Nutrient concentrations and distribution of phytoplankton pigments in recently deposited sediments of a positive tropical estuary

A field experiment was conducted in a Riviera fine sand (Alfisol) with 25-year-old `White Marsh' grapefruit trees on Sour orange rootstock to monitor the downward transport of nutrients from fertilization practices. Fertilizer was applied as either dry granular broadcast (three applications/year) or fertigation (15 applications/year) at N rates of 56, 112, 168, and 336 kg/ha per year using a N:P:K blend (1.0:0.17:1.0). Soil solution was sampled bi-weekly from suction lysimeters, installed under the tree canopy, about 120 cm from the tree trunk, at two depths representing above (120 cm) and below (180 cm) the hard pan. The concentrations of K, Ca, and Mg were greater at the 180- than at 120-cm depth, whereas, the converse was true with respect to the concentration of P in soil solution. Over a 2-year period, the mean concentrations of P and K varied from 0.031-0.976 and 150-250 mg·L–1, respectively. Increased rate of fertilization also appeared to increase the concentrations of Ca and Mg in the soil solution. This could be due to effects of slight acidification of the soil with increased rates of ammonium form of N. A parallel study on pH measurements has shown evidence of soil acidification, under the tree canopy, with increased rates of ammonium fertilization. In a bedded grove, the soil solution above the hard pan is likely to seep into the water furrow, which is discharged into the drainage water.

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Swine Effluent for Tomato in a Plasticulture Production System

HortScience ◽

10.21273/hortsci.33.3.524a ◽

1998 ◽

Vol 33 (3) ◽

pp. 524a-524 ◽

Cited By ~ 1

Author(s):

Kent Cushman ◽

Thomas Horgan

Keyword(s):

Production System ◽

Irrigation System ◽

Dry Weight ◽

Water Source ◽

Nutrient Concentrations ◽

Plastic Mulch ◽

Tomato Production ◽

Swine Effluent ◽

Soluble Fertilizer ◽

Source Number

Tomato was grown in Fall 1997 with swine effluent or commercial soluble fertilizer in a plasticulture production system. Four cultivars, `Mountain Delight', `Celebrity', `Equinox', and `Sunbeam', were transplanted to raised beds with plastic mulch and drip irrigation. Preplant fertilizer was not applied. Effluent from the Wiley L. Bean Swine Demonstration Unit's secondary lagoon was filtered through in-line screen filters and applied directly to the plants through the irrigation system. Toward the end of each application, sodium hypochlorite was injected in the line to achieve a free chlorine concentration of ≈1%. Clogging of filters or drip emitters did not occur. Control plants received 100 ppm N from soluble fertilizer injected in irrigation lines supplied by a municipal water source. Number and weight of tomatoes from plants receiving swine effluent were equal to that of plants receiving soluble fertilizer. No differences in fruit quality were evident between treatments. Plant dry weight was also equal for three out of four cultivars. No differences in soil characteristics were detected between treatments after the study. Chemical analysis of the effluent showed a pH of 7.8 and nutrient concentrations of ≈110 ppm NH4-N, 57 ppm P2O5, 150 ppm K2O, and trace amounts of Cu and Zn. Though no differences in yield were detected in this study, the effluent's high pH and high NH4-N content need to be managed more closely for commercial tomato production.

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Diatom- and Chironomid-Inferred Eutrophication of Bouchie Lake, British Columbia

Water Quality Research Journal ◽

10.2166/wqrj.2005.045 ◽

2005 ◽

Vol 40 (4) ◽

pp. 418-430 ◽

Cited By ~ 2

Author(s):

Markus L. Heinrichs ◽

Brian F. Cumming ◽

Kathleen R. Laird ◽

J. Sanford Hart

Keyword(s):

British Columbia ◽

Land Use Changes ◽

Head Capsule ◽

Relative Increase ◽

Nutrient Concentrations ◽

The Past ◽

Nutrient Levels ◽

Lower Head ◽

Lower Oxygen ◽

Historical Land Use

Abstract Diatom and chironomid analysis of sediments encompassing the past 400 years from Bouchie Lake, British Columbia, suggests two distinct periods of limnological conditions. Prior to 1950 AD, Fragilaria construens and F. pinnata are the most common diatom species, and Chironomus, Procladius and Tanytarsini dominate the chironomid record. Moderately low nutrient concentrations consistent with oligo-mesotrophic lakes are inferred. From 1950, the diatom assemblage is dominated by Stephanodiscus parvus, a eutrophic indicator, whereas the chironomid communities show a relative increase in littoral taxa coincident with lower head capsule abundance. Higher nutrient levels, specifically total phosphorus, which increased from 8 µg L-1 prior to 1950 to 20 µg L-1 currently, are coincident with midge communities indicative of lower oxygen concentrations. Observed biotic changes and nutrient levels inferred from the sediment core correspond to historical land-use changes.

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Nutrient Input and Trophic Status of the “Neue Donau”, a High-Water Control System along the River Danube in Vienna, Austria

Water Science & Technology ◽

10.2166/wst.1990.0021 ◽

1990 ◽

Vol 22 (5) ◽

pp. 137-144 ◽

Cited By ~ 3

Author(s):

M. T. Dokulil ◽

G. A. Janauer

Keyword(s):

Water Quality ◽

Control System ◽

Trophic Status ◽

High Water ◽

Nutrient Concentrations ◽

Nutrient Input ◽

Water Control ◽

Trophic Conditions ◽

River Danube ◽

High Nutrient

The system “Neue Donau” functions as a control system for high waters of the river Danube and is an important recreational area for many people. Water quality and trophic status of the water body is thereforeof prime importance. The high nutrient concentrations of the river Danube (P-tot 238±41µg/l, N-tot 2.53±0.78 mg/l) reach the system via groundwater seepage. Present conditions in the basin of Neue Donau are,as a result of this nutrient in-flux,eutrophic to hypertrophic. Average values during the summer period have declined from 366 µg/l total phosphorus to 78 µg/l, and from 86 µg/l chlorophyll-a tol7µg/l between the years 1985 and 1988. However, a dam which is planned in the river at Vienna will permanently raise the water level of the river thus increasing the the groundwater flow in the direction to the Neue Donau and therefore the nutrient input which will enhance trophic conditions in the impoundment. Since macrophytes play an important role in one part of the system macrophyte management together with measures along the river are some of the suggested strategies to keep the system Neue Donau at acceptable trophic conditions and good water quality.

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Impact of Catchment Urbanisation on Lake Macquarie (Australia)

Water Science & Technology ◽

10.2166/wst.1989.0051 ◽

1989 ◽

Vol 21 (2) ◽

pp. 205-210 ◽

Cited By ~ 1

Author(s):

B. L. Simmons ◽

S. L. Trengove

Keyword(s):

Nutrient Enrichment ◽

Benthic Algae ◽

Water Clarity ◽

Nutrient Concentrations ◽

Lake Area ◽

Seagrass Beds ◽

Coastal Lake ◽

Aesthetic Quality ◽

Wastewater Disposal ◽

Coastal Lakes

Increasing urbanisation of coastal areas is leading to impacts on coastal lakes which decrease their amenity for recreation and tourism. Runoff and wastewater discharge cause siltation, impact seagrass beds and change the characteristics of open waters, affecting boating, swimming, fishing and the aesthetic quality of the locale. Management of urban development and wastewater disposal is required to minimise sedimentation and nutrient enrichment. This could include development restrictions, runoff controls and a strategy for wastewater treatment and discharge. The catchment of Lake Macquarie, a marine coastal lake, has been progressively urbanised since 1945. Urbanisation, through increased stormwater runoff and point source discharges, has caused a major impact on the lake in terms of sedimentation and nutrient enrichment. Losses of lake area and navigable waters have occurred. Accompanying problems include changes in the distribution of seagrass beds and nuisance growths of benthic algae. Since the 1950's, dry weather nutrient concentrations have increased and mean water clarity has decreased. Severe problems, as observed in other New South Wales coastal lakes, for example benthic algae in Lake Illawarra and Tuggerah Lakes, have not yet developed. Because of the lead time taken to implement policies and controls, trends should be identified and policies developed now so as to avoid nutrient buildup and development of sustained problems.

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Loading rates of nutrients discharging from a golf course and a neighboring forested basin

Water Science & Technology ◽

10.2166/wst.1999.0535 ◽

1999 ◽

Vol 39 (12) ◽

pp. 99-107 ◽

Cited By ~ 10

Author(s):

Takao Kunimatsu ◽

Miki Sudo ◽

Takeshi Kawachi

Keyword(s):

Nutrient Loading ◽

Chamaecyparis Obtusa ◽

Phosphorus Loading ◽

Golf Course ◽

Nutrient Concentrations ◽

Golf Courses ◽

Japanese Cypress ◽

Arithmetic Average ◽

Loading Rates ◽

Runoff Rate

In the last ten years, the number of golf courses has been increasing in some countries as the game gains popularity. This indicates, a need to estimate the nutrient loading from golf courses in order to prevent the eutrophication of water bodies. Nutrient concentrations and flow rates of a brook were measured once a week from 1989 to 1990 at two sites: Site A of a brook flowing out from D-golf course (53 ha) and Site B of the same brook discharging into the golf course from an upper forested basin (23 ha) covered mainly with planted Japanese cypress (Chamaecyparis obtusa SIEB. et ZUCC). The bedrock of the area was granite. The annual values of precipitation and mean temperature were 1947 mm and 13.5°C in 1989, respectively. The arithmetic average values of discharge from the forested basin and the golf course were 0.392 and 1.26 mg/l total nitrogen (TN), 0.0072 and 0.145 mg/l total phosphorus (TP), 0.82 and 3.53 mg/l potassium ion (K+, 5.92 and 8.24 mg/l sodium ion (Na+), 2.1 and 9.9 mg/l suspending solid (0.001–2.0 mm, SS), 0.087 and 0.147 mS/cm electric conductivity (EC), and 0.031 and 0.037 m3/km2•s specific discharge, respectively. The loading rates of the forested basin and the golf course were 5.42 and 13.5 TN, 0.133 and 3.04 TP, 8.84 and 33.9 K+, 55.0 and 73.0 Na+, and 54.3 and 118 SS in kg/ha•y. The leaching and runoff rate of nitrogen in the chemical fertilizers applied on the golf course was calculated as 32%. These results indicated the importance of controlling the phosphorus loading for the management of golf courses.

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Development of a water temperature-ecological model to stimulate global warming effects on lake ecosystem

Water Science & Technology ◽

10.2166/wst.1996.0627 ◽

1996 ◽

Vol 34 (7-8) ◽

pp. 237-244 ◽

Cited By ~ 1

Author(s):

Masaaki Hosomi ◽

Tetsu Saigusa ◽

Kenichi Yabunaka ◽

Takuya Okubo ◽

Akihiko Murakami

Keyword(s):

Global Warming ◽

Water Temperature ◽

Thermal Stratification ◽

Ecological Model ◽

Nutrient Release ◽

Eddy Diffusion ◽

Nutrient Concentrations ◽

Lake Ecosystem ◽

Phytoplankton Species ◽

Freezing And Thawing

This paper describes a newly developed combined water temperature-ecological (WT-ECO) model which is employed to simulate the effects of global warming on lake and reservoir ecosystems. The WT model includes (i) variations in the eddy diffusion coefficient based on the degree of thermal stratification and the velocity of wind, and (ii) a sub-model for simulating the freezing and thawing processes of surface water, water temperatures, and the mixing rates between two adjacent layers of water. The ECO model then uses these results to calculate the resultant effect on a lake's ecological dynamics, e.g., composition of phytoplankton species, their respective concentrations, and nutrient concentrations. When the model was benchmarked against Lake Yunoko, a dimictic lake, fairly good agreement was obtained over a 4-yr period; thereby indicating it is suitably calibrated. In addition, to assess the effects of global warming on a lake ecosystem, changes in Lake Yunoko's water temperature/quality were simulated in response to an increase in air temperature of 2 - 4°C. Results indicate that such an increase will (i) increase thermal stratification in summer, which increases the nutrient concentrations in bottom water due to nutrient release from bottom sediment, (ii) increase the concentration of phytoplankton at the beginning of the autumn circulation period, and (iii) change the composition of phytoplankton species.

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