Archive for January, 2021

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Modeling ocean biogeochemical ARGO observations research at Princeton University

Published 19 January 2021 Jobs Closed

Job description

The Atmospheric and Oceanic Sciences Program at Princeton University in cooperation with NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL) seeks a postdoctoral research associate or more senior scientist to assess modes of variability in biogeochemical observations and assess the necessary scope of observations to constrain boundary conditions and underlying biogeochemical functioning towards improved predictability of living marine resources. The incumbent will leverage an existing degree ocean biogeochemical eddying simulation along with a suite of coarse resolution ocean biogeochemical retrospective forecast experiments to a) assess daily variability in BGC ARGO observables, as well as the relationship to underlying biogeochemical interactions, in the California Current Large Marine Ecosystem (CCLME) b) conduct additional model simulations as needed, and c) inform GFDL Earth System Model (ESM) initialization for improved representation and understanding of the CCLME. The incumbent will also assess the large scale variability in water mass structure to contrast large scale drivers of shifting biogeochemical provinces, mesoscale dynamics, and drivers of physical and biogeochemical variability at the ocean weather scale. This multiscale assessment of the underlying variability and its drivers will inform not only interpretation of individual floats, but also serve as a framework to better characterize biogeochemical variability in boundary conditions for regional models, and evaluate the potential for seasonal to decadal scale predictability of hypoxia, ocean acidification, algal blooms and living marine resources. Personnel will join an active group at Princeton and GFDL studying the connections between biogeochemistry, ecosystems, and climate (https://www.gfdl.noaa.gov/marine-ecosystems/). These are two-year positions (subject to renewal after the first year) based at GFDL in Princeton, New Jersey. Complete applications, including a cover letter, CV, publication list, a one to two-page statement of research interests and names of at least 3 references in order to solicit letters of recommendation, should be submitted online by April 30, 2020 for full consideration, though evaluation will be ongoing. Essential Qualifications: PhD is required. Candidates with quantitative, interdisciplinary knowledge from subsets of fields including climate dynamics, ocean and coastal biogeochemistry, marine ecosystem dynamics, and fisheries science and management are particularly encouraged to apply. Experience analyzing large data sets and/or model output is also critical, as is model development experience for those positions. This position is subject to Princeton University’s background check policy. 

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Acclimation and adaptation to elevated pCO2 increase arsenic resilience in marine diatoms

Published 19 January 2021 Science Closed
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Arsenic pollution is a widespread threat to marine life, but the ongoing rise pCO2 levels is predicted to decrease bio-toxicity of arsenic. However, the effects of arsenic toxicity on marine primary producers under elevated pCO2 are not well characterized. Here, we studied the effects of arsenic toxicity in three globally distributed diatom species (Phaeodactylum tricornutum, Thalassiosira pseudonana, and Chaetoceros mulleri) after short-term acclimation (ST, 30 days), medium-term exposure (MT, 750 days), and long-term (LT, 1460 days) selection under ambient (400 µatm) and elevated (1000 and 2000 µatm) pCO2. We found that elevated pCO2 alleviated arsenic toxicity even after short acclimation times but the magnitude of the response decreased after mid and long-term adaptation. When fed with these elevated pCO2 selected diatoms, the scallop Patinopecten yessoensis had significantly lower arsenic content (3.26–52.83%). Transcriptomic and biochemical analysis indicated that the diatoms rapidly developed arsenic detoxification strategies, which included upregulation of transporters associated with shuttling harmful compounds out of the cell to reduce arsenic accumulation, and upregulation of proteins involved in synthesizing glutathione (GSH) to chelate intracellular arsenic to reduce arsenic toxicity. Thus, our results will expand our knowledge to fully understand the ecological risk of trace metal pollution under increasing human activity induced ocean acidification.

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Stuck in a rut: ocean acidification locks algal communities in a simplified state

Published 18 January 2021 Press releases Closed

Out with the old, in with the new, as the New Year’s saying goes, but not where the marine environment is concerned. Researchers from Japan have discovered that ocean acidification keeps algal communities locked in a simplified state of low biodiversity.

In a study published on 11th January 2021 in Global Change Biology, researchers from the University of Tsukuba have revealed that as oceanic carbon dioxide levels rise, the biodiversity and ecological complexity of marine algal communities decline.

Ocean acidification is the continuing increase in the acidity of the Earth’s oceans, caused by the absorption of atmospheric carbon dioxide (CO2). The largest contributor to this acidification is human-caused CO2 emissions from the burning of fossil fuels.

“Ocean acidification is harmful to a lot of different marine organisms,” says lead author of the study Professor Ben P. Harvey. “This affects not only ecosystem functions, but the goods and services that people get from marine resources.”

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Shell mineralogy of a foundational marine species, Mytilus californianus, over half a century in a changing ocean

Published 18 January 2021 Science Closed
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Anthropogenic warming and ocean acidification are predicted to negatively affect marine calcifiers. While negative effects of these stressors on physiology and shell calcification have been documented in many species, their effects on shell mineralogical composition remains poorly known, especially over longer time periods. Here, we quantify changes in the shell mineralogy of a foundation species, Mytilus californianus, under 60 y of ocean warming and acidification. Using historical data as a baseline and a resampling of present-day populations, we document a substantial increase in shell calcite and decrease in aragonite. These results indicate that ocean pH and saturation state, not temperature or salinity, play a strong role in mediating the shell mineralogy of this species and reveal long-term changes in this trait under ocean acidification.

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Resilience to climate change? octopuses adapting to higher ocean acid levels

Published 18 January 2021 Press releases Closed

With the impact of climate change increasing by the day, scientists are studying the ways in which human behavior contributes to the damage. A recent study at Walla Walla University, by a collaboration of researchers from Walla Walla University and La Sierra University, examined the effects of acidic water on octopuses, potentially bringing new insight into both how our activities impact the world around us, and the way that world is adapting in response.

The study, “Impact of Short- and Long-Term Exposure to Elevated Seawater PCO2 on Metabolic Rate and Hypoxia Tolerance in Octopus rubescens,” focused on the metabolic rate of octopuses exposed to water acidified by carbon dioxide, and the changes it made to the animals. CO2 is a key indicator of the growing acidity of our oceans because much of the gas released into the air by humans is dissolving into the seawater.

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The new face of the Antarctic

Published 15 January 2021 Press releases Closed

A new AWI study involving the ICM says that Antarctica could become a greener place in a few years and was colonised by new species from warmer areas because of climate change…

Species from warmer regions could migrate to Antarctica due to climate change / Claudia Colesi
Species from warmer regions could migrate to Antarctica due to climate change / Claudia Colesi

In the future, the Antarctic could become a greener place and be colonised by new species. At the same time, some species will likely disappear. This is one of the main conclusions of an article by a group of researchers from the ICM and other research centres from all over the world published last December in the specialized journal Biological Reviews.

For its preparation, researchers, led by the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), analysed hundreds of articles on the Antarctic published in the past ten years. By doing so, they have provided an exceptionally comprehensive assessment on the biological and biochemical processes at work in the Antarctic and the Southern Ocean that surrounds it, which makes it possible to know their current and future state.

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Ocean acidification affecting California mussels (text and audio)

Published 15 January 2021 Media coverage Closed
Buoys in the water at the Carlsbad Aquafarm where owners grow oysters and mus...
PHOTO BY ERIK ANDERSON
Above: Buoys in the water at the Carlsbad Aquafarm where owners grow oysters and mussels on Aug. 26, 2019.

A UC San Diego researcher says an increasingly acidic ocean is having an impact on shellfish that live in the nearshore environment.

Graduate student Elizabeth Bullard studied recent mussel samples and compared them to records of mussels captured along the California coast 60 years ago.

Bullard expected to find that the animal’s shells were harder and contained more of the carbonate mineral aragonite as the shellfish adjusted to a warming ocean.

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Ocean acidification interacts with growth light to suppress CO2 acquisition efficiency and enhance mitochondrial respiration in a coastal diatom

Published 15 January 2021 Science Closed
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Highlights

  • Ocean acidification (OA) enhances growth of Thalassiosira weissflogii only at limiting low light levels.
  • The energy saved from down-regulation of CCMs under OA rather than “CO2 fertilization aids in the enhancement under low levels of light energy supply.
  • Coastal diatoms can benefit from OA, especially under cloudy weather or conditions of low solar exposures.

Abstract

Diatom responses to ocean acidification have been documented with variable and controversial results. We grew the coastal diatom Thalassiosira weissflogii under 410 (LC, pH 8.13) vs 1000 μatm (HC, pH 7.83) pCO2 and at different levels of light (80, 140, 220 μmol photons m−2 s−1), and found that light level alters physiological responses to OA. CO2 concentrating mechanisms (CCMs) were down-regulated in the HC-grown cells across all the light levels, as reflected by lowered activity of the periplasmic carbonic anhydrase and decreased photosynthetic affinity for CO2 or dissolved inorganic carbon. The specific growth rate was, however, enhanced significantly by 9.2% only at the limiting low light level. These results indicate that rather than CO2 “fertilization”, the energy saved from down-regulation of CCMs promoted the growth rate of the diatom when light availability is low, in parallel with enhanced respiration under OA to cope with the acidic stress by providing extra energy.

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Stable Ca and Sr isotopes support volcanically triggered biocalcification crisis during Oceanic Anoxic Event 1a

Published 14 January 2021 Science Closed
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Large igneous province (LIP) eruptions are hypothesized to trigger biocalcification crises. The Aptian nannoconid crisis, which correlates with emplacement of the Ontong Java Plateau and Oceanic Anoxic Event 1a (OAE 1a, ca. 120 Ma), represents one such example. The Ca isotope (δ44/40Ca) system offers potential to detect biocalcification fluctuations in the rock record because Ca isotope fractionation is sensitive to precipitation rate. However, other primary and secondary processes, such as input-output flux perturbations and early diagenesis, can produce similar signals. Here, we exploit emergent properties of the stable Sr isotope (δ88/86Sr) system to resolve the origin of δ44/40Ca variability during OAE 1a. This study reports high-precision thermal ionization mass spectrometry (TIMS) δ44/40Ca, δ88/86Sr, and 87Sr/86Sr records for Hole 866A of Ocean Drilling Program Leg 143 drilled in Resolution Guyot, mid-Pacific Ocean. The samples span ~27 m.y. from the Barremian (ca. 127 Ma) to the Albian (ca. 100 Ma). The δ44/40Ca and δ88/86Sr secular trends differ from the 87Sr/86Sr record but mimic each other. δ44/40Ca and [Sr], as well as δ44/40Ca and δ88/86Sr, strongly correlate and yield slopes predicted for kinetic control, which demonstrates that variable mass-dependent fractionation rather than end-member mixing dominated the isotopic relationship between carbonates and seawater. Positive δ44/40Ca and δ88/86Sr shifts that begin before OAE 1a and peak within the interval are consistent with reduced precipitation rates. All results combined point to a cascade of effects on rate-dependent Ca and Sr isotope fractionation, which derive from the dynamic interplay between LIP eruptions and biocalcification feedbacks.

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New edition of the “OA-ICC Highlights”, July-December 2020

Published 14 January 2021 Media coverage Closed

The new edition of the “OA-ICC Highlights”, our newsletter, summarizes the project’s main activities and achievements over the period July-December 2020. This newsletter highlights a virtual OA conference, organized with GOA-ON, new funding and staff, and planning for 2021. Previous editions can be viewed here.

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Volcanic eruptions directly triggered ocean acidification during Early Cretaceous

Published 14 January 2021 Media coverage Closed

Around 120 million years ago, the earth experienced an extreme environmental disruption that choked oxygen from its oceans.

Known as oceanic anoxic event (OAE) 1a, the oxygen-deprived water led to a minor — but significant — mass extinction that affected the entire globe. During this age in the Early Cretaceous Period, an entire family of sea-dwelling nannoplankton virtually disappeared.

By measuring calcium and strontium isotope abundances in nannoplankton fossils, Northwestern earth scientists have concluded the eruption of the Ontong Java Plateau large igneous province (LIP) directly triggered OAE1a. Roughly the size of Alaska, the Ontong Java LIP erupted for seven million years, making it one of the largest known LIP events ever. During this time, it spewed tons of carbon dioxide (CO2) into the atmosphere, pushing Earth into a greenhouse period that acidified seawater and suffocated the oceans.

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A Polar outlook: potential interactions of micro- and nano-plastic with other anthropogenic stressors

Published 14 January 2021 Science Closed
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Highlights

  • MP/NP at the poles should be addressed with chemical and climate stressors.
  • MP/NP and anthropogenic stress interactions may vary seasonally and locally.
  • MP/NP research should focus on polar species enduring high anthropogenic stress.

Abstract

Polar marine ecosystems may have higher sensitivity than other ecosystems to plastic pollution due to recurrent physical and biological features; presence of ice and high UV radiation, slow growth rates and weak genetic differentiation of resident biota, accumulation of persistent organic pollutants and heavy metals, and fast rates of warming and global ocean acidification. Here, we discuss potential sources of and exposure to micro- and nano-plastic in polar marine ecosystems and potential mixture effects of micro- and nano-plastic coupled with chemical and climate related stressors. We address the anthropogenic contaminants likely to be ‘high risk’ for interactions in Arctic and Antarctic waters for reasons such as accumulation under sea-ice, a known sink for plastic particulates. Consequently, we address the potential for localised plastic-chemical interactions and possible seasonal fluctuations in interactions associated with freeze-thaw events. The risks for keystone polar species are also considered, incorporating the behavioural and physiological traits of biota and addressing potential ‘hotspot’ areas. Finally, we discuss a possible direction for future research.

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Autonomous in situ calibration of ion‐sensitive field effect transistor pH sensors

Published 14 January 2021 Science Closed
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Ion‐sensitive field effect transistor‐based pH sensors have been shown to perform well in high frequency and long‐term ocean sampling regimes. The Honeywell Durafet is widely used due to its stability, fast response, and characterization over a large range of oceanic conditions. However, potentiometric pH monitoring is inherently complicated by the fact that the sensors require careful calibration. Offsets in calibration coefficients have been observed when comparing laboratory to field‐based calibrations and prior work has led to the recommendation that an in situ calibration be performed based on comparison to discrete samples. Here, we describe our work toward a self‐calibration apparatus integrated into a SeapHOx pH, dissolved oxygen, and CTD sensor package. This Self‐Calibrating SeapHOx is capable of autonomously recording calibration values from a high quality, traceable, primary reference standard: equimolar tris buffer. The Self‐Calibrating SeapHOx’s functionality was demonstrated in a 6‐d test in a seawater tank at Scripps Institution of Oceanography (La Jolla, California, U.S.A.) and was successfully deployed for 2 weeks on a shallow, coral reef flat (Lizard Island, Australia). During the latter deployment, the tris‐based self‐calibration using 15 on‐board samples exhibited superior reproducibility to the standard spectrophotometric pH‐based calibration using > 100 discrete samples. Standard deviations of calibration pH using tris ranged from 0.002 to 0.005 whereas they ranged from 0.006 to 0.009 for the standard spectrophotometric pH‐based method; the two independent calibration methods resulted in a mean pH difference of 0.008. We anticipate that the Self‐Calibrating SeapHOx will be capable of autonomously providing climate quality pH data, directly linked to a primary seawater pH standard, and with improvements over standard calibration techniques.

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Dichotomy between regulation of coral bacterial communities and calcification physiology under ocean acidification conditions

Published 14 January 2021 Science Closed
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Ocean acidification (OA) threatens the growth and function of coral reef ecosystems. A key component to coral health is the microbiome, but little is known about the impact of OA on coral microbiomes. A submarine CO2 vent at Maug Island in the Northern Marianas Islands provides a natural pH gradient to investigate coral responses to long-term OA conditions. Three coral species (Pocillopora eydouxi, Porites lobata, and Porites rus) were sampled from three sites where mean seawater pH is 8.04, 7.98, and 7.94. We characterized coral bacterial communities (using 16S rRNA gene sequencing) and determined pH of the extracellular calcifying fluid (ECF) (using skeletal boron isotopes) across the seawater pH gradient. Bacterial communities of both Porites species stabilized (decreases in community dispersion) with decreased seawater pH, coupled with large increases in the abundance of Endozoicomonas, an endosymbiont. P. lobata experienced a significant decrease in ECF pH near the vent, whereas P. rus experienced a trending decrease in ECF pH near the vent. By contrast, Pocillopora exhibited bacterial community destabilization (increases in community dispersion), with significant decreases in Endozoicomonas abundance, while its ECF pH remained unchanged across the pH gradient. Our study shows that OA has multiple consequences on Endozoicomonas abundance and suggests that Endozoicomonas abundance may be an indicator of coral response to OA. We reveal an interesting dichotomy between two facets of coral physiology (regulation of bacterial communities and regulation of calcification), highlighting the importance of multidisciplinary approaches to understanding coral health and function in a changing ocean.

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Abundances and morphotypes of the coccolithophore Emiliania huxleyi in southern Patagonia compared to neighboring oceans and northern-hemisphere fjords

Published 13 January 2021 Science Closed
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Coccolithophores are potentially affected by ongoing ocean acidification, where rising CO2 lowers seawater pH and calcite saturation state (Ωcal). Southern Patagonian fjords and channels provide natural laboratories for studying these issues due to high variability in physical and chemical conditions. We surveyed coccolithophore assemblages in Patagonian fjords during late-spring 2015 and early-spring 2017. Surface Ωcal exhibited large variations driven mostly by freshwater inputs. High Ωcal conditions (max. 3.6) occurred in the Archipelago Madre de Dios. Ωcal ranged from 2.0–2.6 in the western Strait of Magellan, 1.5–2.2 in the Inner Channel, and was sub-saturating (0.5) in Skyring Sound. Emiliania huxleyi was the only coccolithophore widely distributed in Patagonian fjords (> 96 % of total coccolitophores), only disappearing in the Skyring Sound, a semi-closed mesohaline system. Correspondence analysis associated higher E. huxleyi biomasses with lower diatom biomasses. The highest E. huxleyi abundances in Patagonia were in the lower range of those reported in Norwegian fjords. Predominant morphotypes were distinct from those previously documented in nearby oceans but similar to those of Norwegian fjords. Moderate-calcified forms of E. huxleyi A morphotype were uniformly distributed throughout Patagonia fjords. The exceptional R/hyper-calcified coccoliths, associated with low Ωcal values in Chilean and Peruvian coastal upwellings, were a minor component associated with high Ωcal levels in Patagonia. Outlying mean index (OMI) niche analysis suggested that pH/Ωcal conditions explained most variation in the realized niches of E. huxleyi morphotypes. The moderate-calcified A morphotype exhibited the widest niche-breadth (generalist), while the R/hyper-calcified morphotype exhibited a more restricted realized niche (specialist). Nevertheless, when considering an expanded sampling domain, including nearby Southeast Pacific coastal and offshore waters, even the R/hyper-calcified morphotype exhibited a higher niche breadth than other closely phylogenetically-related coccolithophore species. The occurrence of E. huxleyi in naturally low pH/Ωcal environments indicates that its ecological response is plastic and capable of adaptation.

Continue reading ‘Abundances and morphotypes of the coccolithophore Emiliania huxleyi in southern Patagonia compared to neighboring oceans and northern-hemisphere fjords’

Projections of algae, eelgrass, and zooplankton ecological interactions in the inner Salish Sea – for future climate, and altered oceanic states

Published 13 January 2021 Science Closed
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Highlights

  • Harmonized simulation of DO, pH, and Y2095 climate change impacts in the Salish Sea
  • A 52-fold increase in exposure and near-bed pelagic species to hypoxic waters in Y2095
  • Ocean acidification projections for Y2095 indicate ≈ 20 −114% increase in water column (ΩA) <1)
  • Primary productivity propagation to zooplankton projected for Y2095 with ≈ 13%−25% increases.
  • Eelgrass sensitive to stressors and potential for loss of eelgrass biomass in the future.

Abstract

Future projections based on the IPCC high emissions scenario RCP8.5 have previously shown that the Pacific Northwest coastal waters will be subjected to altered ocean states in the upwelled shelf waters, resulting in higher primary productivity and increased regions of hypoxia and acidification in the inner estuarine waters such as the Salish Sea. However, corresponding effects on the lower trophic levels and submerged aquatic vegetation have not yet been quantified. Supported by new synoptic field data, explicit coupled simulation of algae, zooplankton, and eelgrass biomass was accomplished for the first time in the Salish Sea. We re-applied the improved model to evaluate future ecological response and examined potential algal species shift, but with the effects of zooplankton production, metabolism, and predation-prey interactions included. We also evaluated the role of eelgrass with respect to potential for improvements to dissolved oxygen and pH levels and as a mitigation measure against hypoxia and ocean acidification. The results re-confirm the possibility that there could be a substantial area-days increase (≈52-fold) in exposure of benthic and near-bed pelagic species to hypoxic waters in 2095. The projections for ocean acidification similarly indicate ≈ 20 -114% increase in exposure to lower pH corrosive waters with aragonite saturation state ΩA <1. Importantly, projected increase in primary productivity was shown to propagate to higher trophic levels, with ≈ 13% and 25% increases in micro and mesozooplankton biomass levels. However, the preliminary results also point to sensitivity of the eelgrass model to environmental stressor and potential loss eelgrass biomass in the future.

Continue reading ‘Projections of algae, eelgrass, and zooplankton ecological interactions in the inner Salish Sea – for future climate, and altered oceanic states’

Ocean acidification alters properties of the exoskeleton in adult tanner crabs, Chionoecetes bairdi

Published 13 January 2021 Science Closed
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Ocean acidification can affect the ability of calcifying organisms to build and maintain mineralized tissue. In decapod crustaceans, the exoskeleton is a multilayered structure composed of chitin, protein, and mineral, predominately magnesian calcite or amorphous calcium carbonate (ACC). We investigated the effects of acidification on the exoskeleton of mature (post-terminal-molt) female southern Tanner crabs, Chionoecetes bairdi. Crabs were exposed to one of three pH levels—8.1, 7.8, or 7.5—for two years. Reduced pH led to a suite of body-region-specific effects on the exoskeleton. Microhardness of the claw was 38% lower in crabs at pH 7.5 compared with those at pH 8.1, but carapace microhardness was unaffected by pH. In contrast, reduced pH altered elemental content in the carapace (reduced calcium, increased magnesium), but not the claw. Diminished structural integrity and thinning of the exoskeleton was observed at reduced pH in both body regions; internal erosion of the carapace was present in most crabs at pH 7.5, and the claws of these crabs showed substantial external erosion, with tooth-like denticles nearly or completely worn away. Using infrared spectroscopy, we observed a shift in the phase of calcium carbonate present in the carapace of pH-7.5 crabs: a mix of ACC and calcite was found in the carapace of crabs at pH 8.1, whereas the bulk of calcium carbonate had transformed to calcite in pH-7.5 crabs. With limited capacity for repair, the exoskeleton of long-lived crabs that undergo a terminal molt, such as C. bairdi, may be especially susceptible to ocean acidification.

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Seacarbx – seacarb extension for deep-time carbonate system calculations

Published 12 January 2021 Science Closed

seacarbx is a seacarb extension written in R, which enables to use seacarb (Gattuso et al., 2019) for deep-time carbonate system calculations or for culturing studies carried out in seawater with modified [Mg2+] and [Ca2+]. For this, the functions carb, K0, K1, K2, Ks, Kw, Kb, Kspa, and Kspc were modfied to account for the effect of seawater [Mg2+] and [Ca2+] on the dissociation constants of carbonic and boric acid. In addition to the modified functions, seacarbx contains MyAMI that are tabulated parameters defining the temperature and salinity dependencies of the conditional equilibrium constants for [Mg2+] and [Ca2+] in the range 1–60 mM (from Hain et al., 2015, 2018), as well as a function for bilinear interpolation

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Ocean acidification locks algal communities in a species‐poor early successional stage

Published 12 January 2021 Science Closed
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Long‐term exposure to CO2‐enriched waters can considerably alter marine biological community development, often resulting in simplified systems dominated by turf algae that possess reduced biodiversity and low ecological complexity. Current understanding of the underlying processes by which ocean acidification alters biological community development and stability remains limited, making the management of such shifts problematic. Here, we deployed recruitment tiles in reference (pHT 8.137 ± 0.056 SD) and CO2‐enriched conditions (pHT 7.788 ± 0.105 SD) at a volcanic CO2 seep in Japan to assess the underlying processes and patterns of algal community development. We assessed (i) algal community succession in two different seasons (Cooler months: January–July, and warmer months: July–January), (ii) the effects of initial community composition on subsequent community succession (by reciprocally transplanting preestablished communities for a further 6 months), and (iii) the community production of resulting communities, to assess how their functioning was altered (following 12 months recruitment). Settlement tiles became dominated by turf algae under CO2‐enrichment and had lower biomass, diversity and complexity, a pattern consistent across seasons. This locked the community in a species‐poor early successional stage. In terms of community functioning, the elevated pCO2 community had greater net community production, but this did not result in increased algal community cover, biomass, biodiversity or structural complexity. Taken together, this shows that both new and established communities become simplified by rising CO2 levels. Our transplant of preestablished communities from enriched CO2 to reference conditions demonstrated their high resilience, since they became indistinguishable from communities maintained entirely in reference conditions. This shows that meaningful reductions in pCO2 can enable the recovery of algal communities. By understanding the ecological processes responsible for driving shifts in community composition, we can better assess how communities are likely to be altered by ocean acidification.

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Ocean acidification may make some species glow brighter

Published 12 January 2021 Media coverage Closed
These glowing specks are sea fireflies (Vargula hilgendorfii) on a beach in Japan. A new analysis suggests that they might glow a bit brighter as the ocean becomes more acidic.
TREVOR WILLIAMS/STONE/GETTY IMAGES

A more acidic ocean could give some species a glow-up.

As the pH of the ocean decreases as a result of climate change, some bioluminescent organisms might get brighter, while others see their lights dim, scientists report January 2 at the virtual annual meeting of the Society for Integrative and Comparative Biology.

Bioluminescence is de rigueur in parts of the ocean (SN: 5/19/20). The ability to light the dark has evolved more than 90 times in different species. As a result, the chemical structures that create bioluminescence vary wildly — from single chains of atoms to massive ringed complexes.

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