Soluble Reactive Phosphate Concentrations Research Articles

Comparative utilization of phosphorus from sedimentary and igneous phosphate rock by major biotic components of aquatic ecosystem

Two laboratory experiments were conducted to evaluate the amount of P utilization from two different types of sparingly soluble phosphate rock by aquatic biotic communities. The first type was Mussoorie Phosphate Rock or MPR (sedimentary in origin) and other was Purulia Phosphate Rock or PPR (igneous in origin). The two trials were with eight different treatment combinations. Among various treatments, fish and Chironomid larvae contributed to some extent in increasing the available sediment phosphate content which in turn increased the soluble reactive phosphate (SRP) of overlying water. Concentration of SRP of overlying water decreased in the treatment with zooplanktons. Depletion of SRP of overlying water due to uptake of orthophosphate by Chlorella was also observed. The sedimentary type phosphate rock proved to be more efficient in releasing phosphate than igneous one.

Potential availability of sedimentary phosphorus to sediment resuspension in Florida Bay

Several studies have suggested that phosphorus is a limiting nutrient for seagrass and phytoplankton growth in much of Florida Bay. In fact, soluble reactive phosphate concentrations in Florida Bay waters can be as low as a few nM. Sediments represent the largest phosphorus reservoir because Florida Bay sediments are dominated by carbonate, which has a strong capacity to retain phosphorus. The supply of phosphorus to the water column from sediment resuspension is potentially important in providing the nutrients required for phytoplankton production. Applying an improved sequential extraction technique to sediments collected from 40 geographically representative stations in Florida Bay, this study provides the first detailed spatial distribution of total sedimentary phosphorus (TSP) and its partitioning into five chemically distinguishable pools in the surface, fine‐grained sediments of the bay. A strong gradient of decreasing TSP concentration was observed from the west (14.6 μmol g−1) to east (1.2 μmol g−1) across the central bay. The spatial pattern of TSP is consistent with distribution of both seagrass and phytoplankton that are limited by available phosphorus in Florida Bay. Among the five pools, the authigenic carbonate fluorapatite, biogenic apatite and CaCO3‐bound phosphorus account for the largest fraction (45%) of TSP, of which inorganic phosphorus is the dominant form, and organic phosphorus accounts for about 30% in the western and north central regions and less than 10% in other areas of Florida Bay. The second largest pools are the refractory organic phosphorus (24% of TSP) and reductant‐soluble inorganic phosphorus (19% of TSP). Readily exchangeable phosphorus accounts for 8% of TSP, of which organic phosphorus is 60%. Detrital apatite phosphorus of igneous or metamorphic origin represents the smallest fraction, only 5% of TSP. Spatial distribution of phosphorus and iron in sediments indicates that external sources of these two essential plant nutrients to Florida Bay are spatially separated with phosphorus introduced by west coast waters across the western margin of Florida Bay and iron from freshwater flow into the eastern region.

Application of Green Chemistry: A Miniaturized Procedure for Analysis of Dissolved Phosphate

The objective of this study was to determine if the volume of sample used for analysis of soluble reactive phosphate (SRP) could be reduced from 100 mL (as per a widely used standardized procedure) to 50 or 10 mL to reduce the amount of hazardous waste generated from routine analysis of SRP in water samples from rivers, streams, and ponds in an urbanized landscape, in accordance with the principles of “green chemistry” and the Pollution Prevention Act of 1990. The ascorbic acid-molybdate blue method of Murphy and Riley (1962) was used to determine the concentration of SRP in water samples collected from the East Branch of the DuPage River and from two ponds on the campus of Benedictine University. Mean concentration of SRP determined using a 10 mL sample volume of DuPage River water (x = 1,051 μg PO4-P/L) was significantly greater than the 100 and 50 mL sample volumes, which were not significantly different from each other (x = 1,002 μg PO4-P/L); however, the difference in SRP concentration between 10 mL and 100 and 50 mL sample volumes was only 5%. There was no significant effect of sample volume on SRP concentration for slough or storm water pond samples, but these two pond systems had a low SRP concentration (<3 μg PO4-P/L). The relationship between absorbance and SRP concentration in the ascorbic acid-molybdate blue method was examined between 0 and 2,000 μg PO4-P/L; absorbance was asymptotic between 500 and 2,000 μg PO4-P/L. The results of this study show that the sample volume for analysis of SRP in DuPage River water with the ascorbic acid-molybdate blue method can be reduced by 50% (i.e., reduced from 100 mL to 50 mL) without loss of accuracy, but that samples must be diluted to reduce the concentration of SRP to within the limits of the procedure. The reduction in sample volume represents a substantial reduction in the volume of hazardous waste that is generated, and the overall cost per sample, for routine analysis of SRP in the DuPage River.

What Limits the Productivity of Acid Mine Drainage Treatment Ponds?

Acid mine drainage (AMD) treatment ponds are very common in the U.S. Appalachian coal region and are the main source of many headwater streams. Though the water that discharges from these ponds generally meets state and federal water quality standards, there is a distinct lack of productivity in most of these ponds. Our first objective was to compare the productivity of chemically-treated, biologically-treated, and untreated AMD ponds with uncontaminated (reference) ponds. Next, we used principal component analysis and multiple regression of 20 physicochemical characteristics of these ponds to resolve which factor(s) were responsible for inhibiting productivity. We discovered that chemically-treated AMD ponds and untreated AMD ponds exhibited significantly less gross primary productivity (GPP) than reference ponds; biologically-treated ponds (containing AMD that has passed through a wetland) did not vary significantly from reference ponds. Chemically-treated ponds also had significantly less net primary productivity (NPP) than reference ponds. Community respiration did not vary among the pond types. Our test results indicated that soluble reactive phosphate concentration explained most of the variance in both GPP and NPP. Apparently, phosphate availability, not metal toxicity, regulated phytoplankton productivity in these ponds.

Characterisation and quantification of phosphorus release from profundal bottom sediments in two dimictic lakes during summer stratification

Phosphorus release from the sediment in two dimictic lakes was compared during the summer stratification. Soluble reactive phosphate (SRP) and also NH4 + were released from the anoxic sediment into the water column in Lake Dudinghausen and Lake Tiefer. The sediment released NH4 + and SRP only when oxygen and nitrate/nitrite were absent. Besides the SRP concentration in the hypolimnion, P-binding in the upper sediment changed during summer stratification in both lakes. In Lake Dudinghausen a decrease in the redox-sensitive bound P was observed in the upper sediment. Only in this lake does the classic anoxic P-release by reduction of the FeOOH-phosphate complex play a dominant role. In both lakes, however, the contents of organically bound P increased in the upper 0.5 cm layer during the summer stratification. P-release was calculated using four different methods. The calculated P-release during summer stratification varied between 15 and 207 mg P m-2 y-1 in Lake Dudinghausen and between 22 and 55 mg P m-2 y-1 in Lake Tiefer.

Effects of wildfire ash on water chemistry and biota in South‐Western U.S.A. streams

SUMMARY1. We monitored streams within the Gila River drainage in south‐western New Mexico, U.S.A., over a 5‐year period, to investigate the influence of ash input on water quality and stream biota following forest wildfires.2. Nutrients [ammonium, nitrate, soluble reactive phosphate (SRP)], potassium and alkalinity were most affected by fires; all were increased in stream water following ash input. Concentrations of each returned to prefire conditions within 4 months. Ammonium and nitrate also increased in stream water as a result of atmospheric fallout (e.g. smoke) from fires outside the catchment.3. Periphyton biomass was not affected significantly by wildfires, although there was a shift in diatom assemblage to smaller more adnate taxa. Cocconeis placentula was frequently the dominant postfire species.4. The influence of wildfires on macroinvertebrates ranged from minimal to dramatic reductions in density depending upon the duration of ash flows and the characteristics of the ash material that entered each system. Macroinvertebrate densities returned to prefire conditions within 1 year.5. An in‐situ ashing experiment was conducted on a first‐order stream in the Gila River drainage to monitor on‐site physiochemical and biotic responses during and after fire ash addition, for comparison with ash delivery from real wildfires on monitored streams. Physical–chemical parameters and algae and macroinvertebrates were monitored in an ashed and upstream reference reach for 13 months. Results generally substantiated findings from monitored streams.6. Concentrations of major ions and nutrients, as well as turbidity, conductivity and pH, increased immediately in stream water below the point of ashing, while dissolved oxygen decreased. Changes in water chemistry were short‐lived (=24 h) except for SRP. The concentration of SRP in stream water was significantly higher in the ashed reach than the control reach for at least 1 month after ash input.7. Periphyton biomass and diatom assemblages were not significantly altered in the ashing study, whereas macroinvertebrate density was measurably lower in the ashed reach for nearly a year. Macroinvertebrate drift was over 10‐fold greater in the ashed reach compared with the reference reach during ashing. Dissimilarity between macroinvertebrate communities in the reference and ashed reaches was significantly greater than variation within reaches for nearly a year.

Cyanobacteria associations in shallow polytrophic lakes: influence of environmental factors

Abstract A 2 year field study in two shallow, polytrophic lakes (Langer See and Melangsee) in Brandenburg revealed the importance of environmental factors in controlling the population dynamics of various cyanobacterial species which do not form layers or aggregations. The species belonged to the toxin producing genera Cylindrospermopsis, Planktothrix, Aphanizomenon and Anabaena, and to the nontoxic members of Limnothrix and Pseudanabaena. In German waters, Cylindrospermopsis raciborskii is a neophyte, and exhibits a comparatively low temperature requirement of about 17 °C for germination and growth. The nutrient concentrations were comparable in both the lakes, and did not change measurably during the summer succession. The dissolved nitrogen fractions were well below 50 μg l–1 with total depletion of nitrate. Soluble reactive phosphate concentrations never fell below 3 μg l–1 throughout the summer season. The light attenuation factors (Kd) of 3–5.8 m–1 indicate high self-shading. However, under calm weather conditions, the cyanobacteria were not concentrated in near surface layers and the species composition was relatively uniform in the vertical. In mid-summer, the diazotrophic Nostocales were replaced by Oscillatoriales. Reduced light availability caused by mixing and self-shading is considered to be the main factor causing the summer decline of Nostocales. By means of two weather stations, more frequent, deeper and longer lasting mixing events could be observed in Langer See than in the more shallow, but wind protected Melangsee. The success of Planktothrix agardhii may be due to the more turbulent mixing regime in Langer See. The algal association, S of Reynolds (Reynolds, C.S., 1997), should be modified, since the different species grouped together in S have different responses to turbulent mixing.

Resuspension of bottom sediment by an internal wave in Lake Biwa

AbstractAn internal wave‐induced resuspension of bottom sediment and resultant changes in water chemistry were investigated in the sublittoral area of Lake Biwa in the late stage of the stagnant period. The thermocline was measured at between depths of 15 and 20 m at the beginning of the observation and rapidly dropped by 5 m within 3 h. The downward movement of the thermocline resulted in markedly increased turbidity at the top of the thermocline (20 m in water depth). Concentrations of dissolved methane synchronistically increased with turbidity, especially in the top of the thermocline where there was the highest turbidity. Total dissolved phosphorus and particulate phosphorus also increased in the thermocline. In contrast, the soluble reactive phosphate concentration decreased with time. An increase in the concentrations of particulate metals (aluminium, iron and titanium), which probably originated from mineral particles, was more marked in the water sample collected at 1 m above the bottom than at the peak of turbidity. The results indicated that an internal wave caused resuspension of the bottom sediment and also affected the water chemistry.

Nutrient concentrations and fluxes for podzolic and gley soils at Plynlimon, mid-Wales: implications for modelling inorganic nitrogen and phosphorus in upland UK environments

Abstract. The effect of felling on stream nitrate, ammonium and soluble reactive phosphate (SRP) concentrations is examined for acidic and acid sensitive Sitka Spruce afforested catchments with podzolic and gley soils in mid-Wales. For the streams draining the felled podzolic areas, the concentrations of nitrate can be up to an order of magnitude higher than pre-fell values and post-fell concentrations can even be lower than the pre-fell values. Felling for the podzolic soils barely leads to any changes in ammonium or SRP concentration. For the gley soils, felling results in an order of magnitude increase in nitrate, ammonium and SRP for a small drainage ditch, but the pulse is much reduced before it reaches the main Nant Tanllwyth channel. Rather, within-catchment and within-stream processes not only imbibe nitrate, ammonium and SRP fluxes generated, but in the case of nitrate, concentrations with- and post-felling are lower than pre-felling concentrations. The flux changes involved are described in terms of (a) input-output relationships and (b) "felling disruption" and "felling recovery responses". The findings are linked to issues of hydrobiological controls and forestry management. Keywords: Plynlimon, Hafren, Hore, streams, nitrate, ammonium, SRP, phosphorus, soluble reactive phosphorus, phosphate, orthophosphate, Sitka spruce, forestry, felling, podzol, gley

Phosphoruscalcium carbonate saturation relationships in a lowland chalk river impacted by sewage inputs and phosphorus remediation: an assessment of phosphorus self-cleansing mechanisms in natural waters

The relationship between calcium carbonate saturation and phosphorus concentrations for seven sites on the upper reaches of the River Kennet are examined. The findings are related to issues of groundwater supplies and the introduction of phosphorus treatment of effluent from the Marlborough sewage treatment works (STW) at part of the way along the study reach. Being supplied from a Cretaceous Chalk aquifer, the Kennet is mainly of a calcium-bicarbonate type and has a relatively constant composition of many major water quality determinands. Typically, the waters average a pH of approximately eight (range approx. 7.5–8.5) during the day with the lowest values occurring at the upstream site. Dissolved carbon dioxide varies from approximately 5 to 35 times atmospheric pressure during the late morning with the highest values occurring at the upstream site. However, in-stream biological activity gives rise to marked diurnal fluctuations in pH and dissolved carbon dioxide concentrations and during the summer months, by mid to late afternoon, pH is at its maximum and dissolved carbon dioxide is at its lowest: this is shown by continuous measurements at one of the river sites. Alkalinity and calcium concentrations remain relatively constant at approximately 4700 μEq/l (range 3500–6000 μEq/l) and 120 mg/l (range 85–150 mg/l), respectively, and the waters are oversaturated with respect to calcium carbonate (calcite) typically by a factor of six (range 2–25). Along the reach, soluble reactive phosphate (SRP) increases from the first to the second site with the introduction of sewage supplies from the Marlborough STW, and then declines further downstream as sewage dilution and uptake by the river bed/aquatic plants increases. The differences in concentration decrease after phosphorus removal from Marlborough STW. Despite this change, there is no clear indication of any calcite solubility control except perhaps at times of extreme baseflow during the growing season when within-stream photosynthesis is maximal and within-stream residence times are longer. A comparison of river and groundwater data shows that the groundwaters have similar alkalinities and calcium concentrations. However, the groundwaters have (a) higher carbon dioxide saturations (a factor of 2–5 times the value for the river), (b) lower pHs (0.5–1.5 units), (c) lower SRP concentrations (a quarter or less of the river values) and (d) waters near calcite saturation (unlike the surface waters which are oversaturated). The findings indicate a river system dominated by the input carbon dioxide laden groundwaters in approximate equilibrium with calcite attenuated by within-channel biological and physical processes. Within the river: (a) the waters degas carbon dioxide increasing the pH, producing oversaturated conditions; and (b) oscillating pH-dissolved carbon dioxide levels occur between day and night due to changing balances between photosynthesis and respiration. It seems that lowering the phosphorus levels have not resulted in calcite precipitation within the water column and that no significant within-stream self-cleansing mechanisms are occurring that might be predicted from theory: other components in the water such as dissolved organic carbon may inhibit calcite nucleation. However, the low SRP levels in the groundwater coupled with calcite saturation, may well indicate that phosphorous concentrations within the groundwater are regulated by such processes: the number of calcite nucleating sites are orders of magnitude higher and the calcite inhibitors may be less prevalent.

Seasonal Variability of the Texas ‘Brown Tide’ (Aureoumbra lagunensis) in Relation to Environmental Parameters

The spatial and temporal variation of salinity, specific conductivity, temprature, turbidity, pH, dissolved oxygen, redox potential, soluble reactive phosphate (SRP), ammonium, nitrate, phytoplankton and mesozooplankton within Baffin Bay, Texas were monitored monthly from April 1995–July 1996 to understand better the seasonal variability of the Texas ‘brown tide’, Aureoumbra lagunensis .High A. lagunensis densities (0·05–5·97×106cells ml−1) were observed in the summer months, whereas low densities (<0·01–3·6×106cells ml−1) occurred during the winter. Statistical analysis of results gave no significant relationship between A. lagunensis densities and any physical parameters during most sampling events. Most sampling events exhibited high salinities (S>40) and A. lagunensis densities were greatest between 25 and 30°C. This suggests that A. lagunensis is well adapted to the warm hypersaline environment. Surface water SRP and ammonium concentrations were inversely related to A. lagunensis densities at all sample stations (P< 0·001 and P< 0·05, respectively). Aureoumbra lagunensis densities showed no relation with other chemical parameters. Acartia tonsa , Oithona brevicornis and Oithona sp. were the predominant mesozooplankton during the study. Although A. tonsa occurred in higher concentrations than other mesozooplankton, A. lagunensis and A. tonsa densities showed no significant relationship. Densities ofOithona sp. were inversely related to A. lagunensis cell densities (P< 0·05) signifying possible grazing pressures. These results suggest that additional parameters other than those investigated are contributing to the seasonal variability and the persistence of Texas ‘brown tide.’

Cryptocoryne elliptica, an endangered amphibious plant in Pondok Tanjung forest reserve, Peninsular Malaysia

Crytocoryne elliptica Hook. f. is an endangered plant species endemic to Peninsular Malaysia. The species thrives in swampy and shaded habitats. In its natural habitat, Pondok Tanjung Forest Reserve, this plant coexists with other plants such as Cryptocoryne purpurea Ridl. and homalomena nutans Hook. f. High population densities were observed where the depth of the water was not more than 0.5 m, the pH values ranged between 4.50 and 6.65, conductivity ranged from 7.0 to 10.4 μS cm −1 and dissolved oxygen concentrations and redox potential were relatively low. On the other hand, the habitat had a comparatively high concentration of soluble reactive phosphate and a high percentage of organic matter in the sediment.