scholarly journals A comparison of Holocene testate amoeba assemblages and paleohydrological records from pollen slides and wet-sieved peat

The Holocene ◽  
2020 ◽  
Vol 31 (1) ◽  
pp. 73-82
Author(s):  
Gabriel Magnan ◽  
Terri Lacourse ◽  
Michelle Garneau
Keyword(s):  
British Columbia ◽  
Testate Amoeba ◽  
Assemblage Composition ◽  
Paired Samples ◽  
Sieve Size ◽  
Palynological Assemblages ◽  
Water Based ◽  
Dry Conditions ◽  
Species Specific ◽  
Wet Sieving

In this study, we compared new testate amoeba records produced by the conventional water-based wet-sieving method to testate amoeba data from previous palynological analyses of two Holocene peat profiles from British Columbia, Canada. We used 132 paired samples from the same peat cores to compare the composition of testate amoeba assemblages between the two methods and evaluate the potential of palynological testate amoeba records as quantitative paleohydrological proxies in peatlands. Our results suggest that the palynological treatments (acetolysis, 10% KOH and 150 µm sieving) substantially reduce test concentrations, diversity and richness in most pollen-slide samples. The smaller sieve size used in the palynological treatment (i.e. 150 µm) removed only a small fraction of the total tests, but could introduce a species-specific bias in assemblage composition. However, major shifts between wet and dry conditions, as shown by the water table depth (WTD) reconstructions using wet-sieved samples, were relatively well captured by the palynological datasets in most instances. The palynological assemblages with counts of >50 tests ( n = 30) provided WTD estimates similar to those inferred from the wet-sieved samples as the most dominant hydrophilous and xerophilous taxa were relatively well represented in the pollen-slide samples in the two studied peat cores. Testate amoeba data from pollen slides can provide useful paleohydrological information particularly when combined with other paleoenvironmental proxies. Nonetheless, if the goal is to generate quantitative paleohydrological reconstructions, we recommend that testate amoeba analyses be conducted using the wet-sieving method, as testate amoeba concentrations, diversity and richness are typically much lower in samples prepared with palynological treatments.

scholarly journals Serum Health Biomarkers in African and Asian Elephants: Value Ranges and Clinical Values Indicative of the Immune Response

Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1756
Author(s):  
Katie L. Edwards ◽  
Michele A. Miller ◽  
Jessica Siegal-Willott ◽  
Janine L. Brown
Keyword(s):  
Serum Amyloid A ◽  
Acute Phase Proteins ◽  
Serum Amyloid ◽  
Clinical Samples ◽  
Necrosis Factor Alpha ◽  
Amyloid A ◽  
Paired Samples ◽  
Immune Biomarkers ◽  
Tnf Α ◽  
Species Specific

Serum biomarkers indicative of inflammation and disease can provide useful information regarding host immune processes, responses to treatment and prognosis. The aims of this study were to assess the use of commercially available anti-equine reagents for the quantification of cytokines (tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), interleukins (IL) 2, 6, and 10) in African (Loxodonta africana, n = 125) and Asian (Elephas maximus, n = 104) elephants, and alongside previously validated anti-human reagents for acute-phase proteins (serum amyloid A and haptoglobin), calculate species-specific biomarker value ranges. In addition, we used opportunistically collected samples to investigate the concentrations of each biomarker during identified clinical cases of illness or injury, as a first step to understanding what biomarkers may be useful to managing elephant health. Immune biomarkers were each elevated above the calculated species-specific value ranges in at least one clinical case, but due to variability in both clinical and non-clinical samples, only serum amyloid A was significantly higher in clinical compared to non-clinical paired samples, with tendencies for higher TNF-α and IL-10. We also detected increased secretion of serum amyloid A and all five cytokines following routine vaccination of a single Asian elephant, indicating that these biomarkers can be beneficial for studying normal immune processes as well as pathology. This study indicates that assays developed with commercial reagents can be used to quantify health biomarkers in wildlife species and identifies several that warrant further investigation to elucidate immune responses to various pathologies.

scholarly journals Synthesis and Tribological Properties of Bio-Inspired Nacre-Like Composites

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1563 ◽  
Author(s):  
Hang Zhang ◽  
Shuhai Liu ◽  
Huaping Xiao ◽  
Xun Zhang
Keyword(s):  
Fracture Toughness ◽  
Friction Coefficient ◽  
Layered Structure ◽  
Solid Phase ◽  
Drilling Fluid ◽  
Phase Content ◽  
Wear Scar Diameter ◽  
Solid Phase Content ◽  
Water Based ◽  
Dry Conditions

Ceramic materials possessing the properties of high-strength and rigidity are widely used in industry. The shell nacre has a layered structure containing both macroscopic and microscopic levels and is equipped with superior qualities regarding hardness and strength. Therefore, the ceramic composites with a nacre-like layered structure have the potential to be utilized as sliding bearings employed in the harsh conditions of wells. For the purpose of this paper, a porous Al2O3 ceramics skeleton with nanometer powder is prepared using the freeze-casting method. Then the porous ceramic skeleton is filled with polymer polymethyl methacrylate (PMMA) through mass polymerization to produce a bionic Al2O3/PMMA composite with a lamellar structure. The properties of the prepared composite are determined by the analysis of micro-hardness, fracture toughness, friction coefficient, wear scar diameter, and the morphology of the worn surface. Consequent results indicate that elevation in the A12O3 powder, which acts as the initial solid phase content, prompts the ceramic slurry to exhibit an increase in viscosity and a gradual decrease in the pore size of the ceramic skeleton. The prepared layered Al2O3/PMMA composite possesses high fracture toughness, which closely resembles that of Al, is approximately four times that of the matrix of the Al2O3 ceramics and 16 times that of the PMMA. Three kinds of composites containing different solid phase content are subjected to testing involving lubrication by water-based drilling fluid to determine the friction coefficient of each. The results indicate that an increased load leads to a decreased friction coefficient while the impact of speed is not evident. Under dry conditions, the friction coefficient of three different composites tested, declines with elevated load and speed. With the use of water-based drilling fluid as lubrication, the wear scar diameter increases at higher speed, while dry conditions denote increased load. Abrasive wear is determined to be the principal form of erosion of layered Al2O3/PMMA composites.

Responses of Benthic Macroinvertebrate Species to Manipulation of Interstitial Detritus in Carnation Creek, British Columbia

1985 ◽  
Vol 42 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Joseph M. Culp ◽  
Ronald W. Davies
Keyword(s):  
British Columbia ◽  
Microbial Activity ◽  
Tsuga Heterophylla ◽  
Benthic Macroinvertebrate ◽  
Alnus Rubra ◽  
Detritus Processing ◽  
Specific Manner ◽  
Species Specific ◽  
Macroinvertebrate Species ◽  
Trophic Feeding

Experimental manipulations were conducted in Carnation Creek, British Columbia, to determine the response of macroinvertebrate distribution and abundance to differences in detritus source and quantity. Four treatments (no detritus, low hemlock (Tsuga heterophylla), low alder (Alnus rubra), high alder) with a standardized substrate were established in a riffle and left for 28 d. Densities and/or biomasses of 12 of the 20 colonizing macroinvertebrate taxa were significantly different among the detritus treatments. Microbial activity, detritus processing, and macroinvertebrate abundances were highest in substrate patches with alder detritus. Compared with the no detritus and low hemlock treatments, the low alder treatment increased the abundances of nine taxa and decreased three taxa, while the high alder treatment increased the abundances of six taxa and decreased six taxa. Thus, detritus source and quantity strongly influenced macroinvertebrate community composition within the streambed. Although most of the macroinvertebrates in all treatments were either collector–gatherer or shredder detritivores, these macroinvertebrates responded to changes in detritus in a species-specific manner. Therefore, the Carnation Creek experiments emphasize the importance of interstitial detritus in the substrate as a factor that influences the microdistribution of the benthos at the species, rather than trophic feeding, assemblage level.

Development of a diagnostic molecular marker for Philonema spp. (Nematoda; Dracunculoidea) infecting salmonids in British Columbia

1995 ◽  
Vol 52 (S1) ◽  
pp. 129-133 ◽  
Author(s):  
L. Després ◽  
M.L. Adamson ◽  
T.E. McDonald
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Pcr Amplification ◽  
Base Substitution ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Nematode Parasites ◽  
Rdna Sequences ◽  
Morphological Criteria ◽  
In The Wild ◽  
Species Specific

We developed a species specific DNA probe based on differential PCR amplification that distinguishes two congeneric nematode parasites of salmonids in British Columbia: Philonema agubernaculum Simon and Simon, 1936, usually parasitic in lake resident rainbow trout, Oncorhynchus mykiss; and P. oncorhynchi Kuitunen-Ekbaum, 1933, parasitic in anadromous sockeye salmon, O. nerka. The region differentially amplified was the D3 expansion domain of the 28S rDNA. Sequences of the two species differ in two parts of the domain, one a single base substitution and the other a three base duplication in P. oncorhynchi. A primer specific to P. oncorhynchi (amplifying P. oncorhynchi, not P. agubernaculum) was defined in the duplication region. Using differential amplification, we showed that sockeye smolts are infected with P. agubernaculum, although returning adults harbour only P. oncorhynchi. This technique could conceivably be used to quantify the frequency of heterologous infections in the wild, before infecting worms are identifiable at the species level based on morphological criteria.

scholarly journals Patterns of habitat segregation among large fishes in a Venezuelan floodplain river

2005 ◽  
Vol 3 (1) ◽  
pp. 111-117 ◽  
Author(s):  
Craig A. Layman ◽  
Kirk O. Winemiller
Keyword(s):  
River Channel ◽  
Commercial Fishing ◽  
Biological Interactions ◽  
Habitat Types ◽  
Long Distance ◽  
Assemblage Composition ◽  
Floodplain River ◽  
Main River Channel ◽  
Venezuelan Llanos ◽  
Species Specific

Distribution and abundance of large fishes (SL>100 mm) in the río Cinaruco, a floodplain river in the Venezuelan llanos, were examined by gill net sampling in four habitat types: sand banks, backwater creeks, floodplain lagoons, and river channel. Sampling was standardized using nets (25 m x 2 m) of three mesh sizes set for 24-h periods. Based on data from >10,000 hours of gill netting over three years, there were significant differences in assemblage composition among the four habitats. Pair-wise comparisons suggested differences in assemblage composition between all pairs of habitats except creeks and lagoons. Differences in assemblage composition likely arose from species-specific habitat affinities. For example, 21 taxa were collected from both creeks and lagoons, but not from sand banks or the main river channel; each of these 21 taxa were associated with particular features characteristic of creeks and lagoons (e.g. abundant detritus). Assemblage structure also could be influenced by predation or other biological interactions, but mechanistic experiments are needed to evaluate this hypothesis. Assemblage composition was highly variable within all habitat types, likely the result of spatial and temporal heterogeneity associated with seasonal hydrology. Long distance migrations by prochilodontids and other taxa contributed to higher CPUE during the rising-water period of May 2002. Data from this study will provide a baseline to assess changes in the abundance and distribution of large-bodied fishes in response to increasing impacts from illegal commercial fishing in this region.

Holocene carbon accumulation rates from three ombrotrophic peatlands in boreal Quebec, Canada: Impact of climate-driven ecohydrological change

The Holocene ◽  
2011 ◽  
Vol 21 (8) ◽  
pp. 1217-1231 ◽  
Author(s):  
Simon van Bellen ◽  
Michelle Garneau ◽  
Robert K. Booth
Keyword(s):  
Water Table ◽  
Late Holocene ◽  
C Sequestration ◽  
Carbon Accumulation ◽  
Testate Amoeba ◽  
Ecological Processes ◽  
C Cycle ◽  
Sequestration Potential ◽  
Dry Conditions

Understanding the processes controlling peatland carbon (C) sequestration is critical to anticipate potential changes in the global C cycle in response to climate change. Although identification of these factors may be relatively straightforward on seasonal timescales, at centennial to millennial timescales complexities arise because of interactions between climate, vegetation, hydrology and long-term ecological processes. To better understand the factors controlling long-term C accumulation, Holocene rates of C sequestration were quantified from three pristine ombrotrophic peatlands in boreal Quebec, northeastern Canada (52°N, 75–76°W). Bulk density and loss-on-ignition analyses, combined with radiocarbon dating and age–depth modelling, were used to estimate long-term apparent rates of carbon accumulation. Past changes in vegetation and water-table depth were obtained from plant macrofossil and testate amoeba analysis. Earliest regional peat accumulation started ~7520 cal. BP, with long-term rates of C sequestration varying between 14.9 and 22.6 g/m2 per yr. High C sequestration rates occurred during the mid Holocene when relatively stable Sphagnum section Acutifolia communities were present, while low rates were found during the cooler late Holocene when Cyperaceae and ligneous vegetation were more dominant. However, C sequestration was highly variable among cores, implying that local topography, geomorphology and hydrology, or disturbance factors such as fire, mediate the influence of climate on C accumulation. Reconstructed water-table depths reveal several dry shifts since 3000 cal. BP, suggesting that episodic cold and dry conditions during the late Holocene may have contributed to lower C sequestration rates. Given the intensity of the water-table shifts at these times, we hypothesize that recurrent episodes of frozen subsurface peat might have intensified surface drying. As projected by climate scenarios, anticipated warmer and wetter conditions may lead to greater stability of hummock Sphagna cover and increased C sequestration potential in boreal peatlands.

scholarly journals Performance enhancement of self-compacting concrete in saline environment by hydrophobic surface protection

2019 ◽  
Vol 46 (8) ◽  
pp. 677-686 ◽  
Author(s):  
Mazen J. Al-Kheetan ◽  
Mujib M. Rahman ◽  
Muniswamappa N. Balakrishna ◽  
Denis A. Chamberlain
Keyword(s):  
Performance Enhancement ◽  
Hydrophobic Surface ◽  
Harsh Environments ◽  
Self Compacting Concrete ◽  
Saline Environment ◽  
Surface Protection ◽  
Water Based ◽  
Dry Conditions ◽  
Better Than

The purpose of this research is to enhance the performance of self-compacting concrete (SCC) to make it a more sustainable alternative to traditional concrete. SCC serves the purpose in harsh environments, therefore, requires protection against de-icing agents and harmful saline environments. This paper reports the results from a laboratory study evaluating the efficacy of two impregnants; pure-silane and water-based silane. Both materials were applied on dry and wet SCC specimens manufactured with high and medium doses of superplasticizer. When treatment is applied on dry samples, a significant reduction in chloride penetration was noticed. However, the impregnants were less effective when applied on specimens subjected to intermediate and long-term exposure to water. In dry conditions, pure-silane performed better than the water-based silane, although they had a similar performance when applied on wet specimens. In addition, increasing the internal moisture content has shown an adverse effect on the efficacy of both materials.

scholarly journals Tick-Borne Relapsing Fever in British Columbia, Canada: First Isolation of Borrelia hermsii

1998 ◽  
Vol 36 (12) ◽  
pp. 3505-3508 ◽  
Author(s):  
Satyendra N. Banerjee ◽  
Maya Banerjee ◽  
Keerthi Fernando ◽  
Willy Burgdorfer ◽  
Tom G. Schwan
Keyword(s):  
Monoclonal Antibody ◽  
British Columbia ◽  
Plasmid Dna ◽  
Geographic Area ◽  
Protein Profiles ◽  
Specific Monoclonal Antibody ◽  
Relapsing Fever ◽  
Borrelia Hermsii ◽  
First Case ◽  
Species Specific

The spirochete that causes tick-borne relapsing fever,Borrelia hermsii, was isolated in pure culture during 1995 and 1996 from three acutely ill human patients infected in southern British Columbia, Canada. The geographic area of exposure is a known focus of this disease dating back to 1930 when the first case was recognized in a human. Analyses of plasmid DNA, protein profiles, and reactivity with a species-specific monoclonal antibody identified the new isolates of spirochetes as B. hermsii, all of which were most similar to an isolate of this spirochete from northern California described previously. These are the first reported isolates of B. hermsii from Canada.

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