In the present investigation, induction furnace (IF) steel slag as coarse aggregate with 0%, 20% and 40% replaced concrete specimens of size 150 × 150 × 150 mm was prepared as an initiative to utilize iron-rich IF steel slag. The casted concrete specimens were cured for 28 days at room temperature (28 °C) in freshwater, and the obtained compressive strength is 22.5, 24.0 and 29.2 N/mm2, respectively. The blocks were then immersed in seawater under laboratory condition for 28 days, and variation in pH was monitored at regular intervals. The composition and mineralogical phases [quartz (SiO2), iscorite (Fe7SiO10), hematite (ε-Fe2O3) and almandine (Fe3Al2Si3O10)] present in IF steel slag were identified using XRF and XRD analysis, respectively. Surface morphology and elemental composition were studied using FESEM with EDAX analysis for before and after immersion of concrete blocks in seawater. Structural bonding of concrete blocks before and after immersion was studied using FTIR analysis. Compressive strength of concrete specimens after the immersion in seawater was evaluated and compared with before immersion in seawater. This initiative will be a major support for induction furnace steel industries via economic benefits. Utilization of iron-rich IF steel slag in marine concrete can be a vital candidate for the betterment of marine ecosystem via primary production of marine resources.
Continue reading ‘Recycling of induction furnace steel slag in concrete for marine environmental applications towards ocean acidification studies’Archive Page 244
Recycling of induction furnace steel slag in concrete for marine environmental applications towards ocean acidification studies
Published 26 May 2021 Science ClosedTags: laboratory, socio-economy
Distribution and long-term change of the sea surface carbonate system in the Mozambique Channel (1963-2019)
Published 26 May 2021 Science ClosedTags: chemistry, field, Indian
Highlights
- New observations of the marine carbonate system in the Mozambique Channel.
- First evaluation of long-term trends of sea surface fCO2 and pH in the Mozambique Channel.
- The fCO2 increase and pH decrease are mainly attributed to anthropogenic CO2 uptake.
- Results suggest a strengthening of acidification trend in the Mozambique Channel since the mid-90s.
Abstract
We report new oceanic carbonate system observations obtained during two cruises conducted in January 2004 (OISO-11) and April 2019 (CLIM-EPARSES) in the Mozambique Channel and estimate the long-term trend of sea surface fugacity of CO2 (fCO2) and pH using historical data. While in January 2004 the region was a large CO2 source, the ocean was near equilibrium in April 2019. Although this region experienced a dramatic cyclone event “Idai” in March 2019 leading to low salinity and low dissolved inorganic carbon (CT) and total alkalinity (AT) concentrations in the central channel, salinity normalized AT were unchanged and CT concentrations were higher in 2019 compared to 2004 by about 12 μmol.kg-1, likely due to anthropogenic CO2 uptake over 15 years. Compared to fCO2 observations of 1963 in the channel, the oceanic fCO2 was higher in 2004/2019 by about 100 μatm, an increase close to that observed in the atmosphere (90 ppm). A part of the fCO2 increase from 1963 to 2019 (about +10 μatm) is due to the long-term ocean warming in this region (+0.011 °C.decade-1). We estimated a mean decrease of -0.087 (±0.007) pH unit between 1963 and 2019, typical of the preindustrial versus modern change in the global ocean. Using other observations in the southern part of the Mozambique Channel (around 25°S) we estimated a pH trend of -0.0129.decade-1 (±0.0042) for 1963-1995 and -0.0227.decade-1 (±0.0048) for 1995-2019 suggesting a strengthening of acidification trend in the Mozambique Channel in agreement with the anthropogenic CO2 forcing. For the recent period, these rates were confirmed by reconstructed fCO2 and pH monthly fields using a neural network model. We noted however that the pH trend in the Mozambique Channel appeared lower than previous estimates at the scale of the Indian Ocean. Based on historical atmospheric CO2 data we estimated that pH in the Mozambique Channel was about 8.18 (±0.014) in the year 1800, i.e. 0.13 higher than in 2019. The concentration of CT in the year 1800 was likely around 1915 (±10) μmol.kg-1. These results will contribute to a better understanding of the impacts of ocean acidification on coral reefs since the industrial revolution by (1) providing a reference level for the reconstruction of pH from coral core samples that were collected at different locations in this region in 2019 and (2) by informing environmental authorities aiming at preserving and protecting those threatened ecosystems.
Continue reading ‘Distribution and long-term change of the sea surface carbonate system in the Mozambique Channel (1963-2019)’Ocean acidification and carbon limitation affect photosynthetic capacity of the seagrass (Amphibolis antarctica) and its calcifying epiphytes
Published 26 May 2021 Science ClosedTags: algae, biological response, BRcommunity, calcification, chemistry, Indian, laboratory, phanerogams, photosynthesis, physiology
Amphibolis antarctica seagrass meadows, and their associated calcifying epiphytes, are abundant on Australia’s west coast, but have declined in recent years due to anthropogenic factors such as marine heatwaves, damaging fishing practices and increased turbidity resulting from eutrophication which causes light limitation. Burning fossil fuels has increased the flux of CO2 in to the ocean, lowering surface seawater pH, and making more carbon available for photosynthetic life. There are benefits of increasing CO2 for those seagrasses that are carbon limited, as this alleviates their energetic use of carbon concentrating mechanisms (CCM’S) which are less efficient, and more energy costly than passive diffusion of CO2 across cell walls. This study used pulse amplitude modulation fluorometry to quantify relative electron transport rates (rETR) at a range of pH levels both above and below current ocean pH of 8.1, and found that A. antarctica has significantly decreased rETR at pH treatments of 7.81 and 7.61. Calcifying epiphytes on A. antarctica also had a significant drop in rETR at the lower pH treatments. There was also significantly lowered rETR at higher pH treatments, likely the result of carbon limitation. These results from the lower pH tests may have profound implications for A. antarctica meadows under ocean acidification. A decline in these meadows would cause the loss of ecosystem services provided by them, such as carbon storage and sequestration, commercial fisheries and a decline the abundance of biodiversity that they support.
Continue reading ‘Ocean acidification and carbon limitation affect photosynthetic capacity of the seagrass (Amphibolis antarctica) and its calcifying epiphytes’The effect of climate change on the predatory success of sharks
Published 26 May 2021 Science ClosedTags: adaptation, biological response, chordata, otherprocess, performance, physiology, respiration, review
This literature overview focuses on how shark species, are faring with the anthropogenically induced climatic changes. The ocean is drastically affected by this, which has major implications on the aquatic life. Some effects include increasing temperature, carbon dioxide and acidity levels. This has led to shifts in the predatory success in sharks, which will only increase in severity as climate change intensifies, because changes in climate induce other changes in most aspects of the shark’s life. These can be grouped into three categories: shifts in body functions, behaviors and habitat. Some changes in body function include difficulty integrating sensory cues through reduced neuron receptor function, decreased brain/muscle aerobic potential and changes in growth/development. Behavioral changes include shifted swimming patterns, interacting with different species assemblages and prey behaviors. Lastly, habitat changes affect the shark’s ability to capture prey through increases in salinity, degradation of critical habitat and reduction in dissolved oxygen.
Continue reading ‘The effect of climate change on the predatory success of sharks’Dates: June 1, 2021
Location: United Nations Headquarters in New York or http://webtv.un.org/
The President of the General Assembly will convene a high-level thematic debate on the ocean and Sustainable Development Goal 14: Life Below Water on Tuesday, 1 June 2021, at United Nations Headquarters in New York. With the support of the Governments of Portugal and Kenya – co-hosts of the 2nd United Nations Ocean Conference, as well as H.E. Mr. Peter Thomson, Special Envoy of the Secretary-General on Oceans, this gathering will serve as a drumbeat to generate momentum towards the Conference in Lisbon, when public health safety measures allow.
Coastal and marine ecosystems provide food, livelihoods, and coastal protection to more than a billion people worldwide. The value of the ocean related economic activities are already in excess of $1.5 trillion USD annually. The abundance of our ocean and its resources is an imperative to protect, not just for the enjoyment of future generations, but for the well-being, prosperity and resilience of the present generation. Ocean acidification driven by CO2 emissions and pollution threaten marine environments and ecosystem services. A 100-150% rise in ocean acidity is projected by 2100, affecting half of all marine life. In addition, it is expected that the metric weight of plastic in the ocean will exceed the metric weight of fish by 2050 if current pollution trends continue.
It has been more than three years since the first UN Ocean Conference. With the second Conference still delayed due to the ongoing pandemic, and four SDG14 targets having matured in 2020, Member States and the international community will benefit from a progress update on the achievement of SDG14, and the ocean related goals. As such, the President of the General Assembly will convene a high-level thematic debate at United Nations Headquarters on 1 June 2021, to support the positive momentum of implementation of SDG14.
Continue reading ‘High-level debate on the ocean’Everything is everywhere: physiological responses of the Mediterranean sea and Eastern Pacific ocean Epiphyte Cobetia Sp. to varying nutrient concentration
Published 25 May 2021 Science ClosedTags: adaptation, biological response, BRcommunity, laboratory, molecular biology, nitrogen fixation, otherprocess, phanerogams, physiology, prokaryotes
Bacteria are essential in the maintenance and sustainment of marine environments (e.g., benthic systems), playing a key role in marine food webs and nutrient cycling. These microorganisms can live associated as epiphytic or endophytic populations with superior organisms with valuable ecological functions, e.g., seagrasses. Here, we isolated, identified, sequenced, and exposed two strains of the same species (i.e., identified as Cobetia sp.) from two different marine environments to different nutrient regimes using batch cultures: (1) Cobetia sp. UIB 001 from the endemic Mediterranean seagrass Posidonia oceanica and (2) Cobetia sp. 4B UA from the endemic Humboldt Current System (HCS) seagrass Heterozostera chilensis. From our physiological studies, both strains behaved as bacteria capable to cope with different nutrient and pH regimes, i.e., N, P, and Fe combined with different pH levels, both in long-term (12 days (d)) and short-term studies (4 d/96 h (h)). We showed that the isolated strains were sensitive to the N source (inorganic and organic) at low and high concentrations and low pH levels. Low availability of phosphorus (P) and Fe had a negative independent effect on growth, especially in the long-term studies. The strain UIB 001 showed a better adaptation to low nutrient concentrations, being a potential N2-fixer, reaching higher growth rates (μ) than the HCS strain. P-acquisition mechanisms were deeply investigated at the enzymatic (i.e., alkaline phosphatase activity, APA) and structural level (e.g., alkaline phosphatase D, PhoD). Finally, these results were complemented with the study of biochemical markers, i.e., reactive oxygen species (ROS). In short, we present how ecological niches (i.e., MS and HCS) might determine, select, and modify the genomic and phenotypic features of the same bacterial species (i.e., Cobetia spp.) found in different marine environments, pointing to a direct correlation between adaptability and oligotrophy of seawater.
Continue reading ‘Everything is everywhere: physiological responses of the Mediterranean sea and Eastern Pacific ocean Epiphyte Cobetia Sp. to varying nutrient concentration’Down in arms: marine climate stress inhibits growth and calcification of regenerating Asterias forbesi (Echinodermata: Asteroidea) arms
Published 25 May 2021 Science ClosedTags: biological response, calcification, echinoderms, laboratory, morphology, multiple factors, North Atlantic, performance, physiology, temperature
Anthropogenic CO2 is changing the pCO2, temperature, and carbonate chemistry of seawater. These processes are termed ocean acidification (OA) and ocean warming. Previous studies suggest two opposing hypotheses for the way in which marine climate stress will influence echinoderm calcification, metabolic efficiency, and reproduction: either an additive or synergistic effect. Sea stars have a regenerative capacity, which may be particularly affected while rebuilding calcium carbonate arm structures, leading to changes in arm growth and calcification. In this study, Asterias forbesi were exposed to ocean water of either ambient, high temperature, high pCO2, or high temperature and high pCO2 for 60 days, and the regeneration length of the amputated arm was measured weekly. Ocean acidification conditions (pCO2 ~1180 μatm) had a negative impact on regenerated arm length, and an increase in temperature of +4°C above ambient conditions (Fall, Southern Gulf of Maine) had a positive effect on regenerated arm length, but the additive effects of these two factors resulted in smaller regenerated arms compared to ambient conditions. Sea stars regenerating under high pCO2 exhibited a lower proportion of calcified mass, which could be the result of a more energetically demanding calcification process associated with marine climate stress. These results indicate that A. forbesi calcification is sensitive to increasing pCO2, and that climate change will have an overall net negative effect on sea star arm regeneration. Such effects could translate into lower predation rates by a key consumer in the temperate rocky intertidal of North America.
Continue reading ‘Down in arms: marine climate stress inhibits growth and calcification of regenerating Asterias forbesi (Echinodermata: Asteroidea) arms’Chapter 21 – Coral reefs: globally predicted climate change impact mitigation, mediated by the marine flora and their ecosystem connectivity, with a case study from Neil Island (the Andamans)
Published 25 May 2021 Science ClosedTags: biological response, BRcommunity, corals, education, Indian, mitigation, phanerogams, review
Mangrove–coral habitat is characterized by heterogeneity in the physical environment that allows it to be out of equilibrium with open ocean conditions, resulting in differentiation of local physical, chemical, and biological attributes. This chapter highlights how some mangrove habitats can act as alternate refuges for corals during climate threats, particularly increasing seawater temperature, high levels of solar radiation, and ocean acidification. Coastal ecosystems are interconnected and so any change in one coastal ecosystem will have an impact on other ecosystems. Similarly, recovery and resilience of coastal ecosystems like coral reefs depend on the degree of connectivity and support from the neighboring coastal ecosystems such as seagrass beds. Therefore, healthy seagrass beds are especially vital for the resilience of coral reefs, as they support the coral communities to adapt to climate change impacts. Corals compete with seaweeds for space on the reef. When corals are healthy, the coral–seaweed competition reaches a balance. But, if the corals are not able to do well because of smothering like eutrophication or climate change induced impacts, then seaweeds can take over. Our study results suggest that coral reefs may become increasingly susceptible to seaweed proliferation under ocean acidification. Though the functional links of mangroves, seagrasses, and coral reefs have been studied, their conservation and management aspects due to connectivity and their importance for humans is yet to be understood. Importance of interconnectivity in biodiversity richness is illustrated by presenting the bioresource availability in the existing heterogeneous coral reef, seagrass, and mangrove habitats of the Neil Island, the Andamans and studies on the interactions among them are essential for conservation and management of such precious ecosystems.
Continue reading ‘Chapter 21 – Coral reefs: globally predicted climate change impact mitigation, mediated by the marine flora and their ecosystem connectivity, with a case study from Neil Island (the Andamans)’Date: 29 September – 4 October
Location: Panarea (Aeolian Islands, Italy)
Teaching program:
Topics will cover the geological characteristics of this unique active volcanic area, its biological components adapted, in the local vents systems, to natural oceanacidification, hydrothermal fluids characterization, multi-parameter monitoring techniques and definition of experimental protocols for the sampling and study of the planktonic and benthonic ecosystems, with special focus on assessing effects of climate change and ocean acidification on organisms, communities andhabitat. Special attention will be addressed to Posidonia oceanica meadowsin some of the vent’s systems.
During the diving activities, students will practice bottom and habitat mapping, gas and water sampling, visual census techniques on benthos, Posidonia oceanica meadow’s charaterization, and in situ measurements with reference to the theoretical lessons.
Lessons and practical laboratories, as well as dive briefings, will be provided in English.
A participation certificate will be issued and the scientific dives will be considered for the release of a European Scientific Diver license and an Advance European Scientific Diver license.
…
How to apply:
Request and send the application form, plus a CV, with specific reference to your diving experience, at:
scuolasubpanarea@gmail.com
Application deadline: 31 August 2021
Continue reading ‘5° Scientific diving summer school’When site matters: metabolic and behavioural responses of adult sea urchins from different environments during long-term exposure to seawater acidification
Published 24 May 2021 Science ClosedTags: adaptation, biological response, echinoderms, laboratory, Mediterranean, otherprocess, performance, physiology, respiration
Highlights
- Long-term exposure to reduced pH was performed with sea urchins from different sites
- Seawater acidification affected sea urchin physiological and behavioral parameters
- The effects of reduced pH were less evident in lagoon sea urchins than in coastal ones
- Sea urchin responses change over time possibly related to the gametogenic cycle
- Overall results suggested adaptability of P. lividus to future pH levels
Abstract
CO2-driven ocean acidification affects many aspects of sea urchin biology. However, even in the same species, OA effects are often not univocal due to non-uniform exposure setups or different ecological history of the experimental specimens. In the present work, two groups of adult sea urchins Paracentrotus lividus from different environments (the Lagoon of Venice and a coastal area in the Northern Adriatic Sea) were exposed to OA in a long-term exposure. Animals were maintained for six months in both natural seawater (pHT 8.04) and end-of-the-century predicted condition (-0.4 units pH). Monthly, physiological (respiration rate, ammonia excretion, O:N ratio) and behavioural (righting, sheltering) endpoints were investigated. Both pH and time of exposure significantly influenced sea urchin responses, but differences between sites were highlighted, particularly in the first months. Under reduced pH, ammonia excretion increased and O:N decreased in coastal specimens. Righting and sheltering were impaired in coastal animals, whereas only righting decreased in lagoon ones. These findings suggested a higher adaptation ability in sea urchins from a more variable environment. Interestingly, as the exposure continued, animals from both sites were able to acclimate. Results revealed plasticity in the physiological and behavioural responses of sea urchins under future predicted OA conditions.
Continue reading ‘When site matters: metabolic and behavioural responses of adult sea urchins from different environments during long-term exposure to seawater acidification’Marginal populations show physiological adaptations and resilience to future climatic changes across a North Atlantic distribution
Published 24 May 2021 Science ClosedTags: algae, biological response, BRcommunity, calcification, laboratory, morphology, multiple factors, North Atlantic, physiology, primary production, respiration, temperature
Highlights
- Elevated temperature has a greater effect on calcifying algae populations than pCO2.
- Southern and central populations already live close to their thermal and stress limits, while northern populations appear as the most resilient to environmental changes.
- Light calcification is the most valuable physiological process and is prioritized in populations throughout the geographical gradient in the NE Atlantic.
Abstract
Rising levels of anthropogenic carbon dioxide (CO2) in the atmosphere over the past several decades has resulted in a changing climate and is projected to further fuel global climate change in future centuries. Key components of climate change in the ocean are ocean acidification (decreasing pH and carbonate ion concentration [ CO32- ]) and rising sea surface temperatures. While several studies have investigated the effect of these climatic changes on a single population, very few studies have addressed effects on populations living at the margins of their species distribution and the full distributional range. This gap in knowledge impedes the determination of detailed predictions for most species’ futures. Over the course of four months, we investigated physiological changes (primary production, respiration, calcification and growth rates) of 6 populations of the intertidal ecosystem engineer and articulated coralline alga Corallina officinalis to future climatic conditions (low pH (∼7.8); T + 3 °C; as well as the combination of low pH and T + 3 °C). The populations (n = 2 per geographical location) represent the northern (Iceland) and southern (Spain) margins, as well as the centre (England) of the species distribution in the NE Atlantic. Here, we show that southern and central populations are already living closer to their thermal and stress limits, while Northern populations appear to be the most resilient to environmental changes. We present data confirming light calcification to be the most valuable physiological process which is prioritized in populations throughout the geographical gradient in the NE Atlantic. We found elevated temperature to have a greater effect on populations than pCO2. Investigating and monitoring organism physiology and structure under these extreme environmental conditions provides important information to predict their acclimatisation and resilience to future environmental conditions and potential changes in their distribution.
Kolzenburg R., D’Amore F., McCoy S. J. & Ragazzola F., 2021. Marginal populations show physiological adaptations and resilience to future climatic changes across a North Atlantic distribution. Environmental and Experimental Botany: 104522. doi: 10.1016/j.envexpbot.2021.104522. Article (subscription required).
The combined effects of climate change stressors and predatory cues on a mussel species
Published 24 May 2021 Science ClosedTags: biological response, laboratory, mollusks, mortality, multiple factors, otherprocess, performance, physiology, respiration, South Pacific, temperature
Highlights
- We measured and compared traits at sub-organismal and organismal level.
- Temperature, pH and predator cues affected the mussels’ traits.
- Largest mussels were found at 15 °C (control) in presence of predators.
- Crab cues increased mussel’s wet mass and calcification rate.
Abstract
In order to make adequate projections on the consequences of climate change stressors on marine organisms, it is important to know how impacts of these stressors are affected by the presence of other species. Here we assessed the direct effects of ocean warming (OW) and acidification (OA) along with non-consumptive effects (NCEs) of a predatory crab and/or a predatory snail on the habitat-forming mussel Perumytilus purpuratus. Mussels were exposed for 10–14 weeks to contrasting pCO2 (500 and 1400 μatm) and temperature (15 and 20 °C) levels, in the presence/absence of cues from one or two predator species. We compared mussel traits at sub-organismal (nutritional status, metabolic capacity-ATP production-, cell stress condition via HSP70 expression) and organismal (survival, oxygen consumption, growth, byssus biogenesis, clearance rates, aggregation) levels. OA increased the mussels’ oxygen consumption; and OA combined with OW increased ATP demand and the use of carbohydrate reserves. Mussels at present-day pCO2 levels had the highest protein content. Under OW the predatory snail cues induced the highest cell stress condition on the mussels. Temperature, predator cues and the interaction between them affected mussel growth. Mussels grew larger at the control temperature (15 °C) when crab and snail cues were present. Mussel wet mass and calcification were affected by predator cues; with highest values recorded in crab cue presence (isolated or combined with snail cues). In the absence of predator cues in the trails, byssus biogenesis was affected by OA, OW and the OA × OW and OA × predator cues interactions. At present-day pCO2 levels, more byssus was recorded with snail than with crab cues. Clearance rates were affected by temperature, pCO2 and the interaction between them. The investigated stressors had no effects on mussel aggregation. We conclude that OA, OW and the NCEs may lead to neutral, positive or negative consequences for mussels.
Continue reading ‘The combined effects of climate change stressors and predatory cues on a mussel species’Marine biological laboratory tests first tropical seaweed farm in Puerto Rico
Published 24 May 2021 Web sites and blogs Closed
Ateam of researchers led by Loretta Roberson, associate scientist at the University of Chicago-affiliated Marine Biological Laboratory in Woods Hole, Massachusetts, has installed the first seaweed farm in Puerto Rico and U.S. tropical waters.
The farm is intended to test a system for offshore cultivation of tropical seaweeds to support large-scale production of biomass for biofuels and other products.
“Puerto Rico has stable warm temperatures and ample sunlight year-round, as well as a wide range of exposure to prevailing winds and waves,” said Roberson, the lead principal investigator on this research effort. “These conditions make its southern coastline an ideal test bed for exploring how environmental conditions influence the biological, physiological, and chemical properties of cultivated macroalgae, as well as the impact of seaweed farms on the surrounding environment.”
Additional farms are being tested in Florida and Belize to assess how easy it is to scale up the size of farm operations.
Scientists are interested in seaweed farms because such farms may be able to reduce ocean acidification by pulling carbon dioxide out of the water, as well as pollutants like excess nitrogen and phosphorus from agricultural runoff.
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Continue reading ‘Marine biological laboratory tests first tropical seaweed farm in Puerto Rico’CCC, RARE hold first of three webinars on climate change, coastal, marine ecosystems
Published 24 May 2021 Events , Presentations , Web sites and blogs ClosedQUEZON CITY — The Climate Change Commission (CCC) and its National Panel of Technical Experts (NPTE), in partnership with RARE Philippines and the UP Marine Science Institute (UP-MSI), successfully convened the first of the three-part online webinar series on the effects of climate change on coastal and marine ecosystems.
The virtual webinar, organized in celebration of the Month of the Ocean, gathered more than 500 participants, consisting of members of the academe and research institutions in the Philippines and abroad, government agencies, policymakers, and organizations leading community-based initiatives, to build awareness on the current and future state of marine and coastal ecosystems in the Philippines.
The said webinar featured presentations from NPTE members Dr. Laura T. David and Ms. Lourdes Tibig, and Dr. Caroline Marie B. Jaraula, Assistant Professor from UP-MSI on their studies on historical climate data and evolution of marine and coastal ecosystems and the highlights of ocean acidification as reported on the IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC).
Continue reading ‘CCC, RARE hold first of three webinars on climate change, coastal, marine ecosystems’NCEI will host a remote-only workshop this coming May to seek your feedback in terms of the Ocean Acidification Data Stewardship (OADS) Project data discovery and access interface: https://www.nodc.noaa.gov/oads/stewardship/data_assets.html. The collected feedback will be used to design our new website.
The workshop will be 1 – 3PM (Eastern Time) on May 28, 2021 (Friday), with a pre-workshop assignment.
To register, please follow this link:
https://forms.gle/LuqF9a9YhxMJBBJG7 (Google Form).
Continue reading ‘Upcoming NOAA OAP data discovery and access workshop’We are looking for an MSc candidate to join our multi-disciplinary research team to examine multi-stressor impacts on juvenile shellfish. More specifically, the project will involve the following objectives:
1. Investigate impacts of coinciding climate stressors (e.g. OA, warming) on biological (e.g. growth), physiological (e.g. energetics), and genomic (e.g. gene expression) responses of juvenile shellfish.
2. Compare responses under static and variable stressor conditions to determine whether long-term exposure or acute exposure events (e.g. upwelling events, heatwaves) pose a greater threat to species’ fitness and survival.
3. Investigate whether co-culture of shellfish with macroalgae or sea cucumbers can mitigate climate change impacts and improve resiliency of the aquaculture industry.
The preferred candidate would have:
- Experience/knowledge in wet lab plumbing and tank set up.
- Experience/knowledge in conducting research on marine invertebrates.
- Experience/knowledge in ocean acidification or climate change research.
- Desire to work in a multidisciplinary team.
- Ability to work independently.
- A strong undergraduate track record, including an honour’s degree.
- Good problem-solving skills and resourcefulness.
- A positive attitude and strong work ethic.
The position would start Aug/Sep 2021. The candidate would be based at Fisheries and Oceans Canada’s Pacific Biological Station in Nanaimo, but the MSc degree would be through the University of Victoria. Interested applicants should send an expression of interest letter, recent CV, and undergraduate transcripts to:
Dr. Chris Pearce, Chris.Pearce@dfo-mpo.gc.ca by June 15, 2021.
Continue reading ‘MSc opportunity in ocean acidification (OA) research’Acidification des océans : effets sur les écosystèmes et l’économie maritime (in French)
Published 21 May 2021 Events ClosedINFORMATIONS PRATIQUES
17 juin 2021
De 09h15 à 15h30
Événement exclusivement en ligne
Inscription obligatoire, formulaire si dessous
CONTACT FRB
Claire Salomon
Qu’est-ce que l’acidification des océans ? Quels sont ses effets sur les écosystèmes marins et l’économie maritime, notamment la pêche et la conchyliculture ? Comment agir et adapter les pratiques pour assurer la pérennité des métiers liés aux produits de la mer?
L’acidité des océans a augmenté d’environ 26 % depuis l’époque préindustrielle. Ce phénomène causé par l’augmentation des rejets de CO2 liés à la combustion de combustibles fossiles et autres activités humaines est préjudiciable à de nombreuses espèces marines. Parmi elles, on retrouve les coraux ou encore d’autres espèces dont le squelette ou la coquille se composent de carbonate de calcium. Ces impacts, associés à l’augmentation de la température de la haute mer, à la stratification et à la désoxygénation des eaux souterraines risquent d’affecter la structure globale et le fonctionnement des écosystèmes marins entraînant ainsi des conséquences de grande portée et des impacts socio-économiques potentiellement profonds.
De nombreuses questions subsistent et les chercheurs s’interrogent notamment sur le potentiel des organismes marins à s’adapter à l’acidification des océans et aux implications plus larges pour les écosystèmes océaniques. Mais quels sont ses effets sur les écosystèmes marins et par conséquent sur l’économie maritime, notamment la pêche et la conchyliculture ? Comment agir et adapter les pratiques pour assurer la pérennité des métiers liés aux produits de la mer?
Continue reading ‘Acidification des océans : effets sur les écosystèmes et l’économie maritime (in French)’Effects of ocean acidification on the growth and biochemical composition of a green alga (Ulva fasciata) and its associated microbiota
Published 21 May 2021 Science ClosedTags: algae, biological response, BRcommunity, chemistry, growth, laboratory, molecular biology, photosynthesis, physiology, prokaryotes
In marine ecosystems, fluctuations in surface-seawater carbon dioxide (CO2), significantly influence the whole metabolism of marine algae, especially during the early stages of macroalgal development. In this study, the response of the green alga Ulva fasciata for elevating ocean acidification was investigated using four levels of pCO2 ∼280, 550, 750 and 1050 µatm. Maximum growth rate (6.6 % day-1), protein (32.43 %DW) and pigment (2.9 mg/g) accumulation were observed at pCO2-550 with an increase of ∼2-fold compared to control. On the other hand, lipid and carbohydrate contents recorded their maximum production (4.23 and 46.96 %DW, respectively) at pCO2-750 while control showed 3.70 and 42.37 %DW, respectively. SDS-PAGE showed the presence of unique bands in response to pCO2, especially at 550 µatm. Dominant associated bacteria was shifted from Halomonas hydrothermalis of control to Vibrio toranzoniae at pCO2-1050. These findings suggest that ocean acidification at 550 µatm might impose noticeable effects on growth, protein, pigments, and protein profile of U. fasciata, which could be a good source for fish farming. While, pCO2-750 was recommended for energetic purpose, due to its high lipid and carbohydrate contents.
Continue reading ‘Effects of ocean acidification on the growth and biochemical composition of a green alga (Ulva fasciata) and its associated microbiota’Aragonite saturation state in a continental shelf (Gulf of Cádiz, SW Iberian Peninsula): evidences of acidification in the coastal area
Published 21 May 2021 Science ClosedTags: chemistry, field, North Atlantic
Highlights
- Hydrodinamical conditions determine the spatial variability of ΩAr in surface waters
- Biological processes control ΩAr changes in SML
- In deep waters, the lowest ΩAr values are related to NACWP
- ΩAr and pH have decreased in the coastal areas between 2006 and 2016
Abstract
The spatiotemporal variability of aragonite saturation state (ΩAr) has been studied in the eastern shelf of the Gulf of Cádiz (GoC) (SW Iberian Peninsula). The study was carried out during the years 2014 and 2016 aboard twelve oceanographic cruises, along three or five transects, located between Cape Trafalgar and the Guadiana River. The GoC exhibited oversaturated of calcium carbonate with ΩAr mean values of 2.68 ± 0.30 in surface and 2.05 ± 0.15 in deep waters. pH, total alkalinity (TA), calcium concentration (Ca2+) and ΩAr showed a high variability within the surface mixed layer (SML, z < 100 m). Biological activity seemed to be the main process to determine the ΩAr variability in the SML, revealing a greater importance than temperature, mixing or air-sea processes. The buffer factors of the CO2 system in the GoC have been estimated in the SML waters, and they are related with the biological activity and the temperature changes. A decrease of pH and ΩAr in this SML with depth was observed, due to the increase of the respiratory processes. In deep waters (z > 100 m), TA and Ca2+ concentration presented a conservative behaviour related to the distribution of the different water masses located in the GoC. The vertical variation of ΩAr also depends on the degree of mineralization of these water masses, obtaining the maximum values in the Subtropical North Atlantic Central Water (100 – 200 m), minimum values in the Subpolar North Atlantic Central Water (about 400 m), and intermediate values associated to the presence of the Mediterranean Water (> 500 m). Results showed a significative acidification of the coastal areas, for those depths lower than 100 m from 2006 to 2016, with a mean decrease of pH and ΩAr of -0.0089 and -0.0552 yr-1, respectively.
Continue reading ‘Aragonite saturation state in a continental shelf (Gulf of Cádiz, SW Iberian Peninsula): evidences of acidification in the coastal area’CFOS researcher Natalie Monacci presents the “Ocean Acidification Research Center” as part of the 2021 Arctic Research Open House.
Continue reading ‘Ocean Acidification Research Center (text & video)’
