Most laboratory experiments examining the effect of ocean acidification on marine organisms use stable pH/pCO2 treatments based on average projections for the open ocean. However, pH/pCO2 levels vary spatially and temporally in marine environments, and this variation can affect organism responses to pH/pCO2. On coral reefs, diel pH/pCO2 variability at the individual reef scale has been reported in a few studies, but variation among microhabitats within a reef remains poorly understood. This study determined the pH/pCO2 variability of three different reefs, and three contrasting coral reef microhabitats (dominated by hard coral, soft coral, or open substrate) within each reef. Three SeaFET pH loggers were deployed simultaneously at the three microhabitats within a reef over a 9-day period. This was repeated at three different reefs around the Lizard Island lagoon. The loggers recorded pHT and temperature every 5 min. Water samples were collected from each microhabitat during four points of the tidal cycle (high, low, rising, and falling) and analysed for total alkalinity and dissolved inorganic carbon. The data show a clear diel pCO2 cycle, increasing overnight and decreasing during the day, in association with photosynthesis and respiration cycles. Diel pCO2 differed more between reefs than between microhabitats within reefs. Variation between reefs was most likely influenced by water flow, with the more protected (low flow) reefs experiencing a greater range in pCO2 (Δ 250 μatm) than the exposed (high flow) reefs (Δ 116 μatm). These results add to a growing body of the literature on the diel variation of pCO2 of shallow, nearshore environments and suggest that when projecting future pCO2 levels, it is important to consider reef metabolism as well as physical and hydrodynamic factors.
Archive for July, 2020
Diel pCO2 variation among coral reefs and microhabitats at Lizard Island, Great Barrier Reef
Published 27 July 2020 Science ClosedTags: biogeochemistry, chemistry, field, South Pacific
Are long-term growth responses to elevated pCO2 sex-specific in fish?
Published 27 July 2020 Science ClosedTags: biological response, fish, laboratory, morphology, multiple factors, North Atlantic, reproduction, temperature
Whether marine fish will grow differently in future high pCO2 environments remains surprisingly uncertain. Long-term and whole-life cycle effects are particularly unknown, because such experiments are logistically challenging, space demanding, exclude long-lived species, and require controlled, restricted feeding regimes—otherwise increased consumption could mask potential growth effects. Here, we report on repeated, long-term, food-controlled experiments to rear large populations (>4,000 individuals total) of the experimental model and ecologically important forage fish Menidia menidia (Atlantic silverside) under contrasting temperature (17°, 24°, and 28°C) and pCO2 conditions (450 vs. ~2,200 μatm) from fertilization to ~ a third of this annual species’ life span. Quantile analyses of trait distributions showed mostly negative effects of high pCO2 on long-term growth. At 17°C and 28°C, but not at 24°C, high pCO2 fish were significantly shorter [17°C: -5 to -9%; 28°C: -3%] and weighed less [17°C: -6 to -18%; 28°C: -8%] compared to ambient pCO2 fish. Reductions in fish weight were smaller than in length, which is why high pCO2 fish at 17°C consistently exhibited a higher Fulton’s k (weight/length ratio). Notably, it took more than 100 days of rearing for statistically significant length differences to emerge between treatment populations, showing that cumulative, long-term CO2 effects could exist elsewhere but are easily missed by short experiments. Long-term rearing had another benefit: it allowed sexing the surviving fish, thereby enabling rare sex-specific analyses of trait distributions under contrasting CO2 environments. We found that female silversides grew faster than males, but there was no interaction between CO2 and sex, indicating that males and females were similarly affected by high pCO2. Because Atlantic silversides are known to exhibit temperature-dependent sex determination, we also analyzed sex ratios, revealing no evidence for CO2-dependent sex determination in this species.
Continue reading ‘Are long-term growth responses to elevated pCO2 sex-specific in fish?’
Actes du Colloque: acidification des océans : conséquences sur les écosystèmes et les activités humaines (in French)
Published 24 July 2020 Newsletters and reports ClosedQu’est-ce que l’acidification des océans ? Quelles en seront les conséquences potentielles sur les activités économiques ? Comment réagir ? Telles sont les questions qui ont été abordées lors de cette journée qui a rassemblé scientifiques, acteurs professionnels et associations.
Organisé par la FRB et le MTES en partenariat avec l’Ifremer, ce colloque s’appuie sur les expériences de terrain et sur les résultats des projets scientifiques financés par le ministère de l’écologie dans le cadre du programme de recherche “Acidification des océans”.
Multimarker response of the ragworm Hediste diversicolor (Polychaeta) to seawater acidification derived from potential CO2 leakage from the CCS sub-seabed storage site in the Baltic Sea
Published 24 July 2020 Science ClosedTags: annelids, Baltic, biological response, laboratory, morphology, physiology
Highlights
• Seawater acidification affected physiological traits, LPO and growth of Hediste diversicolor from the southern Baltic Sea.
• Moderate hypercapnia (pH 7.5–7.1) induced an increase in metabolic rate of the polychaetes and a decline of their growth.
• The most acidic environment (pH 6.5) caused metabolic slow down limiting energy turnover and growth.
• Reduced seawater pH did not impact energetic reserves so, proteins were not used as substrates under acidic conditions.
• High tolerance of the ragworms to hypercapnia stems probably from pre-adaptation to natural pH reduction events in sediment.
Abstract
Sub-seabed Carbon Capture and Storage (CCS) is conceived as safe technology with small likehood of negative consequences to the marine ecosystem but CO2 escape from geological reservoir still poses potential environmental risk. If carbon dioxide leakage occurs carbonate chemistry in the bottom zone and sessile benthic fauna are expected to be the most likely affected by elevated levels of CO2. Though generic mechanisms and advisory conclusions on the presumable impact of increased acidity on the marine benthic biota were formulated they cannot be applied uniformly across different environmental variables as specific local conditions may alter biological response to hypercapnia. A laboratory experiment was conducted to quantify the effects of medium-term (8 wk) exposure to seawater acidification (pH 7.7–6.5) on the infaunal polychaete Hediste diversicolor from the southern Baltic Sea using multimarker approach. Under moderate acidity (pH 7.5 and 7.1) the polychaetes were found to increase metabolic rate (by 13.4% and 19.6%, respectively) and reduce their body mass (by 8.1% and 5.5% wet weight, respectively and by 6.1% and 3.0% dry weight, respectively) whilst enhancing synthesis of antioxidant malondialdehyde (by 22.8% and 65.3%, respectively). In the most acidic environment (pH 6.5) the ragworms showed overall metabolic slow down (by 34.8%) and impaired growth (e.g. by 10.2% for length of the first three segments) indicative of low vulnerability to hypercapnia. High implicit tolerance of the polychaetes to increased acidity in the environment stems inevitably from a certain level of pre-adaptation to pH reduction events which occur in organic-rich stratified sediments due to intense aerobic biomineralization leading often to oxygen depletion and formation of toxic hydrogen sulphide. Acidification did not affect energetic reserves suggesting that costs of acid-base maintenance were covered mainly from assimilated food and that proteins were not used as metabolic substrates.
Oxidative stress and antioxidant defence responses in two marine copepods in a high CO2 experiment
Published 24 July 2020 Science ClosedTags: abundance, Arctic, biological response, chemistry, field, laboratory, mesocosms, North Atlantic, otherprocess, physiology, phytoplankton, zooplankton
Highlights
• Temora revealed higher oxidative stress than Calanus in response to treatment CO2
• Food and predators may have controlled the stress levels, both in fjord and experiment
• Calanus migrating deeper than Temora seems more robust against environmental fluctuations
Abstract
We collected samples for oxidative stress and antioxidants in a high CO2 mesocosm experiment for two weeks, focussing on two common crustacean copepods Calanus finmarchicus and Temora longicornis. The samples were collected during a field experiment campaign studying responses of plankton communities to future ocean acidification (OA), off the Norwegian coast south of Bergen. The main results showed that there were species-specific differences between Temora and Calanus, especially in antioxidant defences (glutathione system) and oxidative stress (lipid peroxidation and reduced:oxidised glutathione ratio). Regular monitoring of chlorophyll a and jellyfish abundances taking place during the field campaign revealed that both chl a and predators may have affected the eco-physiological response. Antioxidant and oxidative stress levels are known to respond sensitively to both the food quality and quantity and the predator pressure, apart from environmental (i.e., abiotic) changes. Calanus was more robust towards OA, perhaps due to its high tolerance to a wide range of vertical physical-chemical conditions. Both top-down and bottom-up factors seem to play a role for the outcome of copepod responses to future ocean acidification.
Physiological feeding rates and cilia suppression in blue mussels (Mytilus edulis) with increased levels of dissolved carbon dioxide
Published 23 July 2020 Science ClosedTags: biological response, chemistry, field, laboratory, mollusks, North Atlantic, physiology
Highlights
• Increase carbon dioxide decreases cilia beat frequency for blue mussel.
• Ocean acidification decreased clearance rates in blue mussels.
• Ocean acidification resulted in changes in particle selection for marine bivalves.
Abstract
Gills of marine bivalves, the organs that mediate water flow for feeding and other physiological functions, are exposed to increasing levels of carbon dioxide (CO2) in seawater, in response to ocean acidification (OA). We examined the effects of elevated dissolved CO2 upon filtration and feeding behavior of the blue mussel, Mytilus edulis, under field conditions and in laboratory studies. We further investigated possible changes in cilia beat function in response to elevated dissolved CO2. Physiological filtration and feeding variables measured; included clearance, filtration, organic ingestion, and assimilation rates and selection efficiency, which decreased with increasing CO2. Absorption efficiency was not affected by dissolved CO2. Cilia beat frequency declined in excised lateral cilia (lc) exposed to increasing CO2 levels, which appears to account for decreased clearance rates observed in field and laboratory experiments. Our data suggest that under conditions of increased CO2 blue mussels will experience changes in physiological filtration, feeding rates, and cilia beat function that could have consequences for fitness and performance.
Upwelling intensity modulates the fitness and physiological performance of coastal species: implications for the aquaculture of the scallop Argopecten purpuratus in the Humboldt Current System
Published 23 July 2020 Science ClosedTags: biological response, calcification, chemistry, field, growth, laboratory, mollusks, morphology, mortality, North Atlantic, physiology
Highlights
• The activity of PLV upwelling centre affected the environmental variability of Tongoy Bay.
• Stronger upwelling generated more acidic and low oxygen environmental conditions.
• A. purpuratus showed biological mechanisms to handle acidified and hypoxic conditions.
• More intense upwelling events decreased the survivorship of A. purpuratus.
• A potential upwelling intensification will negatively impact the scallop aquaculture.
Abstract
Understanding how marine species cope with the natural environmental variability of their native habitats will provide significant information about their sensitivity to the potential environmental changes driven by climate change. In particular, marine species inhabiting upwelling ecosystems are experiencing low seawater temperatures, as well as, acidic and low oxygen conditions as a consequence of the nature of the deep upwelled waters. Our study is focused on one of the most important socio-economical resources of the Humboldt Current System (HCS): the scallop Argopecten purpuratus which has been historically subjected to intensive aquaculture in areas influenced by upwelling processes. Here, a long-term field experiment was performed to understand how tolerant and well-locally-adapted is A. purpuratus to upwelling conditions by studying a set of fitness, physiological, and biomineralogical traits. Stronger upwelling generated a minor water column stratification, with lower temperatures, pH, and oxygen conditions. On the contrary, as upwelling weakened, temperature, pH, and oxygen availability increased. Finally, upwelling intensity also determined the number, duration, and intensity of the cooling and de-oxygenation events occurring in A. purpuratus habitat, as well as, the food availability (chlorophyll-a concentration, Chl-a). Physiologically, A. purpuratus was able to cope with stressful environmental conditions imposed by higher upwelling intensities by enhancing its metabolic and calcification rates, as well, producing higher concentrations of the shell organic matter under stronger upwelling conditions. However, these physiological changes impacted the total energy budget, which was highly dependent on Chl-a concentration, revealing traits trade-offs with significant fitness costs (higher mortalities emerged when longer and more intense upwelling events succeed). Our study increases the knowledge about the physiological performance and tolerance of this important resource to the ocean acidification and ocean-deoxygenation imposed by variable upwelling intensities, as well as, its potential vulnerability under future changing conditions driven by a potential upwelling intensification.
Amelioration of ocean acidification and warming effects through physiological buffering of a macroalgae
Published 22 July 2020 Science ClosedTags: algae, biological response, calcification, communityMF, laboratory, morphology, multiple factors, photosynthesis, protists, respiration, temperature
Concurrent anthropogenic global climate change and ocean acidification are expected to have a negative impact on calcifying marine organisms. While knowledge of biological responses of organisms to oceanic stress has emerged from single‐species experiments, these do not capture ecologically relevant scenarios where the potential for multi‐organism physiological interactions is assessed. Marine algae provide an interesting case study, as their photosynthetic activity elevates pH in the surrounding microenvironment, potentially buffering more acidic conditions for associated epiphytes. We present findings that indicate increased tolerance of an important epiphytic foraminifera, Marginopora vertebralis , to the effects of increased temperature (±3°C) and p CO2 (~1,000 µatm) when associated with its common algal host, Laurencia intricata . Specimens of M. vertebralis were incubated for 15 days in flow‐through aquaria simulating current and end‐of‐century temperature and pH conditions. Physiological measures of growth (change in wet weight), calcification (measured change in total alkalinity in closed bottles), photochemical efficiency (Fv/Fm ), total chlorophyll, photosynthesis (oxygen flux), and respiration were determined. When incubated in isolation, M. vertebralis exhibited reduced growth in end‐of‐century projections of ocean acidification conditions, while calcification rates were lowest in the high‐temperature, low‐pH treatment. Interestingly, association with L. intricata ameliorated these stress effects with the growth and calcification rates of M. vertebralis being similar to those observed in ambient conditions. Total chlorophyll levels in M. vertebralis decreased when in association with L. intricata , while maximum photochemical efficiency increased in ambient conditions. Net production estimates remained similar between M. vertebralis in isolation and in association with L. intricata , although both production and respiration rates of M. vertebralis were significantly higher when associated with L. intricata . These results indicate that the association with L. intricata increases the resilience of M. vertebralis to climate change stress, providing one of the first examples of physiological buffering by a marine alga that can ameliorate the negative effects of changing ocean conditions.
Researcher examines future effects of climate change on Sitka’s herring
Published 22 July 2020 Media coverage Closed
Lauren Bell (photographed in March 2020) kneels over one of her many seaweed plants growing in the basement of the Sitka Sound Science Center. Bell spent the last two winters in the center’s basement, studying how warmer, more acidic waters may affect marine organisms in Sitka Sound in the future (KCAW/Rose)
Predicting the future is hard, unless you’ve got a crystal ball. In the basement of the Sitka Sound Science Center, a researcher has designed an experiment to study the future of ocean acidification, and her “crystal ball” is herring.
In Part 2 of KCAW’s two-part story on the 2020 herring season in Sitka Sound, Katherine Rose visits the lab of doctoral researcher Lauren Bell, as she explores possible futures for our oceans, and one of its most important resources.
Lauren Bell stands in about an inch of water, hovering over one of over twenty tanks in the basement of the Sitka Sound Science Center. The equipment used in this experiment is loud, and artificial sunlight bounces off Bell’s face as she tells me about the different types of seaweed she’s growing.
Continue reading ‘Researcher examines future effects of climate change on Sitka’s herring’
High CO2 concentration and iron availability determine the metabolic inventory in an Emiliania huxleyi‐dominated phytoplankton community
Published 22 July 2020 Science ClosedTags: biological response, laboratory, multiple factors, nutrients, physiology, phytoplankton
Ocean acidification (OA), a consequence of anthropogenic carbon dioxide (CO2) emissions, strongly impacts marine ecosystems. OA also influences iron (Fe) solubility, affecting biogeochemical and ecological processes. We investigated the interactive effects of CO2 and Fe availability on the metabolome response of a natural phytoplankton community. Using mesocosms we exposed phytoplankton to ambient (390 μatm) or future CO2 levels predicted for the year 2100 (900 μatm), combined with ambient (4.5 nM) or high (12 nM) dissolved iron (dFe). By integrating over the whole phytoplankton community, we assigned functional changes based on altered metabolite concentrations. Our study revealed the complexity of phytoplankton metabolism. Metabolic profiles showed three stages in response to treatments and phytoplankton dynamics. Metabolome changes were related to the plankton group contributing respective metabolites, explaining bloom decline and community succession. CO2 and Fe affected metabolic profiles. Most saccharides, fatty acids, amino acids, and many sterols significantly correlated with the high dFe treatment at ambient p CO2. High CO2 lowered the abundance of many metabolites irrespective of Fe. However, sugar alcohols accumulated, indicating potential stress. We demonstrate that not only altered species composition, but also changes in the metabolic landscape affecting the plankton community, may change as a consequence of future high‐CO2 oceans.
Biogeography of ocean acidification: differential field performance of transplanted mussels to upwelling-driven variation in carbonate chemistry
Published 22 July 2020 Science ClosedTags: abundance, biological response, chemistry, field, individualmodeling, laboratory, modeling, mollusks, morphology, North Pacific, otherprocess, phytoplankton
Ocean acidification (OA) represents a serious challenge to marine ecosystems. Laboratory studies addressing OA indicate broadly negative effects for marine organisms, particularly those relying on calcification processes. Growing evidence also suggests OA combined with other environmental stressors may be even more deleterious. Scaling these laboratory studies to ecological performance in the field, where environmental heterogeneity may mediate responses, is a critical next step toward understanding OA impacts on natural communities. We leveraged an upwelling-driven pH mosaic along the California Current System to deconstruct the relative influences of pH, ocean temperature, and food availability on seasonal growth, condition and shell thickness of the ecologically dominant intertidal mussel Mytilus californianus. In 2011 and 2012, ecological performance of adult mussels from local and commonly sourced populations was measured at 8 rocky intertidal sites between central Oregon and southern California. Sites coincided with a large-scale network of intertidal pH sensors, allowing comparisons among pH and other environmental stressors. Adult California mussel growth and size varied latitudinally among sites and inter-annually, and mean shell thickness index and shell weight growth were reduced with low pH. Surprisingly, shell length growth and the ratio of tissue to shell weight were enhanced, not diminished as expected, by low pH. In contrast, and as expected, shell weight growth and shell thickness were both diminished by low pH, consistent with the idea that OA exposure can compromise shell-dependent defenses against predators or wave forces. We also found that adult mussel shell weight growth and relative tissue mass were negatively associated with increased pH variability. Including local pH conditions with previously documented influences of ocean temperature, food availability, aerial exposure, and origin site enhanced the explanatory power of models describing observed performance differences. Responses of local mussel populations differed from those of a common source population suggesting mussel performance partially depended on genetic or persistent phenotypic differences. In light of prior research showing deleterious effects of low pH on larval mussels, our results suggest a life history transition leading to greater resilience in at least some performance metrics to ocean acidification by adult California mussels. Our data also demonstrate “hot” (more extreme) and “cold” (less extreme) spots in both mussel responses and environmental conditions, a pattern that may enable mitigation approaches in response to future changes in climate.
Job opportunity: research assistant, Ocean Acidification Community of Practice coordinator, University of Calgary
Published 21 July 2020 Jobs ClosedApplication Deadline:: July 31, 2020
Position Overview: The Department of Geography in the Faculty of Arts invites applications for a Research Assistant. This Full-time Fixed Term position is for approximately 19 months (based on length of grant funding), with the possibility of extension.
This position reports to the Principal Investigator, and will support the activities of the Canadian Ocean Acidification Community of Practice, a MEOPAR initiative. The Research Assistant will ideally be located in Calgary, although a remote location outside of the Province of Alberta may be considered (which would necessitate an independent contractor arrangement). Applicants who are located in Calgary (or intend to relocate) as well as those interested in working outside of the Province of Alberta are both encouraged to respond to this job posting.
Qualifications / Requirements: Undergraduate or Graduate (preferred) degree in marine science, including social science
Research experience in a field related to ocean acidification or climate change; existing connections to the Canadian ocean acidification research community is an asset
Strong organizational and communication skills, initiative, writing ability, and the ability to work independently
Experience with data management, research outreach, and/or communications would be an asset
Carbonated water: teaching climate change and ocean acidification
Published 21 July 2020 Events ClosedDate And Time
Tue, Aug 11, 2020, 9:00 AM – Thu, Aug 13, 2020, 3:00 PM PDT
Location
Padilla Bay NERR, Ω0441 Bay View-Edison RD, Mount Vernon, Washington 98273 USA
Description
A Professional Development workshop for Middle and High School Teachers
Tuesday, August 11, 9:00-11:30 and 1:00-3:00 and Thursday, August 13, 9:00-11:30 and 1:00-3:00. This is an interactive, online class using Zoom.
Participants in this workshop will:
• Gain knowledge of climate change and ocean acidification in the Pacific Northwest
• Explore sources of local environmental data and work towards incorporating data into inquiry-based science learning experiences;
• Receive materials and activities included in the Ocean Sciences Sequence (OSS) curriculum on Climate Change developed by UC Berkeley Lawrence Hall of Science
Continue reading ‘Carbonated water: teaching climate change and ocean acidification’
Controls on boron isotopes in a cold-water coral and the cost of resilience to ocean acidification
Published 21 July 2020 Science ClosedTags: biogeochemistry, biological response, calcification, corals, individualmodeling, laboratory, modeling, morphology, North Pacific
Coral skeletal growth is sensitive to environmental change and may be adversely impacted by an acidifying ocean. However, physiological processes can also buffer biomineralization from external conditions, providing apparent resilience to acidification in some species. These same physiological processes affect skeletal composition and can impact paleoenvironmental proxies. Understanding the mechanisms of coral calcification is thus crucial for predicting the vulnerability of different corals to ocean acidification and for accurately interpreting coral-based climate records. Here, using boron isotope (δ11B) measurements on cultured cold-water corals, we explain fundamental features of coral calcification and its sensitivity to environmental change. Boron isotopes are one of the most widely used proxies for past seawater pH, and we observe the expected sensitivity between δ11B and pH. Surprisingly, we also discover that coral δ11B is independently sensitive to seawater dissolved inorganic carbon (DIC). We can explain this new DIC effect if we introduce boric acid diffusion across cell membranes as a new flux within a geochemical model of biomineralization. This model independently predicts the sensitivity of the δ11B-pH proxy, without being trained to these data, even though calcifying fluid pH (pHCF) is constant. Boric acid diffusion resolves why δ11B is a useful proxy across a range of calcifiers, including foraminifera, even when calcifying fluid pH differs from seawater. Our modeling shows that δ11B cannot be interpreted unequivocally as a direct tracer of pHCF. Constant pHCF implies similar calcification rates as seawater pH decreases, which can explain the resilience of some corals to ocean acidification. However, we show that this resilience has a hidden energetic cost such that calcification becomes less efficient in an acidifying ocean
Ocean acidification alters the responses of invertebrates to wound-activated infochemicals produced by epiphytes of the seagrass Posidonia oceanica
Published 20 July 2020 Science ClosedTags: abundance, algae, annelids, biological response, BRcommunity, crustaceans, laboratory, Mediterranean, mollusks, morphology, otherprocess, performance, phytoplankton
Highlights
• First time evaluation of the effect of infochemicals produced at two pH by the epiphytic community and by selected diatoms.
• O.A. alters the fine-tuned chemical cross-talks between seagrass epiphytes and associated invertebrates.
• Algae play their roles at different concentrations and convey different messages to associated animal communities.
• O.A. has consequences on the structure of associated communities and food webs of seagrass ecosystems.
Abstract
Ocean acidification (OA) influences the production of volatile organic compounds (VOCs) by seagrass leaves and their associated epiphytes. We hypothesize that the perception of “odour” produced by seagrass leaf epiphytes will change with seawater acidification, affecting the behaviour of seagrass-associated invertebrates. To test this hypothesis, we collected epiphytes from leaves of Posidonia oceanica growing at two pH conditions (7.7 and 8.1) and identified the most abundant genera of diatoms. We tested the VOCs produced at pH 8.1 by the epiphytic communities in toto, as well as those produced by selected diatoms, on various invertebrates. A complex set of species-specific and concentration-dependent chemotactic reactions was recorded, according to the pH of seawater. In particular, VOCs produced by individual diatoms triggered contrasting reactions in invertebrates, depending on the pH. The perception of epiphyte VOCs is likely to vary due to alteration of species ability to perceive and/or interpret chemical cues as infochemicals or due to changes in the structure of VOCs themselves. Thus, OA alters the fine-tuned chemical cross-talks between seagrass epiphytes and associated invertebrates, with potential consequences for the structure of communities and food webs of seagrass ecosystems.
Ocean CO2 data collected by RV Celtic Explorer contribute to global science
Published 17 July 2020 Media coverage Closed
Measurements were collected by the RV Celtic Explorer in 2017 and 2018
Surface ocean carbon dioxide observations collected by the Marine Institute’s RV Celtic Explorer have been published in the 2020 version of the Surface Ocean Carbon Atlas (SOCAT).
These data provide scientists, climate researchers and international policy makers with essential information on ocean carbon dioxide measurements.
About 36 billion tonnes of carbon dioxide are added to the atmosphere each year as a result of human activities. The ocean absorbs about one-quarter of these emissions, which helps to slow down climate change by removing CO2 from the atmosphere.
However, absorbing additional CO2 increases the acidity of seawater. This process is known as ocean acidification, and it could have dramatic consequences for marine life.
Continue reading ‘Ocean CO2 data collected by RV Celtic Explorer contribute to global science’
Universal response pattern of phytoplankton growth rates to increasing CO2
Published 16 July 2020 Science ClosedTags: biological response, growth, phytoplankton, review
Phytoplankton growth rate is a key variable controlling species succession and ecosystem structure throughout the surface ocean. Carbonate chemistry conditions are known to influence phytoplankton growth rates but there is no conceptual framework allowing us to compare growth rate responses across taxa. Here we analyse the literature to show that phytoplankton growth rates follow an optimum curve response pattern whenever the tested species is exposed to a sufficiently large gradient in proton (H+) concentrations. Based on previous findings with coccolithophores and diatoms, we argue that this “universal reaction norm” is shaped by the stimulating influence of increasing inorganic carbon substrate (left side of the optimum) and the inhibiting influence of increase H+ (right side of the optimum). We envisage that exploration of carbonate chemistry‐dependent optimum curves as a default experimental approach will boost our mechanistic understanding of phytoplankton responses to ocean acidification, like temperature curves have already boosted our mechanistic understanding to global warming.
Continue reading ‘Universal response pattern of phytoplankton growth rates to increasing CO2’
Seasonal variability in the inorganic ocean carbon cycle in the Northwest Pacific evaluated using a biogeochemical and carbon model coupled with an operational ocean model
Published 16 July 2020 Science ClosedTags: biogeochemistry, modeling, North Pacific, regionalmodeling
Here, we investigate the seasonal variability in the dissolved inorganic carbon (DIC) cycle in the Northwest Pacific using a high-resolution biogeochemical and carbon model coupled with an operational ocean model. Results show that the contribution to DIC from air–sea CO2 exchange is generally offset by vertical mixing at the surface at all latitudes, with some seasonal variation. Biological processes in subarctic regions are evident at the surface, whereas in the subtropical region these processes take place within the euphotic layer and then DIC consumption deepens southward with latitude. Such latitudinal differences in biological processes lead to marked horizontal and vertical contrasts in the distribution of DIC, with modulation by horizontal and vertical advection–diffusion processes.
Effect of the UV filter, Benzophenone-3, on biomarkers of the yellow clam (Amarilladesma mactroides) under different pH conditions
Published 16 July 2020 Science ClosedTags: biological response, laboratory, mollusks, multiple factors, physiology, toxicants
Highlights
• Effects of Benzophenone-3 and low pH on the yellow clam, Amarilladesma mactroides
• Benzophenone-3 affects antioxidant defenses in gills and digestive glands.
• Water acidification affects Ca2+-ATPase activity.
• Water acidification and Benzophenone-3 together inhibit carbonic anhydrase activity.
• Acidification may enhance the toxicity of Benzophenone-3.
Abstract
This work aimed to investigate effects of the ocean contamination by the sunscreen Benzophenone-3 (BP3) and acidification, caused by CO2 enrichment, to the yellow clam, Amarilladesma mactroides. Biochemical biomarkers were analyzed in tissues (gills, digestive gland, and mantle) of clams exposed to the environmental concentration of 1 μg/L BP3, at seawater natural pH (pH 8.1) and at lower pH (pH 7.6). The tissues responded in different ways considering their physiological roles. In general, BP3 altered activity of the enzymes, glutathione-S-transferase (GST) and glutathione cysteine ligase (GCL); but mostly increased the level of glutathione (GSH). These effects were enhanced by acidification, without augmenting lipid peroxidation (LPO). Carbonic anhydrase activity (CA) increased after BP3 exposure in the digestive gland and decreased in the gills at pH 7.6, while Ca2+-ATPase activity was affected by acidification only. Changing levels of these enzymes can alter shell formation and affect the bivalve maintenance in impacted environments.
