scholarly journals Global biogeography of living brachiopods: Bioregionalization patterns and possible controls

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259004
Author(s):  
Facheng Ye ◽  
G. R. Shi ◽  
Maria Aleksandra Bitner
Keyword(s):  
Large Scale ◽  
Coastal Upwelling ◽  
Seawater Temperature ◽  
Regional Scale ◽  
Distribution Patterns ◽  
Global Scale ◽  
Biodiversity Hotspots ◽  
Network Analyses ◽  
Ocean Gyres ◽  
Ecological Variable

The global distribution patterns of 14918 geo-referenced occurrences from 394 living brachiopod species were mapped in 5° grid cells, which enabled the visualization and delineation of distinct bioregions and biodiversity hotspots. Further investigation using cluster and network analyses allowed us to propose the first systematically and quantitatively recognized global bioregionalization framework for living brachiopods, consisting of five bioregions and thirteen bioprovinces. No single environmental or ecological variable is accountable for the newly proposed global bioregionalization patterns of living brachiopods. Instead, the combined effects of large-scale ocean gyres, climatic zonation as well as some geohistorical factors (e.g., formation of land bridges and geological recent closure of ancient seaways) are considered as the main drivers at the global scale. At the regional scale, however, the faunal composition, diversity and biogeographical differentiation appear to be mainly controlled by seawater temperature variation, regional ocean currents and coastal upwelling systems.

scholarly journals Application of global models and satellite data for smaller-scale groundwater recharge studies

2016 ◽  
Author(s):  
Rogier Westerhoff ◽  
Paul White ◽  
Zara Rawlinson
Keyword(s):  
New Zealand ◽  
Satellite Data ◽  
Input Data ◽  
Large Scale ◽  
Regional Scale ◽  
Global Scale ◽  
Global Models ◽  
Scale Models ◽  
Boundary Issues ◽  
Rainfall Recharge

Abstract. Large-scale models and satellite data are increasingly used to characterise groundwater and its recharge at the global scale. Although these models have the potential to fill in data gaps and solve trans-boundary issues, they are often neglected in smaller-scale studies, since data are often coarse or uncertain. Large-scale models and satellite data could play a more important role in smaller-scale (i.e., national or regional) studies, if they could be adjusted to fit that scale. In New Zealand, large-scale models and satellite data are not used for groundwater recharge estimation at the national scale, since regional councils (i.e., the water managers) have varying water policy and models are calibrated at the local scale. Also, some regions have many localised ground observations (but poor record coverage), whereas others are data-sparse. Therefore, estimation of recharge is inconsistent at the national scale. This paper presents an approach to apply large-scale, global, models and satellite data to estimate rainfall recharge at the national to regional scale across New Zealand. We present a model, NGRM, that is largely inspired by the global-scale WaterGAP recharge model, but is improved and adjusted using national data. The NGRM model uses MODIS-derived ET and vegetation satellite data, and the available nation-wide datasets on rainfall, elevation, soil and geology. A valuable addition to the recharge estimation is the model uncertainty estimate, based on variance, covariance and sensitivity of all input data components in the model environment. This research shows that, with minor model adjustments and use of improved input data, large-scale models and satellite data can be used to derive rainfall recharge estimates, including their uncertainty, at the smaller scale, i.e., national and regional scale of New Zealand. The estimated New Zealand recharge of the NGRM model compare well to most local and regional lysimeter data and recharge models. The NGRM is therefore assumed to be capable to fill in gaps in data-sparse areas and to create more consistency between datasets from different regions, i.e., to solve trans-boundary issues. This research also shows that smaller-scale recharge studies in New Zealand should include larger boundaries than only a (sub-)aquifer, and preferably the whole catchment. This research points out the need for improved collaboration on the international to national to regional levels to further merge large-scale (global) models to smaller (i.e., national or regional) scales. Future research topics should, collaboratively, focus on: improvement of rainfall-runoff and snowmelt methods; inclusion of river recharge; further improvement of input data (rainfall, evapotranspiration, soil and geology); and the impact of recharge uncertainty in mountainous and irrigated areas.

scholarly journals Impacts of spatial resolution and representation of flow connectivity on large-scale simulation of floods

2017 ◽  
Author(s):  
Cherry May R. Mateo ◽  
Dai Yamazaki ◽  
Hyungjun Kim ◽  
Adisorn Champathong ◽  
Jai Vaze ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Large Scale ◽  
Flood Hazard ◽  
Regional Scale ◽  
Global Scale ◽  
Test Case ◽  
Efficiency Coefficient ◽  
Computational Power ◽  
Extreme Flood ◽  
Simulation Results

Abstract. Global-scale River Models (GRMs) are core tools for providing consistent estimates of global flood hazard, especially in data-scarce regions. Due to former limitations in computational power and input datasets, most GRMs have been developed to use simplified representation of flow physics and run at coarse spatial resolutions. With increasing computational power and improved datasets, the application of GRMs to finer resolutions is becoming a reality. To support development in this direction, the suitability of GRMs for application to finer resolutions needs to be assessed. This study investigates the impacts of spatial resolution and flow connectivity representation on the predictive capability of a GRM, CaMa-Flood, in simulating the 2011 extreme flood in Thailand. Analyses show that when single downstream connectivity (SDC) is assumed, simulation results deteriorate with finer spatial resolution; Nash–Sutcliffe Efficiency coefficient decreased by more than 35 % between simulation results at 10 km resolution and 1 km resolution. When multiple downstream connectivity (MDC) is represented, simulation results slightly improve with finer spatial resolution. The SDC simulations result in excessive backflows on very flat floodplains due to the restrictive flow directions in finer resolutions. MDC channels attenuated these effects by maintaining flow connectivity and flow capacity between floodplains in varying spatial resolutions. While a regional-scale flood was chosen as a test case, these findings are universal and can be extended to global-scale simulations. These results demonstrate that a GRM can be used for higher resolution simulations of large-scale floods, provided that MDC in rivers and floodplains is adequately represented in the model structure.

scholarly journals Clouds, photolysis and regional tropospheric ozone budgets

2009 ◽  
Vol 9 (3) ◽  
pp. 13889-13916 ◽  
Author(s):  
A. Voulgarakis ◽  
O. Wild ◽  
N. H. Savage ◽  
G. D. Carver ◽  
J. A. Pyle
Keyword(s):  
Tropospheric Ozone ◽  
Large Scale ◽  
Transport Model ◽  
Regional Scale ◽  
Three Dimensional ◽  
Global Scale ◽  
Chemical Production ◽  
Chemical Transport Model ◽  
Photolysis Rates ◽  
Boundary Layer Ozone

Abstract. We use a three-dimensional chemical transport model to examine the shortwave radiative effects of clouds on the tropospheric ozone budget. In addition to looking at changes in global concentrations as previous studies have done, we examine changes in ozone chemical production and loss caused by clouds and how these vary in different parts of the troposphere. On a global scale, we find that clouds have a modest effect on ozone chemistry, but on a regional scale their role is much more significant, with the size of the response dependent on the region. The largest averaged changes in chemical budgets (±10–14%) are found in the marine troposphere, where cloud optical depths are high. We demonstrate that cloud effects are small on average in the middle troposphere because this is a transition region between reduction and enhancement in photolysis rates. We show that increases in boundary layer ozone due to clouds are driven by large-scale changes in downward ozone transport from higher in the troposphere rather than by decreases in in-situ ozone chemical loss rates. Increases in upper tropospheric ozone are caused by higher production rates due to backscattering of radiation and consequent increases in photolysis rates, mainly J(NO2). The global radiative effect of clouds on isoprene is stronger than on ozone. Tropospheric isoprene lifetime increases by 7% when taking clouds into account. We compare the importance of clouds in contributing to uncertainties in the global ozone budget with the role of other radiatively-important factors. The budget is most sensitive to the overhead ozone column, while surface albedo and clouds have smaller effects. However, uncertainty in representing the spatial distribution of clouds may lead to a large sensitivity on regional scales.

scholarly journals Diatoms Si Uptake Capacity Drives Carbon Export In Coastal Upwelling Systems

2016 ◽  
Author(s):  
F. Abrantes ◽  
P. Cermeño ◽  
C. Lopes ◽  
O. Romero ◽  
L. Matos ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Coastal Upwelling ◽  
Net Primary Production ◽  
Regional Scale ◽  
Global Scale ◽  
Global Ocean ◽  
Nutrient Concentrations ◽  
Organic Carbon Content ◽  
Organic Carbon Burial

Abstract. Coastal upwelling systems account for approximately half of global ocean primary production and contribute disproportionately to biologically driven carbon sequestration. Diatoms, silica–precipitating microalgae, constitute the dominant phytoplankton in these productive regions, and their abundance and assemblage composition in the sedimentary record is considered one of the best proxies for primary production. The study of the sedimentary diatom abundance (SDA) and total organic carbon content (TOC) in the five most important coastal upwelling systems of the modern ocean (Iberia-Canary, Benguela, Peru-Humboldt, California and Somalia-Oman) reveals a global-scale positive relationship between diatom production and organic carbon burial. The analysis of SDA in conjunction with environmental variables of coastal upwelling systems such as upwelling strength, satellite-derived net primary production and surface water nutrient concentrations shows different relations between SDA and primary production on the regional scale. At the global-scale, SDA appears modulated by the capacity of diatoms to take up silicic acid, which ultimately sets an upper limit to global export production in these ocean regions.

scholarly journals Diatoms Are Selective Segregators in Global Ocean Planktonic Communities

mSystems ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Flora Vincent ◽  
Chris Bowler
Keyword(s):  
Open Access ◽  
Large Scale ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Distribution Patterns ◽  
Global Scale ◽  
Global Ocean ◽  
Extensive Literature ◽  
Microbial Association ◽  
Species Specific

ABSTRACT Diatoms are a major component of phytoplankton, believed to be responsible for around 20% of the annual primary production on Earth. As abundant and ubiquitous organisms, they are known to establish biotic interactions with many other members of plankton. Through analyses of cooccurrence networks derived from the Tara Oceans expedition that take into account both biotic and abiotic factors in shaping the spatial distributions of species, we show that only 13% of diatom pairwise associations are driven by environmental conditions; the vast majority are independent of abiotic factors. In contrast to most other plankton groups, on a global scale, diatoms display a much higher proportion of negative correlations with other organisms, particularly toward potential predators and parasites, suggesting that their biogeography is constrained by top-down pressure. Genus-level analyses indicate that abundant diatoms are not necessarily the most connected and that species-specific abundance distribution patterns lead to negative associations with other organisms. In order to move forward in the biological interpretation of cooccurrence networks, an open-access extensive literature survey of diatom biotic interactions was compiled, of which 18.5% were recovered in the computed network. This result reveals the extent of what likely remains to be discovered in the field of planktonic biotic interactions, even for one of the best-known organismal groups. IMPORTANCE Diatoms are key phytoplankton in the modern ocean that are involved in numerous biotic interactions, ranging from symbiosis to predation and viral infection, which have considerable effects on global biogeochemical cycles. However, despite recent large-scale studies of plankton, we are still lacking a comprehensive picture of the diversity of diatom biotic interactions in the marine microbial community. Through the ecological interpretation of both inferred microbial association networks and available knowledge on diatom interactions compiled in an open-access database, we propose an ecosystems approach for exploring diatom interactions in the ocean.

scholarly journals Diatoms Si uptake capacity drives carbon export in coastal upwelling systems

2016 ◽  
Vol 13 (14) ◽  
pp. 4099-4109 ◽  
Author(s):  
Fatima Abrantes ◽  
Pedro Cermeno ◽  
Cristina Lopes ◽  
Oscar Romero ◽  
Lélia Matos ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Coastal Upwelling ◽  
Net Primary Production ◽  
Regional Scale ◽  
Global Scale ◽  
Global Ocean ◽  
Nutrient Concentrations ◽  
Organic Carbon Content ◽  
Organic Carbon Burial

Abstract. Coastal upwelling systems account for approximately half of global ocean primary production and contribute disproportionately to biologically driven carbon sequestration. Diatoms, silica-precipitating microalgae, constitute the dominant phytoplankton in these productive regions, and their abundance and assemblage composition in the sedimentary record is considered one of the best proxies for primary production. The study of the sedimentary diatom abundance (SDA) and total organic carbon content (TOC) in the five most important coastal upwelling systems of the modern ocean (Iberia–Canary, Benguela, Peru–Humboldt, California, and Somalia–Oman) reveals a global-scale positive relationship between diatom production and organic carbon burial. The analysis of SDA in conjunction with environmental variables of coastal upwelling systems such as upwelling strength, satellite-derived net primary production, and surface water nutrient concentrations shows different relations between SDA and primary production on the regional scale. On the global scale, SDA appears modulated by the capacity of diatoms to take up silicic acid, which ultimately sets an upper limit to global export production in these ocean regions.

scholarly journals Just Societal Transformation: Perspectives of Pastoralists in the Lower Omo Valley in Ethiopia

2021 ◽  
pp. 1-21
Author(s):  
Sabine Troeger
Keyword(s):  
Climate Change ◽  
Decision Making ◽  
Climate Change Adaptation ◽  
Large Scale ◽  
Regional Scale ◽  
Global Scale ◽  
Development Project ◽  
The Face ◽  
Local Actors ◽  
Sugar Development

AbstractPastoralists’ livelihoods in Africa are highly endangered by adverse forces – the climate change being one among those. Against this background, climate change adaptation is conceptualized as strategic agency in the field of risk-laden livelihood environments, that is, agency in the face of risky options and non-calculable uncertainties.The chapter conceptualizes pastoralists’ livelihoods exposed to a four-fold hierarchy of environmental risks and forces defining the actors’ arena of strategic decision making: From the global scale of ever extending impacts by the climate change imperative, to the national scale of government policies in terms of decentralization, challenging people to govern and define their communal efforts in terms of climate change adaptation, and down to the regional scale, which in the presented case is dominated by a large-scale investment, the Kuraz Sugar Development Project, which again confronts local actors with adverse forces toward villagization and eviction from pasture grounds. Right at the end of this hierarchy and in accordance with discourses on “climate services,” the end-users and local actors, the pastoralists, are confronted with and offered a product that they can input into their decision making: cattle feed from the residues of the irrigated sugar cane. The question remains whether substantive aspects of processes turning into true environmental and social justice in terms of recognition, procedures, and distribution will be paid attention to.

scholarly journals Just Societal Transformation: Perspectives of Pastoralists in the Lower Omo Valley in Ethiopia

2021 ◽  
pp. 1-21
Author(s):  
Sabine Troeger
Keyword(s):  
Climate Change ◽  
Decision Making ◽  
Climate Change Adaptation ◽  
Large Scale ◽  
Regional Scale ◽  
Global Scale ◽  
Development Project ◽  
The Face ◽  
Local Actors ◽  
Sugar Development

AbstractPastoralists’ livelihoods in Africa are highly endangered by adverse forces – the climate change being one among those. Against this background, climate change adaptation is conceptualized as strategic agency in the field of risk-laden livelihood environments, that is, agency in the face of risky options and non-calculable uncertainties.The chapter conceptualizes pastoralists’ livelihoods exposed to a four-fold hierarchy of environmental risks and forces defining the actors’ arena of strategic decision making: From the global scale of ever extending impacts by the climate change imperative, to the national scale of government policies in terms of decentralization, challenging people to govern and define their communal efforts in terms of climate change adaptation, and down to the regional scale, which in the presented case is dominated by a large-scale investment, the Kuraz Sugar Development Project, which again confronts local actors with adverse forces toward villagization and eviction from pasture grounds. Right at the end of this hierarchy and in accordance with discourses on “climate services,” the end-users and local actors, the pastoralists, are confronted with and offered a product that they can input into their decision making: cattle feed from the residues of the irrigated sugar cane. The question remains whether substantive aspects of processes turning into true environmental and social justice in terms of recognition, procedures, and distribution will be paid attention to.

scholarly journals Clouds, photolysis and regional tropospheric ozone budgets

2009 ◽  
Vol 9 (21) ◽  
pp. 8235-8246 ◽  
Author(s):  
A. Voulgarakis ◽  
O. Wild ◽  
N. H. Savage ◽  
G. D. Carver ◽  
J. A. Pyle
Keyword(s):  
Tropospheric Ozone ◽  
Large Scale ◽  
Transport Model ◽  
Regional Scale ◽  
Three Dimensional ◽  
Lower Troposphere ◽  
Global Scale ◽  
Chemical Production ◽  
Chemical Transport Model ◽  
Photolysis Rates

Abstract. We use a three-dimensional chemical transport model to examine the shortwave radiative effects of clouds on the tropospheric ozone budget. In addition to looking at changes in global concentrations as previous studies have done, we examine changes in ozone chemical production and loss caused by clouds and how these vary in different parts of the troposphere. On a global scale, we find that clouds have a modest effect on ozone chemistry, but on a regional scale their role is much more significant, with the size of the response dependent on the region. The largest averaged changes in chemical budgets (±10–14%) are found in the marine troposphere, where cloud optical depths are high. We demonstrate that cloud effects are small on average in the middle troposphere because this is a transition region between reduction and enhancement in photolysis rates. We show that increases in boundary layer ozone due to clouds are driven by large-scale changes in downward ozone transport from higher in the troposphere rather than by decreases in in-situ ozone chemical loss rates. Increases in upper tropospheric ozone are caused by higher production rates due to backscattering of radiation and consequent increases in photolysis rates, mainly J(NO2). The global radiative effect of clouds on isoprene, through decreases of OH in the lower troposphere, is stronger than on ozone. Tropospheric isoprene lifetime increases by 7% when taking clouds into account. We compare the importance of clouds in contributing to uncertainties in the global ozone budget with the role of other radiatively-important factors. The budget is most sensitive to the overhead ozone column, while surface albedo and clouds have smaller effects. However, uncertainty in representing the spatial distribution of clouds may lead to a large sensitivity of the ozone budget components on regional scales.

Arctic snow distribution patterns at the watershed scale

2014 ◽  
Vol 46 (4) ◽  
pp. 507-520 ◽  
Author(s):  
Joel W. Homan ◽  
Douglas L. Kane
Keyword(s):  
Large Scale ◽  
Snow Water Equivalent ◽  
Regional Scale ◽  
Distribution Patterns ◽  
Local Scale ◽  
Small Scale ◽  
Watershed Scale ◽  
Quality Of Data ◽  
Weather Patterns ◽  
Snow Distribution

Watershed-scale hydrologic models require good estimates of spatially distributed snow water equivalent (SWE) at winter's end. Snow on the ground in arctic environments is susceptible to significant wind redistribution, which results in heterogeneous snowpacks. The scarcity and quality of data collected by snow gauges provides a poor indicator of actual snowpack distribution. Snow distribution patterns are similar from year to year because they are largely controlled by the interaction of topography, vegetation, and consistent weather patterns. Consequently, shallow and deep areas of snow tend to be spatially predetermined, resulting in depth (or SWE) differences that may vary as a whole, but not relative to each other. Our aim was to identify snowpack distribution patterns and establish their stability in time and space at a watershed scale. Snow patterns were established by: (1) using numerous field surveys from end-of-winter field campaigns; and (2) differentiating snowpacks that characterize small-scale anomalies (local scale) from snowpacks that represent a large-scale area (regional scale). We concluded that basic snow survey site descriptions could be used to separate survey locations into regional and local-scale representative sites. Removing local-scale influences provides a more accurate representation of the regional snowpack, which will aid in forecasting snowmelt runoff events.

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