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1.
Integrating process‐based flow and temperature models to assess riparian forests and temperature amelioration in salmon streams 
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下载免费PDF全文 Luca Fabris Iain Archibald Malcolm Willem Bastiaan Buddendorf Chris Soulsby 《水文研究》2018,32(6):776-791
The importance of riparian tree cover in reducing energy inputs to streams is increasingly recognized in schemes to mitigate climate change effects and protect freshwater ecosystems. Assessing different riparian management strategies requires catchment‐scale understanding of how different planting scenarios would affect the stream energy balance, coupled with a quantitative assessment of spatial patterns of streamflow generation. Here, we use the physically based MIKE SHE model to integrate simulations of catchment‐scale run‐off generation and in‐stream hydraulics with a heat transfer model. This was calibrated to model the spatio‐temporal distribution of hourly stream water temperature during warm low flow periods in a Scottish salmon stream. The model was explored as a “proof of concept” for a tool to investigate the effects of riparian management on high stream water temperatures that could affect juvenile Atlantic salmon. Uncertainty was incorporated into the assessment using the generalized likelihood uncertainty estimation approach. Results showed that by decreasing both the warming (daylight hours) and the cooling (night‐time hours) rates, forest cover leads to a reduction of the temperature range (with a delay of the time to peak by up to 2 hr) and can therefore be effectively used to moderate projected climate change effects. The modelling presented here facilitated the quantification of potential mitigating effects of alternative riparian management strategies and provided a valuable tool that has potential to be utilized as an evidence base for catchment management guidance. 相似文献
2.
Marcelo F. L. Souza Bjrn Kjerfve Bastiaan Knoppers Weber F. Landim de Souza Raimundo N. Damasceno 《Estuarine, Coastal and Shelf Science》2003,57(5-6):843-858
Lagoa de Araruama in the state of Rio de Janeiro, Brazil, is a hypersaline lagoon with salinity varying spatially from 45 to 56. We collected water samples during monthly cruises throughout the lagoon, and along the streams feeding the system, from April 1991 to March 1992. Nutrients and other water quality parameters exhibited great spatial and temporal variations. Mass balance calculations indicate large amounts of anthropogenic nutrient inputs. The data indicate that the lagoon currently is oligotrophic but is in a state of transition to become a mesotrophic system. Molar dissolved inorganic nitrogen:dissolved inorganic phosphorus (DIN/DIP) varied between 2.2:1 and 659:1 with a volume-weighted average of 22:1. The high DIN/DIP ratio contrasts with that found in nearby lagoons, suggesting that phytoplankton primary production is limited by phosphorus in Lagoa de Araruama. The major loss of DIP is apparently driven by biological assimilation and diagenic reactions in the sediments. Calculations indicate that the lagoon is slightly net autotrophic at +0.9 mol C m−2 yr−1. This suggests that the biomass of the primary producers is restricted by phosphorus availability. Phosphorus retention in the sediment and the hypersaline state of the lagoon prevent changes in autotrophic communities and the formation of eutrophic conditions. 相似文献
3.
The east and northeast Brazil shelves of the Southwest Atlantic harbor some unique conditions for tropical passive margins
with western boundary currents. The narrow and open shelf is almost entirely covered by carbonate sediments due to little
freshwater input and the coast is impacted by the South Equatorial Current (SEC). The wide Abrolhos bank of the east Brazil
shelf, presents more diverse conditions, as it forms a physical barrier to the Brazil Current, and upwelling and land input
become more significant. The main characteristics of the coast and shelf and findings on biogeochemical, sedimentation, and
paleoceanographical processes, addressed by the Joint Oceanographic Projects (JOPS) campaigns, are summarized. 相似文献
4.
A. Mantovanelli E. Marone E. T. da Silva L. F. Lautert M. S. Klingenfuss V. P. Prata Jr. M. A. Noernberg B. A. Knoppers R. J. Angulo 《Estuarine, Coastal and Shelf Science》2004,59(4):523-537
Net transports of water, salt and suspended particulate matter (SPM) for a cross-section in front of the Paranaguá Harbour (Paranaguá Bay, Brazil) are presented for eight distinct tidal cycles. Data include measurements over single spring and neap tidal cycles, during both wet and dry seasons. The main drive forces of circulation and SPM dynamics are identified. Advective transport dominated under moderate to high vertical salinity stratification and weak currents, while mixing processes dominated under well-mixed conditions generated by high currents and low freshwater input. Under partially mixed conditions, both advective and mixing processes were important. The tide-induced residual circulation dictated the magnitude and direction of residual currents and net transports of water and salt, but not of SPM transport. The SPM dynamics was intrinsically related to cyclical processes of erosion, resuspension and deposition driven by tidal currents. The turbulent mixing intensity conditioned the vertical mixing of SPM. Resuspension and vertical mixing were conspicuous in spring cycles, while the horizontal advection preponderated in the neaps. Lags between maximum currents and SPM peak concentrations occurred, with more pronounced hysteresis during ebb periods. 相似文献
5.
Otávio L. G. Maioli Bastiaan A. Knoppers Débora A. Azevedo 《Journal of Atmospheric Chemistry》2009,64(2-3):159-178
Polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons (AHs), such as n-alkanes, hopanes and steranes, were studied in relation to total atmospheric suspended particulates (TSP). Two representative Brazilian cities affected by sugarcane monoculture practices, with their rural surroundings, were chosen for the study. The cities chosen were Maceió (state of Alagoas, NE-Brazil) and Campos dos Goytacazes (state of Rio de Janeiro, SE-Brazil). Samples were collected during the harvesting period, when sugarcane burning occurs, and during the non-harvesting period. The aliphatic hydrocarbon fingerprints suggest a marked contribution of biogenic inputs and a slight contamination by aliphatics in areas far from the urban regions. In the urban areas, some petroleum contributions were observed, marked by the presence of hopanes (m/z 191) and steranes (m/z 217) in the mass chromatographic profiles. A marked increase in PAH concentrations was detected during the sugarcane burning periods, mainly at Campos dos Goytacazes. In a similar approach, n-alkane concentrations and BaP/nC24 ratios were higher during the sugarcane burning periods. These increases were mainly associated with PAH production by the pyrogenic process in relation to aliphatic hydrocarbons with the same carbon numbers. The PAH isomeric ratios and the mixture of petrogenic and pyrogenic compounds of the TSP suggest atmospheric contamination for all regions as a whole, but the more elevated pyrogenic contribution during the sugarcane burning period implies that the impact of this activity is relevant. 相似文献
6.
Bastiaan Notebaert Gert Verstraeten Dimitri Vandenberghe Elena Marinova Jean Poesen Gerard Govers 《第四纪科学杂志》2011,26(1):44-58
Floodplain deposition is an essential part of the Holocene sediment dynamics of many catchments and a thorough dating control of these floodplain deposits is therefore essential to understand the driving forces of these sediment dynamics. In this paper we date floodplain and colluvial deposition in the Belgian Dijle catchment using accelerator mass spectrometric radiocarbon and optical stimulated luminescence dating. Relative mass accumulation curves for the Holocene were constructed for three colluvial sites and 12 alluvial sites. A database was constructed of all available radiocarbon ages of the catchment and this database was analysed using relative sediment mass accumulation rates and cumulative probability functions of ages and site‐specific sedimentation curves. Cumulative probability functions of ages were split into different depositional environments representing stable phases and phases of accelerated clastic deposition. The results indicate that there is an important variation between the different dated sites. After an initial stable early and middle Holocene phase with mainly peat growth in the floodplains, clastic sedimentation rates increased from 4000 BC on. This first phase was more pronounced and started somewhat earlier for colluvial deposits then for alluvial deposits. The main part of the Holocene deposits, both in colluvial and alluvial valleys, was deposited during the last 1 ka. The sedimentation pattern of the individual dated sites and the catchment‐wide pattern indicate that land use changes are responsible for the main variations in the Holocene sediment dynamics of this catchment, while the field data do not provide indications for a climatological influence on the sediment dynamics. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
7.
The coral reef system of the Abrolhos Bank, Brazil, is located between 10 and 65 km off the coast. Suspended particulate
matter between the coast and the inner arc of the reef was mainly composed of kaolinite clay and reworked fossil carbonate
fragments, resuspended from nearshore shoals. Strong permanent and tidal alongshore currents in the nearshore channel together
with the geomorphological configuration of the inner arc formed an efficient hydrodynamic and topographic barrier to offshore
transport of land-derived material. Most of the material was being transported alongshore. Suspended particulate matter between
the inner and outer arcs was dominated by carbonate shells, coral fragments, and needle-shaped biogenic opal, and the reef
system was in large part being dominated by the oligotrophic waters of the Brazil Current. 相似文献
8.
Talitha L. F. Costa Michelle P. Araújo Bastiaan A. Knoppers Renato S. Carreira 《Aquatic Geochemistry》2011,17(1):1-19
In the present work, we evaluated the origin of organic matter in the tropical estuarine-lagoon system of Mundaú–Manguaba,
NE Brazil, by considering the bulk (organic carbon and chlorophyll-a) and lipidic (n-alcohols and sterols) composition of suspended particles. Water samples were collected in August 2006 from
24 stations covering the salinity gradient from the rivers down to the sea outlet. Chlorophyll-a (Chl-a) varied from 22.7 to 134.1 μg L−1 in the lagoons, indicating eutrophic to hypertrophic conditions at the time of sampling. The high correlation between Chl-a and phytol together with the molar C:N ratio indicated the presence of fresh and recently produced autochthonous particulate
organic matter throughout the system, except for the river samples. The elevated concentrations of short-chain n-alcohols
and phytosterols, mainly 24-methylcholesta-5,24(28)-dien-3β-ol, also corroborated the predominance of autochthonous organic
matter in the lagoons but were generated by distinct sources: cianobacteria in the freshwater Manguaba lagoon and diatoms
in the brackish Mundaú lagoon compartments. Input of terrestrial organic matter was only detected in the rivers themselves
or at the upper river–lagoon interfaces. Coprostanol indicated contamination by sewage in Mundaú lagoon and in some rivers,
but at lower levels when compared to other Brazilian coastal lagoons and estuaries. 相似文献
9.
Serena Coetzee Martijn Odijk Bastiaan van Loenen Janette Storm Jantien Stoter 《International Journal of Digital Earth》2020,13(3):355-373
ABSTRACTNational spatial data infrastructures are key to achieving the Digital Earth vision. In many cases, national datasets are integrated from local datasets created and maintained by municipalities. Examples are address, building and topographic information. Integration of local datasets may result in a dataset satisfying the needs of users of national datasets, but is it productive for those who create and maintain the data? This article presents a stakeholder analysis of the Basisregistratie Adressen en Gebouwen (BAG), a collection of base information about addresses and buildings in the Netherlands. The information is captured and maintained by municipalities and integrated into a national base register by Kadaster, the Cadastre, Land Registry and Mapping Agency of the Netherlands. The stakeholder analysis identifies organisations involved in the BAG governance framework, describes their interests, rights, ownerships and responsibilities in the BAG, and maps the relationships between them. Analysis results indicate that Kadaster and the municipalities have the highest relative importance in the governance framework of the BAG. The study reveals challenges of setting up a governance framework that maintains the delicate balance between the interests of all stakeholders. The results provide guidance for SDI role players setting up governance frameworks for national or global datasets. 相似文献
10.
Bastiaan J. Collette Kees Rutten Hans Schouten A. Peter Slootweg 《Marine Geophysical Researches》1974,2(2):133-141
Results are given of the Mid Atlantic Ridge section of a transoceanic survey carried out on board of freighters heading for South America and of ships of both the Royal Navy and the Royal Netherlands Navy. The tracks cross the Mid Atlantic Ridge between 12° and 18°N (GEBCO sheets 153/154). 相似文献