Articles | Volume 16, issue 16
https://doi.org/10.5194/bg-16-3283-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-16-3283-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Dissolved organic nutrients dominate melting surface ice of the Dark Zone (Greenland Ice Sheet)
Alexandra T. Holland
CORRESPONDING AUTHOR
Bristol Glaciology Centre, School of Geographical Sciences, University
of Bristol, Bristol, BS8 1HB, UK
Christopher J. Williamson
Bristol Glaciology Centre, School of Geographical Sciences, University
of Bristol, Bristol, BS8 1HB, UK
School of Biological Sciences, University of Bristol, 24 Tyndall
Avenue, Bristol, BS8 1TQ, UK
Fotis Sgouridis
School of Geographical Sciences, University of Bristol, Bristol, BS8
1RL, UK
Andrew J. Tedstone
Bristol Glaciology Centre, School of Geographical Sciences, University
of Bristol, Bristol, BS8 1HB, UK
Jenine McCutcheon
School of Earth and Environment, University of Leeds, Leeds, LS2 9JT,
UK
Joseph M. Cook
Department of Geography, University of Sheffield, Winter Street,
Sheffield, S3 7ND, UK
Ewa Poniecka
School of Earth and Ocean Sciences, Cardiff University, Main Building,
Park Place, Cardiff, CF10 3AT, UK
Marian L. Yallop
School of Biological Sciences, University of Bristol, 24 Tyndall
Avenue, Bristol, BS8 1TQ, UK
Martyn Tranter
Bristol Glaciology Centre, School of Geographical Sciences, University
of Bristol, Bristol, BS8 1HB, UK
Alexandre M. Anesio
Bristol Glaciology Centre, School of Geographical Sciences, University
of Bristol, Bristol, BS8 1HB, UK
Department of Environmental Science, Aarhus University, Roskilde,
4000, Denmark
The Black & Bloom Group
A full list of authors and their affiliations appears at the end of the paper.
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Eva L. Doting, Ian T. Stevens, Anne M. Kellerman, Pamela E. Rossel, Runa Antony, Amy M. McKenna, Martyn Tranter, Liane G. Benning, Robert G. M. Spencer, Jon R. Hawkings, and Alexandre M. Anesio
EGUsphere, https://doi.org/10.5194/egusphere-2024-492, https://doi.org/10.5194/egusphere-2024-492, 2024
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This study provides new insights into the transformation of dissolved organic matter (DOM) that takes place as meltwater flows through the porous crust of weathering ice that covers glacier ice surfaces during the melt season. Movement of water through the weathering crust is slow, allowing microorganisms and sunlight to alter the DOM in glacial meltwater. This is important as supraglacial meltwaters deliver DOM and nutrients to microorganisms living in downstream receiving aquatic environments.
Mohd Al Farid Abraham, Bernhard David A. Naafs, Vittoria Lauretano, Fotis Sgouridis, and Richard D. Pancost
Clim. Past, 19, 2569–2580, https://doi.org/10.5194/cp-19-2569-2023, https://doi.org/10.5194/cp-19-2569-2023, 2023
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Oceanic Anoxic Event 2 (OAE 2), about 93.5 million years ago, is characterized by widespread deoxygenated ocean and massive burial of organic-rich sediments. Our results show that the marine deoxygenation at the equatorial Atlantic that predates the OAE 2 interval was driven by global warming and associated with the nutrient status of the site, with factors like temperature-modulated upwelling and hydrology-induced weathering contributing to enhanced nutrient delivery over various timescales.
Timo Schmid, Valentina Radić, Andrew Tedstone, James M. Lea, Stephen Brough, and Mauro Hermann
The Cryosphere, 17, 3933–3954, https://doi.org/10.5194/tc-17-3933-2023, https://doi.org/10.5194/tc-17-3933-2023, 2023
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The Greenland Ice Sheet contributes strongly to sea level rise in the warming climate. One process that can affect the ice sheet's mass balance is short-term ice speed-up events. These can be caused by high melting or rainfall as the water flows underneath the glacier and allows for faster sliding. In this study we found three main weather patterns that cause such ice speed-up events on the Russell Glacier in southwest Greenland and analyzed how they induce local melting and ice accelerations.
Beatriz Gill-Olivas, Jon Telling, Mark Skidmore, and Martyn Tranter
Biogeosciences, 20, 929–943, https://doi.org/10.5194/bg-20-929-2023, https://doi.org/10.5194/bg-20-929-2023, 2023
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Microbial ecosystems have been found in all subglacial environments sampled to date. Yet, little is known of the sources of energy and nutrients that sustain these microbial populations. This study shows that crushing of sedimentary rocks, which contain organic carbon, carbonate and sulfide minerals, along with previously weathered silicate minerals, produces a range of compounds and nutrients which can be utilised by the diverse suite of microbes that inhabit glacier beds.
Nicole Clerx, Horst Machguth, Andrew Tedstone, Nicolas Jullien, Nander Wever, Rolf Weingartner, and Ole Roessler
The Cryosphere, 16, 4379–4401, https://doi.org/10.5194/tc-16-4379-2022, https://doi.org/10.5194/tc-16-4379-2022, 2022
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Meltwater runoff is one of the main contributors to mass loss on the Greenland Ice Sheet that influences global sea level rise. However, it remains unclear where meltwater runs off and what processes cause this. We measured the velocity of meltwater flow through snow on the ice sheet, which ranged from 0.17–12.8 m h−1 for vertical percolation and from 1.3–15.1 m h−1 for lateral flow. This is an important step towards understanding where, when and why meltwater runoff occurs on the ice sheet.
Miranda J. Nicholes, Christopher Williamson, Martyn Tranter, Alexandra Holland, Marian Yallop, and Alexandre Anesio
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-227, https://doi.org/10.5194/bg-2020-227, 2020
Publication in BG not foreseen
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This incubation experiment assessed the role of solar radiation and heterotrophic bacteria in the degradation of organic carbon in surface ice of the Greenland Ice Sheet. Although ultraviolet radiation was found to alter carbon composition, heterotrophic degradation caused the greatest changes to both carbon composition and quantity. Both processes are likely interlinked within the surface ice and are fundamental to controlling the composition of carbon exported to downstream environments.
Andrew J. Tedstone, Joseph M. Cook, Christopher J. Williamson, Stefan Hofer, Jenine McCutcheon, Tristram Irvine-Fynn, Thomas Gribbin, and Martyn Tranter
The Cryosphere, 14, 521–538, https://doi.org/10.5194/tc-14-521-2020, https://doi.org/10.5194/tc-14-521-2020, 2020
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Albedo describes how much light that hits a surface is reflected without being absorbed. Low-albedo ice surfaces melt more quickly. There are large differences in the albedo of bare-ice areas of the Greenland Ice Sheet. They are caused both by dark glacier algae and by the condition of the underlying ice. Changes occur over centimetres to metres, so satellites do not always detect real albedo changes. Estimates of melt made using satellite measurements therefore tend to be underestimates.
Joseph M. Cook, Andrew J. Tedstone, Christopher Williamson, Jenine McCutcheon, Andrew J. Hodson, Archana Dayal, McKenzie Skiles, Stefan Hofer, Robert Bryant, Owen McAree, Andrew McGonigle, Jonathan Ryan, Alexandre M. Anesio, Tristram D. L. Irvine-Fynn, Alun Hubbard, Edward Hanna, Mark Flanner, Sathish Mayanna, Liane G. Benning, Dirk van As, Marian Yallop, James B. McQuaid, Thomas Gribbin, and Martyn Tranter
The Cryosphere, 14, 309–330, https://doi.org/10.5194/tc-14-309-2020, https://doi.org/10.5194/tc-14-309-2020, 2020
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Melting of the Greenland Ice Sheet (GrIS) is a major source of uncertainty for sea level rise projections. Ice-darkening due to the growth of algae has been recognized as a potential accelerator of melting. This paper measures and models the algae-driven ice melting and maps the algae over the ice sheet for the first time. We estimate that as much as 13 % total runoff from the south-western GrIS can be attributed to these algae, showing that they must be included in future mass balance models.
Joseph M. Cook, Andrew J. Hodson, Alex S. Gardner, Mark Flanner, Andrew J. Tedstone, Christopher Williamson, Tristram D. L. Irvine-Fynn, Johan Nilsson, Robert Bryant, and Martyn Tranter
The Cryosphere, 11, 2611–2632, https://doi.org/10.5194/tc-11-2611-2017, https://doi.org/10.5194/tc-11-2611-2017, 2017
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Biological growth darkens snow and ice, causing it to melt faster. This is often referred to as
bioalbedo. Quantifying bioalbedo has not been achieved because of difficulties in isolating the biological contribution from the optical properties of ice and snow, and from inorganic impurities in field studies. In this paper, we provide a physical model that enables bioalbedo to be quantified from first principles and we use it to guide future field studies.
Andrew J. Tedstone, Jonathan L. Bamber, Joseph M. Cook, Christopher J. Williamson, Xavier Fettweis, Andrew J. Hodson, and Martyn Tranter
The Cryosphere, 11, 2491–2506, https://doi.org/10.5194/tc-11-2491-2017, https://doi.org/10.5194/tc-11-2491-2017, 2017
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The bare ice albedo of the south-west Greenland ice sheet varies dramatically between years. The reasons are unclear but likely involve darkening by inorganic particulates, cryoconite and ice algae. We use satellite imagery to examine dark ice dynamics and climate model outputs to find likely climatological controls. Outcropping particulates can explain the spatial extent of dark ice, but the darkening itself is likely due to ice algae growth controlled by meltwater and light availability.
Christopher James Williamson, Rupert Perkins, Matthew Voller, Marian Louise Yallop, and Juliet Brodie
Biogeosciences, 14, 4485–4498, https://doi.org/10.5194/bg-14-4485-2017, https://doi.org/10.5194/bg-14-4485-2017, 2017
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Red calcified seaweeds in UK rock pools have seasonal patterns in growth and photosynthesis driven by seawater temperature, light and the chemistry of rock pool water. This is important given future changes in environmental factors such as climate change and ocean acidification. Photosynthesis and calcification are strongly coupled and depend on light and temperature, whilst dissolution is regulated by rock pool water chemistry and is thus particularly vulnerable to environmental change.
James A. Bradley, Sandra Arndt, Marie Šabacká, Liane G. Benning, Gary L. Barker, Joshua J. Blacker, Marian L. Yallop, Katherine E. Wright, Christopher M. Bellas, Jonathan Telling, Martyn Tranter, and Alexandre M. Anesio
Biogeosciences, 13, 5677–5696, https://doi.org/10.5194/bg-13-5677-2016, https://doi.org/10.5194/bg-13-5677-2016, 2016
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Soil development following glacier retreat was characterized using a novel integrated field, laboratory and modelling approach in Svalbard. We found community shifts in bacteria, which were responsible for driving cycles in carbon and nutrients. Allochthonous inputs were also important in sustaining bacterial production. This study shows how an integrated model–data approach can improve understanding and obtain a more holistic picture of soil development in an increasingly ice-free future world.
Robert Raiswell, Jon R. Hawkings, Liane G. Benning, Alex R. Baker, Ros Death, Samuel Albani, Natalie Mahowald, Michael D. Krom, Simon W. Poulton, Jemma Wadham, and Martyn Tranter
Biogeosciences, 13, 3887–3900, https://doi.org/10.5194/bg-13-3887-2016, https://doi.org/10.5194/bg-13-3887-2016, 2016
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Iron is an essential nutrient for plankton growth. One important source of iron is wind-blown dust. The polar oceans are remote from dust sources but melting icebergs supply sediment that contains iron which is potentially available to plankton. We show that iceberg sediments contain more potentially bioavailable iron than wind-blown dust. Iceberg sources will become increasingly important with climate change and increased plankton growth can remove more carbon dioxide from the atmosphere.
Emily C. O'Donnell, Jemma L. Wadham, Grzegorz P. Lis, Martyn Tranter, Amy E. Pickard, Marek Stibal, Paul Dewsbury, and Sean Fitzsimons
Biogeosciences, 13, 3833–3846, https://doi.org/10.5194/bg-13-3833-2016, https://doi.org/10.5194/bg-13-3833-2016, 2016
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We use a novel ion chromatographic analysis that provides the first identification and quantification of major low-molecular-weight dissolved organic carbon (LMW-DOC) compounds in basal ice. LMW-DOC concentrations were dependent on the bioavailability of the overridden organic carbon, which in turn was influenced by the type of overridden material. The overridden material may thus act as a direct (abiotic leaching) and indirect (microbial cycling) source of DOC to the subglacial environment.
Fotis Sgouridis, Andrew Stott, and Sami Ullah
Biogeosciences, 13, 1821–1835, https://doi.org/10.5194/bg-13-1821-2016, https://doi.org/10.5194/bg-13-1821-2016, 2016
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Soil denitrification is considered the most un-constrained process in the global N cycle due to uncertain in situ N2 flux measurements, particularly in natural and semi-natural terrestrial ecosystems. The 15N gas-flux method was adapted by lowering the 15N tracer application rate to 0.04–0.5 kg 15N ha−1. The minimum detectable flux rates were 4 μg N m−2 h−1 and 0.2 ng N m−2 h−1 for the N2 and N2O fluxes respectively. The acetylene inhibition technique underestimated denitrification rates by a factor of 4.
E. C. Lawson, J. L. Wadham, M. Tranter, M. Stibal, G. P. Lis, C. E. H. Butler, J. Laybourn-Parry, P. Nienow, D. Chandler, and P. Dewsbury
Biogeosciences, 11, 4015–4028, https://doi.org/10.5194/bg-11-4015-2014, https://doi.org/10.5194/bg-11-4015-2014, 2014
Related subject area
Earth System Science/Response to Global Change: Climate Change
The effect of forest cover changes on the regional climate conditions in Europe during the period 1986–2015
Carbon cycle feedbacks in an idealized simulation and a scenario simulation of negative emissions in CMIP6 Earth system models
Spatiotemporal heterogeneity in the increase in ocean acidity extremes in the northeastern Pacific
Direct foliar phosphorus uptake from wildfire ash
Anthropogenic climate change drives non-stationary phytoplankton internal variability
The response of wildfire regimes to Last Glacial Maximum carbon dioxide and climate
Simulated responses of soil carbon to climate change in CMIP6 Earth system models: the role of false priming
Alkalinity biases in CMIP6 Earth system models and implications for simulated CO2 drawdown via artificial alkalinity enhancement
Experiments of the efficacy of tree ring blue intensity as a climate proxy in central and western China
Burned area and carbon emissions across northwestern boreal North America from 2001–2019
Quantifying land carbon cycle feedbacks under negative CO2 emissions
The potential of an increased deciduous forest fraction to mitigate the effects of heat extremes in Europe
Ideas and perspectives: Alleviation of functional limitations by soil organisms is key to climate feedbacks from arctic soils
A comparison of the climate and carbon cycle effects of carbon removal by afforestation and an equivalent reduction in fossil fuel emissions
Stability of alkalinity in ocean alkalinity enhancement (OAE) approaches – consequences for durability of CO2 storage
Ideas and perspectives: Land–ocean connectivity through groundwater
Bioclimatic change as a function of global warming from CMIP6 climate projections
Reconciling different approaches to quantifying land surface temperature impacts of afforestation using satellite observations
Drivers of intermodel uncertainty in land carbon sink projections
Reviews and syntheses: A framework to observe, understand and project ecosystem response to environmental change in the East Antarctic Southern Ocean
Acidification impacts and acclimation potential of Caribbean benthic foraminifera assemblages in naturally discharging low-pH water
Monitoring vegetation condition using microwave remote sensing: the standardized vegetation optical depth index (SVODI)
Evaluation of soil carbon simulation in CMIP6 Earth system models
Diazotrophy as a key driver of the response of marine net primary productivity to climate change
Impact of negative and positive CO2 emissions on global warming metrics using an ensemble of Earth system model simulations
Acidification, deoxygenation, and nutrient and biomass declines in a warming Mediterranean Sea
Ocean alkalinity enhancement – avoiding runaway CaCO3 precipitation during quick and hydrated lime dissolution
Assessment of the impacts of biological nitrogen fixation structural uncertainty in CMIP6 earth system models
Soil carbon loss in warmed subarctic grasslands is rapid and restricted to topsoil
The European forest carbon budget under future climate conditions and current management practices
The influence of mesoscale climate drivers on hypoxia in a fjord-like deep coastal inlet and its potential implications regarding climate change: examining a decade of water quality data
Contrasting responses of phytoplankton productivity between coastal and offshore surface waters in the Taiwan Strait and the South China Sea to short-term seawater acidification
Modeling interactions between tides, storm surges, and river discharges in the Kapuas River delta
The application of dendrometers to alpine dwarf shrubs – a case study to investigate stem growth responses to environmental conditions
Climate, land cover and topography: essential ingredients in predicting wetland permanence
Not all biodiversity rich spots are climate refugia
Evaluating the dendroclimatological potential of blue intensity on multiple conifer species from Tasmania and New Zealand
Anthropogenic CO2-mediated freshwater acidification limits survival, calcification, metabolism, and behaviour in stress-tolerant freshwater crustaceans
Quantifying the role of moss in terrestrial ecosystem carbon dynamics in northern high latitudes
On the influence of erect shrubs on the irradiance profile in snow
Tolerance of tropical marine microphytobenthos exposed to elevated irradiance and temperature
Persistent impacts of the 2018 drought on forest disturbance regimes in Europe
Reviews and syntheses: Arctic fire regimes and emissions in the 21st century
Slowdown of the greening trend in natural vegetation with further rise in atmospheric CO2
Effects of elevated CO2 and extreme climatic events on forage quality and in vitro rumen fermentation in permanent grassland
Cushion bog plant community responses to passive warming in southern Patagonia
Blue carbon stocks and exchanges along the California coast
Oceanic primary production decline halved in eddy-resolving simulations of global warming
Assessing climate change impacts on live fuel moisture and wildfire risk using a hydrodynamic vegetation model
Does drought advance the onset of autumn leaf senescence in temperate deciduous forest trees?
Marcus Breil, Vanessa K. M. Schneider, and Joaquim G. Pinto
Biogeosciences, 21, 811–824, https://doi.org/10.5194/bg-21-811-2024, https://doi.org/10.5194/bg-21-811-2024, 2024
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The general impact of afforestation on the regional climate conditions in Europe during the period 1986–2015 is investigated. For this purpose, a regional climate model simulation is performed, in which afforestation during this period is considered, and results are compared to a simulation in which this is not the case. Results show that afforestation had discernible impacts on the climate change signal in Europe, which may have mitigated the local warming trend, especially in summer in Europe.
Ali Asaadi, Jörg Schwinger, Hanna Lee, Jerry Tjiputra, Vivek Arora, Roland Séférian, Spencer Liddicoat, Tomohiro Hajima, Yeray Santana-Falcón, and Chris D. Jones
Biogeosciences, 21, 411–435, https://doi.org/10.5194/bg-21-411-2024, https://doi.org/10.5194/bg-21-411-2024, 2024
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Carbon cycle feedback metrics are employed to assess phases of positive and negative CO2 emissions. When emissions become negative, we find that the model disagreement in feedback metrics increases more strongly than expected from the assumption that the uncertainties accumulate linearly with time. The geographical patterns of such metrics over land highlight that differences in response between tropical/subtropical and temperate/boreal ecosystems are a major source of model disagreement.
Flora Desmet, Matthias Münnich, and Nicolas Gruber
Biogeosciences, 20, 5151–5175, https://doi.org/10.5194/bg-20-5151-2023, https://doi.org/10.5194/bg-20-5151-2023, 2023
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Ocean acidity extremes in the upper 250 m depth of the northeastern Pacific rapidly increase with atmospheric CO2 rise, which is worrisome for marine organisms that rapidly experience pH levels outside their local environmental conditions. Presented research shows the spatiotemporal heterogeneity in this increase between regions and depths. In particular, the subsurface increase is substantially slowed down by the presence of mesoscale eddies, often not resolved in Earth system models.
Anton Lokshin, Daniel Palchan, and Avner Gross
EGUsphere, https://doi.org/10.5194/egusphere-2023-2617, https://doi.org/10.5194/egusphere-2023-2617, 2023
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Ash particles from wildfires are rich in phosphorus (P), a crucial nutrient that constitutes a limiting factor in 43 % of the world's land ecosystems. We hypothesized that wildfire ash could directly contribute to plant nutrition. We found that fire ash application boosts the growth of plants, but the only way plants can uptake P from fire ash is through the foliar uptake pathway, and not through the roots. The fertilization impact of fire ash was maintained also under elevated levels of CO2.
Geneviève W. Elsworth, Nicole S. Lovenduski, Kristen M. Krumhardt, Thomas M. Marchitto, and Sarah Schlunegger
Biogeosciences, 20, 4477–4490, https://doi.org/10.5194/bg-20-4477-2023, https://doi.org/10.5194/bg-20-4477-2023, 2023
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Anthropogenic climate change will influence marine phytoplankton over the coming century. Here, we quantify the influence of anthropogenic climate change on marine phytoplankton internal variability using an Earth system model ensemble and identify a decline in global phytoplankton biomass variance with warming. Our results suggest that climate mitigation efforts that account for marine phytoplankton changes should also consider changes in phytoplankton variance driven by anthropogenic warming.
Olivia Haas, Iain Colin Prentice, and Sandy P. Harrison
Biogeosciences, 20, 3981–3995, https://doi.org/10.5194/bg-20-3981-2023, https://doi.org/10.5194/bg-20-3981-2023, 2023
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We quantify the impact of CO2 and climate on global patterns of burnt area, fire size, and intensity under Last Glacial Maximum (LGM) conditions using three climate scenarios. Climate change alone did not produce the observed LGM reduction in burnt area, but low CO2 did through reducing vegetation productivity. Fire intensity was sensitive to CO2 but strongly affected by changes in atmospheric dryness. Low CO2 caused smaller fires; climate had the opposite effect except in the driest scenario.
Rebecca M. Varney, Sarah E. Chadburn, Eleanor J. Burke, Simon Jones, Andy J. Wiltshire, and Peter M. Cox
Biogeosciences, 20, 3767–3790, https://doi.org/10.5194/bg-20-3767-2023, https://doi.org/10.5194/bg-20-3767-2023, 2023
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This study evaluates soil carbon projections during the 21st century in CMIP6 Earth system models. In general, we find a reduced spread of changes in global soil carbon in CMIP6 compared to the previous CMIP5 generation. The reduced CMIP6 spread arises from an emergent relationship between soil carbon changes due to change in plant productivity and soil carbon changes due to changes in turnover time. We show that this relationship is consistent with false priming under transient climate change.
Claudia Hinrichs, Peter Köhler, Christoph Völker, and Judith Hauck
Biogeosciences, 20, 3717–3735, https://doi.org/10.5194/bg-20-3717-2023, https://doi.org/10.5194/bg-20-3717-2023, 2023
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This study evaluated the alkalinity distribution in 14 climate models and found that most models underestimate alkalinity at the surface and overestimate it in the deeper ocean. It highlights the need for better understanding and quantification of processes driving alkalinity distribution and calcium carbonate dissolution and the importance of accounting for biases in model results when evaluating potential ocean alkalinity enhancement experiments.
Yonghong Zheng, Huanfeng Shen, Rory Abernethy, and Rob Wilson
Biogeosciences, 20, 3481–3490, https://doi.org/10.5194/bg-20-3481-2023, https://doi.org/10.5194/bg-20-3481-2023, 2023
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Investigations in central and western China show that tree ring inverted latewood intensity expresses a strong positive relationship with growing-season temperatures, indicating exciting potential for regions south of 30° N that are traditionally not targeted for temperature reconstructions. Earlywood BI also shows good potential to reconstruct hydroclimate parameters in some humid areas and will enhance ring-width-based hydroclimate reconstructions in the future.
Stefano Potter, Sol Cooperdock, Sander Veraverbeke, Xanthe Walker, Michelle C. Mack, Scott J. Goetz, Jennifer Baltzer, Laura Bourgeau-Chavez, Arden Burrell, Catherine Dieleman, Nancy French, Stijn Hantson, Elizabeth E. Hoy, Liza Jenkins, Jill F. Johnstone, Evan S. Kane, Susan M. Natali, James T. Randerson, Merritt R. Turetsky, Ellen Whitman, Elizabeth Wiggins, and Brendan M. Rogers
Biogeosciences, 20, 2785–2804, https://doi.org/10.5194/bg-20-2785-2023, https://doi.org/10.5194/bg-20-2785-2023, 2023
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Here we developed a new burned-area detection algorithm between 2001–2019 across Alaska and Canada at 500 m resolution. We estimate 2.37 Mha burned annually between 2001–2019 over the domain, emitting 79.3 Tg C per year, with a mean combustion rate of 3.13 kg C m−2. We found larger-fire years were generally associated with greater mean combustion. The burned-area and combustion datasets described here can be used for local- to continental-scale applications of boreal fire science.
V. Rachel Chimuka, Claude-Michel Nzotungicimpaye, and Kirsten Zickfeld
Biogeosciences, 20, 2283–2299, https://doi.org/10.5194/bg-20-2283-2023, https://doi.org/10.5194/bg-20-2283-2023, 2023
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We propose a new method to quantify carbon cycle feedbacks under negative CO2 emissions. Our method isolates the lagged carbon cycle response to preceding positive emissions from the response to negative emissions. Our findings suggest that feedback parameters calculated with the novel approach are larger than those calculated with the conventional approach whereby carbon cycle inertia is not corrected for, with implications for the effectiveness of carbon dioxide removal in reducing CO2 levels.
Marcus Breil, Annabell Weber, and Joaquim G. Pinto
Biogeosciences, 20, 2237–2250, https://doi.org/10.5194/bg-20-2237-2023, https://doi.org/10.5194/bg-20-2237-2023, 2023
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A promising strategy for mitigating burdens of heat extremes in Europe is to replace dark coniferous forests with brighter deciduous forests. The consequence of this would be reduced absorption of solar radiation, which should reduce the intensities of heat periods. In this study, we show that deciduous forests have a certain cooling effect on heat period intensities in Europe. However, the magnitude of the temperature reduction is quite small.
Gesche Blume-Werry, Jonatan Klaminder, Eveline J. Krab, and Sylvain Monteux
Biogeosciences, 20, 1979–1990, https://doi.org/10.5194/bg-20-1979-2023, https://doi.org/10.5194/bg-20-1979-2023, 2023
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Northern soils store a lot of carbon. Most research has focused on how this carbon storage is regulated by cold temperatures. However, it is soil organisms, from minute bacteria to large earthworms, that decompose the organic material. Novel soil organisms from further south could increase decomposition rates more than climate change does and lead to carbon losses. We therefore advocate for including soil organisms when predicting the fate of soil functions in warming northern ecosystems.
Koramanghat Unnikrishnan Jayakrishnan and Govindasamy Bala
Biogeosciences, 20, 1863–1877, https://doi.org/10.5194/bg-20-1863-2023, https://doi.org/10.5194/bg-20-1863-2023, 2023
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Afforestation and reducing fossil fuel emissions are two important mitigation strategies to reduce the amount of global warming. Our work shows that reducing fossil fuel emissions is relatively more effective than afforestation for the same amount of carbon removed from the atmosphere. However, understanding of the processes that govern the biophysical effects of afforestation should be improved before considering our results for climate policy.
Jens Hartmann, Niels Suitner, Carl Lim, Julieta Schneider, Laura Marín-Samper, Javier Arístegui, Phil Renforth, Jan Taucher, and Ulf Riebesell
Biogeosciences, 20, 781–802, https://doi.org/10.5194/bg-20-781-2023, https://doi.org/10.5194/bg-20-781-2023, 2023
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CO2 can be stored in the ocean via increasing alkalinity of ocean water. Alkalinity can be created via dissolution of alkaline materials, like limestone or soda. Presented research studies boundaries for increasing alkalinity in seawater. The best way to increase alkalinity was found using an equilibrated solution, for example as produced from reactors. Adding particles for dissolution into seawater on the other hand produces the risk of losing alkalinity and degassing of CO2 to the atmosphere.
Damian L. Arévalo-Martínez, Amir Haroon, Hermann W. Bange, Ercan Erkul, Marion Jegen, Nils Moosdorf, Jens Schneider von Deimling, Christian Berndt, Michael Ernst Böttcher, Jasper Hoffmann, Volker Liebetrau, Ulf Mallast, Gudrun Massmann, Aaron Micallef, Holly A. Michael, Hendrik Paasche, Wolfgang Rabbel, Isaac Santos, Jan Scholten, Katrin Schwalenberg, Beata Szymczycha, Ariel T. Thomas, Joonas J. Virtasalo, Hannelore Waska, and Bradley A. Weymer
Biogeosciences, 20, 647–662, https://doi.org/10.5194/bg-20-647-2023, https://doi.org/10.5194/bg-20-647-2023, 2023
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Groundwater flows at the land–ocean transition and the extent of freshened groundwater below the seafloor are increasingly relevant in marine sciences, both because they are a highly uncertain term of biogeochemical budgets and due to the emerging interest in the latter as a resource. Here, we discuss our perspectives on future research directions to better understand land–ocean connectivity through groundwater and its potential responses to natural and human-induced environmental changes.
Morgan Sparey, Peter Cox, and Mark S. Williamson
Biogeosciences, 20, 451–488, https://doi.org/10.5194/bg-20-451-2023, https://doi.org/10.5194/bg-20-451-2023, 2023
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Accurate climate models are vital for mitigating climate change; however, projections often disagree. Using Köppen–Geiger bioclimate classifications we show that CMIP6 climate models agree well on the fraction of global land surface that will change classification per degree of global warming. We find that 13 % of land will change climate per degree of warming from 1 to 3 K; thus, stabilising warming at 1.5 rather than 2 K would save over 7.5 million square kilometres from bioclimatic change.
Huanhuan Wang, Chao Yue, and Sebastiaan Luyssaert
Biogeosciences, 20, 75–92, https://doi.org/10.5194/bg-20-75-2023, https://doi.org/10.5194/bg-20-75-2023, 2023
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This study provided a synthesis of three influential methods to quantify afforestation impact on surface temperature. Results showed that actual effect following afforestation was highly dependent on afforestation fraction. When full afforestation is assumed, the actual effect approaches the potential effect. We provided evidence the afforestation faction is a key factor in reconciling different methods and emphasized that it should be considered for surface cooling impacts in policy evaluation.
Ryan S. Padrón, Lukas Gudmundsson, Laibao Liu, Vincent Humphrey, and Sonia I. Seneviratne
Biogeosciences, 19, 5435–5448, https://doi.org/10.5194/bg-19-5435-2022, https://doi.org/10.5194/bg-19-5435-2022, 2022
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The answer to how much carbon land ecosystems are projected to remove from the atmosphere until 2100 is different for each Earth system model. We find that differences across models are primarily explained by the annual land carbon sink dependence on temperature and soil moisture, followed by the dependence on CO2 air concentration, and by average climate conditions. Our insights on why each model projects a relatively high or low land carbon sink can help to reduce the underlying uncertainty.
Julian Gutt, Stefanie Arndt, David Keith Alan Barnes, Horst Bornemann, Thomas Brey, Olaf Eisen, Hauke Flores, Huw Griffiths, Christian Haas, Stefan Hain, Tore Hattermann, Christoph Held, Mario Hoppema, Enrique Isla, Markus Janout, Céline Le Bohec, Heike Link, Felix Christopher Mark, Sebastien Moreau, Scarlett Trimborn, Ilse van Opzeeland, Hans-Otto Pörtner, Fokje Schaafsma, Katharina Teschke, Sandra Tippenhauer, Anton Van de Putte, Mia Wege, Daniel Zitterbart, and Dieter Piepenburg
Biogeosciences, 19, 5313–5342, https://doi.org/10.5194/bg-19-5313-2022, https://doi.org/10.5194/bg-19-5313-2022, 2022
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Long-term ecological observations are key to assess, understand and predict impacts of environmental change on biotas. We present a multidisciplinary framework for such largely lacking investigations in the East Antarctic Southern Ocean, combined with case studies, experimental and modelling work. As climate change is still minor here but is projected to start soon, the timely implementation of this framework provides the unique opportunity to document its ecological impacts from the very onset.
Daniel François, Adina Paytan, Olga Maria Oliveira de Araújo, Ricardo Tadeu Lopes, and Cátia Fernandes Barbosa
Biogeosciences, 19, 5269–5285, https://doi.org/10.5194/bg-19-5269-2022, https://doi.org/10.5194/bg-19-5269-2022, 2022
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Our analysis revealed that under the two most conservative acidification projections foraminifera assemblages did not display considerable changes. However, a significant decrease in species richness was observed when pH decreases to 7.7 pH units, indicating adverse effects under high-acidification scenarios. A micro-CT analysis revealed that calcified tests of Archaias angulatus were of lower density in low pH, suggesting no acclimation capacity for this species.
Leander Moesinger, Ruxandra-Maria Zotta, Robin van der Schalie, Tracy Scanlon, Richard de Jeu, and Wouter Dorigo
Biogeosciences, 19, 5107–5123, https://doi.org/10.5194/bg-19-5107-2022, https://doi.org/10.5194/bg-19-5107-2022, 2022
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The standardized vegetation optical depth index (SVODI) can be used to monitor the vegetation condition, such as whether the vegetation is unusually dry or wet. SVODI has global coverage, spans the past 3 decades and is derived from multiple spaceborne passive microwave sensors of that period. SVODI is based on a new probabilistic merging method that allows the merging of normally distributed data even if the data are not gap-free.
Rebecca M. Varney, Sarah E. Chadburn, Eleanor J. Burke, and Peter M. Cox
Biogeosciences, 19, 4671–4704, https://doi.org/10.5194/bg-19-4671-2022, https://doi.org/10.5194/bg-19-4671-2022, 2022
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Soil carbon is the Earth’s largest terrestrial carbon store, and the response to climate change represents one of the key uncertainties in obtaining accurate global carbon budgets required to successfully militate against climate change. The ability of climate models to simulate present-day soil carbon is therefore vital. This study assesses soil carbon simulation in the latest ensemble of models which allows key areas for future model development to be identified.
Laurent Bopp, Olivier Aumont, Lester Kwiatkowski, Corentin Clerc, Léonard Dupont, Christian Ethé, Thomas Gorgues, Roland Séférian, and Alessandro Tagliabue
Biogeosciences, 19, 4267–4285, https://doi.org/10.5194/bg-19-4267-2022, https://doi.org/10.5194/bg-19-4267-2022, 2022
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The impact of anthropogenic climate change on the biological production of phytoplankton in the ocean is a cause for concern because its evolution could affect the response of marine ecosystems to climate change. Here, we identify biological N fixation and its response to future climate change as a key process in shaping the future evolution of marine phytoplankton production. Our results show that further study of how this nitrogen fixation responds to environmental change is essential.
Negar Vakilifard, Richard G. Williams, Philip B. Holden, Katherine Turner, Neil R. Edwards, and David J. Beerling
Biogeosciences, 19, 4249–4265, https://doi.org/10.5194/bg-19-4249-2022, https://doi.org/10.5194/bg-19-4249-2022, 2022
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To remain within the Paris climate agreement, there is an increasing need to develop and implement carbon capture and sequestration techniques. The global climate benefits of implementing negative emission technologies over the next century are assessed using an Earth system model covering a wide range of plausible climate states. In some model realisations, there is continued warming after emissions cease. This continued warming is avoided if negative emissions are incorporated.
Marco Reale, Gianpiero Cossarini, Paolo Lazzari, Tomas Lovato, Giorgio Bolzon, Simona Masina, Cosimo Solidoro, and Stefano Salon
Biogeosciences, 19, 4035–4065, https://doi.org/10.5194/bg-19-4035-2022, https://doi.org/10.5194/bg-19-4035-2022, 2022
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Future projections under the RCP8.5 and RCP4.5 emission scenarios of the Mediterranean Sea biogeochemistry at the end of the 21st century show different levels of decline in nutrients, oxygen and biomasses and an acidification of the water column. The signal intensity is stronger under RCP8.5 and in the eastern Mediterranean. Under RCP4.5, after the second half of the 21st century, biogeochemical variables show a recovery of the values observed at the beginning of the investigated period.
Charly A. Moras, Lennart T. Bach, Tyler Cyronak, Renaud Joannes-Boyau, and Kai G. Schulz
Biogeosciences, 19, 3537–3557, https://doi.org/10.5194/bg-19-3537-2022, https://doi.org/10.5194/bg-19-3537-2022, 2022
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This research presents the first laboratory results of quick and hydrated lime dissolution in natural seawater. These two minerals are of great interest for ocean alkalinity enhancement, a strategy aiming to decrease atmospheric CO2 concentrations. Following the dissolution of these minerals, we identified several hurdles and presented ways to avoid them or completely negate them. Finally, we proceeded to various simulations in today’s oceans to implement the strategy at its highest potential.
Taraka Davies-Barnard, Sönke Zaehle, and Pierre Friedlingstein
Biogeosciences, 19, 3491–3503, https://doi.org/10.5194/bg-19-3491-2022, https://doi.org/10.5194/bg-19-3491-2022, 2022
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Biological nitrogen fixation is the largest natural input of new nitrogen onto land. Earth system models mainly represent global total terrestrial biological nitrogen fixation within observational uncertainties but overestimate tropical fixation. The model range of increase in biological nitrogen fixation in the SSP3-7.0 scenario is 3 % to 87 %. While biological nitrogen fixation is a key source of new nitrogen, its predictive power for net primary productivity in models is limited.
Niel Verbrigghe, Niki I. W. Leblans, Bjarni D. Sigurdsson, Sara Vicca, Chao Fang, Lucia Fuchslueger, Jennifer L. Soong, James T. Weedon, Christopher Poeplau, Cristina Ariza-Carricondo, Michael Bahn, Bertrand Guenet, Per Gundersen, Gunnhildur E. Gunnarsdóttir, Thomas Kätterer, Zhanfeng Liu, Marja Maljanen, Sara Marañón-Jiménez, Kathiravan Meeran, Edda S. Oddsdóttir, Ivika Ostonen, Josep Peñuelas, Andreas Richter, Jordi Sardans, Páll Sigurðsson, Margaret S. Torn, Peter M. Van Bodegom, Erik Verbruggen, Tom W. N. Walker, Håkan Wallander, and Ivan A. Janssens
Biogeosciences, 19, 3381–3393, https://doi.org/10.5194/bg-19-3381-2022, https://doi.org/10.5194/bg-19-3381-2022, 2022
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In subarctic grassland on a geothermal warming gradient, we found large reductions in topsoil carbon stocks, with carbon stocks linearly declining with warming intensity. Most importantly, however, we observed that soil carbon stocks stabilised within 5 years of warming and remained unaffected by warming thereafter, even after > 50 years of warming. Moreover, in contrast to the large topsoil carbon losses, subsoil carbon stocks remained unaffected after > 50 years of soil warming.
Roberto Pilli, Ramdane Alkama, Alessandro Cescatti, Werner A. Kurz, and Giacomo Grassi
Biogeosciences, 19, 3263–3284, https://doi.org/10.5194/bg-19-3263-2022, https://doi.org/10.5194/bg-19-3263-2022, 2022
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To become carbon neutral by 2050, the European Union (EU27) forest C sink should increase to −450 Mt CO2 yr-1. Our study highlights that under current management practices (i.e. excluding any policy scenario) the forest C sink of the EU27 member states and the UK may decrease to about −250 Mt CO2eq yr-1 in 2050. The expected impacts of future climate change, however, add a considerable uncertainty, potentially nearly doubling or halving the sink associated with forest management.
Johnathan Daniel Maxey, Neil David Hartstein, Aazani Mujahid, and Moritz Müller
Biogeosciences, 19, 3131–3150, https://doi.org/10.5194/bg-19-3131-2022, https://doi.org/10.5194/bg-19-3131-2022, 2022
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Deep coastal inlets are important sites for regulating land-based organic pollution before it enters coastal oceans. This study focused on how large climate forces, rainfall, and river flow impact organic loading and oxygen conditions in a coastal inlet in Tasmania. Increases in rainfall were linked to higher organic loading and lower oxygen in basin waters. Finally we observed a significant correlation between the Southern Annular Mode and oxygen concentrations in the system's basin waters.
Guang Gao, Tifeng Wang, Jiazhen Sun, Xin Zhao, Lifang Wang, Xianghui Guo, and Kunshan Gao
Biogeosciences, 19, 2795–2804, https://doi.org/10.5194/bg-19-2795-2022, https://doi.org/10.5194/bg-19-2795-2022, 2022
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After conducting large-scale deck-incubation experiments, we found that seawater acidification (SA) increased primary production (PP) in coastal waters but reduced it in pelagic zones, which is mainly regulated by local pH, light intensity, salinity, and community structure. In future oceans, SA combined with decreased upward transports of nutrients may synergistically reduce PP in pelagic zones.
Joko Sampurno, Valentin Vallaeys, Randy Ardianto, and Emmanuel Hanert
Biogeosciences, 19, 2741–2757, https://doi.org/10.5194/bg-19-2741-2022, https://doi.org/10.5194/bg-19-2741-2022, 2022
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This study is the first assessment to evaluate the interactions between river discharges, tides, and storm surges and how they can drive compound flooding in the Kapuas River delta. We successfully created a realistic hydrodynamic model whose domain covers the land–sea continuum using a wetting–drying algorithm in a data-scarce environment. We then proposed a new method to delineate compound flooding hazard zones along the river channels based on the maximum water level profiles.
Svenja Dobbert, Roland Pape, and Jörg Löffler
Biogeosciences, 19, 1933–1958, https://doi.org/10.5194/bg-19-1933-2022, https://doi.org/10.5194/bg-19-1933-2022, 2022
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Understanding how vegetation might respond to climate change is especially important in arctic–alpine ecosystems, where major shifts in shrub growth have been observed. We studied how such changes come to pass and how future changes might look by measuring hourly variations in the stem diameter of dwarf shrubs from one common species. From these data, we are able to discern information about growth mechanisms and can thus show the complexity of shrub growth and micro-environment relations.
Jody Daniel, Rebecca C. Rooney, and Derek T. Robinson
Biogeosciences, 19, 1547–1570, https://doi.org/10.5194/bg-19-1547-2022, https://doi.org/10.5194/bg-19-1547-2022, 2022
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The threat posed by climate change to prairie pothole wetlands is well documented, but gaps remain in our ability to make meaningful predictions about how prairie pothole wetlands will respond. We integrate aspects of topography, land cover/land use and climate to model the permanence class of tens of thousands of wetlands at the western edge of the Prairie Pothole Region.
Ádám T. Kocsis, Qianshuo Zhao, Mark J. Costello, and Wolfgang Kiessling
Biogeosciences, 18, 6567–6578, https://doi.org/10.5194/bg-18-6567-2021, https://doi.org/10.5194/bg-18-6567-2021, 2021
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Biodiversity is under threat from the effects of global warming, and assessing the effects of climate change on areas of high species richness is of prime importance to conservation. Terrestrial and freshwater rich spots have been and will be less affected by climate change than other areas. However, marine rich spots of biodiversity are expected to experience more pronounced warming.
Rob Wilson, Kathy Allen, Patrick Baker, Gretel Boswijk, Brendan Buckley, Edward Cook, Rosanne D'Arrigo, Dan Druckenbrod, Anthony Fowler, Margaux Grandjean, Paul Krusic, and Jonathan Palmer
Biogeosciences, 18, 6393–6421, https://doi.org/10.5194/bg-18-6393-2021, https://doi.org/10.5194/bg-18-6393-2021, 2021
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We explore blue intensity (BI) – a low-cost method for measuring ring density – to enhance palaeoclimatology in Australasia. Calibration experiments, using several conifer species from Tasmania and New Zealand, model 50–80 % of the summer temperature variance. The implications of these results have profound consequences for high-resolution paleoclimatology in Australasia, as the speed and cheapness of BI generation could lead to a step change in our understanding of past climate in the region.
Alex R. Quijada-Rodriguez, Pou-Long Kuan, Po-Hsuan Sung, Mao-Ting Hsu, Garett J. P. Allen, Pung Pung Hwang, Yung-Che Tseng, and Dirk Weihrauch
Biogeosciences, 18, 6287–6300, https://doi.org/10.5194/bg-18-6287-2021, https://doi.org/10.5194/bg-18-6287-2021, 2021
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Anthropogenic CO2 is chronically acidifying aquatic ecosystems. We aimed to determine the impact of future freshwater acidification on the physiology and behaviour of an important aquaculture crustacean, Chinese mitten crabs. We report that elevated freshwater CO2 levels lead to impairment of calcification, locomotor behaviour, and survival and reduced metabolism in this species. Results suggest that present-day calcifying invertebrates could be heavily affected by freshwater acidification.
Junrong Zha and Qianlai Zhuang
Biogeosciences, 18, 6245–6269, https://doi.org/10.5194/bg-18-6245-2021, https://doi.org/10.5194/bg-18-6245-2021, 2021
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This study incorporated moss into an extant biogeochemistry model to simulate the role of moss in carbon dynamics in the Arctic. The interactions between higher plants and mosses and their competition for energy, water, and nutrients are considered in our study. We found that, compared with the previous model without moss, the new model estimated a much higher carbon accumulation in the region during the last century and this century.
Maria Belke-Brea, Florent Domine, Ghislain Picard, Mathieu Barrere, and Laurent Arnaud
Biogeosciences, 18, 5851–5869, https://doi.org/10.5194/bg-18-5851-2021, https://doi.org/10.5194/bg-18-5851-2021, 2021
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Expanding shrubs in the Arctic change snowpacks into a mix of snow, impurities and buried branches. Snow is a translucent medium into which light penetrates and gets partly absorbed by branches or impurities. Measurements of light attenuation in snow in Northern Quebec, Canada, showed (1) black-carbon-dominated light attenuation in snowpacks without shrubs and (2) buried branches influence radiation attenuation in snow locally, leading to melting and pockets of large crystals close to branches.
Sazlina Salleh and Andrew McMinn
Biogeosciences, 18, 5313–5326, https://doi.org/10.5194/bg-18-5313-2021, https://doi.org/10.5194/bg-18-5313-2021, 2021
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The benthic diatom communities in Tanjung Rhu, Malaysia, were regularly exposed to high light and temperature variability during the tidal cycle, resulting in low photosynthetic efficiency. We examined the impact of high temperatures on diatoms' photosynthetic capacities, and temperatures beyond 50 °C caused severe photoinhibition. At the same time, those diatoms exposed to temperatures of 40 °C did not show any sign of photoinhibition.
Cornelius Senf and Rupert Seidl
Biogeosciences, 18, 5223–5230, https://doi.org/10.5194/bg-18-5223-2021, https://doi.org/10.5194/bg-18-5223-2021, 2021
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Europe was affected by an extreme drought in 2018. We show that this drought has increased forest disturbances across Europe, especially central and eastern Europe. Disturbance levels observed 2018–2020 were the highest on record for 30 years. Increased forest disturbances were correlated with low moisture and high atmospheric water demand. The unprecedented impacts of the 2018 drought on forest disturbances demonstrate an urgent need to adapt Europe’s forests to a hotter and drier future.
Jessica L. McCarty, Juha Aalto, Ville-Veikko Paunu, Steve R. Arnold, Sabine Eckhardt, Zbigniew Klimont, Justin J. Fain, Nikolaos Evangeliou, Ari Venäläinen, Nadezhda M. Tchebakova, Elena I. Parfenova, Kaarle Kupiainen, Amber J. Soja, Lin Huang, and Simon Wilson
Biogeosciences, 18, 5053–5083, https://doi.org/10.5194/bg-18-5053-2021, https://doi.org/10.5194/bg-18-5053-2021, 2021
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Fires, including extreme fire seasons, and fire emissions are more common in the Arctic. A review and synthesis of current scientific literature find climate change and human activity in the north are fuelling an emerging Arctic fire regime, causing more black carbon and methane emissions within the Arctic. Uncertainties persist in characterizing future fire landscapes, and thus emissions, as well as policy-relevant challenges in understanding, monitoring, and managing Arctic fire regimes.
Alexander J. Winkler, Ranga B. Myneni, Alexis Hannart, Stephen Sitch, Vanessa Haverd, Danica Lombardozzi, Vivek K. Arora, Julia Pongratz, Julia E. M. S. Nabel, Daniel S. Goll, Etsushi Kato, Hanqin Tian, Almut Arneth, Pierre Friedlingstein, Atul K. Jain, Sönke Zaehle, and Victor Brovkin
Biogeosciences, 18, 4985–5010, https://doi.org/10.5194/bg-18-4985-2021, https://doi.org/10.5194/bg-18-4985-2021, 2021
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Satellite observations since the early 1980s show that Earth's greening trend is slowing down and that browning clusters have been emerging, especially in the last 2 decades. A collection of model simulations in conjunction with causal theory points at climatic changes as a key driver of vegetation changes in natural ecosystems. Most models underestimate the observed vegetation browning, especially in tropical rainforests, which could be due to an excessive CO2 fertilization effect in models.
Vincent Niderkorn, Annette Morvan-Bertrand, Aline Le Morvan, Angela Augusti, Marie-Laure Decau, and Catherine Picon-Cochard
Biogeosciences, 18, 4841–4853, https://doi.org/10.5194/bg-18-4841-2021, https://doi.org/10.5194/bg-18-4841-2021, 2021
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Climate change can change vegetation characteristics in grasslands with a potential impact on forage chemical composition and quality, as well as its use by ruminants. Using controlled conditions mimicking a future climatic scenario, we show that forage quality and ruminant digestion are affected in opposite ways by elevated atmospheric CO2 and an extreme event (heat wave, severe drought), indicating that different factors of climate change have to be considered together.
Verónica Pancotto, David Holl, Julio Escobar, María Florencia Castagnani, and Lars Kutzbach
Biogeosciences, 18, 4817–4839, https://doi.org/10.5194/bg-18-4817-2021, https://doi.org/10.5194/bg-18-4817-2021, 2021
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We investigated the response of a wetland plant community to elevated temperature conditions in a cushion bog on Tierra del Fuego, Argentina. We measured carbon dioxide fluxes at experimentally warmed plots and at control plots. Warmed plant communities sequestered between 55 % and 85 % less carbon dioxide than untreated control cushions over the main growing season. Our results suggest that even moderate future warming could decrease the carbon sink function of austral cushion bogs.
Melissa A. Ward, Tessa M. Hill, Chelsey Souza, Tessa Filipczyk, Aurora M. Ricart, Sarah Merolla, Lena R. Capece, Brady C O'Donnell, Kristen Elsmore, Walter C. Oechel, and Kathryn M. Beheshti
Biogeosciences, 18, 4717–4732, https://doi.org/10.5194/bg-18-4717-2021, https://doi.org/10.5194/bg-18-4717-2021, 2021
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Salt marshes and seagrass meadows ("blue carbon" habitats) can sequester and store high levels of organic carbon (OC), helping to mitigate climate change. In California blue carbon sediments, we quantified OC storage and exchange between these habitats. We find that (1) these salt marshes store about twice as much OC as seagrass meadows do and (2), while OC from seagrass meadows is deposited into neighboring salt marshes, little of this material is sequestered as "long-term" carbon.
Damien Couespel, Marina Lévy, and Laurent Bopp
Biogeosciences, 18, 4321–4349, https://doi.org/10.5194/bg-18-4321-2021, https://doi.org/10.5194/bg-18-4321-2021, 2021
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An alarming consequence of climate change is the oceanic primary production decline projected by Earth system models. These coarse-resolution models parameterize oceanic eddies. Here, idealized simulations of global warming with increasing resolution show that the decline in primary production in the eddy-resolved simulations is half as large as in the eddy-parameterized simulations. This stems from the high sensitivity of the subsurface nutrient transport to model resolution.
Wu Ma, Lu Zhai, Alexandria Pivovaroff, Jacquelyn Shuman, Polly Buotte, Junyan Ding, Bradley Christoffersen, Ryan Knox, Max Moritz, Rosie A. Fisher, Charles D. Koven, Lara Kueppers, and Chonggang Xu
Biogeosciences, 18, 4005–4020, https://doi.org/10.5194/bg-18-4005-2021, https://doi.org/10.5194/bg-18-4005-2021, 2021
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We use a hydrodynamic demographic vegetation model to estimate live fuel moisture dynamics of chaparral shrubs, a dominant vegetation type in fire-prone southern California. Our results suggest that multivariate climate change could cause a significant net reduction in live fuel moisture and thus exacerbate future wildfire danger in chaparral shrub systems.
Bertold Mariën, Inge Dox, Hans J. De Boeck, Patrick Willems, Sebastien Leys, Dimitri Papadimitriou, and Matteo Campioli
Biogeosciences, 18, 3309–3330, https://doi.org/10.5194/bg-18-3309-2021, https://doi.org/10.5194/bg-18-3309-2021, 2021
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The drivers of the onset of autumn leaf senescence for several deciduous tree species are still unclear. Therefore, we addressed (i) if drought impacts the timing of autumn leaf senescence and (ii) if the relationship between drought and autumn leaf senescence depends on the tree species. Our study suggests that the timing of autumn leaf senescence is conservative across years and species and even independent of drought stress.
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Short summary
This paper provides a preliminary data set for dissolved nutrient abundance in the Dark Zone of the Greenland Ice Sheet. This 15-year marked darkening has since been attributed to glacier algae blooms, yet has not been accounted for in current melt rate models. We conclude that the dissolved organic phase dominates surface ice environments and that factors other than macronutrient limitation control the extent and magnitude of the glacier algae blooms.
This paper provides a preliminary data set for dissolved nutrient abundance in the Dark Zone of...
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