Effects of oxygen concentration on phosphorus release from reflooded air-dried wetland sediments

1994 ◽  
Vol 45 (7) ◽  
pp. 1319 ◽  
Author(s):  
S Qiu ◽  
AJ McComb
Keyword(s):  
Early Stage ◽  
Sediment Cores ◽  
Lake Management ◽  
Inorganic Phosphorus ◽  
Phosphorus Release ◽  
Phosphorus Loading ◽  
Management Technique ◽  
Anaerobic Conditions ◽  
Air Drying ◽  
North Lake

Intact sediment cores from North Lake (Perth, Western Australia) were air-dried for 40 days, reflooded with lake water and incubated at 20°C. Under aerated conditions, air-drying increased phosphorus release. When aeration was stopped, air-dried sediments continued to release P into the water, but the rate was much slower than that in the early stage of the aeration. The results suggest a gradual depletion of labile phosphorus from the dried sediments. Under anaerobic conditions, the phosphate release was also markedly higher for air-dried sediments than for the 'wet' controls. The accumulation of soluble inorganic phosphorus during air-drying, owing to breakdown of organic material and a drying-induced decrease in phosphate sorption, may be the cause of release on rewetting. The results suggest that drought-induced sediment dehydration in natural wetlands may be followed by a significant increase of internal phosphorus loading under both aerobic and anaerobic conditions. Care must therefore be taken in using drawdown as a lake management technique to improve water quality.

Planktonic and microbial contributions to phosphorus release from fresh and air-dried sediments

1995 ◽  
Vol 46 (7) ◽  
pp. 1039 ◽  
Author(s):  
S Qiu ◽  
AJ McComb
Keyword(s):  
Microbial Biomass ◽  
Sediment Cores ◽  
Phosphorus Release ◽  
Bacterial Respiration ◽  
Air Drying ◽  
Drying And Rewetting ◽  
Dissolved Reactive Phosphorus ◽  
Bacterial Uptake ◽  
Reactive Phosphorus ◽  
North Lake

There was a fivefold increase in the concentration of P (dissolved reactive phosphorus) after intact sediment cores from North Lake, Western Australia, were air-dried and reflooded. Effects of plankton and microbial biomass on phosphorus release were investigated. Freshly killed plankton released P before drying, but less P was released when plankton biomass was air-dried. Bacteria were important contributors of P during drying and rewetting, and their contributions occurred through two processes: (I) when sufficient moisture and oxygen were available, bacteria rapidly removed soluble P from the water and incorporated it into the particulate phase, the amount of P taken up being positively correlated with bacterial respiration; and (2) upon drying, bacterially stored P was partly returned to the water, the release increasing with increasing bacterial uptake. The bacterial contribution of P upon drying was further investigated by sterilizing air-dried and wet sediments with a low dose of gamma irradiation (10 kGy). It was thus possible to discriminate among P contributed from the native (initial) microbial biomass (Pi) before drying, P released from the increased (developed) microbial biomass (Pii) during drying, and P stored in bacteria that had survived air-drying (Ps). It was estimated that air-drying killed about 76% of the microbial biomass. At relatively low external P concentrations (<1000 μg L-1), the increased P brought about by air-drying was mainly derived from killed microbial biomass.

Internal phosphorus loading from bottom sediments of a shallow preliminary reservoir

2008 ◽  
Vol 37 (2) ◽  
Author(s):  
Renata Dondajewska
Keyword(s):  
Bottom Sediments ◽  
Seasonal Variability ◽  
Sediment Cores ◽  
Phosphorus Release ◽  
Ex Situ ◽  
Phosphorus Loading ◽  
Internal Phosphorus Loading

Internal phosphorus loading from bottom sediments of a shallow preliminary reservoirThe aim of the studies done in a shallow preliminary reservoir (western Poland) was to determine the intensity and seasonal variability of phosphorus release from bottom sediments. Ex situ studies were done using intact sediment cores taken in succeeding seasons at 3 research stations. The highest phosphorus loading was observed in spring (May and April), both in 2005 and 2006. The range of loading was between 23.7 and 66.6 mgP m

Studies on Activity of Alkaline Phosphatase and Phosphorus Speciation in Sediments from Lake Hongfeng, China

2010 ◽  
Vol 113-116 ◽  
pp. 412-415
Author(s):  
Jia Jun Deng ◽  
Cui Hong Jiang ◽  
Ji Wei Hu ◽  
Xiong Hui Wei ◽  
Xian Fei Huang ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Organic Phosphorus ◽  
Dry Weight ◽  
Inorganic Phosphorus ◽  
Phosphorus Release ◽  
Guizhou Province ◽  
Phosphorus Loading ◽  
Significant Activity ◽  
Average Value ◽  
High Level

Environmentally significant activity of alkaline phosphatase (APA), phosphorus loading and its species were determined in 14 sediment samples from Lake Hongfeng, one of the key drinking-water sources in Guizhou Province, China. The results of this research indicates that APA presented a high level and notable fluctuations with spatial variations in sediments, ranging from 8.712×10-5 to 25.667×10-5 mol of p-nitrophenol g−1•h-1, and the average value of total phosphorus (TP) in sediments from the lake was 1129.81 mg/kg (dry weight). The content of inorganic phosphorus (IP) was higher than that of organic phosphorus (OP), and the content of the iron/aluminum-bound phosphorus (Fe/Al-P) with phosphorus release risk was also high. In addition, the Pearson’s correlation analysis shows various correlations between APA and Ca-P, Fe/Al-P, OP and IP.

An Assessment of Environmental Changes in Three Lakes from King's County (Nova Scotia, Canada) Using Diatom-Based Paleolimnological Techniques

2008 ◽  
Vol 43 (2-3) ◽  
pp. 85-98 ◽  
Author(s):  
Joshua R. Thienpont ◽  
Brian K. Ginn ◽  
Brian F. Cumming ◽  
John P. Smol
Keyword(s):  
Nova Scotia ◽  
Environmental Changes ◽  
Sediment Cores ◽  
Lake Management ◽  
River System ◽  
210Pb Dating ◽  
Hydroelectric Power ◽  
Diatom Assemblages ◽  
Shoreline Development ◽  
Before And After

Abstract Paleolimnological approaches using sedimentary diatom assemblages were used to assess water quality changes over the last approximately 200 years in three lakes from King's County, Nova Scotia. In particular, the role of recent shoreline development in accelerating eutrophication in these systems was assessed. Sediment cores collected from each lake were analyzed for their diatom assemblages at approximately 5-year intervals, as determined by 210Pb dating. Analyses showed that each system has changed, but tracked different ecosystem changes. Tupper and George lakes recorded shifts, which are likely primarily related to climatic warming, with diatom assemblages changing from a preindustrial dominance by Aulacoseira spp. to present-day dominance by Cyclotella stelligera. In addition to the recent climatic-related changes, further diatom changes in the Tupper Lake core between approximately 1820 and 1970 were coincident with watershed disturbances (farming, forestry, and construction of hydroelectric power infrastructure). Black River Lake has recorded an increase in diatom-inferred total phosphorus since about 1950, likely due to impoundment of the Black River system for hydroelectric generation and subsequent changes in land runoff. Before-and-after (i.e., top-bottom) sediment analyses of six other lakes from King's County provided further evidence that the region is being influenced by climatic change (decreases in Aulacoseira spp., increases in planktonic diatom taxa), as well as showing other environmental stressors (e.g., acidification). However, we recorded no marked increase in diatom-inferred nutrient levels coincident with shoreline cottage development in any of the nine study lakes. Paleolimnological studies such as these allow lake managers to place the current limnological conditions into a long-term context, and thereby provide important background data for effective lake management.

Internal phosphorus loading as the response to complete and then limited sustainable restoration of a shallow lake

2019 ◽  
Vol 55 ◽  
pp. 4
Author(s):  
Katarzyna Kowalczewska-Madura ◽  
Renata Dondajewska ◽  
Ryszard Gołdyn ◽  
Joanna Rosińska ◽  
Stanisław Podsiadłowski
Keyword(s):  
Bottom Sediments ◽  
Littoral Zone ◽  
Ecological Status ◽  
Phosphorus Release ◽  
Phosphorus Loading ◽  
P Release ◽  
Spatial Changes ◽  
Iron Sulphate ◽  
Internal Phosphorus Loading ◽  
Profundal Zone

The urban Swarzędzkie Lake, into which sewage had been diverted many years ago, was still characterised by low ecological status. Three restoration methods were used in order to improve the water quality, i.e. aeration of the waters overlying the bottom sediments, inactivation of phosphorus in the water column with iron sulphate and magnesium chloride and biomanipulation with pike stocking. The aim of the research was to define seasonal and spatial changes of phosphorus internal loading from bottom sediments and to compare this with previous years. We also considered changes in the process of P release when the restoration treatments were limited after 3 yr from 3 methods to 1 method. The highest phosphorus release from bottom sediments was found in the profundal zone, where in summer periods it would reach up to 29.2 mgP m−2 day−1. The lowest P release was observed in the littoral zone, down to a depth of 3 m, where it did not exceed 10.0 mgP m−2 day−1. 31% of the whole load of P released from the bottom sediments was originated from this zone. The research showed an increase of phosphorus release in the first years of restoration treatment and a systematic decrease at all stations in the following years.

scholarly journals Changes in Aroma Profile of Shiitake Mushroom (Lentinus edodes) during Different Stages of Hot Air Drying

Foods ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 444 ◽  
Author(s):  
Lei Qin ◽  
Jing-Xuan Gao ◽  
Jia Xue ◽  
Dong Chen ◽  
Song-Yi Lin ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Sensory Evaluation ◽  
Early Stage ◽  
Organosulfur Compounds ◽  
Lentinus Edodes ◽  
Drying Process ◽  
Shiitake Mushroom ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air

To clarify the changes in the aroma characteristics of shiitake mushrooms (Lentinus edodes) during hot-air drying, volatile compounds of L. edodes were analyzed using sensory evaluation, electronic nose, and purge and trap combined with gas chromatography-mass spectrometry (PT-GC-MS) at different timepoints of the drying process. Results showed that the sensory and volatile profile changed significantly during the drying process at 60 °C for up to 12 h and the drying process could be divided into three stages: early stage (<2 h), middle stage (2–3.5 h) and late stage (>3.5 h). Volatile compounds in fresh L. edodes consisted mainly of ketones and alcohols. The early stage of drying decreased the concentration of ketone and alcohol compounds and promoted the generation of cyclic organosulfur compounds through a series of enzymatic and non-enzymatic reactions, which mainly contribute to the characteristic odor of shiitake mushroom. Partial least squares-discriminant analysis (PLS-DA) showed that the volatile compounds released after different drying times could be divided into four groups, which have been confirmed by sensory evaluation results. The results suggested that the unique flavor of dried mushrooms is mainly due to the activation of enzymes during the drying process, which act on lentinic acid to produce sulfur-containing heterocyclic compounds. We believe that our study makes a potential contribution to the mushroom cultivation and processing industry to achieve an improvement in sensory quality.

scholarly journals Incubation Studies on Exchangable Zn for Varying Levels of added Zn Under Aerobic and Anaerobic Conditions in Grey Terrace Soils, Non Calcarious Floodplain Soils and Calcarious Floodplain Soils

2013 ◽  
Vol 9 (1-2) ◽  
pp. 9-15 ◽  
Author(s):  
KH Talukder ◽  
IU Ahmed ◽  
MS Islam ◽  
MS Islam ◽  
M Asaduzzaman ◽  
...  
Keyword(s):  
Anaerobic Condition ◽  
Early Stage ◽  
Aerobic Condition ◽  
Anaerobic Conditions ◽  
Floodplain Soil ◽  
Zinc Fractions ◽  
Floodplain Soils ◽  
Soil Zn ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

Fractions studies were done to know how the zinc applied to different soils was distributed in to various fractions when the soils incubated under aerobic and anaerobic condition. The added zinc provided significant increase in exchangeable Zn both under aerobic and anaerobic conditions although anaerobic condition gave lower results than aerobic condition. The higher results were obtained at early stage of incubation and it gradually reduced as the incubation period proceeded to 90 days. These results showed all most similar trends for all the soils under study. In general, added zinc showed significantly higher results to the different fractions of soil Zn both under anaerobic and aerobic incubation with very few exceptions. The highest amount of added Zn (12 kg/ha) always produced greater results than the lower doses. Only exchangeable Zn was found higher in the 1st measurement at 15 DAI then gradually decreased but in other cases, gradual increase in zinc fractions was seen as the incubation study proceed to longer duration provided with very few exceptions. In many cases, the exchangeable-Zn found higher only at 15 DAI but sharply reduced at 30 DAI. In general, the Gray Terrace Soil produced the highest results followed by Non Calcareous Gray Floodplain and the lowest results were observed in Dark Grey Floodplain & Brown Floodplain Soil. DOI: http://dx.doi.org/10.3329/jsf.v9i1-2.14643 J. Sci. Foundation, 9(1&2): 9-15, June-December 2011

Relative Importance of Phosphorus Supply to Phytoplankton Production: Fish Excretion versus External Loading

1990 ◽  
Vol 47 (2) ◽  
pp. 364-372 ◽  
Author(s):  
Åge Brabrand ◽  
Bjørn Andreas Faafeng ◽  
Jens Petter Moritz Nilssen
Keyword(s):  
Algal Growth ◽  
Perca Fluviatilis ◽  
Rutilus Rutilus ◽  
Phosphorus Release ◽  
Selenastrum Capricornutum ◽  
Phosphorus Loading ◽  
External Loading ◽  
Phytoplankton Production ◽  
Roach Rutilus Rutilus ◽  
Order Of Magnitude

In laboratory tanks with bream (Abramis brama), perch (Perca fluviatilis), and roach (Rutilus rutilus) concentrations of phosphorus and nitrogen increased with time. Phosphorus was mainly released as soluble molybdate-reactive phosphorus (SRP); nitrogen almost exclusively as ammonium. The release increased with the species' tendency to forage on littoral sediments and with a smaller fish size. Bioassays with the test algae Selenastrum capricornutum showed that released phosphorus was readily available to algal growth. The total supply of phosphorus to the epilimnion of Lake Gjersjøen was calculated from the external supply from the tributaries and the estimated phosphorus release from total roach biomass. From May to October 1980 phosphorus release from the roach population contributed about the same order of magnitude as the total phosphorus loading from the watershed. During the period with the most serious phosphorus depletion to the phytoplankton (July, August, and September), the phosphorus supply from fish was about double that of the external phosphorus supply, confirming the important role of sediment-feeding fish populations in the eutrophication processes of lakes.

Release of Phosphorus by Certain Benthic Invertebrates

1981 ◽  
Vol 38 (8) ◽  
pp. 978-981 ◽  
Author(s):  
Wayne S. Gardner ◽  
Thomas F. Nalepa ◽  
Michael A. Quigley ◽  
John M. Malczyk
Keyword(s):  
Benthic Invertebrates ◽  
Lake Michigan ◽  
Nutrient Release ◽  
Dry Weight ◽  
Inorganic Phosphorus ◽  
Benthic Invertebrate ◽  
Phosphorus Release ◽  
Release Rates ◽  
Temperature Regimes ◽  
Two Temperature

Phosphate release rates by Stylodrilus heringianus, tubificids, and Chironomus spp. were quantified in laboratory experiments by incubating the animals in wet sand under two temperature regimes (5 and 20 °C) and under two nutritional states (full and empty guts). Inorganic phosphorus release rates (± SE) for animals incubated 24 h ranged from 0.12 ± 0.02 (n = 5) nmol phosphorus (P)∙(mg ash-free dry weight)−1∙h−1 for S. heringianus beginning with cleared guts at 5 °C to 0.81 ± 0.09 (n = 5) nmol P∙(mg ash-free dry weight)−1∙h−1 for chironomids beginning with full guts at 20 °C. Calculations based on total invertebrate bio-mass and mean basal release rate suggest that benthic invertebrate excretion could account for most P released from aerobic Lake Michigan sediments.Key words: phosphorus, benthic invertebrates, macroinvertebrates, excretion, nutrients, sediments, nutrient release

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