scholarly journals Sensitivity of pelagic calcification to ocean acidification

2011 ◽  
Vol 8 (2) ◽  
pp. 433-458 ◽  
Author(s):  
R. Gangstø ◽  
F. Joos ◽  
M. Gehlen
Keyword(s):  
Ocean Acidification ◽  
Carbon Emissions ◽  
Large Scale ◽  
Field Experiments ◽  
Emission Scenario ◽  
Atmospheric Co2 ◽  
Soluble Form ◽  
Saturation State ◽  
Biogeochemical Models ◽  
Wide Range

Abstract. Ocean acidification might reduce the ability of calcifying plankton to produce and maintain their shells of calcite, or of aragonite, the more soluble form of CaCO3. In addition to possibly large biological impacts, reduced CaCO3 production corresponds to a negative feedback on atmospheric CO2. In order to explore the sensitivity of the ocean carbon cycle to increasing concentrations of atmospheric CO2, we use the new biogeochemical Bern3D/PISCES model. The model reproduces the large scale distributions of biogeochemical tracers. With a range of sensitivity studies, we explore the effect of (i) using different parameterizations of CaCO3 production fitted to available laboratory and field experiments, of (ii) letting calcite and aragonite be produced by auto- and heterotrophic plankton groups, and of (iii) using carbon emissions from the range of the most recent IPCC Representative Concentration Pathways (RCP). Under a high-emission scenario, the CaCO3 production of all the model versions decreases from ~1 Pg C yr−1 to between 0.36 and 0.82 Pg C yr−1 by the year 2100. The changes in CaCO3 production and dissolution resulting from ocean acidification provide only a small feedback on atmospheric CO2 of −1 to −11 ppm by the year 2100, despite the wide range of parameterizations, model versions and scenarios included in our study. A potential upper limit of the CO2-calcification/dissolution feedback of −30 ppm by the year 2100 is computed by setting calcification to zero after 2000 in a high 21st century emission scenario. The similarity of feedback estimates yielded by the model version with calcite produced by nanophytoplankton and the one with calcite, respectively aragonite produced by mesozooplankton suggests that expending biogeochemical models to calcifying zooplankton might not be needed to simulate biogeochemical impacts on the marine carbonate cycle. The changes in saturation state confirm previous studies indicating that future anthropogenic CO2 emissions may lead to irreversible changes in ΩA for several centuries. Furthermore, due to the long-term changes in the deep ocean, the ratio of open water CaCO3 dissolution to production stabilizes by the year 2500 at a value that is 30–50% higher than at pre-industrial times when carbon emissions are set to zero after 2100.

scholarly journals Sensitivity of the marine carbonate cycle to atmospheric CO<sub>2</sub>

2010 ◽  
Vol 7 (5) ◽  
pp. 7029-7090
Author(s):  
R. Gangstø ◽  
F. Joos ◽  
M. Gehlen
Keyword(s):  
Ocean Acidification ◽  
Carbon Emissions ◽  
Large Scale ◽  
Field Experiments ◽  
Open Water ◽  
Atmospheric Co2 ◽  
Soluble Form ◽  
Wide Range ◽  
High Emission ◽  
Ocean Carbon

Abstract. Ocean acidification might reduce the ability of calcifying plankton to produce and maintain their shells of calcite, or of aragonite, the more soluble form of CaCO3. In addition to possibly large biological impacts, reduced CaCO3 production corresponds to a negative feedback on atmospheric CO2. In order to explore the sensitivity of the ocean carbon cycle to increasing concentrations of atmospheric CO2, we use the new biogeochemical Bern3D/PISCES model. The model reproduces the large scale distributions of biogeochemical tracers. With a range of sensitivity studies, we explore the effect of (i) using different parameterizations of CaCO3 production fitted to available laboratory and field experiments, of (ii) letting calcite and aragonite be produced by auto- and heterotrophic plankton groups, and of (iii) using carbon emissions from the range of the most recent IPCC Representative Concentration Pathways (RCP). Under a high-emission scenario, the CaCO3 production of all the model versions decreases from ~1 Pg C yr−1 to between 0.36 and 0.82 Pg C yr−1 by the year 2100. By the year 2500, the ratio of open water CaCO3 dissolution to production stabilizes at a value that is 30–50% higher than at pre-industrial times when carbon emissions are set to zero after 2100. Despite the wide range of parameterizations, model versions and scenarios included in our study, the changes in CaCO3 production and dissolution resulting from ocean acidification provide only a small feedback on atmospheric CO2 of 1–11 ppm by the year 2100.

scholarly journals Sensitivity of pelagic CaCO<sub>3</sub> dissolution to ocean acidification in an ocean biogeochemical model

2013 ◽  
Vol 10 (7) ◽  
pp. 11343-11373
Author(s):  
A. Regenberg ◽  
B. Schneider ◽  
R. Gangst&amp;oslash;
Keyword(s):  
Ocean Acidification ◽  
Ion Concentration ◽  
Biogeochemical Model ◽  
Saturation State ◽  
Saturation Concentration ◽  
Carbonate Ion ◽  
Biogeochemical Models ◽  
Wide Range ◽  
The Impact

Abstract. In ocean biogeochemical models pelagic CaCO3 dissolution is usually calculated as R = k * Sn, where k is the dissolution rate constant transforming S, the degree of (under-) saturation of seawater with respect to CaCO3, into a time dependent rate R, and n is the reaction rate order. Generally, there are two ways to define the saturation state of seawater with respect to CaCO3: (1) Δ[CO32−], which reflects the difference between the in-situ carbonate ion concentration and the saturation concentration, and (2) Ω, which is approximated by the ratio of in-situ carbonate ion concentration over the saturation concentration. Although describing the same phenomenon, the deviation from equilibrium, both expressions are not equally applicable for the calculation of CaCO3 dissolution in the ocean across pressure gradients, as they differ in their sensitivity to ocean acidification (change of [CO32−]) over depth. In the present study we use a marine biogeochemical model to test the sensitivity of pelagic CaCO3 dissolution to ocean acidification (1–4 × CO2 + stabilization), exploring the possible parameter space for CaCO3 dissolution kinetics as given in the literature. We find that at the millennial time scale there is a wide range of CaCO3 particle flux attenuation into the ocean interior (e.g. a reduction of −55 to −85% at 1000 m depth), which means that there are significant differences in the impact on particle ballasting, depending on the kinetic expression applied.

scholarly journals On the Shoulders of Giants: Continuing the Legacy of Large-Scale Ecosystem Manipulation Experiments in Puerto Rico

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 210 ◽  
Author(s):  
Tana Wood ◽  
Grizelle González ◽  
Whendee Silver ◽  
Sasha Reed ◽  
Molly Cavaleri
Keyword(s):  
Puerto Rico ◽  
Tropical Forests ◽  
Large Scale ◽  
Field Experiments ◽  
Management Strategies ◽  
Luquillo Experimental Forest ◽  
Hurricane Disturbance ◽  
Wide Range ◽  
History Of ◽  
Forest Function

There is a long history of experimental research in the Luquillo Experimental Forest in Puerto Rico. These experiments have addressed questions about biotic thresholds, assessed why communities vary along natural gradients, and have explored forest responses to a range of both anthropogenic and non-anthropogenic disturbances. Combined, these studies cover many of the major disturbances that affect tropical forests around the world and span a wide range of topics, including the effects of forest thinning, ionizing radiation, hurricane disturbance, nitrogen deposition, drought, and global warming. These invaluable studies have greatly enhanced our understanding of tropical forest function under different disturbance regimes and informed the development of management strategies. Here we summarize the major field experiments that have occurred within the Luquillo Experimental Forest. Taken together, results from the major experiments conducted in the Luquillo Experimental Forest demonstrate a high resilience of Puerto Rico’s tropical forests to a variety of stressors.

scholarly journals Temporal changes in surface partial pressure of carbon dioxide and carbonate saturation state in the eastern equatorial Indian Ocean during the 1962–2012 period

2014 ◽  
Vol 11 (22) ◽  
pp. 6293-6305 ◽  
Author(s):  
L. Xue ◽  
W. Yu ◽  
H. Wang ◽  
L.-Q. Jiang ◽  
L. Feng ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Indian Ocean ◽  
Partial Pressure ◽  
Ocean Acidification ◽  
Inorganic Carbon ◽  
Equatorial Indian Ocean ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Saturation State ◽  
Eastern Equatorial Indian Ocean

Abstract. Information on changes in the oceanic carbon dioxide (CO2) concentration and air–sea CO2 flux as well as on ocean acidification in the Indian Ocean is very limited. In this study, temporal changes of the inorganic carbon system in the eastern equatorial Indian Ocean (EIO, 5° N–5° S, 90–95° E) are examined using partial pressure of carbon dioxide (pCO2) data collected in May 2012, historical pCO2 data since 1962, and total alkalinity (TA) data calculated from salinity. Results show that sea surface pCO2 in the equatorial belt (2° N–2° S, 90–95° E) increased from ∼307 μatm in April 1963 to ∼373 μatm in May 1999, ∼381 μatm in April 2007, and ∼385 μatm in May 2012. The mean rate of pCO2 increase in this area (∼1.56 μatm yr−1) was close to that in the atmosphere (∼1.46 μatm yr−1). Despite the steady pCO2 increase in this region, no significant change in air–sea CO2 fluxes was detected during this period. Ocean acidification as indicated by pH and saturation states for carbonate minerals has indeed taken place in this region. Surface water pH (total hydrogen scale) and saturation state for aragonite (Ωarag), calculated from pCO2 and TA, decreased significantly at rates of −0.0016 ± 0.0001 and −0.0095 ± 0.0005 yr−1, respectively. The respective contributions of temperature, salinity, TA, and dissolved inorganic carbon (DIC) to the increase in surface pCO2 and the decreases in pH and Ωarag are quantified. We find that the increase in DIC dominated these changes, while contributions from temperature, salinity, and TA were insignificant. The increase in DIC was most likely associated with the increasing atmospheric CO2 concentration, and the transport of accumulated anthropogenic CO2 from a CO2 sink region via basin-scale ocean circulations. These two processes may combine to drive oceanic DIC to follow atmospheric CO2 increase.

scholarly journals Quantifying the impact of ocean acidification on our future climate

2014 ◽  
Vol 11 (14) ◽  
pp. 3965-3983 ◽  
Author(s):  
R. J. Matear ◽  
A. Lenton
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Ocean Acidification ◽  
Observational Studies ◽  
Emission Scenario ◽  
Biogeochemical Cycles ◽  
Future Climate ◽  
Atmospheric Co2 ◽  
First Order ◽  
The Impact

Abstract. Ocean acidification (OA) is the consequence of rising atmospheric CO2 levels, and it is occurring in conjunction with global warming. Observational studies show that OA will impact ocean biogeochemical cycles. Here, we use an Earth system model under the RCP8.5 emission scenario to evaluate and quantify the first-order impacts of OA on marine biogeochemical cycles, and its potential feedback on our future climate. We find that OA impacts have only a small impact on the future atmospheric CO2 (less than 45 ppm) and global warming (less than a 0.25 K) by 2100. While the climate change feedbacks are small, OA impacts may significantly alter the distribution of biological production and remineralisation, which would alter the dissolved oxygen distribution in the ocean interior. Our results demonstrate that the consequences of OA will not be through its impact on climate change, but on how it impacts the flow of energy in marine ecosystems, which may significantly impact their productivity, composition and diversity.

scholarly journals A large-scale forest fragmentation experiment: the Stability of Altered Forest Ecosystems Project

2011 ◽  
Vol 366 (1582) ◽  
pp. 3292-3302 ◽  
Author(s):  
Robert M. Ewers ◽  
Raphael K. Didham ◽  
Lenore Fahrig ◽  
Gonçalo Ferraz ◽  
Andy Hector ◽  
...  
Keyword(s):  
Forest Fragmentation ◽  
Large Scale ◽  
Forest Cover ◽  
Forest Ecosystems ◽  
Field Experiments ◽  
Spatial Scales ◽  
Ecological Impacts ◽  
Data Types ◽  
Wide Range ◽  
The Stability

Opportunities to conduct large-scale field experiments are rare, but provide a unique opportunity to reveal the complex processes that operate within natural ecosystems. Here, we review the design of existing, large-scale forest fragmentation experiments. Based on this review, we develop a design for the Stability of Altered Forest Ecosystems (SAFE) Project, a new forest fragmentation experiment to be located in the lowland tropical forests of Borneo (Sabah, Malaysia). The SAFE Project represents an advance on existing experiments in that it: (i) allows discrimination of the effects of landscape-level forest cover from patch-level processes; (ii) is designed to facilitate the unification of a wide range of data types on ecological patterns and processes that operate over a wide range of spatial scales; (iii) has greater replication than existing experiments; (iv) incorporates an experimental manipulation of riparian corridors; and (v) embeds the experimentally fragmented landscape within a wider gradient of land-use intensity than do existing projects. The SAFE Project represents an opportunity for ecologists across disciplines to participate in a large initiative designed to generate a broad understanding of the ecological impacts of tropical forest modification.

scholarly journals Historical reconstruction of ocean acidification in the Australian region

2016 ◽  
Vol 13 (6) ◽  
pp. 1753-1765 ◽  
Author(s):  
Andrew Lenton ◽  
Bronte Tilbrook ◽  
Richard J. Matear ◽  
Tristan P. Sasse ◽  
Yukihiro Nojiri
Keyword(s):  
Surface Temperature ◽  
Ocean Acidification ◽  
Sea Surface Temperature ◽  
Ocean Dynamics ◽  
Sea Surface ◽  
Atmospheric Co2 ◽  
Reference Station ◽  
Historical Reconstruction ◽  
Saturation State ◽  
Aragonite Saturation

Abstract. The ocean has become more acidic over the last 200 years in response increasing atmospheric carbon dioxide (CO2) levels. Documenting how the ocean has changed is critical for assessing how these changes impact marine ecosystems and for the management of marine resources. Here we use present-day ocean carbon observations, from shelf and offshore waters around Australia, combined with neural network mapping of CO2, sea surface temperature, and salinity to estimate the current seasonal and regional distributions of carbonate chemistry (pH and aragonite saturation state). The observed changes in atmospheric CO2 and sea surface temperature (SST) and climatological salinity are then used to reconstruct pH and aragonite saturation state changes over the last 140 years (1870–2013). The comparison with data collected at Integrated Marine Observing System National Reference Station sites located on the shelf around Australia shows that both the mean state and seasonality in the present day are well represented, with the exception of sites such as the Great Barrier Reef. Our reconstruction predicts that since 1870 decrease in aragonite saturation state of 0.48 and of 0.09 in pH has occurred in response to increasing oceanic uptake of atmospheric CO2. Large seasonal variability in pH and aragonite saturation state occur in southwestern Australia driven by ocean dynamics (mixing) and in the Tasman Sea by seasonal warming (in the case of the aragonite saturation state). The seasonal and historical changes in aragonite saturation state and pH have different spatial patterns and suggest that the biological responses to ocean acidification are likely to be non-uniform depending on the relative sensitivity of organisms to shifts in pH and saturation state. This new historical reconstruction provides an important link to biological observations that will help to elucidate the consequences of ocean acidification.

scholarly journals Historical reconstruction of ocean acidification in the Australian region

2015 ◽  
Vol 12 (11) ◽  
pp. 8265-8297 ◽  
Author(s):  
A. Lenton ◽  
B. Tilbrook ◽  
R. J. Matear ◽  
T. Sasse ◽  
Y. Nojiri
Keyword(s):  
Ocean Acidification ◽  
Dominant Mode ◽  
Ocean Dynamics ◽  
Atmospheric Co2 ◽  
Reference Station ◽  
Historical Reconstruction ◽  
Carbonate Chemistry ◽  
Saturation State ◽  
Aragonite Saturation ◽  
Concentration Changes

Abstract. The increase in atmospheric greenhouse gases over the last 200 years has caused an increase in ocean acidity levels. Documenting how the ocean has changed is critical for assessing how these changes could impact marine ecosystems and for the management of marine resources. We use present day ocean carbon observations from shelf and offshore waters around Australia, combined with neural network mapping of CO2, to estimate the current seasonal and regional distributions of carbonate chemistry (pH and aragonite saturation state). These predicted changes in carbonate chemistry are combined with atmospheric CO2 concentration changes since to reconstruct pH and aragonite saturation state changes over the last 140 years (1870–2013). The comparison with data collected at Integrated Marine Observing System National Reference Station sites located on the shelf around Australia shows both the mean state and seasonality for the present day is well represented by our reconstruction, with the exception of sites such as the Great Barrier Reef. Our reconstruction predicts that since 1870 an average decrease in aragonite saturation state of 0.48 and of 0.09 in pH has occurred in response to increasing oceanic uptake of atmospheric CO2. Our reconstruction shows that seasonality is the dominant mode of variability, with only small interannual variability present. Large seasonal variability in pH and aragonite saturation state occur in Southwestern Australia driven by ocean dynamics (mixing) and in the Tasman Sea by seasonal warming (in the case of aragonite saturation state). The seasonal and historical changes in aragonite saturation state and pH have different spatial patterns and suggest that the biological responses to ocean acidification are likely to be non-uniform depending on the relative sensitivity of organisms to shifts in pH and saturation state. This new historical reconstruction provides an important to link to biological observations to help elucidate the consequences of ocean acidification.

scholarly journals Increase in ocean acidity variability and extremes under increasing atmospheric CO<sub>2</sub>

2020 ◽  
Author(s):  
Friedrich A. Burger ◽  
Thomas L. Frölicher ◽  
Jasmin G. John
Keyword(s):  
Ocean Acidification ◽  
Extreme Events ◽  
Co2 Emission ◽  
Emission Scenario ◽  
Short Term ◽  
Saturation State ◽  
High Co2 ◽  
Ensemble Simulations ◽  
The Impact

Abstract. Ocean acidity extreme events are short-term periods of extremely high [H+] concentrations. The uptake of anthropogenic CO2 emissions by the ocean is expected to lead to more frequent and intense ocean acidity extreme events, not only due to mean ocean acidification, but also due to increases in ocean acidity variability. Here, we use daily output from ensemble simulations of a comprehensive Earth system model under a low and high CO2 emission scenario to isolate and quantify the impact of changes in variability on changes in ocean acidity extremes. We show that the number of days with extreme [H+] conditions for surface waters is projected to increase by a factor of 14 by the end of the 21st century under a high CO2 emission scenario relative to preindustrial levels. The duration of individual events is projected to triple, and the maximal intensity and the volume extent in the upper 200 m to quintuple. Similar changes are projected in the thermocline. At surface, the changes are mainly driven by increases in [H+] seasonality, whereas changes in interannual variability are also important in the thermocline. Increases in [H+] variability and extremes arise predominantly from increases in the sensitivity of [H+] to variations in its drivers. In contrast to [H+] extremes, the occurrence of short-term extremes in low aragonite saturation state due to changes in variability is projected to decrease. An increase in [H+] variability and an associated increase in extreme events superimposed onto the long-term ocean acidification trend will enhance the risk of severe and detrimental impacts on marine organisms, especially for those that are adapted to a more stable environment.

scholarly journals Large-scale field phenotyping using backpack LiDAR and GUI-based CropQuant-3D to measure structural responses to different nitrogen treatments in wheat

2021 ◽  
Author(s):  
Yulei Zhu ◽  
Gang Sun ◽  
Guohui Ding ◽  
Jie Zhou ◽  
Mingxing Wen ◽  
...  
Keyword(s):  
Large Scale ◽  
Structural Changes ◽  
Field Experiments ◽  
Computing Time ◽  
Point Clouds ◽  
Combined System ◽  
Wheat Varieties ◽  
Wide Range ◽  
Field Phenotyping ◽  
Nitrogen Treatments

Plant phenomics is widely recognised as a key area to bridge the gap between traits of agricultural importance and genomic information. A wide range of field-based phenotyping solutions have been developed. Nevertheless, disadvantages of these current systems have been identified concerning mobility, affordability, accuracy, scalability, and the ability to analyse big data collected. Here, we present a novel solution that combines a commercial backpack LiDAR device and graphical user interface (GUI) based software called CropQuant-3D, which has been applied to analyse 3D morphological traits in wheat. To our knowledge, this is the first use of backpack LiDAR in field-based plant research, acquiring millions of 3D points to represent spatial features of crops. A key part of the innovation is the GUI-based software that can extract plot-based traits from large and complex point clouds with limited computing time. We describe how we developed and used the combined system to quantify canopy structural changes, impossible to measure previously. Also, we demonstrate the biological relevance of our work through a case study that examined wheat varieties to three different levels of nitrogen fertilisation in field experiments. The results indicate that the solution can differentiate significant genotype and treatment effects on key traits, with strong correlations with manual measurements. Hence, we believe that the solution presented here could consistently and speedily quantify traits at a larger scale, indicating the system could be used as a reliable research tool in large-scale and multi-location field phenotyping to contribute to the resolution of the phenotyping bottleneck.

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