scholarly journals Air–water CO<sub>2</sub> evasion from US East Coast estuaries

2017 ◽  
Vol 14 (9) ◽  
pp. 2441-2468 ◽  
Author(s):  
Goulven Gildas Laruelle ◽  
Nicolas Goossens ◽  
Sandra Arndt ◽  
Wei-Jun Cai ◽  
Pierre Regnier
Keyword(s):  
East Coast ◽  
Regional Scale ◽  
Global Scale ◽  
Biogeochemical Processes ◽  
Wide Range ◽  
Tidal Estuaries ◽  
Net Heterotrophy ◽  
Carbon Processing ◽  
Year 2000 ◽  
Us East Coast

Abstract. This study presents the first regional-scale assessment of estuarine CO2 evasion along the US East Coast (25–45° N). The focus is on 42 tidal estuaries, which together drain a catchment of 697 000 km2 or 76 % of the total area within this latitudinal band. The approach is based on the Carbon–Generic Estuary Model (C-GEM) that allows the simulation of hydrodynamics, transport, and biogeochemistry for a wide range of estuarine systems using readily available geometric parameters and global databases of seasonal climatic, hydraulic, and riverine biogeochemical information. Our simulations, performed using conditions representative of the year 2000, suggest that, together, US East Coast estuaries emit 1.9 Tg C yr−1 in the form of CO2, which corresponds to about 40 % of the carbon inputs from rivers, marshes, and mangroves. Carbon removal within estuaries results from a combination of physical (outgassing of supersaturated riverine waters) and biogeochemical processes (net heterotrophy and nitrification). The CO2 evasion and its underlying drivers show important variations across individual systems, but reveal a clear latitudinal pattern characterized by a decrease in the relative importance of physical over biogeochemical processes along a north–south gradient. Finally, the results reveal that the ratio of estuarine surface area to the river discharge, S∕Q (which has a scale of per meter discharged water per year), could be used as a predictor of the estuarine carbon processing in future regional- and global-scale assessments.

scholarly journals Air-water CO<sub>2</sub> evasion from U.S. East Coast estuaries

2016 ◽  
Author(s):  
Nicolas Goossens ◽  
Goulven Gildas Laruelle ◽  
Sandra Arndt ◽  
Wei - Jun Cai ◽  
Pierre Regnier
Keyword(s):  
East Coast ◽  
Global Scale ◽  
Biogeochemical Processes ◽  
Global Databases ◽  
Wide Range ◽  
Tidal Estuaries ◽  
Net Heterotrophy ◽  
Carbon Processing ◽  
Model C ◽  
Latitudinal Band

Abstract. This study presents the first regional-sca–45° N). The focus is on 43 tidal estuaries, which together drain a catchment of 697 103 km2 or 76 % of the total area within this latitudinal band. The approach is based on the Carbon – Generic Estuarine Model (C-GEM) that allows simulating hydrodynamics, transport and biogeochemistry for a wide range of estuarine systems using readily available geometric parameters and global databases of seasonal climatic, hydraulic, and riverine biogeochemical information. Together, US East coast estuaries emit 1.9 TgC yr−1, which correspond to about 40 % of the carbon inputs from rivers, marshes and mangroves. Carbon removal within estuaries results from a combination of physical (outgassing of supersaturated riverine waters) and biogeochemical processes (net heterotrophy and nitrification). The CO2 evasion and its underlying drivers show important variations across individual systems, but reveal a clear latitudinal pattern characterized by a decrease in the relative importance of physical over biogeochemical processes along a North-South gradient. Finally, results reveal that the ratio of estuarine surface area to the river discharge, S/Q (which has a scale of per meter discharged water per year), could be used as a predictor of the estuarine carbon processing in future regional and global scale assessments.

scholarly journals What is the P value of Siberian soils? Soil phosphorus status in south-western Siberia and comparison with a global data set

2016 ◽  
Vol 13 (8) ◽  
pp. 2493-2509 ◽  
Author(s):  
Félix Brédoire ◽  
Mark R. Bakker ◽  
Laurent Augusto ◽  
Pavel A. Barsukov ◽  
Delphine Derrien ◽  
...  
Keyword(s):  
Agricultural Development ◽  
Western Siberia ◽  
Regional Scale ◽  
Global Scale ◽  
Available P ◽  
Northern Eurasia ◽  
Data Set ◽  
Slow Kinetics ◽  
Wide Range ◽  
Plant Available P

Abstract. Climate change is particularly strong in northern Eurasia and substantial ecological changes are expected in this extensive region. The reshaping and migration northwards of bioclimatic zones may offer opportunities for agricultural development in western and central Siberia. However, the bioclimatic vegetation models currently employed for projections still do not consider soil fertility, in spite of this being highly critical for plant growth. In the present study, we surveyed the phosphorus (P) status in the south-west of Siberia where soils have developed on loess parent material. We selected six sites differing in pedoclimatic conditions and the soil was sampled at different depths down to 1 m in aspen (Populus tremula L.) forest as well as in grassland areas. The P status was assessed by conventional methods and by isotope dilution kinetics. We found that P concentrations and stocks, as well as their distribution through the soil profile, were fairly homogeneous on the regional scale studied, although there were some differences between sites (particularly in organic P). The young age of the soils, together with slow kinetics of soil formation processes have probably not yet resulted in a sufficiently wide range of soil physico-chemical conditions to observe a more diverging P status. The comparison of our data set with similar vegetation contexts on the global scale revealed that the soils of south-western Siberia, and more generally of northern Eurasia, often have (very) high levels of total, organic and inorganic P. The amount of plant-available P in topsoils, estimated by the isotopically exchangeable phosphate ions, was not particularly high but was intermediate on the global scale. However, large stocks of plant-available P are stored in subsurface layers which currently have low fine-root exploration intensities. These results suggest that the P resource is unlikely to constrain vegetation growth and agricultural development under the present conditions or in the near future.

scholarly journals First-order estimate of the planktic foraminifer biomass in the modern global oceans

2012 ◽  
Vol 5 (1) ◽  
pp. 243-280
Author(s):  
R. Schiebel ◽  
A. Movellan
Keyword(s):  
Water Depth ◽  
Marine Ecosystem ◽  
Regional Scale ◽  
Global Scale ◽  
Order Estimate ◽  
Minimum Diameter ◽  
First Order ◽  
The North ◽  
Wide Range ◽  
Standing Stocks

Abstract. Planktic foraminifera are heterotrophic mesozooplankton of global marine abundance. The position of planktic foraminifers in the marine food web is different compared to other protozoans and ranges above the base of heterotrophic consumers. Being secondary producers with an omnivorous diet, which ranges from algae to small metazoans, planktic foraminifers are not limited to a single food source, and are assumed to occur at a balanced abundance displaying the overall marine biological productivity at a regional scale. We have calculated the assemblage carbon biomass from data on standing stocks between the sea surface and 2500 m water depth, based on 754 protein-biomass data of 21 planktic foraminifer species and morphotypes, produced with a newly developed method to analyze the protein biomass of single planktic foraminifer specimens. Samples include symbiont bearing and symbiont barren species, characteristic of surface and deep-water habitats. Conversion factors between individual protein-biomass and assemblage-biomass are calculated for test sizes between 72 and 845 μm (minimum diameter). The calculated assemblage biomass data presented here include 1057 sites and water depth intervals. Although the regional coverage of database is limited to the North Atlantic, Arabian Sea, Red Sea, and Caribbean, our data include a wide range of oligotrophic to eutrophic waters covering six orders of magnitude of assemblage biomass. A first order estimate of the global planktic foraminifer biomass from average standing stocks (>125 μm) ranges at 8.5–32.7 Tg C yr−1 (i.e. 0.008–0.033 Gt C yr−1), and might be more than three time as high including the entire fauna including neanic and juvenile individuals adding up to 25–100 Tg C yr−1. However, this is a first estimate of regional planktic-foraminifer assemblage-biomass (PFAB) extrapolated to the global scale, and future estimates based on larger data-sets might considerably deviate from the one presented here. This paper is supported by, and a contribution to the Marine Ecosystem Data project (MAREDAT). Data are available from www.pangaea.de (http://doi.pangaea.de/10.1594/PANGAEA.777386).

scholarly journals What is the P value of Siberian soils?

2015 ◽  
Vol 12 (23) ◽  
pp. 19819-19859 ◽  
Author(s):  
F. Brédoire ◽  
M. R. Bakker ◽  
L. Augusto ◽  
P. A. Barsukov ◽  
D. Derrien ◽  
...  
Keyword(s):  
Regional Scale ◽  
Global Scale ◽  
Parent Material ◽  
Available P ◽  
Northern Eurasia ◽  
P Value ◽  
Slow Kinetics ◽  
Wide Range ◽  
Agriculture Development ◽  
Plant Available P

Abstract. Climate change is particularly strong in Northern Eurasia and substantial ecological changes are expected in this wide region. The reshaping and the migration northward of bioclimatic zones may offer opportunities for agriculture development in western and central Siberia. However, the bioclimatic vegetation models currently employed for projections still do not consider soil fertility whereas it is highly critical for plant growth. In the present study, we surveyed the phosphorus (P) status in the south-west of Siberia where soils are developed on loess parent material. We selected six sites differing by pedoclimate conditions and sampled the soil at different depths down to one meter in aspen (Populus tremula L.) forest as well as in grassland areas. The P status was assessed by conventional methods and by isotope dilution kinetics. We found that P concentrations and stocks, as well as their distribution through the soil profile, were rather homogeneous at the studied regional scale, although there were some differences among sites (particularly in organic P). The young age of the soils, together with slow kinetics of soil forming processes, have probably not yet conducted to a sufficiently wide range of soil physico-chemical conditions to observe more diverging P status. The comparison of our dataset to similar vegetation contexts on the global scale revealed that the soils of south-western Siberia, and more generally of Northern Eurasia, has often (very) high levels of total, organic and inorganic P. The amount of plant-available P in topsoils, estimated by the isotopically exchangeable phosphate ions, was not particularly high, but intermediate at the global scale. However, large stocks of plant-available P are stored in subsurface layers which have currently low fine root exploration intensities. These results suggest that the P resource is unlikely to constrain vegetation growth and agriculture development in the present and near future conditions.

scholarly journals First-order estimate of the planktic foraminifer biomass in the modern ocean

2012 ◽  
Vol 4 (1) ◽  
pp. 75-89 ◽  
Author(s):  
R. Schiebel ◽  
A. Movellan
Keyword(s):  
Water Depth ◽  
Marine Ecosystem ◽  
Regional Scale ◽  
Global Scale ◽  
Order Estimate ◽  
Planktic Foraminifera ◽  
First Order ◽  
The North ◽  
Carbon Biomass ◽  
Wide Range

Abstract. Planktic foraminifera are heterotrophic mesozooplankton of global marine abundance. The position of planktic foraminifers in the marine food web is different compared to other protozoans and ranges above the base of heterotrophic consumers. Being secondary producers with an omnivorous diet, which ranges from algae to small metazoans, planktic foraminifers are not limited to a single food source, and are assumed to occur at a balanced abundance displaying the overall marine biological productivity at a regional scale. With a new non-destructive protocol developed from the bicinchoninic acid (BCA) method and nano-photospectrometry, we have analysed the protein-biomass, along with test size and weight, of 754 individual planktic foraminifers from 21 different species and morphotypes. From additional CHN analysis, it can be assumed that protein-biomass equals carbon-biomass. Accordingly, the average individual planktic foraminifer protein- and carbon-biomass amounts to 0.845 μg. Samples include symbiont bearing and symbiont-barren species from the sea surface down to 2500 m water depth. Conversion factors between individual biomass and assemblage-biomass are calculated for test sizes between 72 and 845 μm (minimum test diameter). Assemblage-biomass data presented here include 1128 sites and water depth intervals. The regional coverage of data includes the North Atlantic, Arabian Sea, Red Sea, and Caribbean as well as literature data from the eastern and western North Pacific, and covers a wide range of oligotrophic to eutrophic waters over six orders of magnitude of planktic-foraminifer assemblage-biomass (PFAB). A first order estimate of the average global planktic foraminifer biomass production (>125 μm) ranges from 8.2–32.7 Tg C yr−1 (i.e. 0.008–0.033 Gt C yr−1), and might be more than three times as high including neanic and juvenile individuals adding up to 25–100 Tg C yr−1. However, this is a first estimate of regional PFAB extrapolated to the global scale, and future estimates based on larger data sets might considerably deviate from the one presented here. This paper is supported by, and a contribution to the Marine Ecosystem Data project (MAREDAT). Data are available from http://www.pangaea.de (http://doi.pangaea.de/10.1594/PANGAEA.777386).

Are local losses of biodiversity causing degraded ecosystem function?

2017 ◽  
Author(s):  
Mark Vellend
Keyword(s):  
Ecosystem Function ◽  
Species Interactions ◽  
Regional Scale ◽  
Temporal Trends ◽  
Biodiversity Loss ◽  
Large Degree ◽  
Global Scale ◽  
Degraded Ecosystem ◽  
Biodiversity Change ◽  
Local Extirpation

This chapter highlights the scale dependence of biodiversity change over time and its consequences for arguments about the instrumental value of biodiversity. While biodiversity is in decline on a global scale, the temporal trends on regional and local scales include cases of biodiversity increase, no change, and decline. Environmental change, anthropogenic or otherwise, causes both local extirpation and colonization of species, and thus turnover in species composition, but not necessarily declines in biodiversity. In some situations, such as plants at the regional scale, human-mediated colonizations have greatly outnumbered extinctions, thus causing a marked increase in species richness. Since the potential influence of biodiversity on ecosystem function and services is mediated to a large degree by local or neighborhood species interactions, these results challenge the generality of the argument that biodiversity loss is putting at risk the ecosystem service benefits people receive from nature.

scholarly journals Extensive reduction of surface UV radiation since 1750 in world's populated regions

2009 ◽  
Vol 9 (20) ◽  
pp. 7737-7751 ◽  
Author(s):  
M. M. Kvalev&amp;aring;g ◽  
G. Myhre ◽  
C. E. Lund Myhre
Keyword(s):  
Uv Radiation ◽  
Correlation Coefficients ◽  
Ultra Violet ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Polar Regions ◽  
Ultra Violet Radiation ◽  
Wide Range ◽  
Extensive Surface ◽  
Year 2000

Abstract. Human activity influences a wide range of components that affect the surface UV radiation levels, among them ozone at high latitudes. We calculate the effect of human-induced changes in the surface erythemally weighted ultra-violet radiation (UV-E) since 1750. We compare results from a radiative transfer model to surface UV-E radiation for year 2000 derived by satellite observations (from Total Ozone Mapping Spectroradiometer) and to ground based measurements at 14 sites. The model correlates well with the observations; the correlation coefficients are 0.97 and 0.98 for satellite and ground based measurements, respectively. In addition to the effect of changes in ozone, we also investigate the effect of changes in SO2, NO2, the direct and indirect effects of aerosols, albedo changes and aviation-induced contrails and cirrus. The results show an increase of surface UV-E in polar regions, most strongly in the Southern Hemisphere. Furthermore, our study also shows an extensive surface UV-E reduction over most land areas; a reduction up to 20% since 1750 is found in some industrialized regions. This reduction in UV-E over the industrial period is particularly large in highly populated regions.

scholarly journals Relationships among the springtime ground–level NOx, O3 and NO3 in the vicinity of highways in the US East Coast

2011 ◽  
Vol 2 (3) ◽  
pp. 374-383 ◽  
Author(s):  
Fei Song ◽  
Jin Young Shin ◽  
Rafael Jusino‐Atresino ◽  
Yuan Gao
Keyword(s):  
East Coast ◽  
Ground Level ◽  
The Us ◽  
Us East Coast

scholarly journals International Law and International Relations Theory: A New Generation of Interdisciplinary Scholarship

1998 ◽  
Vol 92 (3) ◽  
pp. 367-397 ◽  
Author(s):  
Anne-Marie Slaughter ◽  
Andrew S. Tulumello ◽  
Stepan Wood
Keyword(s):  
International Relations ◽  
International Law ◽  
International Relations Theory ◽  
Regime Theory ◽  
Joint Research ◽  
Wide Range ◽  
American Society ◽  
Interdisciplinary Scholarship ◽  
United Nations System ◽  
Year 2000

Nine years ago, Kenneth Abbott published an article exhorting international lawyers to read and master regime theory, arguing that it had multiple uses for the study of international law. He went as far as to call for a “joint discipline” that would bridge the gap between international relations theory (IR) and international law (IL). Several years later, one of us followed suit with an article mapping the history of the two fields and setting forth an agenda for joint research. Since then, political scientists and international lawyers have been reading and drawing on one another’s work with increasing frequency and for a wide range of purposes. Explicitly interdisciplinary articles have won the Francis Deák Prize, awarded for the best work by a younger scholar in this Journal, for the past two years running; the publication of an interdisciplinary analysis of treaty law in the Harvard International Law Journal prompted a lively exchange on the need to pay attention to legal as well as political details; and the Hague Academy of International Law has scheduled a short course on international law and international relations for its millennial lectures in the year 2000. Further, the American Society of International Law and the Academic Council on the United Nations System sponsor joint summer workshops explicidy designed to bring young IR and IL scholars together to explore the overlap between their disciplines.

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