Non-Energy Resources,Connecticut Coastal Waters,Year 9 and 10 Activities

The Connecticut effort in year 9 of the Continental Margins Program concentrated on a 13.6-mi2 area south of the Housatonic River. This area was chosen for a side-scan sonar survey because it lies on and adjacent to the bathymetric expressions of two fairly large, subcropping, potential sources of coarse material. Previous seismic work in the area indicated that outcrops or subcrops of these potential source deposits could be delineated using their bathymetric expression. Owing to the limited resolution of the seismic data, a correlation between bottom type and underlying source deposits could not be made with the seismics alone. Results from the November 1993 side-scan survey show that although the source deposits have discernible bathymetric expressions, they are not cropping out as much as expected. As a result, bottom type is not necessarily determined by subcropping deposits in this particular area. Year 10 work was concentrated in Fishers Island Sound, where three areas of potential interest for near-shore gravel resources had previously been identified. These areas were surveyed, during the spring of 1996, using the RoxAnn Seabed Classification System. A small video camera and a Van Veen grab sampler were used to calibrate and verify the RoxAnn data. Although previous sampling had indicated the presence of gravel or gravelly sediment in all of the survey areas, the RoxAnn results showed less gravel than anticipated. Vibrant eelgrass beds and other habitat indicators were detected in all of the survey areas. Given the variable sediment results, and the high habitat potential of the areas surveyed, the likelihood of developing a sand and gravel supply from the near shore of Fishers Island Sound appears quite low.     

A Method for Direct Assessment of the “Non Rainfall” Atmospheric Water Cycle: Input and Evaporation From the Soil

“Non rainfall” atmospheric water (dew, fog, vapour adsorption) supplies a small amount of water to the soil surface that may be important for arid soil micro-hydrology and ecology. Research into the direct effects of this water on soil is, however, lacking due to instrument and technical constraints. We report on the design, development, construction and findings of an automated microlysimeter instrument to directly measure this soil water cycle in Stellenbosch, South Africa during winter. Performance of the microlysimeter was satisfactory and results obtained were compared to literature and fell within the expected range. “Non rainfall” atmospheric water input into bare soil (river sand) was between 0.88 and 1.10?mm per night while evaporation was between 1.39 and 2.71?mm per day. The study also attempted to differentiate the composition of “non rainfall” atmospheric water and results showed that vapour adsorption contributed the bulk of this input.     

全球重要农业文化遗产(GIAHS)经济评估概念框架:以中国稻鱼共生系统为例（英文）

全球重要农业文化遗产(GIAHS)项目是2002年由联合国粮农组织(FAO)发起,旨在建立全球重要农业文化遗产及其有关的景观、生物多样性、知识和文化保护体系,并在世界范围内得到认可与保护,使之成为可持续管理的基础。农业文化遗产地往往被认为比非遗产地更具经济价值,但目前还没有经济学分析来证明这一点,也没有任何针对农业文化遗产地的复杂的经济性能标准来长期监测其经济功能。本研究的目的在于建立一个经济评价方法,可用于遗产地与非遗产地之间比较。为此,本文选择了成本效益分析(CBA)方法。鉴于数据可得性的限制,经济分析的框架应该包括分析的方向、假设和数据要求,由此指导未来对GIAHS的经济评价。本研究选择中国青田稻鱼共生系统作为案例,根据数据可得性并针对不同活动(旅游,国内和国际市场的销售产品)以及相似系统间比较进行计算。     

A record of phosphorus dynamics in oligotrophic lake sediment

Historical phosphorus (P) dynamics were studied using sediment cores from three oligotrophic, acidic lakes in Maine, USA. Long-term oligotrophy of these lakes is consistent with high sediment aluminum (as Al(OH)₃) concentrations, as Al inhibits internal P loading, even under reducing conditions. The role of microbially-mediated reactions in controlling redox conditions was evaluated by estimating microbial biomass and relative abundance of specific functional groups. Sediments were fractionated using a sequential chemical extraction technique and all lakes met criteria for P retention based on threshold sediment concentrations of Al, Fe, and P fractions as determined by (Kopáček et al. (2005) Limnol Oceanogr 52: 1147–1155). Sediment NaOH-extractable molybdate-reactive P (rP) and non-reactive P (nrP) represent P associated with non-reducible phases, and organic matter-related P, respectively. Total P (TP) does not decrease with sediment depth, as is typical of eutrophic lake sediments; however, nrP/TP decreases and rP/TP increases for all three lakes, indicating nrP mineralization without any significant upward diffusion and release into the hypolimnion; i.e. diagenesis of P is conservative within the sediment. Two diagenetic models were developed based on nrP and rP concentrations as a function of sediment age. The first model assumes a first-order decay of nrP, the rate coefficient being a function of time, and represents irreversible nrP mineralization, where the produced PO₄ is permanently sequestered by the sediment. The second model assumes a first-order reversible transformation between nrP and rP, representing biotic mineralization of organic P followed by incorporation of inorganic P into microbial biomass. Both models reflect preservation of TP with no loss to overlying water. The rate coefficients give us insight into qualities of the sediment that have affected mineralization and sequestration of phosphorus throughout the ²¹⁰Pb-dateable history of each lake. Similar models could be constructed for other lakes to help reconstruct their trophic histories. Paleolimnological reconstruction of the sediment P record in oligotrophic lakes shows mineralization of nrP to rP, but unlike the case in eutrophic lake sediments, sediment TP is preserved in these sediments.     

Effect of removing small (<150?μm) chironomids on inferring temperature in cold lakes

Sieving samples for chironomid analysis with a 150 μm mesh was shown to greatly reduce sample preparation time, and use of only larger specimens did not affect chironomid-inferred salinities in African lakes. Here, we tested if this method is suitable for temperature reconstruction in colder lakes at higher latitudes. Removal of specimens <150 μm in two training sets, one from Canada and one from Sweden, had little impact on the performance statistics of the calibration models. Chironomid abundance, however, decreased greatly because more than half of the head capsules in assemblages were <150 μm. This had major impacts on the temperature reconstructions. Inferences were on average 2°C warmer with the modified models (all specimens >150 μm) than those obtained with the full model (all specimens >100 μm). General patterns of temperature change were also altered. For Lake 7 on Southampton Island, Canada, a cooling trend was reconstructed with the full Canadian model while the modified Canadian model yielded a warming trend. When only specimens >150 μm were used, two to three times more wet sediment was needed to obtain a sufficient number of head capsules. These results indicate that, in cold lakes (mean July/August air temperature ≤11°C), large proportions of head capsules are <150 μm, and sieving the samples in a 150 μm mesh leads to altered temperature reconstructions.     

Fishing for diatoms: fish gut analysis reveals water quality changes over a 75-year period

Defining the reference state of some perturbed streams and rivers is challenging since their non-altered state is undocumented. Despite the near-absence of pristine sites in highly anthropogenic areas, information about aquatic communities that existed prior to human disturbance can be obtained from historic sources. Sediment coring is commonly used in paleolimnology to estimate past environmental conditions of lakes, but this technique is often not appropriate for studies of lotic systems. An alternative is to use diatom assemblages present in the guts of fish that were captured in the streams prior to significant human disturbance. The purpose of the present study was to evaluate the biological integrity of several streams in Ontario and Québec during the early twentieth century based on “paleo” diatom assemblages extracted from the guts of fish stored in museums. The Eastern Canadian diatom index (IDEC: Indice Diatomées de l’Est du Canada) was used to evaluate the biological status of “paleo” and “modern” diatom assemblages. The IDEC shows the position of diatom assemblages on a general pollution gradient. The comparison of IDEC values calculated for the 1925–1948 and the 2003–2007 periods showed that several streams were severely polluted in the early 1900s. In general, present water quality has declined compared to the early 1900s. The biological integrity of only three of the 22 sites has increased. IDEC values were not influenced by the species of fish studied.     

Grid-size dependence of Cauchy boundary conditions used to simulate stream–aquifer interactions

This work examines the simulation of stream–aquifer interactions as grids are refined vertically and horizontally and suggests that traditional methods for calculating conductance can produce inappropriate values when the grid size is changed. Instead, different grid resolutions require different estimated values. Grid refinement strategies considered include global refinement of the entire model and local refinement of part of the stream. Three methods of calculating the conductance of the Cauchy boundary conditions are investigated. Single- and multi-layer models with narrow and wide streams produced stream leakages that differ by as much as 122% as the grid is refined. Similar results occur for globally and locally refined grids, but the latter required as little as one-quarter the computer execution time and memory and thus are useful for addressing some scale issues of stream–aquifer interactions. Results suggest that existing grid-size criteria for simulating stream–aquifer interactions are useful for one-layer models, but inadequate for three-dimensional models. The grid dependence of the conductance terms suggests that values for refined models using, for example, finite difference or finite-element methods, cannot be determined from previous coarse-grid models or field measurements. Our examples demonstrate the need for a method of obtaining conductances that can be translated to different grid resolutions and provide definitive test cases for investigating alternative conductance formulations.     

Successional changes in soil and hyporheic nitrogen fertility on an alluvial flood plain: implications for riparian vegetation

In floodplain primary succession, vegetation colonizes nitrogen-poor alluvial deposits and fertility improves as soil nitrogen accumulates over time. It is generally assumed that vegetation assimilates the vast majority of its nitrogen from the soil; however, recent studies have suggested that the hyporheic zone also may be an important nitrogen source. We investigated the potential relative importance of hyporheic nitrogen by comparing fertility indices, specifically total (TN), dissolved inorganic (DIN), potentially mineralizable (PMN) and ion exchange resin nitrogen (IERN) in both soils and the hyporheic zone at early, mid and late succession stands on an expansive river flood plain. We also constructed mesocosms to assess growth of cottonwood cuttings with access to soil and/or hyporheic water. We found TN and PMN increased from early to mid succession in both the soil (to 10 cm) and hyporheic zone (in a 10 cm layer). While TN, DIN and PMN were an order of magnitude higher in the soil than in the hyporheic zone, IERN was higher in the hyporheic zone, indicating that subsurface flow through the flood plain may be important in delivering nitrogen to the root zone. However, even when flux was added to the hyporheic PMN pool, nitrogen availability in the hyporheic zone (in a 10 cm layer) was vastly lower than soil PMN (to 10 cm). Further, the instantaneous standing stock of DIN in the surface soil alone was about equal to the sum of the DIN pool, the mean subsurface flux and the PMN pool in a 10 cm layer of hyporheic zone. In the mesocosm experiment, cottonwood cuttings with access to both soil and hyporheic water grew fastest; however, they also had the lowest foliar nitrogen concentrations, indicating that this was not due to greater nitrogen availability. In the field, nitrogen content of cottonwood foliage increased along with soil (but potentially hyporheic as well) nitrogen accumulation during succession, suggesting the vegetation responded to increasing nitrogen fertility. We conclude that at least on a per unit-volume basis, the hyporheic zone probably provides little nitrogen relative to the surface soil, except on new alluvial bars that characteristically are nitrogen poor. Therefore, the hyporheic zone is probably a much smaller nitrogen source for mature forests relative to the surface soil unless the vegetation exploits a much larger volume of the hyporheic zone than surface soil.     

The role of long‐term human impact on avulsion and fan development

This study aims to understand (mainly qualitatively) the long‐term role of human impact on avulsion processes and the development of fluvial (mega‐) fans in semi‐arid environments. In this paper we refer to human impact as the direct influences of actions on the river's hydraulics (i.e. flow regulation, flow diversion and channel engineering). In five case‐studies drawn from the Khuzestan plains in southwest Iran we have analysed the setup and triggering conditions of specific avulsions that occurred in the past (timescale of millennia) and identified the role of human interference in their causation. Our analysis is based on the integration of historical, archaeological, geomorphological and geological data. Through this study we demonstrate that avulsions in the Khuzestan plains are the result of long‐term and complex interplay between multiple human‐induced and natural causes. In similar ways human‐induced actions may play important roles during different phases of avulsion development. The ‘success‘ of an avulsion in the post‐triggering phase may be defined by human‐induced setup causes as well as morphodynamic processes. We suggest that present‐day flood events may be partly inherited from long‐term human alterations of the natural processes. These finding could have implications for any fluvial system (e.g. distributive fluvial systems, deltas) where avulsion plays a major role in their development and research tends to emphasize on natural mechanisms. Copyright © 2016 John Wiley & Sons, Ltd.     

A Review of “Renewable Energy Project Development Under the Clean Development Mechanism: A Guide for Latin America”

Books reviewed in this article:

Kurt E. Engelmann and Vjeran Pavlakovic (eds.), Rural Development in Eurasia and the Middle East: Land Reform, Demographic Change, and Environmental Constraints

Gregory C. Randall, America's Original GI Town: Park Forest, Illinois

John B. Rehder, Delta Sugar: Louisiana's Vanishing Plantation Landscape

Cathy D. Knepper, Greenbelt, Maryland: A Living Legacy of the New Deal

Char Miller (ed.), Fluid Arguments: Five Centuries of Western Water Conflict

Edward F. Bergman, The Spiritual Traveler: New York City: The Guide to Sacred Spaces and Peaceful Places

Rachel Pain, Michael Barke, Duncan Fuller, Jamie Gough, Robert MacFarlane, and Graham Mowl, Introducing Social Geographies

Tor A. Benjaminsen, and Christian Lund, (eds.), Politics, Property, and Production in the West African Sahel: Understanding Natural Resources Management

Al Gedicks, Resource Rebels: Native Challenges to Mining and Oil Corporations

Maryann P. Feldman and Nadine Massard (eds.), Institutions and Systems in the Geography of Innovation

Richard Foglesong, Married to the Mouse: Walt Disney World and Orlando

Annick Germain, and Damaris Rose, Montréal: The Quest for a Metropolis

George F. Rengert, Mark T. Mattson, and Kristin D. Henderson, Campus Security: Situational Crime Prevention in High–Density Environments

Vaclav Smil, Feeding the World: A Challenge for the Twenty–First Century

Pu Miao (ed.), Public Places in Asia Pacific Cities: Current Issues and Strategies

Lisa M. Benton and John Rennie Short (eds.), Environmental Discourse and Practice: A Reader

Philip Scranton (ed.), The Second Wave: Southern Industrialization from the 1940s to the 1970s

Barry Dalal–Clayton and David Dent, Knowledge of the Land: Land Resources Information and Its Use in Rural Development