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1

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Effects of single and repeated experimental acid pulses on invertebrates in a high altitude Sierra Nevada stream (1994)

KRATZ, KIM W. ; COOPER, SCOTT D. ; MELACK, JOHN M.

Oxford, UK : Blackwell Publishing Ltd

Freshwater biology 32 (1994), S. 0

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ISSN: 1365-2427

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: 1. We examined responses of aquatic macroinvertebrates to pulsed acidification experiments in twelve streamside channels located in the Sierra Nevada, California. Experiment 1 consisted of a single 8 h acid addition, and Experiment 2 consisted of two 8 h acid additions administered 2 weeks apart. Replicated treatments (four reps/ treatment) consisted of a control (pH 6.5–6.7) and pH levels of 5.1–5.2 and 4.4–4.6. Invertebrate drift was monitored continuously and benthic densities were determined before and after acid addition.2. Drift responses to pH reduction were: (i) increased drift during acidification in pH 5.2 and pH 4.6 treatment channels, often with depressed post-acidification drift in treatment channels relative to controls (exhibited by Baetis only). Depressed post-acidification drift in treatment channels appeared to be due to low benthic densities because a positive relationship between benthic and drift densities was noted for most common taxa; (ii) increased drift rates during acidification only at pH 4.6 (Epeorus, Drunella, Paraleptophlebia, Zapada, and Simulium); (iii) decreased drift at pH 5.2 and/or pH 4.6 relative to control channels (Rhyacaphila and chironomid larvae); (iv) no significant response to acidification (Ameletus, Amiocentrus, Dixa and Hydroporus).3. A high proportion (45–100%) of acid-induced drift in Baetis, Epeorus, and chironomid larvae could be attributed to dead, drifting individuals.4. Except for chironomids, most common invertebrates (i.e. Baetis and Paraleptophlebia) showed reduced benthic densities in treatment relative to control channels after acidification.5. For sensitive taxa, drift was enhanced and benthic densities reduced by single (Experiment 1) and initial [Experiment 2(a)] acid pulses. Drift responses to a second acid pulse [Experiment 2(b)] were not as pronounced as those to the single or initial acid pulses [Experiments 1 and 2(a)], and the second acid pulse had no additional effect on benthic density.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1365-2427.1994.tb00875.x

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2

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Responses of zooplankton and zoobenthos to experimental acidification in a high-elevation lake (Sierra Nevada, California, U.S.A.) (1990)

BARMUTA, LEON A. ; COOPER, SCOTT D. ; HAMILTON, STEPHEN K. ; [et al.]

Oxford, UK : Blackwell Publishing Ltd

Freshwater biology 23 (1990), S. 0

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ISSN: 1365-2427

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: SUMMARY. 1. During the summer of 1987 we conducted an acidification experiment using large enclosure at Emerald Lake, a dilute, high-elevation lake in the Sierra Nevada, California, U.S.A. The experiment was designed to examine the effects of acidification on the zooplankton and zoobenthos assemblages of Sierran lakes.2. Treatments consisted of a control (pH 6.3) and pH levels of 5.8, 5.4, 5.3, 5.0 and 4.7; each treatment was run in triplicate. The experiment lasted 35 days.3. The zooplankton assemblage was sensitive to acidification. Daphnia rosea Sars emend. Richard and Diaptomns signicauda Lilljeborg decreased in abundance below pH 5.5–5.8, and virtually disappeared below pH 5.0. Bosmina longirostris (Müller) and Keratella taurocephala Ahlstrom became more abundant with decreasing pH. although B. longirostris was rare in the pH 4.7 treatment. These species might serve as reliable indicators of early acidification in lakes such as Emerald Lake.4. The elimination of D. rosea in acidified treatments probably allowed the more acid-tolerant taxa to increase in abundance because interspecific competition was reduced. Even slight acidification can therefore alter the structure of the zooplankton assemblage.5. In contrast to the zooplankton, there was no evidence that the zoobenthos in the enclosures was affected by acidification.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1365-2427.1990.tb00296.x

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3

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Artemia monica cyst production and recruitment in Mono Lake, California, USA (1990)

Dana, Gayle L. ; Jellison, Robert ; Melack, John M.

Springer

Hydrobiologia 197 (1990), S. 233-243

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ISSN: 1573-5117

Keywords: Artemia monica ; cyst production ; recruitment

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Annual egg production was determined for Artemia monica in Mono Lake, California, from 1983 to 1987. Annual oviparous (overwintering cyst) production was 3 and 7 million cysts m−2 yr−1 in 1986 and 1987, respectively, as measured by in situ sediment traps. Cyst production for the entire five year period was calculated using Artemia census data and inter-brood duration derived from mixolimnetic temperature. These estimates ranged from 2 to 5 million cysts m−2 yr−1. This method underestimated annual production by 30%, when compared to estimates using sediment traps. Cyst production was similar during 1983–1986 and showed a significant increase in 1987, which was due primarily to a larger reproductive population later in the year. Recruitment into the adult populations of the following spring ranged between 1.4 to 3.2%. Overall abundance of this generation reflected the patterns in annual cyst production. Compensatory effects must operate on the second generation of each year, since summer populations were similar in all years despite differences in cyst production.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00026953

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4

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Photosynthetic activity of phytoplankton in a high altitude lake (Emerald Lake, Sierra Nevada, California) (1992)

Sickman, James O. ; Melack, John M.

Springer

Hydrobiologia 230 (1992), S. 37-48

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ISSN: 1573-5117

Keywords: photosynthesis ; alpine lake ; phytoplankton

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Photosynthetic activity by phytoplankton was measured during the ice-free seasons of 1984, 1985 and 1987 using the 14C radioassay in high altitude Emerald Lake (California). Relative quantum yield (αB) and light-saturated chlorophyll-specific carbon uptake (Pm B) were calculated from the relationship of light and photosynthesis fitted to a hyperbolic tangent function. Temporal changes in Pm B showed no regular pattern. Seasonal patterns of αB generally had peaks in the summer and autumn. Phytoplankton biomass (as measured by chlorophyll a) and light-saturated carbon uptake (Pm) had peaks in the summer and autumn which were associated with vertical mixing. Estimates of mean daily carbon production were similar among the three years: 57 mg C m−2 2 d−1 in 1984, 70 mg C m−2 2 d−1 in 1985 and 60 mg C m−2 d−1 in 1987. Primary productivity in Emerald Lake is low compared to other montane lakes of California and similar to high-altitude or high-latitude lakes in other regions.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00015113

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5

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Relationships between Artemia monica life history characteristics and salinity (1993)

Dana, Gayle L. ; Jellison, Robert ; Melack, John M. ; [et al.]

Springer

Hydrobiologia 263 (1993), S. 129-143

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ISSN: 1573-5117

Keywords: Artemia monica ; salinity effects ; life history characteristics

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Relationships between Artemia monica life history characteristics and salinity were determined using data from four published studies and three experiments presented here. Salinity explained 40 to 93 percent of the variation in ten life history characteristics. Reductions in hatching success, survival, length, weight, ovigery, and brood size were observed as salinity increased from 76 to 168 g l−1. Inter-brood duration, and time to hatching and reproduction were protracted as salinity was elevated. Salinity effects on life history characteristics appeared to be gradual and continuous rather than exhibiting thresholds. The one exception was naupliar survival, which was constant between 76 and 133 g l−1 followed by a decrease above 133 g l−1.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00006264

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6

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Atmospheric deposition and solute export in giant sequoia — mixed conifer watersheds in the Sierra Nevada, California (1991)

Stohlgren, Thomas J. ; Melack, John M. ; Esperanza, Anne M. ; [et al.]

Springer

Biogeochemistry 12 (1991), S. 207-230

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ISSN: 1573-515X

Keywords: atmospheric deposition ; coniferous watershed ; forest ecosystem ; solute export ; stream discharge

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology , Geosciences

Notes: Abstract Atmospheric depostion and stream discharge and solutes were measured for three years (September 1984 — August 1987) in two mixed conifer watersheds in Sequoia National Park, in the southern Sierra Nevada of California. The Log Creek watershed (50 ha, 2067–2397 m elev.) is drained by a perennial stream, while Tharp's Creek watershed (13 ha, 2067–2255 m elev.) contains an intermittent stream. Dominant trees in the area include Abies concolor (white fir), Sequoiadendron giganteum (giant sequoia), A. magnifica (red fir), and Pinus lambertiana (sugar pine). Bedrock is predominantly granite and granodiorite, and the soils are mostly Pachic Xerumbrepts. Over the three year period, sulfate (SO4 2−), nitrate (NO3 −), and chloride (Cl−1) were the major anions in bulk precipitation with volume-weighted average concentrations of 12.6, 12.3 and 10.0 μeq/1, respectively. Annual inputs of NO3-N, NH4-N and SO4-S from wet deposition were about 60 to 75% of those reported from bulk deposition collectors. Discharge from the two watersheds occurs primarily during spring snowmelt. Solute exports from Log and Tharp's Creeks were dominated by HCO3 −, Ca2+ and Na+, while H+, NO3 −, NH4 + and PO4 3− outputs were relatively small. Solute concentrations were weakly correlated with instantaneous stream flow for all solutes (r2 〈0.2) except HCO3 − (Log Cr. r2 = 0.72; Tharp's Cr. r2 = 0.38), Na+ (Log Cr. r2 = 0.56; Tharp's Cr. r2 = 0.47), and silicate (Log Cr. r2 = 0.71; Tharp's Cr. r2 = 0.49). Mean annual atmospheric contributions of NO3-N (1.6 kg ha−1), NH4-N (1.7 kg ha−1), and SO4-S (1.8 kg ha−1), which are associated with acidic deposition, greatly exceed hydrologic losses. Annual watershed yields (expressed as eq ha−1) of HCO3 − exceeded by factors of 2.5 to 37 the annual atmospheric deposition of H+.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00002608

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