Sedimentological and Biological Changes in the Windsor Mudflat, an Area of Induced Siltation

1980 ◽  
Vol 37 (9) ◽  
pp. 1387-1397 ◽  
Author(s):  
Ted R. Turk ◽  
Michael J. Risk ◽  
Roy W. M. Hirtle ◽  
Ross K. Yeo
Keyword(s):  
Organic Carbon ◽  
Water Content ◽  
Macoma Balthica ◽  
Biological Characteristics ◽  
High Water Content ◽  
Intertidal Mudflat ◽  
Organic Carbon Content ◽  
Corophium Volutator ◽  
Tidal Power ◽  
Shell Size

The causeway-induced mudflat at Windsor, Nova Scotia, was studied to determine the effect of rapid sedimentation on the sedimentological and biological characteristics of an intertidal mudflat. Compared to typical Minas Basin mudflats, the Windsor flat has high water content, (50% vs. 30% wet wt, approximately) small grain sizes, and elevated organic carbon content (0.82% vs. 0.24% dry wt). The two principal infaunal species of the Windsor flat, the amphipod Corophium volutator and the clam Macoma balthica, are less abundant than in nearby typical flats (~840 vs. ~13 000/m2 and ~640 vs. ~1500/m2, respectively), while the polychaete Heteromastus filiformis is particularly abundant at Windsor. Macoma balthica at Windsor grow faster and have a shorter lifespan (~6 yr vs. ~13 yr) than at other Minas Basin flats. Compared to other Minas Basin Macoma, the weight of Windsor Macoma increases more slowly with increasing shell size, possibly an adaptation to the more fluid Windsor sediments.These sedimentological and biological characteristics exist at Windsor nearly 10 yr after the start of flat development and show little tendency to approach typical mudflat characteristics. Our results indicate, therefore, that secondary productivity of Macoma and Corophium could be reduced by about two-thirds for at least a decade in existing Minas Basin mudflats that are covered by Windsor-type sediments as a result of the construction of a tidal power dam.Key words: Bay of Fundy, tidal power, sedimentation, water content, organic carbon, infauna, Corophium volutator, Macoma balthica, growth, mortality

scholarly journals Can a single dose of biochar affect selected soil physical and chemical characteristics?

2018 ◽  
Vol 66 (4) ◽  
pp. 421-428 ◽  
Author(s):  
Dušan Igaz ◽  
Vladimír Šimanský ◽  
Ján Horák ◽  
Elena Kondrlová ◽  
Jana Domanová ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Base Cations ◽  
N Fertilization ◽  
Exchange Capacity ◽  
Organic Carbon Content ◽  
Soil Sorption ◽  
Linear Relationships

Abstract During the last decade, biochar has captured the attention of agriculturalists worldwide due to its positive effect on the environment. To verify the biochar effects on organic carbon content, soil sorption, and soil physical properties under the mild climate of Central Europe, we established a field experiment. This was carried out on a silty loam Haplic Luvisol at the Malanta experimental site of the Slovak Agricultural University in Nitra with five treatments: Control (biochar 0 t ha−1, nitrogen 0 kg ha−1); B10 (biochar 10 t ha−1, nitrogen 0 kg ha−1); B20 (biochar 20 t ha−1, nitrogen 0 kg ha−1); B10+N (biochar 10 t ha−1, nitrogen 160 kg ha−1) and B20+N (biochar 20 t ha−1, nitrogen 160 kg ha−1). Applied biochar increased total and available soil water content in all fertilized treatments. Based on the results from the spring soil sampling (porosity and water retention curves), we found a statistically significant increase in the soil water content for all fertilized treatments. Furthermore, biochar (with or without N fertilization) significantly decreased hydrolytic acidity and increased total organic carbon. After biochar amendment, the soil sorption complex became fully saturated mainly by the basic cations. Statistically significant linear relationships were observed between the porosity and (A) sum of base cations, (B) cation exchange capacity, (C) base saturation.

Changes in dispersible clay content, organic carbon content, and electrolyte composition following incubation of sodic soil

Soil Research ◽  
1998 ◽  
Vol 36 (6) ◽  
pp. 883 ◽  
Author(s):  
P. N. Nelson ◽  
J. A. Baldock ◽  
J. M. Oades
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Water Content ◽  
Clay Content ◽  
Electrolyte Composition ◽  
Organic Carbon Content ◽  
Sodic Soils ◽  
Sodic Soil ◽  
Clay Dispersion ◽  
Dispersible Clay

Measurement of dispersible clay is important for the diagnosis of structural stability problems in soil. However, clay dispersibility is known to change with water content and time. The purpose of the present study was to determine how incubation of sodic soil under different water content regimes influences clay dispersibility. Two topsoils (depth 0-0·1 m), one sodic [exchangeable sodium percentage (ESP) 9 · 7] and the other non-sodic (ESP 3·8), were collected from an experimental pasture at Kyabram, Victoria, and 2 soils, a sodic topsoil (depth 0-0·1 m, ESP 6·9) and the corresponding subsoil (depth 0·2-0 m, ESP 25·7), were collected from a cropped field at Two Wells, South Australia. The soils were incubated for 264 days in a split-plot design. The main treatments were soil type and incubation water content: continuously air-dry, continuously wet (-50 kPa), or with wet/dry cycles. The subtreatment was water content at analysis: air dry or wet (-50 kPa). Clay dispersion was greater when measured on wet soils than dry soils, irrespective of water contents during the prior incubation. Electrical conductivity increased, and sodium adsorption ratio (SAR), pH, and organic carbon content decreased as a function of the time for which the soils were wet. In the Kyabram soils that were wet when analysed, easily dispersible clay content increased with SAR. Decreases in moderately dispersible clay under the wetting/drying regime were not related to electrolyte composition, and were attributed to particle rearrangement and cementation. The decreases in clay dispersibility with time occurred despite net losses of carbohydrate and aliphatic materials. An implication of the work is that the decomposition of soil organic matter, even in the absence of fresh additions, may reduce clay dispersion in sodic soils by altering electrolyte concentration and composition.

scholarly journals A near infrared index to assess effects of soil texture and organic carbon content on soil water content

2018 ◽  
Vol 70 (1) ◽  
pp. 151-161 ◽  
Author(s):  
I. Soltani ◽  
Y. Fouad ◽  
D. Michot ◽  
P. Bréger ◽  
R. Dubois ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Texture ◽  
Near Infrared ◽  
Organic Carbon Content

scholarly journals Effects of reduced and traditional tillage on soil properties and diversity of diatoms under winter wheat

2018 ◽  
Vol 32 (3) ◽  
pp. 403-409 ◽  
Author(s):  
Jadwiga Stanek-Tarkowska ◽  
Ewa A. Czyż ◽  
Anthony R. Dexter ◽  
Cezary Sławiński
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Winter Wheat ◽  
Soil Properties ◽  
Water Content ◽  
Bulk Density ◽  
Reduced Tillage ◽  
Research Station ◽  
Organic Carbon Content ◽  
Dispersible Clay

Abstract The aim of this study was to quantify soil properties, microbial biodiversity and crop yield under two tillage systems used for winter wheat production in monoculture. The study was conducted in the period 2013-2016, on a long-term field experiment on a silt loam at the Krasne Research Station near Rzeszów, Poland. Traditional tillage involved soil inversion whereas reduced tillage was a non-inversion system. The following soil properties: chemical (soil organic carbon, pH, available P, K, Mg), physical (soil bulk density, water content, stability in water), and biological (the diversity of diatoms) were measured on samples collected throughout the growing season and at harvest. Soil organic carbon content, water content and bulk density in the 0-5 and 5-10 cm layers were greater in reduced tillage than in traditional tillage. Under reduced tillage the amount of readily dispersible clay was reduced giving increased soil stability in water. Soil under reduced tillage had greater diversity of diatoms (139 taxa) than that under traditional tillage (102 taxa). Wheat yields were positively correlated with precipitation, soil water content and soil organic carbon, and negatively correlated with readily dispersible clay.

scholarly journals The use of in situ volumetric water content at field capacity to improve the prediction of soil water retention properties

2008 ◽  
Vol 88 (4) ◽  
pp. 533-541 ◽  
Author(s):  
Hassan Al Majou ◽  
Ary Bruand ◽  
Odile Duval
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Water Content ◽  
Bulk Density ◽  
Water Retention ◽  
Field Capacity ◽  
Volumetric Water Content ◽  
Organic Carbon Content ◽  
Water Retention Properties

Most pedotransfer functions (PTF) developed over the past three decades to generate water retention characteristics use soil texture, bulk density and organic carbon content as predictors. Despite the high number of PTFs published, most being class- or continuous-PTFs, the accuracy of prediction remains limited. In this study, we compared the performance of different class- and continuous-PTFs developed with a regional database. Results showed that the use of in situ volumetric water content at field capacity as a predictor led to much better estimation of water retention properties compared with using predictors derived from the texture, or the organic carbon content and bulk density. This was true regardless of the complexity of the PTFs developed. Results also showed that the best prediction quality was achieved by using the in situ volumetric water content at field capacity after stratification by texture. Comparison of in situ volumetric water content at field capacity, with the water retained at different matric potentials as measured in the laboratory, showed field capacity to approximate 100 hPa, whatever the soil texture. Finally, the lack accuracy of PTFs that do not use the in situ volumetric water content at field capacity as predictor did not appear due to the test soils being unrepresentative of the soils used to develop the PTFs, but were instead related to poor correlations between the predictors used and the water retention properties. Key words: Pedotransfer functions, root mean square error, mean error of prediction, standard deviation of prediction, texture, bulk density, organic carbon content

Effect of Sedimentation on Infaunal Invertebrate Populations of Cobequid Bay, Bay of Fundy

1981 ◽  
Vol 38 (6) ◽  
pp. 642-648 ◽  
Author(s):  
Ted R. Turk ◽  
Michael J. Risk
Keyword(s):  
Grain Size ◽  
Macoma Balthica ◽  
Fine Sand ◽  
Coarse Sand ◽  
Sediment Deposition ◽  
Mya Arenaria ◽  
Bay Of Fundy ◽  
Corophium Volutator ◽  
Tidal Power ◽  
Order Of Magnitude

Construction of a tidal dam in the upper reaches of the Bay of Fundy is expected to result in deposition of sediment. We investigated the effect of sediment deposition on populations of three major benthic species of the upper reaches: Corophium volutator, Macoma balthica, and Mya arenaria. In fences and boxes that induced deposition on intertidal mudflats, accumulation of 1.0–3.5 cm of sediment at rates of 1.9–10.2 cm/mo caused Corophium density to decrease sharply, usually by an order of magnitude. Macoma density was generally unaffected. In fishing weirs, mud that accumulated at 1.5 cm/mo to a mean depth of 5.2 cm supported normal Corophium densities. The effect of sedimentation on Mya depends strongly on grain size: LD50 was 24 cm for coarse sand, 6 cm for fine sand, and 3 cm for mud. Mya is able to burrow upward in accumulating coarse sand. Even moderate rates and depths of sediment deposition, particularly of fine sediment, could have a major adverse effect on existing Corophium and Mya populations.Key words: Bay of Fundy, tidal power, sedimentation, grain size, water content, Corophium volutator, Macoma balthica, Mya arenaria

Intertidal Catastrophes: Effect of Storms and Hurricanes on Intertidal Benthos of the Minas Basin, Bay of Fundy

1979 ◽  
Vol 36 (6) ◽  
pp. 667-669 ◽  
Author(s):  
R. K. Yeo ◽  
M. J. Risk
Keyword(s):  
Key Words ◽  
Surface Sediment ◽  
Macoma Balthica ◽  
Bay Of Fundy ◽  
Lateral Migration ◽  
Corophium Volutator ◽  
Tidal Power ◽  
Secondary Productivity

Hurricane Beulah (July 1975) and a major storm both caused catastrophic mortalities among intertidal benthos of the Minas Basin. In both events, surface sediment was scoured off the flats, resulting in high mortalities in shallow-burrowing organisms. The storm was a more severe catastrophe than the hurricane. The demonstrated high secondary productivity of these flats is difficult to reconcile with these observations; extensive lateral migration of the benthos may aid in recovery from catastrophes. Key words: benthos, intertidal productivity, Bay of Fundy, tidal power, catastrophes, Macoma balthica, Corophium volutator

Hydrogels as Antibacterial Biomaterials

2018 ◽  
Vol 24 (8) ◽  
pp. 843-854 ◽  
Author(s):  
Weiguo Xu ◽  
Shujun Dong ◽  
Yuping Han ◽  
Shuqiang Li ◽  
Yang Liu
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Tissue Engineering ◽  
Water Content ◽  
Oxygen Permeability ◽  
Structural Diversity ◽  
High Water ◽  
Clinical Applications ◽  
High Water Content ◽  
Biomedical Field

Hydrogels, as a class of materials for tissue engineering and drug delivery, have high water content and solid-like mechanical properties. Currently, hydrogels with an antibacterial function are a research hotspot in biomedical field. Many advanced antibacterial hydrogels have been developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs and structural diversity. In this article, an overview is provided on the preparation and applications of various antibacterial hydrogels. Furthermore, the prospects in biomedical researches and clinical applications are predicted.

Sign in / Sign up

Export Citation Format

Share Document