Discoloration of Polyvinyl Chloride (PVC) Tape as a Proxy for Water-Table Depth in Peatlands: Validation and Assessment of Seasonal Variability

Summary 1. Discoloration of polyvinyl chloride (PVC) tape has been used in peatland ecological and hydrological studies as an inexpensive way to monitor changes in water-table depth and reducing conditions. 2. We investigated the relationship between depth of PVC tape discoloration and measured water-table depth at monthly time steps during the growing season within nine kettle peatlands of northern Wisconsin. Our specific objectives were to: (1) determine if PVC discoloration is an accurate method of inferring water-table depth in Sphagnum -dominated kettle peatlands of the region; (2) assess seasonal variability in the accuracy of the method; and (3) determine if systematic differences in accuracy occurred among microhabitats, PVC tape colour and peatlands. 3. Our results indicated that PVC tape discoloration can be used to describe gradients of water-table depth in kettle peatlands. However, accuracy differed among the peatlands studied, and was systematically biased in early spring and late summer/autumn. Regardless of the month when the tape was installed, the highest elevations of PVC tape discoloration showed the strongest correlation with midsummer (around July) water-table depth and average water-table depth during the growing season. 4. The PVC tape discoloration method should be used cautiously when precise estimates are needed of seasonal changes in the water-table

Environmental Controls on Pore Number in Hyalosphenia papilio: Implications for Paleoenvironmental Reconstruction

Testate amoebae are routinely used as paleoenvironmental indicators. However, considerable variability occurs in test morphology, even within commonly identified taxa. Relationships between morphological variability and environmental conditions might be useful in paleohydrological studies of peatlands, assuming good preservation of characteristics. Hyalosphenia papilio is a common taxon, well preserved in Sphagnum peatlands, that displays variability in the number of pores on the broad side of the test. We assessed whether variability in pore number was related to substrate moisture by comparing the abundance of individuals with different numbers of pores to measured water-table depths at 67 sites in North America. Results indicated that the abundance of individuals with higher numbers of pores increased in wetter conditions. Individuals with 2 pores were relatively widespread, although they dominated drier habitats. Transfer functions developed with and without pore-number quantification suggest that when communities contain abundant individuals with greater than 2 pores, water-table depth reconstructions can be improved by including pore-number information. Results have implications for peatland paleohydrological studies and suggest that greater exploitation of morphological variability could improve testate amoeba-based reconstructions of past environmental change

Lake-level Variability and Water Availability in the Great Lakes

Key components of water availability in a hydrologic system4 are the amount of water in storage and the variability of that amount. In the Great Lakes Basin, a vast amount of water is stored in the lakes themselves. Because of the lakes’ size, small changes in water levels cause huge changes in the amount of water in storage. Approximately 5,439 mi3 of water, measured at chart datum, is stored in the Great Lakes. A change of 1 ft in water level over the total Great Lakes surface area of 94,250 mi2 means a change of 18 mi3 of water in storage. Changes in lake level over time also play an important role in human activities and in coastal processes and nearshore ecosystems, including development and maintenance of beaches, dunes, and wetlands. The purpose of this report is to present recorded and reconstructed (pre-historical) changes in water levels in the Great Lakes, relate them to climate changes of the past, and highlight major water-availability implications for storage, coastal ecosystems, and human activities. Reconstructed water-level changes have not been completed for all Great Lakes; consequently, this report presents these changes primarily for Lakes Michigan and Huron, with some reference to Lake Superior also

To plant or not to plant? Results from a century-long forest planting experiment

Understanding the long-term affects of management strategies on secondary forest development is particularly important as reforestation and afforestation efforts gain momentum. A forest plantation established in 1915, and left with no active management for a century, was recently rediscovered in eastern Pennsylvania and provides unique insight on the long-term effects of planting on forest succession. The initial planting arrangement of the Lehigh University Experimental Forest, in 43 monospecific and bispecific plots, left a strong legacy on the community composition and forest structure even after 100 years. The legacy of planting was also evident in differing spatial distribution of trees and recruitment dynamics in the LUEF when compared to a non-planted, unmanaged secondary forest

Late Holocene Lake-level Variation in Southeastern Lake Superior: Tahquamenon Bay, Michigan

Internal architecture and ages of 71 beach ridges in the Tahquamenon Bay embayment along the southeastern shore of Lake Superior on the Upper Peninsula of Michigan were studied to generate a late Holocene relative lake-level curve. Establishing a long-term framework is important to examine the context of historic events and help predict potential future changes critical for effective water resource management. Ridges in the embayment formed between about 4,200 and 2,100 calendar years before 1950 (cal. yrs. B.P.) and were created and preserved every 28 ± 4.8 years on average. Groups of three to six beach ridges coupled with inflections in the lake-level curve indicate a history of lake levels fluctuations and outlet changes. A rapid lake-level drop (approximately 4 m) from about 4,100 to 3,800 cal. yrs. B.P. was associated with a fall from the Nipissing II high-water-level phase. A change from a gradual fall to a slight rise was associated with an outlet change from Port Huron, Michigan/Sarnia, Ontario to Sault Ste. Marie, Michigan/Ontario. A complete outlet change occurred after the Algoma high-water-level phase (ca. 2,400 cal. yrs. B.P.). Preliminary rates of vertical ground movement calculated from the strandplain are much greater than rates calculated from historical and geologic data. High rates of vertical ground movement could have caused tectonism in the Whitefish Bay area, modifying the strandplain during the past 2,400 years. A tectonic event at or near the Sault outlet also may have been a factor in the outlet change from Port Huron/Sarnia to Sault Ste. Marie

Gene expression profiling of human alveolar macrophages infected by B. anthracis spores demonstrates TNF-α and NF-κb are key components of the innate immune response to the pathogen

<p>Abstract</p> <p>Background</p> <p><it>Bacillus anthracis</it>, the etiologic agent of anthrax, has recently been used as an agent of bioterrorism. The innate immune system initially appears to contain the pathogen at the site of entry. Because the human alveolar macrophage (HAM) plays a key role in lung innate immune responses, studying the HAM response to <it>B. anthracis </it>is important in understanding the pathogenesis of the pulmonary form of this disease.</p> <p>Methods</p> <p>In this paper, the transcriptional profile of <it>B. anthracis </it>spore-treated HAM was compared with that of mock-infected cells, and differentially expressed genes were identified by Affymetrix microarray analysis. A portion of the results were verified by Luminex protein analysis.</p> <p>Results</p> <p>The majority of genes modulated by spores were upregulated, and a lesser number were downregulated. The differentially expressed genes were subjected to Ingenuity Pathway analysis, the Database for Annotation, Visualization and Integrated Discovery (DAVID) analysis, the Promoter Analysis and Interaction Network Toolset (PAINT) and Oncomine analysis. Among the upregulated genes, we identified a group of chemokine ligand, apoptosis, and, interestingly, keratin filament genes. Central hubs regulating the activated genes were TNF-α, NF-κB and their ligands/receptors. In addition to TNF-α, a broad range of cytokines was induced, and this was confirmed at the level of translation by Luminex multiplex protein analysis. PAINT analysis revealed that many of the genes affected by spores contain the binding site for c-Rel, a member of the NF-κB family of transcription factors. Other transcription regulatory elements contained in many of the upregulated genes were c-Myb, CP2, Barbie Box, E2F and CRE-BP1. However, many of the genes are poorly annotated, indicating that they represent novel functions. Four of the genes most highly regulated by spores have only previously been associated with head and neck and lung carcinomas.</p> <p>Conclusion</p> <p>The results demonstrate not only that TNF-α and NF-κb are key components of the innate immune response to the pathogen, but also that a large part of the mechanisms by which the alveolar macrophage responds to <it>B. anthracis </it>are still unknown as many of the genes involved are poorly annotated.</p

A Review of the N-bound and the Maximal Mass Conjectures Using NUT-Charged dS Spacetimes

The proposed dS/CFT correspondence remains an intriguing paradigm in the context of string theory. Recently it has motivated two interesting conjectures: the entropic N-bound and the maximal mass conjecture. The former states that there is an upper bound to the entropy in asymptotically de Sitter spacetimes, given by the entropy of pure de Sitter space. The latter states that any asymptotically de Sitter spacetime cannot have a mass larger than the pure de Sitter case without inducing a cosmological singularity. Here we review the status of these conjectures and demonstrate their limitation. We first describe a generalization of gravitational thermodynamics to asymptotically de Sitter spacetimes, and show how to compute conserved quantities and gravitational entropy using this formalism. From this we proceed to a discussion of the N-bound and maximal mass conjectures. We then illustrate that these conjectures are not satisfied for certain asymptotically de Sitter spacetimes with NUT charge. We close with a presentation of explicit examples in various spacetime dimensionalities.Comment: 49 pages, 17 figures, a few typos corrected, addendum added with regard to some references that were later brought to our attentio