocean species’ extinction
Published 18 June 2021 Web sites and blogs ClosedThe asteroid that likely caused dinosaur extinction 66 million years ago triggered strong global cooling and a massive bloom of algae, causing mass extinction also in marine ecosystems. This is the result of a new study from scientists of the Potsdam Institute for Climate Impact Research (PIK). The researchers simulated the ocean productivity before and after the asteroid impact – and found a brief global algal bloom peaking at a productivity seven times higher than in the pre-impact ocean. Since the algae likely produced toxins, their increase could have contributed to the extinction of species in the ocean.
“The impact of a large asteroid near Chicxulub, Mexico, is increasingly recognised as the trigger of the dinosaur extinction, causing global darkness and a pronounced cooling,” explains Julia Brugger, lead author of the study published in the Geophysical Research Letters and now at the Senckenberg Biodiversity and Climate Research Centre Frankfurt (SBiK-F). “However, the links between this impact and the changes in the marine biosphere are still not fully understood. For the first time, using an enhanced Earth-system model that can simulate how the ocean biosphere reacts to changes in climate and nutrient supply, we were now able to show that the asteroid impact caused a relatively short-lived, yet massive algal bloom – this is an important new aspect helping us to understand what happened in the aftermath of the Chicxulub impact.”
Continue reading ‘Asteroid impact in Earth’s past caused brief bloom of algae and substantial ocean species’ extinction’Coastal Acidification” – description of one part of our climate change research that focuses on coastal acidification is. The presentation defines what coastal acidification is and why it’s important, and it describes our research on its causes and how to predict how and when acidification events are likely to occur.
Continue reading ‘EPA: coastal acidification (text & video)’
“14: Life Below Water”
Augmented Reality Mural, June 2021
South Pointe Elementary School
1050 4th St, Miami Beach, FL 33139
UN Sustainable Development Goal 14: Life Below Water is to conserve and sustainably use the oceans, seas and marine resources for sustainable development.
Our oceans are in trouble. Marine biodiversity is threatened by overfishing, pollution, plastics and ocean acidification from climate change. Year after year, we have been pushing the boundaries of the ocean’s sustainability, and in so doing we have been challenging our own.
- Nearly 90% of the world’s marine fish stocks are overexploited or depleted.
- Every day around 8 million pieces of plastic makes their way into our oceans.
- Ocean heat is at record levels, causing widespread marine heatwaves.
This mural is the first of a mural series for the Miami-Dade Public School District to raise awareness for the UN Sustainable Development Goals (SDGs). The SDGs are a collection of 17 interlinked global goals designed to be a “blueprint to achieve a better and more sustainable future for all”.
The Before It’s Too Late team worked alongside students from South Pointe Elementary, Miami Beach Senior High and Miami Lakes Technical school to create this mural. The mural comes alive as an underwater coral reef designed by students using Tilt Brush, Blender and Unity.
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Continue reading ‘“14: life below water”at South Pointe Elementary’Impacts of ocean acidification on growth and toxin content of the marine diatoms Pseudo-nitzschia australis and P. fraudulenta
Published 17 June 2021 Science ClosedTags: biological response, growth, laboratory, multiple factors, physiology, phytoplankton
Highlights
- P. fraudulenta and P. australis strains were able to acclimate and maintain high growth rates at current pH (8.07) and projected pH in 2100 (7.77) compared to the lowest pH level (7.40).
- Domoic acid content was significantly higher for all P. australis toxic strains acclimated at the ambient pH level (8.07), and lowest at pH (7.77).
- Strong inter- and intra-specific variation related to the geographical area and the culturing history of Pseudo-nitzschia strains.
Abstract
This paper present the effects of ocean acidification on growth and domoic acid (DA) content of several strains of the toxic Pseudo-nitzschia australis and the non-toxic P. fraudulenta. Three strains of each species (plus two subclones of P. australis) were acclimated and grown in semi-continuous cultures at three pH levels: 8.07, 7.77, and 7.40, in order to simulate changes of seawater pH from present to plausible future levels. Our results showed that lowering pH from current level (8.07) to predicted pH level in 2100 (7.77) did not affect the mean growth rates of some of the P. australis strains (FR-PAU-17 and L3-100), but affected other strains either negatively (L3-30) or positively (L3.4). However, the growth rates significantly decreased with pH lowered to 7.40 (by 13% for L3-100, 43% for L3-30 and 16% for IFR-PAU-17 compared to the rates at pH 8.07). In contrast, growth rates of the non-toxic P. fraudulenta strains were not affected by pH changing from 8.07 to 7.40.
The P. australis strains produced DA at all pH levels tested, and the highest particulate DA concentration normalized to cell abundance (pDA) was found at pH 8.07. Total DA content (pDA and dissolved DA) was significantly higher at current pH (8.07) compared to pH (7.77), exept for one strain (L 3.4) where no difference was found. At lower pH levels 7.77 – 7.40, total DA content was similar, except for strains IFR-PAU-17 and L3-100 which had the lowest content at the pH 7.77. The diversity in the responses in growth and DA content highlights the inter- and intra-specific variation in Pseudo-nitzschia species in response to ocean acidification. When exploring environmental responses of Pseudo-nitzschia using cultured cells, not only strain-specific variation but also culturing history should be taken into consideration, as the light levels under which the subclones were cultured, afterwards affected both maximum growth rates and DA content.
Continue reading ‘Impacts of ocean acidification on growth and toxin content of the marine diatoms Pseudo-nitzschia australis and P. fraudulenta’Effect of seawater acidification and plasticizer (Bisphenol-A) on aggregation of nanoparticles
Published 17 June 2021 Science ClosedTags: laboratory, morphology, multiple factors, toxicants
This study investigated the effect of an organic pollutant (Bisphenol A, an endocrine-disrupting chemical) on the stability of a mixture of nanoparticles (NPs). Experiments were conducted in seawater chemistry condition with TiO2/ZnO NP concentration ratio: 0.01, 10.1, 1, 10,100; pH: 7.4 and 8.1; BPA concentration: 1 and 10μg/L. The presence of BPA was found to increase the size of NP. Lower pH of 7.4 increased size of NPs from 3 to 297% (at 1 μg/L BPA; NP ratio = 0.1 to 100). Aggregation rate constant values ranged between 0.17 and 1.81nm/sec in pH 7.4 suspension and between 0.48 and 56nm/sec in pH 8.1 suspension. Factors such as pH and NP mass concentration had major effects on size change for suspension having the same ratio of TiO2/ZnO. NP aggregate was comprised of 97% ZnO NP, 3% TiO2 NP and had 1.39mg/kg BPA. Overall, this study found dominance of van der Waals forces of attraction in mixture suspension of NPs and BPA. The obtained result on NP persistence in seawater can now be used in estimating exposure doses of a mixture of nanoparticles during inadvertent exposure.
Continue reading ‘Effect of seawater acidification and plasticizer (Bisphenol-A) on aggregation of nanoparticles’Effect of coastal development on larval fish abundance in Klang Strait (Malaysia)
Published 17 June 2021 Science ClosedTags: abundance, biological response, fish, Indian, individualmodeling, laboratory, modeling, otherprocess, reproduction
Highlights
- BACI model detects larval fish abundance before and after 30 years of development.
- Lower larval diversity and abundance at impact than at offshore control stations.
- The inshore-offshore cline in abundance can be related to lower SST and higher pH.
- Total larval fish abundance increased despite changes in zooplankton composition.
- 1st and 2nd stage larvae of certain families increased after development impact.
Abstract
Changes in larval fish assemblages were studied before (1985-86) and after (2013–2014) rapid coastal development in the Klang Strait, Malaysia, based on a Before-After-Control-Impact (BACI) experimental design. Fish larvae were sampled by bongo-nets along an 18-km transect from the impact station at the Kapar power station (KPS) to four control stations in increasingly offshore waters. Families Gobiidae, Clupeidae, Sciaenidae and Engraulidae were most abundant at both sampling periods, demonstrating their adaptability and resilience to the natural and anthropogenic disturbances. Coastal development has reduced larval fish abundance at KPS, inevitably shifting higher larval abundance to the control stations. This shift is related to lower sea surface temperature and higher pH. Despite the coastal disturbances, there was an overall increase in total larval fish abundance attributed to the preflexion stage of the Gobiidae, Sciaenidae, Engraulidae, Cynoglossidae and Callionymidae, and the yolk-sac and preflexion larvae of unidentified taxa.
Continue reading ‘Effect of coastal development on larval fish abundance in Klang Strait (Malaysia)’Cultivating marine macroalgae in CO2-enriched seawater: a bio-economic approach
Published 17 June 2021 Science ClosedTags: algae, biological response, laboratory, morphology, multiple factors, photosynthesis, temperature
Highlights
- Seasonal variability of temperature under ambient or enriched CO2 conditions affect productivity in two model fleshy seaweeds, Ulva rigida and Gracilaria conferta.
- The growth of these seaweeds can be doubled when exposed to high CO2 concentrations.
- Maximal short-run profits were obtained at ca. 22.5 °C and 27.5 °C for U. rigida and G. conferta, respectively.
- Based on the seaweeds respond to external seasonal changes in temperature and CO2 concentration, farmers may decide what and where to grow seasonally.
Abstract
By the end of the current century atmospheric CO2 concentration may reach 1000 ppm, more than twice the present level set at ca. 400 ppm. Marine macroalgae (seaweeds) contribute to global primary production and by taking up CO2 they may ameliorate and regulate global climate change. Seaweeds also have direct and indirect economic importance by providing food and bioactive compounds for human benefit. Nonetheless, all these benefits could be jeopardized by the ongoing pressures, both local and global, on marine environments. In this study we examine the effects of dissolved CO2 and seasonal seawater temperature on the growth rates (measured weekly changes in biomass and expressed on a daily basis) of two model species, Ulva rigida (Chlorophyta) and Gracilaria conferta (Rhodophyta), which are common in the intertidal zone of the Israeli Mediterranean Sea, and cultivated by the local seaweed industry. The seaweeds were grown in land-based 40 L fiberglass tanks fertilized with sufficient N and P, supplied with running seawater and continuous air bubbling to keep equal exposure of the seaweeds to nutrients and light. The tanks were also provided with aeration with regular air (ambient CO2, ~ 400 ppm) or CO2-enriched air (~780 ppm). Seaweeds exposed to CO2–enriched seawater grew faster, 32.5 and 8.5% growth per day for U. rigida and G. conferta, respectively. Following calculations of productivity rates, market price, and input cost, we estimate production and show a quadratic production function with respect to temperature for each CO2 concentration. Thus, there is an optimal temperature that maximizes seaweed output. Based on the production function estimates and using market prices, maximal short-run profits were obtained at ca. 22.5 °C and 27.5 °C for U. rigida and G. conferta, respectively. These results may provide useful information for seaweed growers on what and where to grow seasonally, and how farming activities should adapt to external changes in temperature and CO2 concentration.
Continue reading ‘Cultivating marine macroalgae in CO2-enriched seawater: a bio-economic approach’The Byrne lab goes West: three CMS students set sail on 45-day Pacific Ocean cruise
Published 17 June 2021 Web sites and blogs Closed
The NOAA West Coast Ocean Acidification (WCOA) cruise is part of a decades-long program that monitors chemical parameters all along the west coast of the United States, from Canada to Mexico. The major goal is to understand trends in the Pacific Ocean, with a specific focus on environmental parameters that influence ocean acidification – a major threat to ocean health, food security, economies, and more. The cruise departs for another trek this summer, along with three CMS students on board. Macarena Martín Mayor, Katelyn Schockman, and Kalla Fleger from Bob Byrnes’ lab study chemical oceanography and will be joining the action aboard the R/V Ronald H. Brown.
The team will sample the same 145 stations that have been sampled for decades. Of the 26 scientists on the cruise representing labs from all across the world, each group is tasked with a specific parameter to measure. These range from total alkalinity to inorganic carbon to nutrients. Like a puzzle, each group will piece together their speciality to create a broader picture of the chemical conditions in the Pacific Ocean.
Continue reading ‘The Byrne lab goes West: three CMS students set sail on 45-day Pacific Ocean cruise’SOCAT wants to highlight the work by the regional and global groups – further information about these groups can be found here. We further thank all data contributors, quality controllers and other contributors for version 2021.
The Surface Ocean CO₂ Atlas (SOCAT) is a synthesis activity for quality-controlled, surface ocean fCO₂ (fugacity of carbon dioxide) observations by the international marine carbon research community (>100 contributors). SOCAT data is publicly available, discoverable and citable. SOCAT enables quantification of the ocean carbon sink and ocean acidification and evaluation of ocean biogeochemical models. SOCAT, which celebrated its 10th anniversary in 2017, represents a milestone in biogeochemical and climate research and in informing policy.
SOCAT data are released in versions. Each succeeding version contains new data sets as well as updates of older ones. The first version of SOCAT was released in 2011, the second and third version followed biennially. Automation allowed annual public releases since version 4. The latest SOCAT version (version 2021) has 30.6 million observations from 1957 to 2020 for the global oceans and coastal seas. Calibrated sensor data are also available.
SOCAT version 2021 was released on the 15th of June 2021, containing data submitted on or before 15th of January 2021. Data submissions for the next version are welcome at any time, and will be included in the next SOCAT release in 2022.
SOCAT is a core Global Ocean Observing System data product for biogeochemistry endorsed by the Global Ocean Observing System GOOS.
Satellite observations are needed to understand ocean acidification and multi-stressor impacts on fish stocks in a changing Arctic Ocean
Published 16 June 2021 Science ClosedTags: Arctic, biological response, chemistry, fish, mortality, performance, physiology, reproduction, review
It is widely projected that under future climate scenarios the economic importance of Arctic Ocean fish stocks will increase. The Arctic Ocean is especially vulnerable to ocean acidification and already experiences low pH levels not projected to occur on a global scale until 2100. This paper outlines how ocean acidification must be considered with other potential stressors to accurately predict movement of fish stocks toward, and within, the Arctic and to inform future fish stock management strategies. First, we review the literature on ocean acidification impacts on fish, next we identify the main obstacles that currently preclude ocean acidification from Arctic fish stock projections. Finally, we provide a roadmap to describe how satellite observations can be used to address these gaps: improve knowledge, inform experimental studies, provide regional assessments of vulnerabilities, and implement appropriate management strategies. This roadmap sets out three inter-linked research priorities: (1) Establish organisms and ecosystem physiochemical baselines by increasing the coverage of Arctic physicochemical observations in both space and time; (2) Understand the variability of all stressors in space and time; (3) Map life histories and fish stocks against satellite-derived observations of stressors.
Continue reading ‘Satellite observations are needed to understand ocean acidification and multi-stressor impacts on fish stocks in a changing Arctic Ocean’Coastal Ocean Data Analysis Product in North America (CODAP-NA) – an internally consistent data product for discrete inorganic carbon, oxygen, and nutrients on the North American ocean margins (update)
Published 16 June 2021 Science ClosedTags: biogeochemistry, chemistry, methods, North Atlantic, North Pacific
Internally consistent, quality-controlled (QC) data products play an important role in promoting regional-to-global research efforts to understand societal vulnerabilities to ocean acidification (OA). However, there are currently no such data products for the coastal ocean, where most of the OA-susceptible commercial and recreational fisheries and aquaculture industries are located. In this collaborative effort, we compiled, quality-controlled, and synthesized 2 decades of discrete measurements of inorganic carbon system parameters, oxygen, and nutrient chemistry data from the North American continental shelves to generate a data product called the Coastal Ocean Data Analysis Product in North America (CODAP-NA). There are few deep-water (> 1500 m) sampling locations in the current data product. As a result, crossover analyses, which rely on comparisons between measurements on different cruises in the stable deep ocean, could not form the basis for cruise-to-cruise adjustments. For this reason, care was taken in the selection of data sets to include in this initial release of CODAP-NA, and only data sets from laboratories with known quality assurance practices were included. New consistency checks and outlier detections were used to QC the data. Future releases of this CODAP-NA product will use this core data product as the basis for cruise-to-cruise comparisons. We worked closely with the investigators who collected and measured these data during the QC process. This version (v2021) of the CODAP-NA is comprised of 3391 oceanographic profiles from 61 research cruises covering all continental shelves of North America, from Alaska to Mexico in the west and from Canada to the Caribbean in the east. Data for 14 variables (temperature; salinity; dissolved oxygen content; dissolved inorganic carbon content; total alkalinity; pH on total scale; carbonate ion content; fugacity of carbon dioxide; and substance contents of silicate, phosphate, nitrate, nitrite, nitrate plus nitrite, and ammonium) have been subjected to extensive QC. CODAP-NA is available as a merged data product (Excel, CSV, MATLAB, and NetCDF; https://doi.org/10.25921/531n-c230, https://www.ncei.noaa.gov/data/oceans/ncei/ocads/metadata/0219960.html, last access: 15 May 2021) (Jiang et al., 2021a). The original cruise data have also been updated with data providers’ consent and summarized in a table with links to NOAA’s National Centers for Environmental Information (NCEI) archives (https://www.ncei.noaa.gov/access/ocean-acidification-data-stewardship-oads/synthesis/NAcruises.html).
Continue reading ‘Coastal Ocean Data Analysis Product in North America (CODAP-NA) – an internally consistent data product for discrete inorganic carbon, oxygen, and nutrients on the North American ocean margins (update)’A comparative accuracy of regularized and tension spline methods to estimate and model the surface water pH of Pulau Tuba, Langkawi, Kedah
Published 16 June 2021 Science ClosedTags: chemistry, field, Indian, modeling, regionalmodeling
This research is conducted to assess the accuracy of spline interpolation methods to predict and model the surface water pH of Pulau Tuba, Langkawi, Kedah, Malaysia. In-situ sampling activities using pH-meter and Geographic Positioning Systems (GPS) were carried out during high tides and at noon in November 2018. The development of spatial models were constructed using the Regularized and Tension spline methods. Then, validation of models was carried out to compare the observed and predicted values of pH using correlation analysis, regression analysis, and error analysis. The accuracy of the developed map was calculated using the overall accuracy equation. The research found that the regularized spline method had more accuracy in estimating surface water pH variability than the tension spline method. The Pearson correlation coefficient (r), Coefficient of determination (R2), Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) were reported at 0.896, 0.803, 0.0265 and 0.0344 for the regularized spline method, respectively. The developed spatial model was then transformed into a map by adding map elements such as legend, title, north arrow, and scales for effective visualization. The developed map has an accuracy of 87.50%. The surface water pH was found at the range of 7-8. The low reading of pH is expected due to the addition of rainwater that lowered the pH of the coastal water of Pulau Tuba, Langkawi, Kedah. The research outcomes would benefit the government and non-government agencies to monitor the coastal and ocean acidification and the development of strategic policies and rules to reduce the impact of anthropogenic activities and climate change for this area.
Continue reading ‘A comparative accuracy of regularized and tension spline methods to estimate and model the surface water pH of Pulau Tuba, Langkawi, Kedah’The effects of temperature and pH change on the snapping sound characteristic of Alpheus edwardsii
Published 16 June 2021 Science ClosedTags: biological response, crustaceans, Indian, laboratory, multiple factors, performance, temperature
Aim: The current study undertook manipulative experiments to observe changes in snapping shrimp sound signals in relation to temperature and pH changes.
Methodology: Sounds of intertidal snapping shrimp (Alpheus edwardsii) sequentially exposed to different temperature/pH treatments manipulation for a period of 2 week each, were recorded in the laboratory and analysed. The acoustic characteristics of snapping sound signal were examined to relate to the change in temperature, pH and combination of both parameters.
Results: Our results showed that there was a significant reduction in the frequency of peak amplitude of snapping sound wave following a two week exposure to a combination of temperature and pH treatments. The frequency of snapping shrimp sound decreased by approximately 30% when exposed to a 2°C increase in temperature and a 0.7 unit decrease in pH, however, elevated temperature alone caused no significant effect on the peak frequency of snapping shrimp sound.
Interpretation: The finding suggests that following the prediction values of temperature and pH changes due to climate change in the coming century may implicate the ambient noise at habitats where snapping shrimps dominate.
Continue reading ‘The effects of temperature and pH change on the snapping sound characteristic of Alpheus edwardsii’
