Archive Page 117

Re-evaluation of carbonic acid dissociation constants across conditions and the implications for ocean acidification

Published 19 May 2023 Science Closed
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Highlights

  • pHt should be measured directly rather than calculated from TA and DIC.
  • Uncertainty in the constants contributes up to 680 m of uncertainty in the aragonite saturation horizon depth.
  • Calculated pHt at pCO2 between ~500–800 μatm are particularly poor, suggesting an underestimation of future ocean acidification in models.
  • Evaluation of an unidentified or organic component of TA was inconclusive.

Abstract

With the increasing threat of ocean acidification and the important role of the oceans in the global carbon cycle, highly precise, accurate, and intercomparable determination of inorganic carbon system parameters is required. Thermodynamic relationships enable the system to be fully constrained using a combination of direct measurements and calculations. However, calculations are complicated by many formulations for dissociation constants (over 120 possible combinations). To address these important issues of uncertainty and comparability, we evaluated the various combinations of constants and their (dis)agreement with direct measurements over a range of temperature (−1.9–40 °C), practical salinity (15–39) and pCO2 (150–1200 μatm). The results demonstrate that differences between the calculations and measurements are significantly larger than measurement uncertainties, meaning the oft-stated paradigm that one only needs to measure two parameters and the others can be calculated does not apply for climate quality ocean acidification research. The uncertainties in calculated pHt prevent climate quality pHt from being calculated from total alkalinity (TA) and dissolved inorganic carbon (DIC) and should be directly measured instead. However, climate quality TA and DIC can often be calculated using measured pH and DIC or TA respectively. Calculations are notably biased at medium-to-high pCO2 values (~500–800 μatm) implying models underestimate future ocean acidification. Uncertainty in the dissociation constants leads to significant uncertainty in the depth of the aragonite saturation horizon (>500 m in the Southern Ocean) and must be considered when studying calcium carbonate cycling. Significant improvements in the precision of the thermodynamic constants are required to improve pHt calculations.

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GOA-ON webinar: multinational efforts in the search for a global solution for the production and certification of reference materials for measurements of the seawater carbonate system

Published 19 May 2023 Events , Presentations Closed

Date and time: 31 May 2023, 13:00 UTC

Moderator: Artur P. Palacz, International Ocean Carbon and Biogeochemistry Coordination Project (IOCCP)

Speakers: Maribel I. García-Ibáñez, Institut de Ciències del Mar (ICM), CSIC; Regina Easley, National Institute of Standards and Technology (NIST)

High-quality measurements of the seawater carbonate system allow us to quantify and understand the oceanic uptake of atmospheric carbon dioxide (CO2) and monitor ocean acidification. Those seawater carbonate system measurements rely on the availability of reference materials (RMs). The COVID-19 pandemic highlighted the fragility of the production system of the seawater RMs for the carbonate system, currently depending on one single laboratory. With that in mind, a new model for seawater RMs for the carbonate system, centered on regional hubs, is being discussed to create a more resilient system. The proposed new model for seawater RMs for the carbonate system requires unprecedented involvement of National Metrology Institutes (NMIs) on a global level. The integration of the new model into the global metrology landscape will help to produce the RMs that are comparable and metrologically traceable to the International System of Units.

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Call for public comments on scope and actions for the United States Ocean Acidification Action Plan

Published 19 May 2023 Program Closed

Deadline for public comments: 17 June 2023

The Department of State and National Oceanic and Atmospheric Administration (NOAA) will be accepting public comments on the proposed scope for the upcoming United States Ocean Acidification Action Plan (OA–AP). Drafting a national OA–AP is a commitment made by all members of the International Alliance to Combat Ocean Acidification (OA Alliance). The document will highlight our leadership in reducing carbon emissions, strengthening monitoring, research and coordination research efforts, and investing in adaptive measures.

Comments are due by June 17, 2023. Please note that all comments and suggestions may not be included in the final document.   

If you have questions about the United States OA–AP, contact Meaghan Cuddy at CuddyMR@state.gov or at (202) 340–3272.

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Short-term variation of pH in seawaters around coastal areas of Japan: characteristics and forcings

Published 18 May 2023 Science Closed
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The pH of coastal seawater varies based on several local forcings, such as water circulation, terrestrial inputs, and biological processes, and these forcings can change along with global climate change. Understanding the mechanism of pH variation in each coastal area is thus important for a realistic future projection that considers changes in these forcings. From 2020 to 2021, we performed parallel year-round observations of pH and related ocean parameters at five stations around the Japanese coast (Miyako Bay, Shizugawa Bay, Kashiwazaki Coast, Hinase Archipelago, and Ohno Strait) to understand the characteristics of short-term pH variations and their forcings. Annual variability (~1 standard deviation) of pH and aragonite saturation state (Ωara) were 0.05–0.09 and 0.25–0.29, respectively, for three areas with low anthropogenic loadings (Miyako Bay, Kashiwazaki Coast, and Shizugawa Bay), while it increased to 0.16–0.21 and 0.52–0.58, respectively, in two areas with medium anthropogenic loadings (Hinase Archipelago and Ohno Strait in Seto Inland Sea). Statistical assessment of temporal variability at various timescales revealed that most of the annual variabilities in both pH and Ωara were derived by short-term variation at a timescale of < 10 days, rather than seasonal-scale variation. Our analyses further illustrated that most of the short-term pH variation was caused by biological processes, while both thermodynamic and biological processes equally contributed to the temporal variation in Ωara. The observed results showed that short-term acidification with Ωara < 1.5 occurred occasionally in Miyako and Shizugawa Bays, while it occurred frequently in the Hinase Archipelago and Ohno Strait. Most of such short-term acidified events were related to short-term low-salinity events. Our analyses showed that the amplitude of short-term pH variation was linearly correlated with that of short-term salinity variation, and its regression coefficient at the time of high freshwater input was positively correlated with the nutrient concentration of the main river that flows into the coastal area.

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Ocean acidification enhances primary productivity and nocturnal carbonate dissolution in intertidal rock pools

Published 18 May 2023 Science Closed
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Human CO2 emissions are modifying ocean carbonate chemistry, causing ocean acidification, and likely already impacting marine ecosystems. In particular, there is concern that coastal, benthic calcifying organisms will be negatively affected by ocean acidification, a hypothesis largely supported by laboratory studies. The inter-relationships between carbonate chemistry and marine calcifying communities in situ are complex and natural mesocosms such as tidal pools can provide useful community-level insights. In this study, we manipulated the carbonate chemistry of intertidal pools to investigate the influence of future ocean acidification on net community production (NCP) and calcification (NCC) at emersion. Adding CO2 at the start of the tidal emersion to simulate future acidification (+1500 μatm pCO2, target pH: 7.5) modified net production and calcification rates in the pools. By day, pools were fertilized by the increased CO2 (+20 % increase in NCP, from 10 to 12 mmol O2 m−2 hr−1), while there was no measurable impact on NCC. During the night, pools experienced net community dissolution (NCC < 0), even in present-day conditions, when waters were supersaturated with regards to aragonite. Adding CO2 in the pools increased nocturnal dissolution rates by 40 % (from −0.7 to −1.0 mmol CaCO3 m−2 hr−1) with no consistent impact on night community respiration. Our results suggest that ocean acidification is likely to alter temperate intertidal community metabolism on sub-daily timescales, enhancing both diurnal community production and nocturnal calcium carbonate dissolution.

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Atmospheric carbon dioxide and changing ocean chemistry

Published 18 May 2023 Science Closed
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“They call it life, we call it pollution” is an infamous quote which ignores many facts about why carbon dioxide (CO2) poses a significant problem for the ocean. But before we get to this, let’s start at the beginning. All organisms on Earth require a particular set of elements for growth. In the case of plants, these elements are needed to synthesise organic matter in a process called primary production via photosynthesis, and in the case of animals, these elements are directly assimilated by either consuming plant material or by preying on other animals. In this respect, one of the key elements is carbon. Being the molecular backbone for a number of vital organic compounds such as sugars, proteins and nucleic acids (containing genetic information), carbon can be considered as the building block of life.

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Job opportunity: Laboratory Technician, Marine Science Center, Northeastern University

Published 18 May 2023 Jobs Closed

Location: Massachusetts, United States

Employment Type: Full Time

Job summary

The Ries Lab at Northeastern’s Marine Science Center is seeking a Laboratory Technician to maintain and operate all systems within its laboratories, exercise functional supervision over supporting research staff and students, order supplies and consumables, act as the lab compliance liaison, manage laboratory waste, maintain the chemical and gas inventory and the BIORAD/EHS webpage, train instrument users, calibrate and operate instruments, run samples for internal and external users, record and tabulate instrument usage, invoice, conduct basic organization and cleaning of the lab, assist with basic or applied research (both laboratory- and field-based), write SOPs, and manage, report, and archive experimental samples and data.

The successful applicant will be hard-working, discovery-driven, and intellectually curious. Applicants should have a solid foundation in carbonate biogeochemistry, geology, carbon sequestration, biomineralization, ocean acidification, and/or basic chemistry and possess strong writing and analytical skills. Appointment is for one year with the possibility of renewal in subsequent years pending availability of applicable funding.

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Warmer and more acidic conditions enhance performance of an endemic low shore gastropod

Published 17 May 2023 Science Closed
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Changing ocean temperatures are predicted to challenge marine organisms, especially when combined with other factors, such as ocean acidification. Acclimation, as a form of phenotypic plasticity, can however, moderate the consequences of changing environments for biota. Our understanding of how altered temperature and acidification together influence species acclimation responses is, however, limited compared to responses to single stressors. This study investigated how temperature and acidification affected the thermal tolerance and righting speed of the Girdled Dogwhelk, Trochia cingulata (Linnaeus, 1771). Whelks were acclimated for two weeks to combinations of three temperatures (11°C: cold, 13°C: moderate and 15°C: warm) and two pH regimes (8.0: moderate and 7.5: acidic). We measured the temperature sensitivity of righting response by generating thermal performance curves from individual data collected at seven test temperatures and determined critical thermal minima (CTmin) and maxima (CTmax). We found that T. cingulata has a broad basal thermal tolerance range (∼38°C) and after acclimation to the warm temperature regime, both the optimal temperature for maximum righting speed and CTmax increased. Contrary to predictions, acidification did not narrow this population’s thermal tolerance but increased CTmax. These plastic responses are likely driven by the predictable exposure to temperature extremes measured in the field which originate from the local tidal cycle and the periodic acidification associated with ocean upwelling in the region. This acclimation ability suggests that T. cingulata has at least some capacity to buffer the thermal changes and increased acidification predicted to occur with climate change.

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Impacts of ocean acidification and warming on post-larval growth and metabolism in two populations of the great scallop (Pecten maximus L.) 

Published 17 May 2023 Science Closed
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Ocean acidification and warming are key stressors for many marine organisms. Some organisms display physiological acclimatisation or plasticity, but this may vary across species ranges, especially if populations are adapted to local climatic conditions. Understanding how acclimatisation potential varies among populations is therefore important in predicting species responses to climate change. We carried out a common garden experiment to investigate how different populations of the economically important great scallop (Pecten maximus) from France and Norway responded to variation in temperature and pCO2 concentration. After acclimation, post-larval scallops (spat) were reared for 31 days at one of two temperatures (13°C and 19°C) under either ambient or elevated pCO2 (pH 8.0 and pH 7.7). We combined measures of proteomic, metabolic, and phenotypic traits to produce an integrative picture of how physiological plasticity varies between the populations. The proteome of French spat showed significant sensitivity to environmental variation, with 12 metabolic, structural and stress-response proteins responding to temperature and/or pCO2. Principal component analysis revealed seven energy metabolism proteins in French spat that were consistent with countering ROS stress under elevated temperature. Oxygen uptake in French spat did not change under elevated temperature, but increased under elevated pCO2. In contrast, Norwegian spat reduced oxygen uptake under both elevated temperature and pCO2. Metabolic plasticity seemingly allowed French scallops to maintain greater energy availability for growth than Norwegian spat. However, increased physiological plasticity and growth in French spat may come at a cost, as French (but not Norwegian) spat showed reduced survival under elevated temperature.

Continue reading ‘Impacts of ocean acidification and warming on post-larval growth and metabolism in two populations of the great scallop (Pecten maximus L.) ‘

‘Sea butterfly’ life cycle threatened by climate change may impact Southern Ocean ecosystem

Published 17 May 2023 Press releases Closed

The world’s oceans absorb approximately a quarter of all carbon dioxide (CO2) emissions. During absorption, CO2 reacts with seawater and oceanic pH levels fall. This is known as ocean acidification and results in lower carbon ion concentrations. Certain ocean inhabitants use carbon ion to build and sustain their shells. Pteropods, which are important components of the marine ecosystem, are among them.

Certain aspects about pteropods, including life cycles and population dynamics, are not well-studied. This is partly due to their size—some sea butterfly species measure less than a millimeter—and poor long-term survival in captivity. Now, a team of marine scientists has examined life cycles, abundance, and seasonal variability of shelled sea butterflies in the north-east Scotia Sea, a region undergoing some of the fastest climate change in the Southern Ocean.

“Decline in Antarctic Ocean pteropod populations could have cascading ramifications to the food web and carbon cycle,” said Dr. Clara Manno, a researcher at the British Antarctic Survey and corresponding author of the study published in Frontiers in Marine Science. “Knowledge about the life cycle of this keystone organism may improve prediction of ocean acidification impacts on the Antarctic ecosystem.”

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Contrasting life cycles of Southern Ocean pteropods alter their vulnerability to climate change

Published 16 May 2023 Science Closed
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Pteropods are a key part of biogeochemical cycling and epipelagic food webs in the Southern Ocean. However, shelled pteropods are vulnerable to climate change, due to their aragonite shells being particularly sensitive to ocean acidification. Currently our understanding of pteropod responses to environmental change is hindered by uncertainties surrounding their life cycles and population dynamics. In this study, we describe polar shelled pteropod diversity in the north-eastern Scotia Sea, inferring life history and population structures of the dominant pteropod species, Limacina rangii (formerly Limacina helicina antarctica) and Limacina retroversa. An annual timeseries of Limacina shell morphometrics was derived from individuals collected in a moored sediment trap at 400 m depth. We found that L. rangii and L. retroversa have contrasting life history strategies. L. rangii has a continuous spawning and recruitment period from November to March and can overwinter as juveniles and adults. L. retroversa has discrete spawning events from November to May, producing non–overlapping cohorts of juveniles and adults. Their development to the adult stage takes between two and five months, upon which they overwinter as adults. Our findings suggest different vulnerabilities of L. rangii and L. retroversa to a changing ocean. For example, since all life stages of L. rangii co-exist, vulnerability of one cohort is not detrimental to the stability of the overall population whereas, if one L. retroversa cohort fails to recruit, the entire population is threatened. Changes in pteropod populations could have cascading ramifications to Antarctic ecosystems and carbon cycling.

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Recalibrating the significance of the decline effect in fish ocean acidification research

Published 16 May 2023 Science Closed
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The recently described decline effect in ocean acidification impacts on fish behaviour should not be equated with negligible effects. Here, existing mechanistic data are used to argue for continued research and cautions against “throwing the baby out with the bathwater.”

The past few years have seen a seismic shift in the scientific consensus of ocean acidification and its impacts on fishes, particularly the adverse effects on behaviour. Foundational early work on coral reef fishes detailed olfactory disturbances that left fish unable to detect or discriminate predator cues and necessary habitat settlement cues—both of which were held up as potentially serious consequences of ocean acidification that may threaten global fish populations [1]. A decade later, Clark and colleagues published a rigorous follow-up that questioned the reproducibility of the early work on fish behaviour [2], and while several design aspects were disputed [3], the prevailing opinions on the behavioural effects of ocean acidification on fishes began to change. The recently published meta-analysis by Clements and colleagues [4] reinforced this shift by demonstrating a decline in effect size response ratios over time in studies exploring the impacts of ocean acidification on fish behaviour. The authors argued that ocean acidification has negligible effects on fish behaviour. More alarming was the determination that a University investigative panel concluded that a prominent author of the early ocean acidification studies committed scientific misconduct in the form of data fabrication and falsification [5]. This has led to one retraction of a high-impact work on coral reef fishes, although as of this writing, no ocean acidification papers have been retracted nor any expressions of concern been issued. Nonetheless, guilt by association has coloured the field of ocean acidification and fish behaviour. Despite all of this, I would urge the scientific community to remember the classic idiom and not “throw the baby out with the bathwater”.

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Phosphate limitation and ocean acidification co-shape phytoplankton physiology and community structure

Published 16 May 2023 Science Closed
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A new study reports synergistic inhibitory effects of ocean acidification and phosphate limitation on the nitrogen-fixing capacity of a globally important cyanobacterium species. Inspired by the report, this Comment presents the complexity of how ocean acidification and phosphate limitation affect phytoplankton physiologies and species beyond nitrogen fixation and cyanobacteria, and what future research is needed to address the remaining crucial questions.

Increasing CO2 emission and climate change have manifold impacts on ocean primary production and carbon sequestration. One of the direct effects comes from ocean acidification due to the dissolution of ~30% of the increased CO2 into the ocean, whereas indirect impacts mainly stem from warming-driven ocean stratification that impedes upwelling of nutrient-rich deep waters leading to oligotrophication of the vast central ocean basin1. Between nitrogen and phosphate, the two major productivity-limiting nutrients, phosphate is the ‘ultimate’ limiting nutrient as it has no biogenic source, and its growth-limiting condition in the oceans is more prevalent than previously thought2. Nitrogen, in contrast, can be sourced from the atmosphere by diazotrophic bacteria through nitrogen fixation, which is often co-limited by phosphate and iron scarcity2.

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Fossil coccolith morphological attributes as a new proxy for deep ocean carbonate chemistry

Published 16 May 2023 Science Closed
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Understanding the variations in past ocean carbonate chemistry is critical to elucidating the role of the oceans in balancing the global carbon cycle. The fossil shells from marine calcifiers present in the sedimentary record are widely applied as past ocean carbon cycle proxies. However, the interpretation of these records can be challenging due to the complex physiological and ecological response to the carbonate system during an organisms’ life cycle and the potential for preservation at the seafloor. Here we present a new dissolution proxy based on the morphological attributes of coccolithophores from the Noëlaerhabdaceae family (Emiliania huxleyi > 2 µm, and small Gephyrocapsa spp.). To evaluate the influences of coccolithophore calcification and coccolith preservation on fossil morphology, we measured morphological attributes, mass, length, thickness, and shape factor (ks) of coccoliths in a laboratory dissolution experiment and surface sediment samples from the South China Sea. The coccolith morphological data in surface sediments were also analyzed with environment settings, namely surface temperature, nutrients, pH, chlorophyll a concentration, and carbonate saturation of bottom water by a redundancy analysis. Statistical analysis indicates that carbonate saturation of the deep ocean explains the highest proportion of variation in the morphological data instead of the environmental variables of the surface ocean. Moreover, the dissolution trajectory in the ks vs. length of coccoliths is comparable between natural samples and laboratory dissolution experiments, emphasizing the importance of carbonate saturation on fossil coccolith morphology. However, the mean ks alone cannot fully explain the main variations observed in our work. We propose that the normalized ks variation (), which is the ratio between the standard deviation of ks (σ) and the mean ks, could reflect different degrees of dissolution and size-selective dissolution, influenced by the assemblage composition. Applied together with the  ratio, the ks factor of fossil coccoliths in deep ocean sediments could be a potential proxy for a quantitative reconstruction of past carbonate dissolution dynamics.

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Calcium isotopes reveal shelf acidification on southern Neotethyan margin during the Smithian-Spathian boundary cooling event

Published 15 May 2023 Science Closed
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The Smithian-Spathian transition of the late Early Triassic was a critical period of environmental and biological upheavals, following the end-Permian mass extinction. Changes in carbonate deposition during this period have been attributed to intensified upwelling along shelf margins, but relevant studies are scarce. Here, we present calcium isotopes of bulk marine carbonate (δ44/40Cacarb) from a Smithian–Spathian boundary (SSB) succession (Guryul Ravine section, Kashmir) on the southern margin of the Neo-Tethys. Our smoothed δ44/40Cacarb curve reveals a ~ 0.2‰ negative shift (from ~ − 1.1‰ to ~ − 1.3‰) across the SSB, concurrent with a ~ +10‰ shift in δ13Ccarb. While increased Ca isotopic fractionation could play a role, we specifically examine potential impacts due to changes in marine Ca fluxes. Using a Ca-cycle mass balance model, we explore scenarios of decreased carbonate burial flux (Fcarb), decreased riverine flux (Friv), and a combination of these processes. The modeling suggest that a pulse decrease in Fcarb by 40% over ~0.06 Myr match the negative shift in δ44/40Cacarb at Guryul Ravine. We infer that this decrease was likely related to intensified upwelling of acidic deep seawater due to invigorated global-oceanic circulation during the SSB cooling event. We suggest that the regionally diverse excursions in δ44/40Cacarb in the Tethyan region could be attributed to spatially varied upwellings in the shelf margin. The upwelling of acidic and anoxic deep seawater may have driven the second-order extinction of ammonoids and conodonts at the beginning of the SSB cooling event.

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Cardiovascular responses to increased temperature and lower pH for six cold water Opisthobranch species

Published 15 May 2023 Science Closed
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Increasing sea surface temperatures and ocean acidification continue to threaten marine life globally, especially in coastal waters where effects are often exacerbated. Individually, temperature and acidification negatively affect marine organisms, but interactive effects, vary depending on phylum and life cycle stage. Opisthobranch sea slugs, having short and complex life cycles, were studied for cardiac response to increasing temperature and to interactive effects of temperature and pH. Six cold-water, cosmopolitan species (Aeolidia papillosa, Cuthona gymnota, Dendronotus frondosus, Flabellina verrucosa, Onchidoris bilamellata, and Placida dendritica) common in the Gulf of Maine were selected. To determine response to temperature, heartbeats of test animals starting at 4 °C were recorded at increasing temperature intervals of 4 °C, until they slowed or ceased. Interactive effects were examined at pH 8 (control) and pH 7 coincident with temperature increases (4o to 16 °C). Overall, upper pejus temperatures tested ranged from 16o to 28 °C, with the largest species having the lowest temperature threshold and smallest having the highest. Although interactive effects were not significant, the negative synergistic effect of suppressed heart rate across temperatures was significant for three species and apparent in two others. As significant predators of sessile prey, especially within fouling communities, environmental impacts on sea slugs have the potential to alter both community structure and prey abundance within their environment, potentially reflecting larger implications affecting the biodiversity and abundance of prey populations within their environment.

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Drivers of marine CO2-carbonate chemistry in the northern Antarctic Peninsula

Published 15 May 2023 Science Closed
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Abstract

The Bransfield Strait is a climate change hotspot at the tip of the northern Antarctic Peninsula (NAP). The region is marked by a mixture of relatively warm waters from the Bellingshausen Sea with cold shelf waters from the Weddell Sea. Additionally, its deep central basin (>800 m) preserves seawater properties from the north-western Weddell Sea continental shelf. This study assessed long-term changes in carbonate chemistry in the Bransfield Strait and found that the hydrographic setting (i.e., a mixture between modified-Circumpolar Deep Water with Dense Shelf Water [DSW]) drives temporal variability of carbonate parameters. The western basin has experienced decreases in pH (seawater scale) over the last three decades (1996–2019), varying from −0.003 to −0.017 pH units yr−1, while Ωar decreased from −0.01 to −0.07 yr−1 throughout the water column. The central basin was characterized by a high contribution of DSW with high carbon dioxide (CO2) content and the decomposition of organic matter produced and transported into its deep layer. With lower variability for all carbonate system variables, the eastern basin was likely regulated by internal mixing. Overall, the entire strait is almost reaching a CO2-saturated condition, highlighting how sensitive subpolar regions are to the effects of human-induced climate change.

Key Points

  • The western basin experiences steeper pH decreases than the surrounding areas at a rate of −0.017 pHsws units yr−1 due to Circumpolar Deep Water intrusions
  • Dense Shelf Water inflow into the deep layer of the central basin promoted a CT increase of about 50 μmol kg−1 in the 2010s relative to the 2000s
  • Internal mixing has likely reduced spatiotemporal variability of carbonate chemistry in the eastern basin since the 1990s
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A scientometric review of climate change and research on crabs

Published 15 May 2023 Science Closed
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Highlights

  • Analyzed 2834 articles and 107,502 cited references from the (WOSCC) database, spanning 1977 to 2022.
  • Identified leading contributors, institutions, research hotspots, and frontiers in the field.
  • Categorized pivotal research issues and delineated the knowledge structure pertaining to marine biodiversity.
  • Explored emergent research frontiers and hotspots in marine biodiversity studies.
  • Assessed the current state of research and pinpointed prospective future avenues for investigation in this domain.

Abstract

Crabs categorized as cold-blooded organisms are especially at risk as climate change worsens. Their current situation was not well documented, especially in terms of scientometric analysis. The present study aims to investigate the relationship between research on crabs and climate change-related studies, with a focus on identifying trends and hotspots over time. The analysis was based on a collection of over 2834 relevant documents and 107,502 cited references indexed in the Web of Science Core Collection (WOSCC) database from 1977 to 2022. The findings indicated an increase in research in recent decades, with the USA as the largest contributor, followed by China and Brazil. Researchers from the USA and Germany were among the top published authors in the field. The most highly cited studies in WOSCC focused on the relationship between harmful algal blooms and crab research. Of these studies, 20 clusters were generated, with the most influential cluster identified as related to “ocean acidification,” “blue king crab,” and “mud crab fishery.” The most frequently cited and influential keywords in the field were “climate change” and “hypoxia,” respectively. Our conclusion is that the fields of “research on crabs” and “climate change” are thriving and that further exploration of the adaptation strategies of these organisms is necessary. This knowledge will benefit scientific communities, philanthropic funders or related governments, fisheries-related industries, and NGOs towards the sustainable management of commercial crab species in the future.

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The Dungeness crab is losing its sense of smell, putting it at risk – and climate change may be to blame

Published 15 May 2023 Press releases Closed

A new study by researchers at the University of Toronto finds that climate change is causing a commercially significant marine crab to lose its sense of smell, which could partially explain why their populations are thinning. 

The research was done on Dungeness crabs and found that ocean acidification causes them to physically sniff less, impacts their ability to detect food odours and even decreases activity in the sensory nerves responsible for smell.  

“This is the first study to look at the physiological effects of ocean acidification on the sense of smell in crabs,” says Cosima Porteus, an assistant professor in the department of biological sciences at U of T Scarborough and co-author of the study along with post-doctoral researcher Andrea Durant.      

The Earth’s oceans are becoming more acidic because they are absorbing increasing amounts of carbon dioxide in the atmosphere. Such ocean acidification is a direct consequence of burning fossil fuels and carbon pollution – and several studies have shown it’s having an impact on the behaviour of marine wildlife.

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Continue reading ‘The Dungeness crab is losing its sense of smell, putting it at risk – and climate change may be to blame’

House passes two bipartisan science committee bills

Published 15 May 2023 Press releases Closed

(Washington, DC) – Today, the U.S. House of Representatives considered and passed two bipartisan Science, Space, and Technology Committee bills: H.R. 676, the Coastal Communities Ocean Acidification Act of 2023 and H.R. 1715, the Advanced Weather Model Computing Development Act.

“I applaud the passage of these two bipartisan pieces of Committee legislation,” said Chairman Frank Lucas. “Improved community engagement with Indian Tribes, as well as state and local government, will improve NOAA’s work to support the health and long-term growth of our marine ecosystems. Collaboration between the Department of Energy and NOAA will not only improve NOAA’s forecasting, but the opportunity to analyze large weather data sets will help to advance machine learning at DOE. […]”

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H.R. 676, the Coastal Communities Ocean Acidification Act of 2023, requires the National Oceanic and Atmospheric Administration (NOAA) to collaborate with State and local governments and Indian Tribes on vulnerability assessments related to ocean acidification, research planning, and similar activities.

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