Lake Sedimentary Environments and Roles of Accumulating Organic Matter in Biogeochemical Cycling Processes and Contaminants Loading Are Invasions of Water Hyacinth in Lake Victoria from 1989 a Concern?

AbstractUrea-based multi-coated slow release fertilizer was produced using water hyacinth, humic substances, and chitosan, with water rich in natural organic matter as a solvent. Elemental analysis showed that the nitrogen content of the fertilizer (FERT) was around 20%. Swelling tests demonstrated the effectiveness of the water hyacinth crosslinker, which reduced the water permeability of the material. Leaching tests showed that FERT released a very low concentration of ammonium (0.82 mg L−1), compared to the amount released from urea (43.1 mg L−1). No nitrate leaching was observed for FERT, while urea leached 13.1 mg L−1 of nitrate. In water and soil, FERT showed maximum releases after 30 and 40 days, respectively, while urea reached maxima in just 2 and 5 days, respectively. The results demonstrated the promising ability of FERT to reduce nitrogen losses, as well as to minimize environmental impacts in the soil–plant-atmosphere system and to improve the efficiency of nitrogen fertilization. Graphic abstract

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Paleoenvironment of the Lower–Middle Cambrian Evaporite Series in the Tarim Basin and Its Impact on the Organic Matter Enrichment of Shallow Water Source Rocks

Minerals ◽

10.3390/min11070659 ◽

2021 ◽

Vol 11 (7) ◽

pp. 659

Author(s):

Mingyang Wei ◽

Zhidong Bao ◽

Axel Munnecke ◽

Wei Liu ◽

G. William M. Harrison ◽

...

Keyword(s):

Organic Matter ◽

Shallow Water ◽

Tarim Basin ◽

Water Environment ◽

Water Source ◽

Major Elements ◽

Source Rocks ◽

Middle Cambrian ◽

Sedimentary Environments ◽

The Impact

Just as in deep-water sedimentary environments, productive source rocks can be developed in an evaporitic platform, where claystones are interbedded with evaporites and carbonates. However, the impact of the paleoenvironment on the organic matter enrichment of shallow water source rocks in an evaporite series has not been well explored. In this study, two wells in the central uplift of the Tarim Basin were systematically sampled and analyzed for a basic geochemical study, including major elements, trace elements, and total organic carbon (TOC), to understand the relationship between TOC and the paleoenvironmental parameters, such as paleosalinity, redox, paleoclimate, paleo-seawater depth, and paleoproductivity. The results show that the Lower–Middle Cambrian mainly developed in a fluctuating salinity, weak anoxic to anoxic, continuous dry and hot, and proper shallow water environment. The interfingering section of evaporites, carbonates, and claystones of the Awatag Fm. have higher paleoproductivity and higher enrichment of organic matter. Paleosalinity, redox, paleoclimate, paleo-seawater depth, and paleoproductivity jointly control the organic matter enrichment of shallow water source rocks in the evaporite series. The degree of enrichment of organic matter in shallow water source rocks first increases and then decreases with the increase in paleosalinity. All the samples with high content of organic matter come from the shallower environment of the Awatag Fm.

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Effect of water hyacinth on distribution of sulphate-reducing bacteria in sediments of Lake Victoria

Water SA ◽

10.4314/wsa.v30i3.5092 ◽

2004 ◽

Vol 30 (3) ◽

Cited By ~ 3

Author(s):

Frederick J Muyodi ◽

Mugassa ST Rubindamayugi ◽

Adelaide K Semesi

Keyword(s):

Water Hyacinth ◽

Lake Victoria ◽

Sulphate Reducing Bacteria ◽

Effect Of Water ◽

Reducing Bacteria

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Preliminary Studies on the Effects of Water Hyacinth on the Diversity, Abundance and Ecology of the Littoral Fish Fauna in Lake Victoria, Uganda

The Limnology, Climatology and Paleoclimatology of the East African Lakes ◽

10.1201/9780203748978-36 ◽

2019 ◽

pp. 643-655

Author(s):

N.G. Willoughby ◽

I.G. Watson ◽

T. Twongo

Keyword(s):

Water Hyacinth ◽

Lake Victoria ◽

Fish Fauna ◽

Littoral Fish

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SHIMMER (1.0): a novel mathematical model for microbial and biogeochemical dynamics in glacier forefield ecosystems

Geoscientific Model Development ◽

10.5194/gmd-8-3441-2015 ◽

2015 ◽

Vol 8 (10) ◽

pp. 3441-3470 ◽

Cited By ~ 7

Author(s):

J. A. Bradley ◽

A. M. Anesio ◽

J. S. Singarayer ◽

M. R. Heath ◽

S. Arndt

Keyword(s):

Organic Matter ◽

Microbial Biomass ◽

Microbial Growth ◽

Model Development ◽

Biogeochemical Cycling ◽

Biogeochemical Model ◽

Model Parameters ◽

Glacier Forefield ◽

Unconstrained Model

Abstract. SHIMMER (Soil biogeocHemIcal Model for Microbial Ecosystem Response) is a new numerical modelling framework designed to simulate microbial dynamics and biogeochemical cycling during initial ecosystem development in glacier forefield soils. However, it is also transferable to other extreme ecosystem types (such as desert soils or the surface of glaciers). The rationale for model development arises from decades of empirical observations in glacier forefields, and enables a quantitative and process focussed approach. Here, we provide a detailed description of SHIMMER, test its performance in two case study forefields: the Damma Glacier (Switzerland) and the Athabasca Glacier (Canada) and analyse sensitivity to identify the most sensitive and unconstrained model parameters. Results show that the accumulation of microbial biomass is highly dependent on variation in microbial growth and death rate constants, Q10 values, the active fraction of microbial biomass and the reactivity of organic matter. The model correctly predicts the rapid accumulation of microbial biomass observed during the initial stages of succession in the forefields of both the case study systems. Primary production is responsible for the initial build-up of labile substrate that subsequently supports heterotrophic growth. However, allochthonous contributions of organic matter, and nitrogen fixation, are important in sustaining this productivity. The development and application of SHIMMER also highlights aspects of these systems that require further empirical research: quantifying nutrient budgets and biogeochemical rates, exploring seasonality and microbial growth and cell death. This will lead to increased understanding of how glacier forefields contribute to global biogeochemical cycling and climate under future ice retreat.

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