Estuarine biofilm patterns: Modern analogues for Precambrian self-organization     

Roeland C. van de Vijsel  Jim van Belzen  Tjeerd J. Bouma  Daphne van der Wal  Valentina Cusseddu  Sam J. Purkis  Max Rietkerk  Johan van de Koppel 《地球表面变化过程与地形》2020,45(5):1141-1154

This field and laboratory study examines whether regularly patterned biofilms on present-day intertidal flats are equivalent to microbially induced bedforms found in geological records dating back to the onset of life on Earth. Algal mats of filamentous Vaucheria species, functionally similar to microbial biofilms, cover the topographic highs of regularly spaced ridge–runnel bedforms. As regular patterning is typically associated with self-organization processes, indicators of self-organization are tested and found to support this hypothesis. The measurements suggest that biofilm-induced sediment trapping and biostabilization enhance bedform relief, strength and multi-year persistence. This demonstrates the importance of primitive organisms for sedimentary landscape development. Algal-covered ridges consist of wavy-crinkly laminated sedimentary deposits that resemble the layered structure of fossil stromatolites and microbially induced sedimentary structures. In addition to layering, both the morphological pattern and the suggested formation mechanism of the recent bedforms are strikingly similar to microbialite strata found in rock records from the Precambrian onwards. This implies that self-organization was an important morphological process in times when biofilms were the predominant sessile ecosystem. These findings furthermore emphasize that self-organization dynamics, such as critical transitions invoking ecosystem emergence or collapse, might have been captured in fossil microbialites, influencing their laminae. This notion may be important for paleoenvironmental reconstructions based on such strata. © 2019 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd  相似文献   

A hydropedological approach to simulate streamflow and soil water contents with SWAT+     

Johan van Tol  Katrin Bieger  Jeffrey G. Arnold 《水文研究》2021,35(6):e14242

Reflecting internal catchment hydrological processes in hydrological models is important for accurate predictions of the impact of climate and land-use change on water resources. Characterizing these processes is however difficult and expensive due to their dynamic nature and spatio-temporal variability. Hydropedology is a relatively new discipline focusing on the synergistic integration of hydrology, soil physics and pedology. Hydropedological interpretations of soils and soil distribution can be used to characterize key hydrological processes, especially in areas with no or limited hydrometric measurements. Here we applied a hydropedological approach to reflect flowpaths through detailed routing in SWAT+ for a 157 ha catchment (Weatherley) in South Africa. We compared the hydropedological approach and a standard (no routing) approach against measured streamflow (two weirs) and soil water contents (13 locations). The catchment was treated as ‘ungauged’ and the model was not calibrated against hydrometric measurements in order to determine the direct contribution of hydropedology on modelling efficiency. Streamflow was predicted well without calibration (NSE > 0.8; R² > 0.82) for both approaches at both weirs. The standard approach yielded slightly better streamflow predictions. The hydropedological approach resulted in considerable improvements in the simulation of soil water contents (R² increased from 0.40 to 0.49 and PBIAS decreased from 40% to 20%). The routing capacity of SWAT+ as employed in the hydropedological approach reduced the underestimation of wetland water regimes drastically and resulted in a more accurate representation of the dominant hydrological processes in this catchment. We concluded that hydropedology can be a valuable source of ‘soft data’ to reflect internal catchment structure and processes and, potentially, for realistic calibrations in other studies, especially those conducted in areas with limited hydrometric measurements.  相似文献   

The geochemical effects of olivine slurry replenishment and dolostone assimilation in the plumbing system of the Franklin Large Igneous Province,Victoria Island,Arctic Canada     

Ben Hayes  C. Johan Lissenberg  Jean H. Bédard  Charlie Beard 《Contributions to Mineralogy and Petrology》2015,169(2):1-18

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Wind Statistics from a Forested Landscape     

Johan Arnqvist  Antonio Segalini  Ebba Dellwik  Hans Bergström 《Boundary-Layer Meteorology》2015,156(1):53-71

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Rhizofiltration of a Heavy Metal (Lead) Containing Wastewater Using the Wetland Plant Carex pendula     

Brijesh K. Yadav  Maarten A. Siebel  Johan J. A. van Bruggen 《洁净——土壤、空气、水》2011,39(5):467-474

Rhizofiltration is a subset technique of phytoremediation which refers to the approach of using plant biomass for removing contaminants, primarily toxic metals, from polluted water. The effective implementation of this in situ remediation technology requires experimental as well as conceptual insight of plant–water interactions that control the extraction of targeted metal from polluted water resources. Therefore, pot and simulation experiments are used in this study to investigate the rhizofiltration of a lead containing wastewater using plants of Carex pendula, a common wetland plant found in Europe. The metal contaminant extraction along with plant growth and water uptake rates from a wastewater having varying Pb concentration is studied experimentally for 2 wk. The temporal distribution of the metal concentration in the wastewater and the accumulated metal in different compartments of C. pendula at the end are analyzed using atomic absorption spectrometry. Parameters of the metal uptake kinetics are deduced experimentally for predicting the metal removal by root biomass. Further, mass balance equations coupled with the characterized metal uptake kinetics are used for simulating the metal partitioning from the wastewater to its accumulation in the plant biomass. The simulated metal content in wastewater and plant biomass is compared with the observed data showing a good agreement with the later. Results show that C. pendula accumulates considerable amounts of lead, particularly in root biomass, and can be considered for the cleanup of lead contaminated wastewaters in combination with proper biomass disposal alternatives. Also, the findings can be used for performing further non‐hydroponics experiment to mimic the real wetland conditions more closely.  相似文献   

Reply to comment on ‘Up‐scaling potential impacts on water flows from agricultural water interventions: opportunities and trade‐offs in the Osman Sagar catchment,Musi sub‐basin,India’. Hydrological Processes 27: 3905–3921 by Bouma et al.,          下载免费PDF全文

Kaushal K. Garg  Suhas P. Wani  Jennie Barron  Louise Karlberg  Johan Rockstrom 《水文研究》2014,28(8):3352-3355

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A synoptic decomposition of rainfall over the Cape south coast of South Africa     

Christien J. Engelbrecht  Willem A. Landman  Francois A. Engelbrecht  Johan Malherbe 《Climate Dynamics》2015,44(9-10):2589-2607

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Carbonate slope re-sedimentation in a tectonically-active setting (Western Sicily Cretaceous Escarpment,Italy)     

Vincenzo Randazzo  Johan Le Goff  Pietro Di Stefano  John Reijmer  Simona Todaro  Maria Simona Cacciatore 《Sedimentology》2020,67(5):2360-2391

Tectonic processes are widely considered as a mechanism causing carbonate platform margin instabilities leading to the emplacement of mass transport deposits and calciturbidites. However, only few examples establishing a clear link between tectonics and re-sedimentation processes are known from the literature. The two-dimensional and three-dimensional wire-cut walls of hundreds of quarries extracting ornamental limestones (for example, Perlato di Sicilia) from the Western Sicily Cretaceous Escarpment in Italy expose a series of mass transport deposits. The depositional architecture, spatial facies distribution and sedimentary features of these deposits were studied in detail. Thin section analysis was used to define the microfacies characteristics and to determine the age of the re-sedimented limestones. Eleven facies types grouped into four facies associations were recognized that defined specific depositional processes and environments. The stratigraphic architecture of the slope was reconstructed using four composite facies successions based on the detailed analysis and correlation of the field sections. The palaeoslope orientation was reconstructed based on the analysis of synsedimentary faults, slump scars and pinch-out geometries. The Western Sicily Cretaceous Escarpment was strongly influenced by synsedimentary transtensional tectonics in combination with magmatic processes, as suggested by the presence of tuffites and pillow lava intercalations within the re-sedimented carbonate series. These volcanics point to a major role of crustal shear as a trigger for mass transport deposit emplacement. The facies distribution along the Western Sicily Cretaceous Escarpment delivers new insights into the deformation processes accompanying the crustal extension of the Cretaceous western Tethys realm.  相似文献   

Social–ecological memory in urban gardens—Retaining the capacity for management of ecosystem services     

Stephan Barthel  Carl Folke  Johan Colding 《Global Environmental Change》2010,20(2):255-265

Many ecosystem services are in decline. Local ecological knowledge and associated practice are essential to sustain and enhance ecosystem services on the ground. Here, we focus on social or collective memory in relation to management practice that sustains ecosystem services, and investigate where and how ecological practices, knowledge and experience are retained and transmitted. We analyze such social–ecological memory of allotment gardens in the Stockholm urban area, Sweden. Allotment gardens support ecosystem services such as pollination, seed dispersal and pest regulation in the broader urban landscape. Surveys and interviews were preformed over a four-year period with several hundreds of gardeners. We found that the allotment gardens function as communities-of-practice, where participation and reification interact and social–ecological memory is a shared source of resilience of the community by being both emergent and persistent. Ecological practices and knowledge in allotment gardens are retained and transmitted by imitation of practices, oral communication and collective rituals and habits, as well as by the physical gardens, artifacts, metaphors and rules-in-use (institutions). Finally, a wider social context provides external support through various forms of media, markets, social networks, collaborative organizations, and legal structures. We exemplify the role of urban gardens in generating ecosystem services in times of crisis and change and conclude that stewards of urban green areas and the social memory that they carry may help counteract further decline of critical ecosystem services.  相似文献   

Reply to discussion of Gabrielsen et al. (2010) by Nielsen et al. (this volume): Latest Caledonian to present tectonomorphological development of southern Norway     

Roy H. Gabrielsen  Jan Inge Faleide  Christophe Pascal  Alvar Braathen  Johan Petter Nystuen  Bernd Etzelmuller  Sejal O'Donnell 《Marine and Petroleum Geology》2010

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