Heat flow and regional uplift at the north-eastern border of the Ebro basin, NE Spain     

Julia Cabal  Manel Fernàndez 《Geophysical Journal International》1995,121(2):393-403

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Ecological classification of macrophytes and phytobenthos for rivers in Germany according to the water framework directive   总被引：9，自引：0，他引：9  

Jochen Schaumburg  Christine Schranz  Julia Foerster  Antje Gutowski  Gabriele Hofmann  Petra Meilinger  Susanne Schneider  Ursula Schmedtje 《Limnologica》2004,34(4):283-301

A new assessment system for macrophytes and phytobenthos in German rivers meeting the requirements of the Water Framework Directive (WFD) of the European Community is described. Biocoenotic types based on biological, chemical and hydromorphological data from over 200 river sites covering the main ecoregions, hydromorphological stream types and degradation forms have been defined. For developing a classification system the quality element macrophytes and phytobenthos was divided into three components: macrophytes, benthic diatoms and remaining phytobenthos. For macrophytes seven types including one subtype, for benthic diatoms 14 types including three subtypes and for the remaining phytobenthos five river types were identified. The benthic vegetation at reference condition was described for most of the river types. Degradation is characterised as deviation in benthic vegetation species composition and abundance from the reference biocoenosis. For classification in five ecological status classes, several metrics were developed and used in combination with existing indices. For some of the described river types additional investigations are necessary before a classification system can be developed.  相似文献   

The Pacific Northwest Coastal Ecosystems Regional Study     

Julia K. Parrish  Robert Bailey  Andrea E. Copping  John E. Stein 《Estuaries and Coasts》2003,26(4):991-993

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Seabirds as indicators: An exploratory analysis of physical forcing in the Pacific Northwest coastal environment     

Julia K. Parrish  Stephani G. Zador 《Estuaries and Coasts》2003,26(4):1044-1057

Bottom-up control, or physical forcing of upper trophic populations, is often cited as a major factor regulating marine species. In particular, seabirds are often cited as indicators of relative productivity and health of the marine environment. The degree to which physical forcing plays a dominant role and the mechanisms of effect remain unclear. We test the relationship between measures of oceanographic and atmospheric forcing, proxied by commonly available monthly to daily indices, and the response of populations of a ubiquitous seabird of the Pacific Northwest coastal environment, the common murre,Uria aalge. We constructed two models: an annualized bottom-up model that examines the degree to which population response variables, including population size, breeding success, and foraging parameters, are correlated with oceanographic forcing at space and time scales relevant to murre biology; and a daily direct forcing model that examines the degree to which diet choices reflect specific, local oceanographic signals. Our bottom-up model suggests that murres are regulated by bottom-up forcing, and that the strength of the association between physical change and population response may be mediated by density dependence. Our direct forcing model indicated that chick diet is affected by both local and remote parameters, including upwelling, tide, and the Pacific Decadal Oscillation. We conclude that murres, and seabirds in general, can be used as indicators of local to basinwide physical change, but only under certain conditions: the life history of the species, and the specific local population, must be well known; a conceptual model that links life history traits to measures of physical change at biologically relevant space and time scales must be developed; and larger populations that are more apt to show density-dependent effects should be selected.  相似文献   

The use of large bottomless lysimeters in the determination of water balances for a raised mire     

Julia C. Kelemen  Hugh A. P. Ingram 《水文研究》1999,13(1):101-111

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Does Pumping Volume Affect the Concentration of Micropollutants in Groundwater Samples?          下载免费PDF全文

Inge H. van Driezum  Julia Derx  Ernis Saracevic  Alexander K.T. Kirschner  Regina Sommer  Andreas H. Farnleitner  Alfred Paul Blaschke 《Ground Water Monitoring & Remediation》2017,37(4):82-88

Information on concentrations of micropollutants (such as pharmaceuticals, pesticides, and industrial chemicals) in most highly dynamic riverbank filtration (RBF) systems is lacking, in contrast to data on standard chemical parameters. Sampling protocols have thus far been based on the stabilization of standard chemical parameters in relatively pristine environments. To determine whether groundwater samples for micropollutant analysis can be taken at a similar pumping volume as samples for testing standard chemical parameters in both environments, three groundwater monitoring wells in an RBF system were sampled at two points in time (after pumping of 3 well volumes and after pumping of 15 well volumes). Micropollutant concentrations were not significantly different between the two sampling points; therefore, appropriate samples can be drawn after pumping 3 well volumes. For a specific microbiological parameter (leucin incorporation), a statistically significant difference was found.  相似文献   

Monitoring gravel augmentation in a large regulated river and implications for process‐based restoration          下载免费PDF全文

Fanny Arnaud  Hervé Piégay  David Béal  Pierre Collery  Lise Vaudor  Anne‐Julia Rollet 《地球表面变化过程与地形》2017,42(13):2147-2166

The artificial gravel augmentation of river channels is increasingly being used to mitigate the adverse effects of river regulation and sediment starvation. A systematic framework for designing and assessing such gravel augmentations is still lacking, notably on large rivers. Monitoring is required to quantify the movement of augmented gravel, measure bedform changes, assess potential habitat enhancement, and reduce the uncertainty in sediment management. Here we present the results of an experiment conducted in the Rhine River (French and German border). In 2010, 23 000 m³ of sediments (approximately the mean annual bedload transport capacity) were supplied in a by‐passed reach downstream of the Kembs dam to test the feasibility of enhancing sediment transport and bedform changes. A 620‐m‐long and 12‐m‐wide gravel deposit was created 8 km downstream from the dam. Monitoring included topo‐bathymetric surveys, radio‐frequency particle tracking using passive integrated transponder (PIT) tags, bed grain size measurement, and airborne imagery. Six surveys performed since 2009 have been described (before and after gravel augmentation, and after Q₂ and Q₁₅ floods). The key findings are that (i) the augmented gravel was partially dispersed by the first flood event of December 2010 (Q₁); (ii) PIT tags were found up to 3200 m downstream of the gravel augmentation site after four years, but the effects of gravel augmentation could not be clearly distinguished from the effects of floods and internal remobilization on more than 3500 m downstream; (iii) linear and log‐linear relationships linking bedload transport, particle mobility, and grain size were established; and (iv) combined bathymetry and PIT tag surveys were useful for evaluating potential environmental risks and the first morpho‐ecological responses. This confirmed the complementary nature of such techniques in the monitoring of gravel augmentation in large rivers. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

California Current Large Marine Ecosystem: Publicly available dataset of state and federal laws and regulations     

Julia A. Ekstrom 《Marine Policy》2009

Transitioning ocean governance into an ecosystem-based approach requires improved knowledge of ecosystems and existing management systems. While there has been increased effort to compile and synthesize ecological data, relatively little scholarship has been focused on improving and understanding ocean management systems. This paper presents a unique dataset that makes objective analyses of ocean management possible across multiple jurisdictions and sectors in the California Current. Following an explanation of the criteria used to compile relevant statutes and regulations, the paper suggests applications for the dataset including education and policy uses and ecosystem-based management tool development to identify and measure problems of fragmented management.  相似文献   

Seasonal drivers and patterns of sediment temperatures in a New England salt marsh     

Julia A. Guimond  Barret L. Kurylyk  Robert A. Sohn 《水文研究》2024,38(2):e15100

Salt marshes are globally important ecosystems and thus their resilience to climate change holds societal importance. To date, studies addressing salt marsh responses to climate change have focused on sea-level rise and biogeochemical feedbacks with increasing inundation. Less is known about how salt marsh sediment temperatures, which impact physical, biological, and chemical ecosystem processes, will respond to climate change. In this study, we present multi-depth sediment temperature and porewater level data from low-, mid-, and high-marsh sites at a New England salt marsh for a 1-year period and investigate how salt marsh sediment temperatures respond to atmospheric and oceanic forcing. We use spectral analyses to identify the frequencies at which sediment temperatures vary and link the temperature variations to specific forcing mechanisms. We find that all sites across the marsh responded to air temperature with roughly equal amplitude whereas the responses to radiative heating and ocean tides varied spatially. The high-marsh site is more sensitive to radiative heating than the mid- and low-marsh sites. The low-marsh is affected by tidal processes and inundation whereas the high- and mid-marsh sites are not. In addition, we find that the bulk thermal diffusivity of the saturated sediments decreases with distance from the tidal channel. These factors contribute to considerable temporal and spatial variability in sediment temperatures with elevation, distance from the tidal channel, and time of year (season) being most important.  相似文献   

Intertidal spring dynamics and coastal nutrient loading revealed through geophysics,drone surveys,and in-situ monitoring     

Alexandra C. Oliver  Rob C. Jamieson  Kathryn A. Smith  Julia A. Cantelon  Barret L. Kurylyk 《水文研究》2024,38(5):e15144

Coastal eutrophication poses an increasing risk to ecosystem health due to enhanced nutrient loading to the global coastline. Submarine groundwater discharge (SGD) represents a significant pathway for nitrate-nitrogen (NO₃-N) transport to the coast, but diffusive SGD transport is difficult to monitor directly, given the low flux rates and expansive discharge areas. In contrast, focused SGD from intertidal springs can potentially be sampled and directly gauged, providing unique insight into SGD and associated contaminant transport. Basin Head is a coastal lagoon in Prince Edward Island, Canada that is a federally protected ecosystem. Nitrate-nitrogen is conveyed from agricultural fields in the contributing watershed to the eutrophic lagoon via intertidal groundwater springs and groundwater-dominated tributaries. We used several field methods to characterize groundwater discharge, nutrient loading, and in-channel mixing associated with intertidal springs. The tributaries and intertidal springs were gauged and sampled to estimate a representative summer nitrate load to the lagoon. Our analysis revealed that NO₃-N export to the lagoon through tributaries and springs throughout summer 2023 was on average 401 kg N/month, with the combined spring loading comparable in magnitude to the combined tributary loading. We collected thermal infrared and visual imagery using drone surveys and found spatial overlap between cold-water plumes from the spring discharge and macroalgae blooms, indicating the local thermal and ecosystem impacts of the focused SGD. We also mapped the electrical resistivity (salinity) distribution in the water column around one large spring with electromagnetic geophysics at different tidal stages to reveal the three-dimensional spring plume dynamics. Results showed that the fresher spring water floated above the saline lagoon water with the brackish plume oriented in the direction of the tidal current. Collectively, our multi-pronged field investigations help elucidate the hydrologic, thermal, and nutrient dynamics of intertidal springs and the cascading ecosystem impacts.  相似文献