Sinkhole Characterization and Karst Conduit Identification Beneath a Natural Prairie in Northeastern Illinois

Twin-bearing pregnancies of sheep reared in harsh environmental conditions result in maternal undernutrition and feto-maternal oxidative stress, leading to intrauterine growth restriction (IUGR). We assessed the efficiency of supplementation with antioxidant herbal vitamins C and E alone or in combination with concentrate throughout gestation on pregnancy outcomes, pre-weaning growth, and survival of twin lambs from grazing ewes at the Magellan Steppe. Four groups (n = 30 each) of twin-bearing ewes received a base natural prairie (P) diet, supplemented with either herbal vitamins C 500 mg and E 350 IU per day (V) or concentrated food (S); groups were: P, P + V, P + S, and P + VS. Vitamins and concentrate were supplemented until parturition. At birth, lambs were weighed, and blood was drawn for total antioxidant capacity (TAC) evaluation. Lamb body weight (BW) and survival rate were evaluated at mid-lactation (60 days) and at weaning (120 days). Vitamin supplementation resulted in increased lamb birth weight and TAC, with a trend towards higher BW at weaning, while nutritional supplementation only had a positive effect on birth weight. Lamb survival was higher in both vitamin supplemented groups. In conclusion, supplementation with herbal vitamins C and E alone or in combination with concentrate food during pregnancy may constitute a good nutritional strategy for sheep reared in harsh environmental conditions.

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Assessing lateral flows and solute transport during floods in a conduit-flow-dominated karst system using the inverse problem for the advection–diffusion equation

Hydrology and Earth System Sciences ◽

10.5194/hess-21-3635-2017 ◽

2017 ◽

Vol 21 (7) ◽

pp. 3635-3653 ◽

Cited By ~ 15

Author(s):

Cybèle Cholet ◽

Jean-Baptiste Charlier ◽

Roger Moussa ◽

Marc Steinmann ◽

Sophie Denimal

Keyword(s):

Inverse Problem ◽

Solute Transport ◽

Unsaturated Zone ◽

Flood Routing ◽

Saturated Zone ◽

Karst System ◽

Advection Diffusion Equation ◽

Advection Diffusion ◽

Karst Conduit ◽

Conduit Network

Abstract. The aim of this study is to present a framework that provides new ways to characterize the spatio-temporal variability of lateral exchanges for water flow and solute transport in a karst conduit network during flood events, treating both the diffusive wave equation and the advection–diffusion equation with the same mathematical approach, assuming uniform lateral flow and solute transport. A solution to the inverse problem for the advection–diffusion equations is then applied to data from two successive gauging stations to simulate flows and solute exchange dynamics after recharge. The study site is the karst conduit network of the Fourbanne aquifer in the French Jura Mountains, which includes two reaches characterizing the network from sinkhole to cave stream to the spring. The model is applied, after separation of the base from the flood components, on discharge and total dissolved solids (TDSs) in order to assess lateral flows and solute concentrations and compare them to help identify water origin. The results showed various lateral contributions in space – between the two reaches located in the unsaturated zone (R1), and in the zone that is both unsaturated and saturated (R2) – as well as in time, according to hydrological conditions. Globally, the two reaches show a distinct response to flood routing, with important lateral inflows on R1 and large outflows on R2. By combining these results with solute exchanges and the analysis of flood routing parameters distribution, we showed that lateral inflows on R1 are the addition of diffuse infiltration (observed whatever the hydrological conditions) and localized infiltration in the secondary conduit network (tributaries) in the unsaturated zone, except in extreme dry periods. On R2, despite inflows on the base component, lateral outflows are observed during floods. This pattern was attributed to the concept of reversal flows of conduit–matrix exchanges, inducing a complex water mixing effect in the saturated zone. From our results we build the functional scheme of the karst system. It demonstrates the impact of the saturated zone on matrix–conduit exchanges in this shallow phreatic aquifer and highlights the important role of the unsaturated zone on storage and transfer functions of the system.

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Population dynamics of muskrats in experimental marshes at Delta, Manitoba

Canadian Journal of Zoology ◽

10.1139/z93-228 ◽

1993 ◽

Vol 71 (8) ◽

pp. 1620-1628 ◽

Cited By ~ 23

Author(s):

William R. Clark ◽

Darryl W. Kroeker

Keyword(s):

Water Level ◽

Mass Gain ◽

Winter Survival ◽

Spatial And Temporal Variation ◽

Open Population ◽

Wetland Complex ◽

Estimate Population Size ◽

Different Levels ◽

Natural Prairie

Muskrat populations were studied in relation to water level and vegetation succession in an experimental wetland complex at Delta Marsh, Manitoba, Canada, flooded to three different levels: normal (long-term average elevation); medium (30 cm above normal); and high (60 cm above normal). Trapping in October and May, combined with closed and open population estimators, was usesd to estimate population size, survival, and recruitment. Muskrat densities reached > 30/ha after the second growing season. Populations in medium and high treatments initially reached densities greater than in normal cells, but all populations decreased to < 1/ha in May 1988. Winter survival declined from 0.31 in 1986 to 0.09 in 1987 and recruitment had declined significantly by May 1988. Winter survival, per-capita recruitment, body condition, and winter mass changes were inversely related to population density, but not consistently related to water level treatments. Survival was directly related to winter mass gain although recruitment the following spring was not. The most influential demographic factor in observed declines in density was decreased winter survival, which was consistently low in all treatments once flooding reduced the emergent vegetation. In natural prairie marsh systems, spatial and temporal variation in vegetation response to flooding contributes to variation in the density dependence of both the survival and recruitment of muskrats.

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