Algal Demand Drives Sediment Phosphorus Release in a Shallow Eutrophic Cove

2019 ◽  
Vol 62 (5) ◽  
pp. 1315-1324
Author(s):  
James A. McCarty
Keyword(s):  
Water Quality ◽  
Shallow Water ◽  
Sediment Core ◽  
Algal Growth ◽  
Phosphorus Release ◽  
Water Bodies ◽  
Release Rates ◽  
Sediment Samples ◽  
P Release ◽  
Core Incubation

Abstract. Algae play an important role in the internal nutrient cycling of shallow lakes and coves. Algae of shallow water bodies have been shown to thrive and even lead to eutrophic conditions despite a lack of measurable quantities of biologically available phosphorus (P) in the water during summer months. To study how sediment P release and algal growth are connected, water and sediment samples were collected in a shallow eutrophic cove on Beaver Lake in northwest Arkansas. Water quality profiles depicting temperature, dissolved oxygen, nutrients, metals, and photic zone chlorophyll-a were collected weekly from 21 May to 10 July 2018 at three points in the cove: one shallow, one at the cove midpoint, and one at the deepest part of the cove. Cove sediment samples were collected at similar points as the water quality samples for equilibrium P concentration (EPCo) analysis, sediment core incubation, and sediment composition. EPCo for the sediments ranged from 0.024 to 0.027 mg L-1. Sediment cores exposed to aerobic conditions typical of shallow areas had P release rates ranging from 1.37 to 2.02 mg m-2 d-1. Concentrations of soluble reactive P (SRP) in the water column from the weekly water quality sampling averaged 0.002 ±0.003 mg L-1, and photic zone SRP concentrations averaged 0.002 ±0.004 mg L-1 for all sampling sites. The chlorophyll-a concentration increased from 10 to 40 µg L-1 during the period from 21 May to 25 June. When SRP << EPCo, conditions favor the release of SRP from sediments to the overlying water. This was confirmed with the aerobic sediment core incubation in which algal demand was controlled using dark conditions and the release rates were >1.37 mg L-1 d-1. Core aerobic release rates and EPCo conditions both confirmed the release of P under aerobic conditions; however, it appears that algal demand sustained low SRP conditions. This created a nutrient cycle in which algae imposed a nutrient gradient favoring P release by keeping SRP conditions below the EPCo. This study indicates that algal growth potential in shallow water bodies is not limited by SRP concentrations measured within the water column. Studies of shallow water bodies with low SRP concentrations and high productivity should look to the sediments as a source of P to fuel algal growth. Finally, these findings suggest that coves play an integral part in algal production and should not be overlooked when determining the overall P budget for a lake or reservoir. Keywords: Aerobic phosphorus release, Equilibrium phosphorus concentration, Sediment core incubation.

Sediment Phosphorus Release in a Shallow Eutrophic Reservoir Cove

2019 ◽  
Vol 62 (5) ◽  
pp. 1269-1281
Author(s):  
James A. McCarty
Keyword(s):  
Dissolved Oxygen ◽  
Unit Area ◽  
Phosphorus Release ◽  
Bed Sediment ◽  
Anaerobic Conditions ◽  
Release Rates ◽  
P Release ◽  
Sensor Platform ◽  
Beaver Lake ◽  
P Flux

Abstract. Internal phosphorus (P) loading is a leading contributor to eutrophication in reservoirs and can cause harmful algal blooms as well as treatment issues for drinking water reservoirs. Coves are an area of reservoirs that have not received adequate attention, even though they experience higher nutrient and sediment deposition and primary production per unit area when compared to the pelagic zone of the reservoir. This study investigates a shallow eutrophic cove in a northwest Arkansas reservoir called Beaver Lake to better understand the cove’s potential to contribute to P loading and eutrophication within the reservoir. The study period was 3 to 16 July 2018. Water column profiles of depth, temperature, and dissolved oxygen were measured with a floating sensor platform that also contained a weather station. Cove bed sediment samples were collected at three locations in the cove and analyzed for chemical composition through Mehlich III extraction and P, nitrate + nitrite (N+N), and ammonia release rates with aerobic and anaerobic sediment core incubations. Bathymetry data were collected using a depth sonar system. Sensor platform profiles indicated dynamic bottom temperature and dissolved oxygen conditions with transient influxes of hypoxic waters that occurred several times for less than 24 h. The P release rates from bed sediment incubations were as high as 2.02 mg m-2 d-1 under aerobic conditions and 4.45 mg m-2 d-1 under anaerobic conditions. Upon initiation of nitrogen gas bubbling in the sediment cores, anaerobic conditions were delayed by the presence of N+N. Phosphorus release did not occur until denitrification decreased the N+N concentrations enough for reducing conditions to be present. For the study period, a P flux into the water of roughly 1 kg was determined using cove profiles, bathymetry, and P release rates. When compared to whole-lake P release averages for Beaver Lake, eutrophic coves are a disproportionate source of P per unit area within the reservoir. This may offer opportunities for more efficient use of internal loading remediation techniques, such as alum application. The results of this study also suggest that we should not continue to overlook shallow-area bed sediment P flux when considering the P mass balance of a reservoir. Keywords: Eutrophication, Sediment core incubation, Stratification.

Holistic water quality dynamics in rural artificial shallow water bodies

2018 ◽  
Vol 223 ◽  
pp. 676-684 ◽  
Author(s):  
Abul Hasan Md Badiul Alam ◽  
Koichi Unami ◽  
Masayuki Fujihara
Keyword(s):  
Water Quality ◽  
Shallow Water ◽  
Water Bodies

Seasonality in phosphorus release rates from the sediments of a hypereutrophic lake under a matrix of pH and redox conditions

2000 ◽  
Vol 57 (5) ◽  
pp. 1033-1041 ◽  
Author(s):  
Michael R Penn ◽  
Martin T Auer ◽  
Susan M Doerr ◽  
Charles T Driscoll ◽  
Carol M Brooks ◽  
...  
Keyword(s):  
Average Rate ◽  
Sediment Cores ◽  
Redox Status ◽  
Phosphorus Release ◽  
Water Interface ◽  
Concentration Gradients ◽  
Release Rates ◽  
Release Process ◽  
P Release

Phosphorus release rates were measured on intact sediment cores collected from the major depositional basin of Onondaga Lake, a dimictic, calcareous, hypereutrophic system in Syracuse, N.Y., U.S.A. Release experiments were conducted under a matrix of redox and pH conditions to investigate the importance of Ca- and Fe-related physicochemistry on sediment cores collected seasonally, i.e., during the spring, summer, fall, and winter periods. Strong seasonal variation in P release was observed, with rates ranging from ~3 to 38 mg P·m-2·day-1. This variation is attributed to changes in redox status and P concentration gradients at the sediment-water interface. An oxidized microlayer at the sediment-water interface partially inhibits sediment P release under isothermal, well-mixed conditions in the spring and fall. Phosphorus trapped in the oxic microlayer (sorption) is freed when the microlayer is chemically reduced at the onset of anoxia and high P release rates are observed. The oxidized microlayer serves to regulate seasonality in rates of sediment P release but does not influence long-term sediment-water exchange. It is proposed that the long-term P release process is best represented by a time-weighted annual average rate, calculated here to be ~10 mg P·m-2·day-1.

scholarly journals Controlling Eutrophication via Surface Aerators in Irregular-Shaped Urban Ponds

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3360
Author(s):  
Aimin Hao ◽  
Sohei Kobayashi ◽  
Dong Xia ◽  
Qi Mi ◽  
Ning Yan ◽  
...  
Keyword(s):  
Water Quality ◽  
Trophic State ◽  
Algal Growth ◽  
Phosphorus Release ◽  
Cyanobacterial Blooms ◽  
Dramatic Improvement ◽  
Small Surface ◽  
Chl A ◽  
The North ◽  
Urban Ponds

Surface aerators have often been introduced in urban ponds for esthetics, but their roles in remediating water quality are less understood. Effects of surface aerators on controlling eutrophication were examined in two urban ponds, in which anaerobic odors and cyanobacterial blooms had occurred and several aerators had been installed. In one of the ponds, a dramatic improvement in dissolved oxygen (DO) (from 1.8 to 8.1 mg L−1) and total phosphorus (TP) (from 1.6 to 0.4 mg L−1) was evident based on the comparison before and after the aeration. Although cyano-bloom did not occur, phytoplankton was dominated by cyanobacteria Microcystis species in both periods. Chlorophyll a (Chl-a) increased (from 29 to 51 μg L−1) and water transparency decreased (from 81 to 27 cm) after the aeration. In the other pond with an irregular shape, water quality was monitored two years after the installation to examine seasonal variation in trophic state and its spatial variation associated with aerator distribution. The water was mixed vertically well for the whole pond, as indicated by small surface-to-bottom differences in temperature. DO decreased in summer after rainfall but was always >5.7 mg L−1. Total nitrogen (TN) and TP were 0.8–2.3 and 0.03–0.07 mg L−1, respectively, and no cyano-blooms were observed across sites throughout the year. Phytoplankton was dominated by green algae and diatom species, which may be favored by the lower phosphorus level of the pond. Chl-a was higher and transparency was lower in the north side, which had more aerators and less shade from trees and buildings. These results suggest that surface aerators increased DO by vertical and horizontal mixing of water, reduced phosphorus release from sediment, and prevented cyano-bloom occurrence, but they did not improve Chl-a level and transparency. Rather, aeration can promote algal growth, and thus, additional purifying measures such as filtration and contact oxidation are required to further improve the trophic state of these ponds.

scholarly journals Microbiological Assessment of Elechi Creek Receiving Wastewater Effluents from Industrial Operations in Port Harcourt City

2021 ◽  
pp. 40-49
Author(s):  
D. N. Ogbonna ◽  
P. C. Meregini-Ikechukwu ◽  
L. B. Kpormon
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Infectious Diseases ◽  
Heterotrophic Bacteria ◽  
Total Coliform ◽  
Water Bodies ◽  
Bacterial Isolates ◽  
Sediment Samples ◽  
Coliform Count ◽  
Wastewater Effluents

Disposal of wastewater and other effluents into water bodies from activities around water bodies have for long been of major concern and challenge to the environment leading to several infectious diseases. The amount of industrial untreated solid wastes from companies, wastewater from car washing activities, open drainages and agricultural runoffs located close to Elechi creek constitutes the wastewater effluents received by the creek thus resulting in the imbalance of the ecosystem. The study was therefore aimed at determining the microbiology of water quality at different stations of the Elechi creek. Surface water, wastewater and sediment samples were collected during a seven month period and analysed using standard microbiological procedures. Results obtained revealed that the average microbial counts ranged as follows: Total Heterotrophic bacteria 1.12±0.13x108 to 1.28±0.09x108 cfu/ml, Total coliform count; 6.4±0.21 to 7.8±0.13 cfu/ml, Total Staphylococcus Count; 6.9±0.06 to 7.9±0.08 cfu/ml, Total Shigella count; 7.9±0.11 to 8.5±0.14 cfu/ml, Total Salmonella Count; 5.4±0.13 to 7.9±0.08 cfu/ml, Total Vibrio Count; 5.9±0.13 to 7.4±0.09 cfu/ml, and Total Pseudomonad Count; 2.5±0.08 to 4.8 ±0.10 cfu/ml, in surface water, Total Heterotrophic bacteria 1.02±0.08 x108 cfu/ml to 2.68±0.08 x108 cfu/ml, Total coliform count; 4.4±0.10a to 4.9±0.11a cfu/ml, Total Staphylococcus Count;4.7±0.10 to 5.9±0.12 cfu/ml, Total Shigella count; 4.0±0.08 to 4.8±0.11 cfu/ml, Total Salmonella Count; 3.2±0.16 to 4.6±0.08 cfu/ml, Total Vibrio Count; 2.0±0.15 to 4.8±0.11 cfu/ml, and Total Pseudomonad Count2.7±0.13 to 3.9±0.09cfu/ml, in wastewater and Total Heterotrophic bacteria 2.16±0.07 x109 cfu/g to 2.24±0.09 x109 cfu/g, Total coliform count; 1.01±0.13 to 1.36±0.06b cfu/g, Total Staphylococcus Count; 6.8±0.11 to 9.1±0.08 cfu/g, Total Shigella count; 4.0±0.09 to 6.5±0.06 cfu/ml, Total Salmonella Count; 4.1±0.11 to 9.7±0.12 cfu/g, Total Vibrio Count; 6.8±0.10 to 9.5±0.09 cfu/g, and Total Pseudomonad Count; 4.0±0.16 to 5.9±0.07 cfu/g, in sediment samples. Bacterial isolates belonging to the genera Bacillus, Staphylococcus, Enterococcus, Pseudomonas, Proteus, Klebsiella, Providencia, Escherichia coli, Salmonella, Shigella, Vibrio and Enterobacter were isolated and identified. The occurrences of these bacterial isolates as potential pathogens could cause poor water quality through fouling and render the water for various uses and may pose a public health threat to our water resources. Adherence to good hygienic practices and proper treatment of wastewater before discharge into the environment should be encouraged to minimize the spread of infectious diseases and fouling of water bodies. This may also affect the aquatic life in such ecosystems.

Sources and leaching of manganese and iron in the Saigon River Basin, Vietnam

2011 ◽  
Vol 63 (10) ◽  
pp. 2231-2237 ◽  
Author(s):  
Nguyen Thi Van Ha ◽  
Satoshi Takizawa ◽  
Kumiko Oguma ◽  
Nguyen Van Phuoc
Keyword(s):  
Water Quality ◽  
Low Ph ◽  
Ho Chi Minh City ◽  
Viet Nam ◽  
Leaching Tests ◽  
Acid Sulfate Soil ◽  
Release Rates ◽  
Sediment Samples ◽  
High Concentrations ◽  
Fe Reduction

High concentrations of manganese and iron in the Saigon River are major problems for the water supply in Ho Chi Minh City (HCMC), Viet Nam. To identify their sources and leaching processes, we surveyed water quality along the Saigon River and ran batch leaching tests using soil and sediment samples. Two important leaching processes were identified: acidic leaching from acid sulfate soil (ASS) in the middle reaches of the river, and Mn dissolution and Fe reduction from sediments in the downstream reaches. Low pH caused the concurrent release of Fe and Mn from the ASS. In contrast, anoxia caused the release of Fe but not Mn from the sediments, whereas low pH facilitated Mn dissolution. Sediments are a more important source of Mn because of their higher Mn contents (10 times) and release rates (14 times) than those from ASS.

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