Global extent and distribution of artificial, residential waterways in estuaries     

Nathan J. Waltham  Rod M. Connolly 《Estuarine, Coastal and Shelf Science》2011,94(2):192-197

Artificial residential waterways are now widespread in the world’s estuaries. We used the global mapping tool, Google Earth, to determine that there are nearly 4000 linear km of artificial waterways globally, covering an area of 270 km². Residential waterways constructed as open, flow-through canal estates are at their greatest extent in North America (77% of global linear extent), where systems are typically longer and narrower, with more openings and dead-ends than systems elsewhere. The remaining canal estates are spread across all other continents except Antarctica: Asia (7%), Europe (7%), Oceania (7%), South America (0.9%), and Africa (0.6%). A relatively recent design change from open canals to artificial estuarine lakes with tidal barriers has occurred on all continents except Africa, most extensively in Australia (14 km² area, 57 independent systems). The extremely large expansion in artificial residential waterways aimed at increasing opportunities for waterfront living by humans has also modified and expanded estuarine habitat available to aquatic biota. Research can best underpin planning and management of these types of waterways by focussing on their value as habitat and their provision of other goods and services.  相似文献   

Importance of intracellular Fe pools on growth of marine diatoms by using unialgal cultures and on the Oyashio region phytoplankton community during spring     

Koji Sugie  Kenshi Kuma  Satoshi Fujita  Satomi Ushizaka  Koji Suzuki  Tsutomu Ikeda 《Journal of Oceanography》2011,67(2):183-196

We report on the ability for luxury Fe uptake and the potential for growth utilizing intracellular Fe pools for 4 coastal centric diatom isolates and in situ phytoplankton assemblages, mainly composed of diatoms. Iron uptake of the diatom isolates and natural phytoplankton assemblages in the Oyashio region during spring blooms were prevented by adding hydroxamate siderophore desferrioxamine B (DFB). After the addition of DFB, intracellular Fe in the diatom isolates supported 2.4–4.2 cell divisions with 1.2–2.6 Chl a doublings. The intracellular Fe was primarily used for cell generation rather than Chl a production, leading to a reduction in the Chl a cell quota in the Fe-starved cells with time. The metabolic properties of the Fe-starved cells with their cell morphologies were different among species or genera. An on-deck incubation experiment also exhibited 1.9 cell divisions and 0.81 Chl a doublings of phytoplankton after the addition of DFB, also indicating the preference of cell generation over Chl a production. A decrease in the level of cellular Chl a, a main light-harvesting pigment in Fe-starved diatoms, may become a superior survival strategy to protect the cells from high irradiance that can cause photo-oxidative damages through photosynthesis. Such relatively low-Fe with high-light conditions could often occur in surface waters of the Oyashio region from spring to summer.  相似文献   

Climate change and infectious diseases: Can we meet the needs for better prediction?     

Xavier Rodó  Mercedes Pascual  Francisco J. Doblas-Reyes  Alexander Gershunov  Dáithí A. Stone  Filippo Giorgi  Peter J. Hudson  James Kinter  Miquel-Àngel Rodríguez-Arias  Nils Ch. Stenseth  David Alonso  Javier García-Serrano  Andrew P. Dobson 《Climatic change》2013,118(3-4):625-640

The next generation of climate-driven, disease prediction models will most likely require a mechanistically based, dynamical framework that parameterizes key processes at a variety of locations. Over the next two decades, consensus climate predictions make it possible to produce forecasts for a number of important infectious diseases that are largely independent of the uncertainty of longer-term emissions scenarios. In particular, the role of climate in the modulation of seasonal disease transmission needs to be unravelled from the complex dynamics resulting from the interaction of transmission with herd immunity and intervention measures that depend upon previous burdens of infection. Progress is also needed to solve the mismatch between climate projections and disease projections at the scale of public health interventions. In the time horizon of seasons to years, early warning systems should benefit from current developments on multi-model ensemble climate prediction systems, particularly in areas where high skill levels of climate models coincide with regions where large epidemics take place. A better understanding of the role of climate extremes on infectious diseases is urgently needed.  相似文献   

Redistribution of sewage-nitrogen in estuarine food webs following sewage treatment upgrades     

Kylie A. Pitt  Rod M. Connolly 《Marine pollution bulletin》2009,58(4):573-580

Stable nitrogen isotopes were used to assess the effects of wastewater treatment plant (WWTP) upgrades on the utilisation of sewage-N by estuarine biota in Moreton Bay, Australia. We measured δ¹⁵N of filamentous algae, mangrove leaves and shore crabs at the Brisbane and Logan Rivers before and after scheduled WWTP upgrades, and at two reference rivers where WWTPs had been upgraded >4 years previously. The total N discharged into Brisbane River decreased by >80% after the upgrades had occurred, but N loads remained similar at Logan River despite the upgrade. In Brisbane River, δ¹⁵N values of algae and crabs decreased and were comparable to the reference rivers within 1-2 years but no changes occurred at Logan River. The δ¹⁵N of mangrove leaves remained elevated in all rivers, indicating that sewage-N remained a major source to mangroves either from residual WWTP discharges or from N accumulated in the sediments over many years.  相似文献   

Heterogeneity in supraglacial debris thickness and its role in glacier mass changes of the Mount Gongga   总被引：3，自引：0，他引：3  

Yong Zhang  Yukiko Hirabayashi  Koji Fujita  ShiYin Liu  Qiao Liu 《中国科学:地球科学(英文版)》2016,59(1):170-184

In the Tibetan Plateau, many glaciers have extensive covers of supraglacial debris in their ablation zones, which affects glacier response to climate change by altering ice melting and spatial patterns of mass loss. Insufficient debris thickness data make it difficult to analyze regional debris-cover effects. Maritime glaciers of the Mount Gongga have been characterized by a substantial reduction in glacier area and ice mass in recent decades. The thermal property of the debris layer estimated from remotely sensed data reveals that debris-covered glaciers are dominant in this region, on which the proportion of debris cover to total glacier area varies from 1.74% to 53.0%. Using a physically-based debris-cover effect assessment model, we found that although the presence of supraglacial debris has a significant insulating effect on heavily debris-covered glaciers, it accelerates ice melting on ~10.2% of total ablation zone and produces rapid wastage of ~25% of the debris-covered glaciers, leading to the similar mass losses between the debris-covered and debris-free glaciers. Widespread debris cover also facilitates the development of active terminus regions. Regional differences in debris-cover effects are apparent, highlighting the importance of debris cover for understanding glacier mass changes in the Tibetan Plateau and other mountain ranges around the world.  相似文献   

Nitrogen isotopic discrimination by water column nitrification in a shallow coastal environment     

Ryo Sugimoto  Akihide Kasai  Toshihiro Miyajima  Kouichi Fujita 《Journal of Oceanography》2008,64(1):39-48

Temporal changes in nitrogen isotopic composition (δ¹⁵N) of the NO₃ ⁻ pool in the water column below the pycnocline in Ise Bay, Japan were investigated to evaluate the effect of nitrification on the change in the δ¹⁵N in the water column. The δ¹⁵N of NO₃ ⁻ in the lower layers varied from −8.5‰ in May to +8.4‰ in July in response to the development of seasonal hypoxia and conversion from NH₄ ⁺ to NO₃ ⁻. The significantly ¹⁵N-depleted NO₃ ⁻ in May most likely arose from nitrification in the water column. The calculated apparent isotopic discrimination for water column nitrification (ɛ_nit = δ¹⁵N_substrate − δ¹⁵N_product) was 24.5‰, which lies within the range of previous laboratory-based estimates. Though prominent deficits of NO₃ ⁻ from hypoxic bottom waters due to denitrification were revealed in July, the isotopic discrimination of denitrification in the sediments was low (ɛ_denit = ∼1‰). δ¹⁵N_NO3 in the hypoxic lower layer mainly reflects the isotopic effect of water column nitrification, given that water column nitrification is not directly linked with sedimentary denitrification and the effect of sedimentary denitrification on the change in δ¹⁵N_NO3 is relatively small.  相似文献   

The thin layer of Warm Ionized Gas: towards a 3-D reconstruction of the spatial distribution of HII regions     

Roberta Paladini  Rod Davies  Gianfranco DeZotti 《Astrophysics and Space Science》2004,289(3-4):363-366

HII regions are known to contribute to the so-called thin layer of the diffuse Warm Ionized Gas. In order to constrain thiscontribution, we reconstruct the 3-D distribution of the sources.A detailed spatial analysis of the largest up-to-date sample of HIIregions is presented.  相似文献   

A possible origin of magnetic fields in galaxies and clusters: strong magnetic fields at  z∼ 10 ?     

Yutaka Fujita †  Tsunehiko N. Kato 《Monthly notices of the Royal Astronomical Society》2005,364(1):247-252

  相似文献   

Photometric study of new southern SU UMa-type dwarf novae and candidates: V877 Ara, KK Tel and PU CMa     

Taichi Kato  Roland Santallo  Greg Bolt  Tom Richards  Peter Nelson  Berto Monard  Makoto Uemura  Seiichiro Kiyota  Rod Stubbings  rew Pearce  Tsutomu Watanabe  Patrick Schmeer  Hitoshi Yamaoka 《Monthly notices of the Royal Astronomical Society》2003,339(3):861-871

  相似文献   

First results from the Very Small Array – I. Observational methods     

Robert A. Watson  Pedro Carreira  Kieran Cleary  Rod D. Davies  Richard J. Davis  Clive Dickinson  Keith Grainge †  Carlos M. Gutiérrez  Michael P. Hobson  Michael E. Jones  Rüdiger Kneissl  Anthony Lasenby  Klaus Maisinger  Guy G. Pooley  Rafael Rebolo  José Alberto Rubiño-Martin ‡  Ben Rusholme §  Richard D. E. Saunders  Richard Savage  Paul F. Scott  An&#;e Slosar  Pedro J. Sosa Molina  Angela C. Taylor  David Titterington  Elizabeth Waldram  Althea Wilkinson 《Monthly notices of the Royal Astronomical Society》2003,341(4):1057-1065

  相似文献