ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00173.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractResearch was conducted to determine the efficiency and effects of chemically treating Dogway Fork, a West Virginia stream acidified by acid precipitation. We report on the water‐powered rotary drum system used to apply calcium carbonate slurry to the stream. Two companion papers cover the biological and chemical effects of this treatment. The rotary drums provided near‐continuous treatment over a 4–year period. Limestone aggregate (1.3–3.8 cm) high in calcium carbonate was ground within the drums into slurry form. The relatively low cost of aggregate and its ease of storage permitted economical treatment. The system compared favorably to other types of slurry dosers. Limestone particles deposited in the stream sediment continued over time to be dissolved. They were significant in the overall dissolution efficiency of the limestone treatment. This sediment calcite also provided supplementary neutralization when high flow requirements exceeded the drum station's dosing cap

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00174.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractLimestone neutralization of the acidic water of Dog‐way Fork in West Virginia resulted in significant improvements in both water quality and fish populations. Pretreatment water chemistry showed the stream to be highly acidified by acid precipitation, with pH under 5.0 and high aluminum concentrations. During treatment, the goals for the target area of pH 6.5 and acid‐neutralizing capacity of 50 μmeq/L were met for 75.8% and 67% of the time, respectively. A pH 6.0 or above was maintained over 93% of the time. Monomeric aluminum concentrations were reduced significantly, and calcium to hydrogen ionic ratios were over 10 in the target area. Prior to treatment, no resident fish population was found in Dogway Fork. During five years of treatment, conditions were favorable for fish reproduction and survival. Eight fish species inhabited the stream, six were reproducing there, and a fishable brook trout population was establi

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00175.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractDogway Fork, West Virginia, is a second–order stream affected by acid precipitation. One goal of the Acid Precipitation Mitigation Program was to determine if the composition or population levels of benthic macroinvertebrates were affected by limestone neutralization of the acidic waters (pH 4.5). Two techniques were used to determine any effects: seasonal Surber samples andin situbioassays with selected genera. Prior to treatment, macroinvertebrate densities were low but represented a diverse group of acidtolerant taxa. During treatment, fewer macroinvertebrates were collected in the treated segment than in the untreated control. This appears to be a result of a number of factors, including substrate, flows, drift, fish predation, accumulation of limestone fines, and changes in water chemistry. Bioassays suggest that the limestone fines were not directly detrimental to the organisms but may have limited available habitat in the mixing zone. Limestone treatment affected the species composition of Dogway Fork. During four years of treatment, several new acid‐sensitive taxa were collected in the treated segment. Data suggest that, with continued treatment, populations of these taxa can be expected to incre

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00176.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractLaurel Branch (Tennessee, U.S.A.), an acid‐sensitive stream in the southern Appalachian Mountains, was limed as a part of the Acid Precipitation Mitigation Program funded by the U.S. Fish and Wildlife Service. Objectives were (1) to evaluate the effectiveness of stream liming by means of a hydropowered doser design, and (2) to monitor stream response(s) to increased pH and alkalinity. Precipitation in the region was documented to be acidic, with a mean pH of 4.54 in 1987. Preliming evaluations conducted from 1986 through 1988 depicted Laurel Branch as soft (hardness less than 5 mg/L CaCO3, pH 6.2–6.6), dilute (ionic strength less than 400 μeq/L), and lightly buffered (alkalinity less than 100 μeq/L). Because of the apparent relationship between flow and water chemistry, Laurel Branch was considered susceptible to episodic acidification caused by storms. In June 1989, a hydro–powered limestone doser was installed to treat the lower 3 km of the stream. Approximately 8.2 tonnes of crushed limestone were added during an 18–month treatment phase that concluded in December 1990. Technical and design problems with the doser reduced efficiency and limited the scale of liming through much of the first 6 months of operation. Design modifications and equipment upgrades in late 1989 corrected most of the problems and improved doser performance in 1990. No substantial chemical or biological changes were detected within the treated reach of Laurel Branch as a result of liming. Time–series statistical analyses showed small but significant changes in total alkalinity (10 μeq/L average increase) and dissolved calcium at all limed sites. pH (as hydrogen ion) increased 0.16 and 0.13 units at two limed sites that were 1 km and 2 km below the doser, respectively. At the lowermost limed site 3 km below the doser, a significant decrease in pH was detected which was probably flow‐related. Mean length of age–0 (juvenile) and age‐1 rainbow trout increased marginally during liming, suggesting improved fish growth, but increases were not significant. Densities of an acid‐sensitive macrobenthic taxon (Baetis spp.) increased during liming, whereas densities of an acid‐tolerant taxon (Leuctra spp.) remained unchanged. In general, observed biological changes were considered minimal; they were judged unrelated to liming but rather of seasonal and/or spatial origin. The regional drought of 1987 and 1988 was considered a confounding factor. With most of the baseline data collected during these years, vastly differing hydrology in 1989 and 1990 (“wet” years regionally) became problematic and may have distorted some responses and masked others. It is also possible that biological responses may have been delayed because of the small magnitude of chemical changes, particularly pH and alkalinity. A calcium mass budget estimated that up to 62% of the calcium added was accounted for in chemistry data from limed sites, with increases most visible in the spring and summer of 1990. Results indicated that, although the Laurel Branch watershed does receive acidic precipitation, current biological communities show high levels of integrity and little apparent degradation related to acidification. If watershed buffering capabilities are depleted from continued acidic deposition, however, stream biota ma

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00177.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractWhetstone Brook is a trout stream located in north‐central Massachusetts that is degraded by acid precipitation. The stream was treated with 56 tonnes of powdered limestone by a prototype, water‐powered doser as part of the U.S. Fish and Wildlife Service's Acid Precipitation Mitigation Program. The goal of liming Whetstone Brook was to raise the pH to 6.5 and acid neutralizing capacity (ANC) to at least 50 μeq/1 in a 3.2‐km reach. This goal was achieved despite the fact that during the 31 months of treatment stream flow was 37% higher than during the pretreatment period. During the treatment period, pH averaged 6.54 and ANC averaged 69.75. During the pretreatment period average pH was 5.97 and average ANC was 20.26. In the control section of Whetstone Brook, both pH and ANC were lower during the treatment period than during the pretreatment period. During treatment, monomeric aluminum, a form toxic to fish, declined in the treated section and increased in the control section. Total calcium, sediment calcium, and pore‐water calcium increased in the treated section during treatment but declined in the control section. The other base anions and cations, nutrients, and physical parameters were not significantly affected b

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00178.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractDensity, age structure, and growth rates of wild brook trout (Salvelinus fontinalis)and brown trout (Salmo trutta)in Whetstone Brook in northcentral Massachusetts were monitored for 4 years before and 3 years during limestone treatment to mitigate acidic conditions. The population density of brook trout increased significantly during treatment. Liming did not have any significant effects on the growth rates of brook trout or brown trout. Actual survival rates of brook trout and brown trout were not calculated due to the low density of both species, but more older individuals of both species were captured during the treatment period. Fulton condition factors (an index of fish condition) increased significantly for both brook trout and brown trout during treatment. Seven‐dayin situbioassays of brown trout and rainbow trout demonstrated that liming improved the chemical environment for fish in Whetstone Brook. During a pretreatment bioassay in 1987, 100% rainbow trout mortality was observed at both the control and treatment stations in Whetstone Brook. Brown trout mortality was 67% in the control station and 70% in the treatment station. The pH during the 1987 bioassay averaged 4.90 in the control station and 4.99 in the treated station. During a bioassay conducted in 1990 after treatment began, rainbow trout mortality was 100% in the control station and 0% in the treatment station. Brown trout mortality was 17% in the control station and 0% in the treatment station. The pH during the 1990 bioassay averaged 5.23 in the control station and 6.60 in the treatment station. Analysis of total aluminum in the gills of fish from the 1990 bioassay revealed higher levels in fish from the control station than in those from the treatment statio

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00179.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractWe monitored the invertebrate fauna in Whetstone Brook for 3 years before and after limestone treatment to mitigate low pH conditions caused by acid precipitation. Sampling was conducted during the spring, summer, and fall by both qualitative and quantitative methods. The fauna in Whetstone Brook in the control and treatment sections was dominated by chironomids (Diptera), simuliids (Diptera),Leuctra(Plecop‐tera) andHydropsyche(Trichoptera) in both pretreatment and treatment periods. The acid‐sensitive mayfly generaEpeorusincreased during liming in the treated section of the stream but also declined during the same period in the control section. Annelida increased during the treatment period in both sections of the stream. The chironomid and black fly populations were not affected by liming. The lack of impact to the black fly population was surprising because larvae are obligate filter‐feeders and feed on suspended seston in the same size range as the limestone slurry that was used to treat Whetstone Brook. Treatment did not change species diversity and taxa richness in the treated section of Whetsone Brook, but both indices declined during the treatment period in the control section of Whetstone Brook. This decline was attributed to the poorer water quality of the untreated section of Whetstone Brook during the treatment period, which was due to higher‐than‐average precipitation. Percent community similarity analysis indicated that the community composition changed more in the treated section of Whetstone Brook than in the control section as a result of treatment. We conclude that the invertebrate fauna in the treated section of Whetstone Brook was not negatively affected by liming, but that population density and diversity did not

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00180.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA limestone slurry was sprayed on the surface of Thrush Lake, a small headwater lake in northeastern Minnesota, to test a treatment designed to protect acid‐sensitive waters from anthropogenic acidification. The 6‐year study, consisting of pretreatment, transition, and post‐treatment phases, was part of the four‐state Acid Precipitation Mitigation Program directed by the U.S. Fish and Wildlife Service. Measured water‐chemistry parameters, including acid‐neutralizing capacity, pH, dissolved calcium, and dissolved inoroganic carbon, increased following treatment, although local climatic conditions influenced the magnitude and duration of the chemical changes. Physical changes to the lake, other than an increase in conductivity and a short‐term alteration of water clarity subsequent to treatment, were not documented. The composition of the zooplankton community was altered, with the proportion of rotifers increasing after treatment. Individual zooplankton species showed a variety of changes in abundance that were associated with treatment over both seasonal and multi‐year intervals. For example,Holopedium gibbemmwas absent from lake samples immediately following treatment and recovered within a season, whereasDiaptomus minutusandKeratella taurocephalapopulations were reduced after treatment and had not recovered by the end of the study. Alternately,Asplanchna priodontaincreased in abundance after treatment. These observed abundance patterns were generally consistent with previzous acidification or base‐addition studies. In contrast, the changes in community composition of zooplankton did not consistently fit patterns developed from regional studies across water‐chemistry gradients. These differences emphasize the importance of biotic as well as abiotic factors in controlling zooplankton co

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00181.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThrush Lake, Minnesota, was treated with limestone in 1988 to evaluate the efficacy of protective base addition against the loss of sport fisheries in a sensitive, mildly acidic lake. Prior to treatment, the lake was stressed (pH 6.46, ANC 64 μeq/L) but not severely degraded by acidic deposition and had a macrophyte community typical of lakes in northeastern Minnesota with low acid‐neutralizing capacity (ANC). This paper describes the changes observed in aquatic plant communities during the 5 years after treatment, as pH and ANC slowly returned to pretreatment levels.Sphagnum platyphyllum, intolerant of non‐acid conditions, was completely eliminated from the lake. The charo‐phyte,Nitella, that originally shared dominance in the deep littoral zone withS. platyphyllum, decreased in importance during the first 2 years after treatment. Two vascular plants,Potamogeton pusillusandNajas flexilis, were first found in the lake the year after treatment and were abundant for 2 years after liming, probably in response to a combination of more neutral pH and reduced cover ofNitella.As the ANC and pH slowly returned to pretreatment conditions,Nitellaagain increased in coverage and depth range, with a concomitant decrease in P.pusillusandN. flexilis.The moss, S.platyphyllum, had not reinvaded the lake by 1993, 2 years after its dramatic d

ISSN:1061-2971    

DOI:10.1111/j.1526-100X.1996.tb00182.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY