Hematology and Some Biochemical Parameters of Wild Rodents in Pistachio Gardens of Kerman Province, Southeast Iran

Wild rodents were collected using live snap traps in pistachio gardens of Kerman Province, Southeast Iran from 2007 to 2009, then some physiological parameters of them were measured. The samples were identified as follow: Nesokia indica, Meriones persicus, Meriones lybicus and Tatera indica. Blood samples were obtained from the heart, then the blood parameters (glucose, cholesterol, triglyceride, total protein, HDL, red and white blood cell number) in wild species of rodents and laboratory rat were compared. The results showed that there were no significant differences in serum glucose, triglyceride, HDL and total protein levels among different experimental groups. The concentration of cholesterol in T. indica was more than that in N. indica (P < 0.01). The total numbers of red blood cells also showed significant difference between wild garden rodent species and laboratory rat (P < 0.01), while the numbers of white blood cells showed no significant difference.     

Patterns in swimming by a scyphomedusa: a novel approach to quantifying behavior in individuals

Behavior is commonly studied at the group level using several individuals, but there is increasing evidence that the behavior of a few individuals often has a disproportionate effect on the response of a population to its environment. The present study used a suite of statistical techniques, random series analysis, analysis of variance, spectral analysis, and goodness-of-fit tests of frequency histograms, to quantitatively describe the time-dependent changes in individual behavior. Each technique reveals a different facet of the behavior and, when simultaneously applied to the data, distinguishes significant differences among the behaviors of several individuals. The approach was developed and tested on the swimming behavior of four specimens of the scyphomedusa Aurelia aurita (Linnaeus, 1758), which were observed for 19 days, beginning 16 January 1998, and videotaped under identical environmental conditions during that period. The analyses showed that each medusa swam in a unique pattern, varying swimming at characteristic frequencies. Application of the approach to individual-based numerical modeling, to the role of endogenous stimuli in the behavioral repertoire, and to in situ studies of animal behavior is discussed.Communicated by J.P. Grassle, New Brunswick     

Fish distributions and nutrient cycling in streams: can fish create biogeochemical hotspots?

Rates of biogeochemical processes often vary widely in space and time, and characterizing this variation is critical for understanding ecosystem functioning. In streams, spatial hotspots of nutrient transformations are generally attributed to physical and microbial processes. Here we examine the potential for heterogeneous distributions of fish to generate hotspots of nutrient recycling. We measured nitrogen (N) and phosphorus (P) excretion rates of 47 species of fish in an N-limited Neotropical stream, and we combined these data with population densities in each of 49 stream channel units to estimate unit- and reach-scale nutrient recycling. Species varied widely in rates of N and P excretion as well as excreted N:P ratios (6-176 molar). At the reach scale, fish excretion could meet >75% of ecosystem demand for dissolved inorganic N and turn over the ambient NH4 pool in <0.3 km. Areal N excretion estimates varied 47-fold among channel units, suggesting that fish distributions could influence local N availability. P excretion rates varied 14-fold among units but were low relative to ambient concentrations. Spatial variation in aggregate nutrient excretion by fish reflected the effects of habitat characteristics (depth, water velocity) on community structure (body size, density, species composition), and the preference of large-bodied species for deep runs was particularly important. We conclude that the spatial distribution of fish could indeed create hotspots of nutrient recycling during the dry season in this species-rich tropical stream. The prevalence of patchy distributions of stream fish and invertebrates suggests that hotspots of consumer nutrient recycling may often occur in stream ecosystems.     

Light-dependence of carbon and sulfur production by polar clones of the genus Phaeocystis

Blooms of the marine prymnesiophyte genus Phaeocystis link the oceanic and atmospheric compartments of the carbon and sulfur cycles. Modeling the fluxes of dimethylsulfide from the ocean to the atmosphere has been limited due to a lack of information on functional responses to environmental variables. In this study, the light-dependence of extracellular carbon production and dimethyl sulfide (DMS) production by non-axenic polar clones of Phaeocystis spp. was examined at different growth stages. Comparative experiments were run with non-axenic arctic clones of the diatoms Thalassiossira nordenskioeldii and Skeletonema costatum. A large portion of carbon incorporated by the colonial stage of Phaeocystis spp. is released extracellularly, in particular in stationary colonies. This extracellular production can be modeled as a function of irradiance, as for carbon incorporation. In Phaeocystis spp., cellular and extracellular carbon incorporation represent different uptake rates, indicating the formation of two distinct carbon pools. The release of extracellular carbon by polar Phaeocystis spp. was not a constant fraction of total production over the irradiance range used. We observed little extracellular carbon production by cells at high irradiance, and maximal rates were observed at intermediate irradiance. Newly incorporated carbon that accumulates in the mucilage of the colonial stage of antarctic Phaeocystis sp. during photosynthesis was not reutilized for cellular growth during the dark period, as observed for temperate clones. In contrast, only a minor fraction of the radiocarbon incorporated by the diatoms was released extracellularly for all growth stages. The production of DMS was an order of magnitude higher for Phaeocystis spp. than for diatoms. The chlorophyll-specific production of DMS and DMSP (dimethylsulphoniopropionate, the precursor to DMS) by Phaeocystis spp. showed a hyperbolic response to irradiance, while arctic diatoms (weak or non-producers of DMS), on the other hand, did not show any light-dependency of DMS production. An inverse relationship between DMS and DMSP production in stationary clones of arctic P. pouchetii was observed, but not for the exponentially growing antarctic clone. Stationary colonies also had higher DMS and dissolved DMSP production rates than exponentially growing ones. These relationships can be extrapolated to the field in areas where Phaeocystis spp. dominates.     

Experimental determination of the kinetic rate law for the oxidation of perchloroethylene by potassium permanganate

Flushing soils contaminated with trichloroethylene (TCE) and perchloroethylene (PCE) with a permanganate (MnO₄⁻) solution has been shown to reduce the solvent content of the soil. Experiments were performed to quantify the rate at which KMnO₄ oxidizes aqueous solutions of PCE over a range of concentrations. In a series of homogeneous reactors, aqueous phase PCE concentrations were monitored over time in nine experimental trials with excess oxidant concentrations ranging from 5 to 30 g/l. Analysis of the data was performed to quantify the oxidation reaction order with respect to PCE and KMnO₄ and the reaction rate constant. The reaction between PCE and KMnO₄ was determined to be first-order with respect to both PCE and KMnO₄ with an overall specific reaction rate coefficient of 2.45±0.65 M⁻¹ min⁻¹.     

Development of an Earthen Dam Break Database

Earthen embankment dams comprise 85% of all major operational dams in the United States. Assessment of peak flow rates for these earthen dams and the impacts on dam failure are of high interest to engineers and planners. Regression analysis is a frequently used risk assessment approach for earthen dams. In this paper, we present a decision support tool for assessing the applicability of nine regression equations commonly used by practitioners. Using data from 108 case studies, six parameters were observed to be significant factors predicting for peak flow as a metric for risk analysis. We present our work on an expanded earthen dam break database that relates the regression equations and underlying data. A web application, regression selection tool, is also presented to assess the appropriateness of a given model for a given test point. This graphical display allows users to visualize how their data point compares with the data used for the regression equation. These contributions improve estimates and better inform decision makers regarding operational and safety decisions.     

Yields of Dissolved Organic C,N, and P. from Three High-Elevation Catchments,Colorado Front Range,U.S.A.

Ecosystem dynamics in high-elevation watersheds are extremely sensitive to changes in chemical, energy, and water fluxes. Here we report information on yields of dissolved organic C, N, and P for the 1999 snowmelt runoff season from three high-elevation catchments in the Colorado Front Range, U.S.A.: Green Lake 4 (GL4) and Albion townsite (ALB) on North Boulder Creek and the Saddle Stream (SS), a tributary catchment dominated by alpine tundra. Dissolved organic carbon (DOC) concentrations in stream waters ranged from <1 to 10 mg C L^-1, with the highest values occurring at the SS site. Dissolved organic nitrogen (DON) concentrations ranged from below detection limits to 0.28 mg N L^-1 and were again highest at the tundra-dominatedsite. Dissolved organic phosphorus (DOP) concentrations were at or near detection limits throughout the season in all three catchments indicating a strong terrestrial retention of P. OnlyDOC showed a significant relationship to discharge. Yields of DOC in the three catchments ranged from 10.6 to 11.8 kg C ha^-1 while yields of DON and DOP ranged from 0.32 to 0.41 and 0.02 to 0.08 kg ha^-1, respectively. The relatively highyield of organic N and P relative to C from the highest elevationsite (GL4) was somewhat surprising and points to either: (1) a source of dissolved organic material (DOM) in the upper reaches of the catchment that is enriched in these nutrients or (2) theselective uptake and processing of organic N and P downstream ofthe sampling site. Additionally, seasonal changes in the relativeimportance of DOM precursor materials appear to result in changesin the N content of DOM at both the GL4 and ALB sites.     

Comparison of Stormwater Lag Times for Low Impact and Traditional Residential Development1

Abstract: This study compared lag time characteristics of low impact residential development with traditional residential development. Also compared were runoff volume, peak discharge, hydrograph kurtosis, runoff coefficient, and runoff threshold. Low impact development (LID) had a significantly greater centroid lag‐to‐peak, centroid lag, lag‐to‐peak, and peak lag‐to‐peak times than traditional development. Traditional development had a significantly greater depth of discharge and runoff coefficient than LID. The peak discharge in runoff from the traditional development was 1,100% greater than from the LID. The runoff threshold of the LID (6.0 mm) was 100% greater than the traditional development (3.0 mm). The hydrograph shape for the LID watershed had a negative value of kurtosis indicating a leptokurtic distribution, while traditional development had a positive value of kurtosis indicating a platykurtic distribution. The lag times of the LID were significantly greater than the traditional watershed for small (<25.4 mm) but not large (≥25.4 mm) storms; short duration (<4 h) but not long duration (≥4 h) storms; and low antecedent moisture condition (AMC; <25.4 mm) storms but not high AMC (≥25.4 mm) storms. This study indicates that LID resulted in lowered peak discharge depth, runoff coefficient, and discharge volume and increased lag times and runoff threshold compared with traditional residential development.     

Effects of Harvesting on Genetic Diversity in Old-Growth Eastern White Pine in Ontario, Canada

Genetic diversity measures at 54 isozyme loci coding for 16 enzymes in megagametophytes were compared between preharvest and postharvest gene pools of two adjacent virgin, old-growth (∼250 years) stands of eastern white pine ( Pinus strobus L.) in the Galloway Lake Old Pine Area of central Ontario. The concurrence of genetic diversity changes between the stands suggests that real and repeatable genetic erosion occurred in these gene pools as a result of harvesting. The total and mean number of alleles detected in each stand were reduced by approximately 25% after tree density reductions of 75%. The percentage of polymorphic loci dropped by about 33% from preharvest levels. About 40% of the low frequency (0.25> p ≥ 0.01) alleles and 80% of the rare ( p < 0.01) alleles were lost from each stand because of harvesting. Hypothetical multilocus gametic diversity was reduced by about 40% in each stand after harvesting. Latent genetic potential of each stand was reduced by about 50%, suggesting that the ability of these gene pools to adapt to changing environmental conditions may have been compromised. Heterozygosity estimates in the postharvest stands did not reflect reductions in allelic richness due to harvesting. Observed heterozygosity increased by 12% in one stand after harvesting, even though other genetic diversity measures decreased. Gene frequency changes due to harvesting imply that gene pools of naturally regenerated progeny stands may be quite different from the original parental stands. Silvicultural practices should ensure that the gene pools of remaining pristine old-growth stands have been reconstituted in the regenerating stands.