A High Arctic soil ecosystem resists long-term environmental manipulations

The study was conducted for exploration of physico-chemical parameters and ionic constituents of groundwater used in irrigation of four upazilas namely Tangail Sadar, Kalihati, Delduar and Nagarpur upazila of Tangail district during the months of March, April and May of 2015. The physico-chemical parameters (pH, EC and TDS), ionic constituents (Ca2+, Mg2+, Na+, K+, Cl-, CO32-, HCO3-, PO43- and SO42-) and trace metal (Fe and Mn) were analyzed to assess the quality of irrigation in relation to soil properties and crop growth. The pH of groundwater indicates slightly alkaline in nature. As regards to EC the groundwater was in good class and medium salinity hazards in quality for irrigation and the concentration of TDS indicates water as fresh water. The concentration of Ca2+, Mg2+, Na+, K+, Cl-, CO32-, HCO3-, PO43- and SO42- of groundwater were recorded within the permissible limit for irrigation and these ions might not create hazardous impact on soil ecosystem for growing crops. The trace amount of Fe and Mn was detected in irrigation water. In the study area, the groundwater was within the recommended limit and would not create problem for irrigation and that have not long term effects on irrigating agricultural crops which could be safely used for irrigation purposes.Res. Agric., Livest. Fish.3(1): 115-119, April 2016

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Diagnosing the decline in climatic mass balance of glaciers in Svalbard over 1957–2014

The Cryosphere ◽

10.5194/tc-11-191-2017 ◽

2017 ◽

Vol 11 (1) ◽

pp. 191-215 ◽

Cited By ~ 30

Author(s):

Torbjørn Ims Østby ◽

Thomas Vikhamar Schuler ◽

Jon Ove Hagen ◽

Regine Hock ◽

Jack Kohler ◽

...

Keyword(s):

Mass Balance ◽

Linear Trend ◽

Model Performance ◽

Marked Change ◽

Ice Cores ◽

High Arctic ◽

Reanalysis Data ◽

Svalbard Archipelago ◽

Summer Temperatures

Abstract. Estimating the long-term mass balance of the high-Arctic Svalbard archipelago is difficult due to the incomplete geodetic and direct glaciological measurements, both in space and time. To close these gaps, we use a coupled surface energy balance and snow pack model to analyse the mass changes of all Svalbard glaciers for the period 1957–2014. The model is forced by ERA-40 and ERA-Interim reanalysis data, downscaled to 1 km resolution. The model is validated using snow/firn temperature and density measurements, mass balance from stakes and ice cores, meteorological measurements, snow depths from radar profiles and remotely sensed surface albedo and skin temperatures. Overall model performance is good, but it varies regionally. Over the entire period the model yields a climatic mass balance of 8.2 cm w. e. yr−1, which corresponds to a mass input of 175 Gt. Climatic mass balance has a linear trend of −1.4 ± 0.4 cm w. e. yr−2 with a shift from a positive to a negative regime around 1980. Modelled mass balance exhibits large interannual variability, which is controlled by summer temperatures and further amplified by the albedo feedback. For the recent period 2004–2013 climatic mass balance was −21 cm w. e. yr−1, and accounting for frontal ablation estimated by Błaszczyk et al.(2009) yields a total Svalbard mass balance of −39 cm w. e. yr−1 for this 10-year period. In terms of eustatic sea level, this corresponds to a rise of 0.037 mm yr−1. Refreezing of water in snow and firn is substantial at 22 cm w. e. yr−1 or 26 % of total annual accumulation. However, as warming leads to reduced firn area over the period, refreezing decreases both absolutely and relative to the total accumulation. Negative mass balance and elevated equilibrium line altitudes (ELAs) resulted in massive reduction of the thick (>  2 m) firn extent and an increase in the superimposed ice, thin (<  2 m) firn and bare ice extents. Atmospheric warming also leads to a marked change in the thermal regime, with cooling of the glacier mid-elevation and warming in the ablation zone and upper firn areas. On the long-term, by removing the thermal barrier, this warming has implications for the vertical transfer of surface meltwater through the glacier and down to the base, influencing basal hydrology, sliding and thereby overall glacier motion.

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Process-Oriented Modeling of a High Arctic Tundra Ecosystem: Long-Term Carbon Budget and Ecosystem Responses to Interannual Variations of Climate

Journal of Geophysical Research Biogeosciences ◽

10.1002/2017jg003956 ◽

2018 ◽

Vol 123 (4) ◽

pp. 1178-1196 ◽

Cited By ~ 4

Author(s):

Wenxin Zhang ◽

Per-Erik Jansson ◽

Guy Schurgers ◽

Jørgen Hollesen ◽

Magnus Lund ◽

...

Keyword(s):

Carbon Budget ◽

Arctic Tundra ◽

High Arctic ◽

Interannual Variations ◽

Ecosystem Responses ◽

Tundra Ecosystem ◽

Process Oriented

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Persistence and nontarget effects of Bacillusthuringiensis in soil: a review

Canadian Journal of Forest Research ◽

10.1139/x93-287 ◽

1993 ◽

Vol 23 (11) ◽

pp. 2329-2342 ◽

Cited By ~ 60

Author(s):

J.A. Addison

Keyword(s):

Forest Ecosystems ◽

Soil Microflora ◽

Natural Soil ◽

Ecological Role ◽

Laboratory Studies ◽

Soil Ecosystem ◽

Bacterial Populations ◽

Nontarget Effects

This review presents information on the occurrence, persistence and nontarget effects of Bacillusthuringiensis Berliner (B.t.) in soil, with particular emphasis on forest ecosystems. Both field and laboratory studies have confirmed that B.t. is able to survive for several years after spraying, but studies on long-term persistence and possible accumulation of spores in soils are inadequate. The ecological role of B.t. in the soil ecosystem is poorly understood; we do not even know where and under what conditions B.t. multiplies in nature. Information on the effects of B.t. on soil microflora is contradictory, with studies variously suggesting that B.t. caused an increase, a decrease, or did not affect indigenous bacterial populations. Toxicity of B.t. to species of several invertebrate taxa (Acarina, Nematoda, Collembola, Annelida, Hymenoptera) inhabiting the soil has been demonstrated, but only rarely is it possible to relate dosage information to field situations, and in many cases the B.t. subspecies tested are not currently used for pest control in North America. There is an urgent need for further research to elucidate the relationships between B.t. and the natural soil microflora and fauna.

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