Protein expression signatures: an application of proteomics

The methods of proteomics, the study of the protein complement of the genome, are applicable to environmental testing. Sets of proteins specific to different stressors can be isolated using computer imaging software. Individual proteins can be identified by mass spectrometry. The Protein Expression Signatures (PES) obtained have potential in diagnosing adverse factors in the environment. The challenge is to demonstrate their feasibility in complex environments. We have shown that PES for three endocrine disrupting compounds in trout (Onchorhynchus mykiss), can be detected in mixed sewage effluent. Other studies support these results. As protein databases expand, identification becomes routine, and capture molecules specific to each protein are developed, the possibility of simple field tests for multiple stressors becomes real.     

Rhizocarpon calibration curve for the Aoraki/Mount Cook area of New Zealand

Development of Rhizocarpon growth curve from the Aoraki/Mount Cook area of New Zealand provides a means to assess Little Ice Age glacier behaviour and suggests approaches that have wider application. Employing a sampling strategy based on large populations affords the opportunity to assess which of various metrics (e.g. single largest, average of five largest, mean of an entire population) best characterise Rhizocarpon growth patterns. The 98% quantile from each population fitted with a quadric curve forms a reliable representation of the growth pattern. Since this metric does not depend on the original sample size, comparisons are valid where sample strategy must be adapted to local situations or where the original sample size differs. For the Aoraki/Mount Cook area a surface 100 years old will have a 98% quantile lichen diameter of 34.3 mm, whereas a 200‐year‐old surface will have a lichen diameter of 73.7 mm. In the Southern Alps, constraints from the age range of calibration points, the flattening of the quadric calibration curve and ecological factors limit the useful age range to approximately 250 years. Copyright © 2005 John Wiley & Sons, Ltd.     

Transport and fate of chloride from road salt within a mixed urban and agricultural watershed in Illinois (USA): assessing the influence of chloride application rates

In a typical winter season, approximately 471,000 tons of road salt are deposited along roadways in Illinois, USA. An estimated 45% of the deposited road salt will infiltrate through the soils and into shallow aquifers. Transported through shallow aquifers, chloride associated with the road salts has the potential to reside within groundwater for years based on the pathway, the geologic material, and the recharge rate of the aquifer system. Utilizing MODFLOW and MT3D, simulations employing various road-salt application rates were conducted to assess the net accumulation of chloride and the residence times of chloride in an agriculture-dominated watershed that originates in an urban area. A positive-linear relationship was observed between the application rate of chloride and both the maximum chloride concentration and total mass accumulated within the watershed. Simulated annual recharge rates along impacted surfaces ranged from 1,000 to 10,000 mg/L. After 60 years of application, simulated chloride concentrations in groundwater ranged from 197 to 1,900 mg/L. For all application rates, chloride concentrations within the groundwater rose at an annual rate of >3 mg/L. While concentrations increase throughout the system, the majority of chloride accumulation occurs near the roads and the urban areas. Model simulations reveal a positive relationship between application rate and residence time of chloride (1,123–1,288 days based on application rate). The models indicate that continued accumulation of chloride in shallow aquifers can be expected, and methods that apply less chloride effectively need to be examined.

     

Post-Marquette discharge from Glacial Lake Agassiz into the Superior basin

Glacial Lake Agassiz, the largest of the North American glacial lakes, discharged through several different outlets during its history, although the timing and location of discharge remain controversial. However, one discharge event is well established based on extensive onshore observations: drainage through the Nipigon Lake area into the Superior basin about 10,700 years ago, following retreat of ice of the Marquette advance from the basin. High-resolution, single-channel seismic-reflection data collected with a small airgun were acquired to test the hypothesis that the Post-Marquette drainage event left diagnostic stratigraphic and geomorphic signatures beneath Lake Superior. The unique bathymetry of northwestern Lake Superior, where water depth plunges off Nipigon and Black Bays, makes this location ideal for the characterization of the post-Marquette depositional and erosional features. According to our hypothesis, the initial, sudden discharge of high-velocity water would have eroded channels through the bays. The steep and sudden drop-off into the Superior basin would have caused the flow to slow and drop much of the sediment it was carrying. Our results confirm the existence of both erosional features and depositional sediment packages related to Lake Agassiz discharge at this time. The erosional features include deeply incised bedrock channels in the bays. The depositional features comprise subaqueous fans that are thickest in the deep water areas adjacent to the outlets and thin lakeward and laterally away from the channels. The seismic character of the basal units of the fans, proximal to the channels, is chaotic and only very weakly stratified, suggesting that these deposits represent coarse sediment laid down during the initial, high-energy stages of the flood. These sediments are overlain by a stratified package which is interpreted as the fine grained sediment associated with the later, low-energy stages of the flood. The combination of channels and subaqueous fans is inferred to be diagnostic of high-energy Lake Agassiz discharge into the Superior basin, and they serve as analogs for hypothesized discharge at other times.     

The Forest in the Future: A Response to Seeing the Forest for the Trees

Abstract

In this commentary, we highlight some of the strengths of the bibliometric analysis conducted by Qin et al. that examines the relationships between environmental and natural resource sociologies through citation networks, coauthorship, and keyword usage. We also suggest some ways that the analysis could be expanded or built upon, and ideas for further distinct, but related, inquiry. We also reflect on our own identification, training, and mentoring within the two subfields and draw upon responses from a small purposefully selected sample of other early/mid-career environmental and natural resource sociologists to start a conversation about what the relationship between the two fields might look like in the future.     

Effect of monochloramine on isolated fulvic acid

Monochloramine is interesting both as a selective oxidant of fulvic acid and as a drinking water disinfectant. In this study, the controlled reaction of aquatic fulvic acid with monochloramine did not result in products detectable by ether extraction-gas chromatography-flame ionization detection techniques. Evidence of a reaction was shown by bleaching of the fulvic acid solution (decreased absorbance at 465 nm) and chlorine substitution. Chlorine-containing products were quantified by the total carbon adsorbable organic halide (TOX) parameter. Bleaching and organic chlorine formation were much less extensive than in the reaction of free chlorine with fulvic acid. Monochloramine was shown to produce an organic chlorine fraction more hydrophilic and with higher molecular size than that produced by chlorine and fulvic acid. Results suggest that monochloramine may be useful tool for the investigation of certain humic functionalities because it reacts rather selectively and to a small extent with aquatic fulvic acid.     

Integrated 3D forward stratigraphic and petroleum system modeling of the Levant Basin,Eastern Mediterranean

The Eastern Mediterranean Levant Basin is a proven hydrocarbon province with recent major gas discoveries. To date, no exploration wells targeted its northern part, in particular the Lebanese offshore. The present study assesses the tectono‐stratigraphic evolution and related petroleum systems of the northern Levant Basin via an integrated approach that combines stratigraphic forward modeling and petroleum systems/basin modeling based on the previous published work. Stratigraphic modeling results provide a best‐fit realisation of the basin‐scale sedimentary filling, from the post‐rift Upper Jurassic until the Pliocene. Simulation results suggest dominant eastern marginal and Arabian Plate sources for Cenozoic siliciclastic sediments and a significant contribution from the southern Nilotic source mostly from Lower Oligocene to Lower Miocene. Basin modeling results suggest the presence of a working thermogenic petroleum system with mature source rocks localised in the deeper offshore. The generated hydrocarbons migrated through the deep basin within Jurassic and Cretaceous permeable layers towards the Latakia Ridge in the north and the Levant margin and offshore topographic highs. Furthermore, the basin model indicates a possibly significant influence of salt deposition during Messinian salinity crisis on formation fluids. Ultimately, the proposed integrated workflow provides a powerful tool for the assessment of petroleum systems in underexplored areas.     

Millennial-scale variations in western Sierra Nevada precipitation during the last glacial cycle MIS 4/3 transition

Dansgaard–Oeschger (D–O) cycles had far-reaching effects on Northern Hemisphere and tropical climate systems during the last glacial period, yet the climatic response to D–O cycles in western North America is controversial, especially prior to 55 ka. We document changes in precipitation along the western slope of the central Sierra Nevada during early Marine Oxygen Isotope Stages (MIS) 3 and 4 (55–67 ka) from a U-series dated speleothem record from McLean's Cave. The timing of our multi-proxy geochemical dataset is coeval with D–O interstadials (15–18) and stadials, including Heinrich Event 6. The McLean's Cave stalagmite indicates warmer and drier conditions during Greenland interstadials (GISs 15–18), signified by elevated δ¹⁸O, δ¹³C, reflectance, and trace element concentrations, and less radiogenic ⁸⁷Sr/⁸⁶Sr. Our record extends evidence of a strong linkage between high-latitude warming and reduced precipitation in western North America to early MIS 3 and MIS 4. This record shows that the linkage persists in diverse global climate states, and documents the nature of the climatic response in central California to Heinrich Event 6.     

Post‐Younger Dryas deglaciation of the Greenland western margin as revealed by spatial analysis of lakes

Lake shapes and their spatial distribution are important geomorphological indicators in previously glaciated areas. Their shapes are influenced by the underlying geological structure and processes of glacial sediment deposition or erosion. Since these processes act on large areas, distribution of lakes can reflect the intensity of glacial erosional/depositional processes and their spatial extent. Landsat imagery was used to extract lake outlines from a selected pilot‐study area on the widest ice‐free coastal margin of the south‐western Greenland north of Kangerlussuaq. Analysis included image classification and spatial analysis of lakes with elevation data using geographic information system (GIS) tools. A morphometric index was applied to extract kettle lakes as indicators of a specific glacial process – ice stagnation. Analysis of their spatial distribution helped in the reconstruction of glacial dynamics in formerly glaciated terrain. Our results show that spatial lake distribution combined with elevation analysis can be used to identify zones of glacial erosion and deposition. The highest concentrations of lakes within the study area occupy the elevation range between 164 and 361 m above sea level (a.s.l.). This zone can be identified as an area where intensive glacial erosion took place in the past. The widespread distribution of modeled kettle lake features within the same elevation range and across the study area suggests that the last deglaciation process was accompanied by abandonment of blocks of stagnant ice. This conclusion is supported by surface exposure ages obtained in the same study area and published elsewhere. Copyright © 2009 John Wiley & Sons, Ltd.