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  • 1
    Electronic Resource
    Electronic Resource
    The effects of hydropsychid colonization on algal response to nutrient enrichment in a small Michigan stream, U.S.A. (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 33 (1995), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. We tested the hypothesis that the indirect effects of colonization by Hydropsyche spp. (Trichoptera: Hydropsychidae) may be greater than direct effects of nutrients on the benthic algal community growth. Two sets of nutrient-releasing substrates (a total of twenty-four) were deployed into a small pristine stream in northern Michigan. Each set was composed of four treatments replicated three times: (i) no nutrient enrichment (C), (ii) 0.5 M phosphate-P enrichment (P), (iii) 0.5 M nitrate-N enrichment (N) and (iv) 0.5 M phosphate-P plus 0.5 M nitrate-N enrichment (P + N). All hydropsychids colonizing on the substrate in one set (twelve substrates) were removed regularly and the other set (twelve substrates) with undisturbed hydropsychids served as the controls.2. Algal biomass and gross primary productivity were estimated as chlorophyll a (chl a) concentration, algal biovolume, and carbon fixation rate, respectively. There was a significant interactive effect of hydropsychid colonization and P enrichment on algal biomass measured as chl a concentration. With removal of hydropsychids, chl a concentration increased 11-fold in the P enrichment treatments relative to the controls. The effects of P on chl a was, however, not significant in the presence of hydropsychids. Such interactive effects were not observed when algal responses were measured as biovolume and carbon fixation rate (GPP).3. It is recommended that algal responses to nutrient enrichment should be measured as biovolume or carbon fixation rate in small streams where hydropsychids are commonly present.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1995.tb00401.x
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  • 2
    Electronic Resource
    Electronic Resource
    Early Colonization Patterns of Diatoms and Protozoa in Fourteen Fresh-water Lakes (1983)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 30 (1983), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Polyurethane substrates were anchored near the surface of 14 lakes in the northern tip of the lower peninsula of Michigan. I wo substrates were removed from each take and taken to the laboratory after 1, 3, 6, 15, and 21 days of exposure. At the laboratory, one substrate was used for determining the number of species of diatoms and the other for protozoa. A cluster analysis of the matrix of Jaccard's coefficients for all diatom samples from all lakes showed that virtually all samples from any given lake consistently clustered together. This indicates that, with respect to species occurrence, distinct and compositionally stable diatom assemblages formed on the substrates in fewer than 21 days. Analysis of all protozoan samples from all lakes did not show such clustering, however, and the correspondence of clusters for protozoan and diatom communities for the 14 lakes was not particularly good. This suggests that the link between the two groups at the species level is not particularly strong during the early phases of artificial substrate colonization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1983.tb01031.x
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  • 3
    Electronic Resource
    Electronic Resource
    Monitoring river periphyton with artificial benthic substrates (1980)
    Springer
    Hydrobiologia 69 (1980), S. 235-244 
    Details
    ISSN: 1573-5117
    Keywords: periphyton ; diatom ; benthic ; monitoring ; algae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The objective of this research was to identify the materials and methods necessary to study the attached algal community on a river bottom in deep water. The study site was the Susquehanna River near Falls, Pennsylvania. Artificial substrates of smooth glass, frosted glass, Vermont slate, ‘sandy slate’ (flagstone) and acrylic plate were placed on the stream bottom in detritus free sample holders by scuba divers. Both monthly and long-term cumulative samples were collected from the plates employing scuba and a Bar-Clamp sampler. River stones (natural substrates) were collected for comparison. Samples were analyzed in a Palmer Cell under a Bausch and Lomb research microscope. Diatoms were the most important colonizers of river stones, with the genera Nitzschia and Navicula most abundant. Highest periphyton densities occurred on natural substrates in winter with a maximum of 2.2 × 104 units/ mm2. Artificial substrates with one month exposure periods accumulated maximum periphyton density from May through October with relatively low densities in winter. Cumulative artificial substrates were most like river stones in patterns of colonization. Frosted acrylic is recommended for future studies employing benthic artificial periphyton substrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046798
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  • 4
    Electronic Resource
    Electronic Resource
    Studies on Lake Erie's littoral algae; Host specificity and temporal periodicity of epiphytic diatoms (1983)
    Springer
    Hydrobiologia 99 (1983), S. 7-18 
    Details
    ISSN: 1573-5117
    Keywords: algae ; diatoms ; periphyton ; Lake Erie ; epiphytes ; littoral zone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Substratum specificity and temporal periodicity of the attached diatom flora upon three aquatic vascular plants and an artificial substratum were examined in three Lake Erie marshes. No qualitative or quantitative specificity for substrata was observed. Variability of diatom assemblage structure within replicate samples of a particular substratum type was as great as, or greater than, variability between substrata. Diatom assemblages upon dowel rod displayed a mid to late summer density maximum. Variability of density maxima upon natural substrata was attributed to different growth rates of the host macrophytes. Diatom assemblages within each sampling site possessed a distinct temporal periodicity indicating that factors affecting diatom growth are heterogeneous in distribution throughout Lake Erie's littoral zone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00013712
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  • 5
    Electronic Resource
    Electronic Resource
    The response of benthic algae to manipulations of light in four acidic lakes in northern Michigan. (1999)
    Springer
    Hydrobiologia 394 (1999), S. 69-81 
    Details
    ISSN: 1573-5117
    Keywords: Periphyton ; metaphyton ; acid lakes ; light ; DOC ; Zygnematales ; diatoms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We investigated the effects of light on benthic algal communities in four acidic lakes (Johnson Lake, McNearney Lake, Avery Lake and Garlinghouse Lake) in northern Michigan (U.S.A.) that differed in dissolved organic content. In mid-summer, a series of light filters was placed 1 cm above the sediment of each lake at a depth of 2–3 m to filter out 0%, 80% and 90% of light reaching the lake bottom. After 5 weeks, the biomass and taxonomic composition of algal communities developing under these light conditions were quantified. Light accounted for most of the variation in algal biomass (r 2=0.79). High-light conditions promoted filamentous green-algal ( Zygnematales) growth, while diatoms and desmids had both a greater absolute and relative abundance in lower light conditions. We hypothesize that shading by large colonies of filamentous green algae, common in acidic lakes could positively affect diatom abundance possibly by protection from U V-light or photoinhibition. Large colonies of Mougeotia sp. could also benefit by self-shading in excessive light conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003509420743
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  • 6
    Electronic Resource
    Electronic Resource
    Benthic algal response to N and P enrichment along a pH gradient (1989)
    Springer
    Hydrobiologia 179 (1989), S. 119-127 
    Details
    ISSN: 1573-5117
    Keywords: benthic algae ; nutrients ; pH ; community structure ; cell size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nutrient enrichment and its effect on benthic algal growth, community composition, and average cell size was assessed across two sites of differing pH within a single habitat. Nutrients were added using in situ substrata, which released either N, P, or no additional nutrients (controls) at each site for 21 days. Upon collection, chlorophyll and biovolume standing stocks of the attached algal microflora were measured. Chlorophyll concentration was different among all treatments, accumulating greatest on P, followed by N, and the least on C substrata (P 〈 0.001) and was highest at site-2 (P 〈 0.001), while total algal biovolume was highest on P compared to both N and C substrata (P 〈 0.05) and did not vary between sites. Increased growth on P substrata was due to the enhanced biovolume of filamentous green algae, although the affected taxa varied between sites. Biovolume to cell density ratios (as a measure of average cell size) were highest on P substrata over both N-enriched and control substrata (P 〈 0.05) and this pattern was similar between sites. Progression towards a community composed of larger cells following P enrichment observed along this pH gradient, seems to be related to the dominance of larger celled filamentous green algae. Thus, nutrients exhibited greater control on benthic algal growth than did changes in hydrogen ion concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00007599
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  • 7
    Electronic Resource
    Electronic Resource
    Independent and interactive effects of nutrients and grazers on benthic algal community structure (1994)
    Springer
    Hydrobiologia 291 (1994), S. 201-209 
    Details
    ISSN: 1573-5117
    Keywords: algae ; Baetis tricaudatus ; grazing ; Helicopsyche borealis ; interaction ; nutrient ; periphyton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Algal responses to nutrients, grazing by Helicopsyche borealis, and concurrent grazing by Helicopsyche and Baetis tricaudatus were examined in recirculating stream chambers. Alagl communities, dominated by Achnanthes minutissima, Cocconeis placentula, and Synedra ulna, were primarily phosphorus-limited. Algal populations responded after only 6 days of nutrient enrichment. Initially, both the adnate diatom Cocconeis and erect diatom Synedra showed positive response to nutrient enrichment. Accumulation of algal biomass between day 3 and 6 in the P enriched treatment was resulted primarily from the growth of Synedra, an overstory rosette-like diatom colony. Such a shift in dominant growth from adnate to erect diatoms is a general phenomenon in periphyton succession in the absence of disturbance. Algal species showed differential responses to an increase of Helicopsyche densities. The accrual rate of Achnanthes continuously decreased with increasing grazer densities. The accrual rates of both Cocconeis and Synedra declined but reached plateaus between medium and high grazing densities. Baetis effectively and exclusively depressed Synedra and had no significant impact on Cocconeis. After concurrent grazing, algal communities were mainly dominated by Cocconeis (approximately 80% of total algal biovolume). The grazer' s mouth structures, grazing efficiencies, and mobility may account for the differential effects of concurrent grazing on algal communities. Significant interactive effects of P and grazing by Helicopsyche indicated that both nutrient addition and grazing may exert significant impact on algal communities. However, grazing may have a much stronger effect on algae than nutrients. Our results indicate that enhancement of algal biomass by P was dampened by grazing activities and that P had no effect on algal biomass in the presence of grazers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014709
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  • 8
    Electronic Resource
    Electronic Resource
    Biomass and compositional changes in the periphytic community of an artificial stream in response to lowered pH (1987)
    Springer
    Water, air & soil pollution 33 (1987), S. 165-177 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Two artificial streams simulating low-order, softwater streams of the Upper Peninsula of Michigan were employed to examine the effects of lowered pH on periphytic algae. The control stream contained water with a circumneutral pH whereas the pH of the water in the acidified stream was decreased to pH 4 with H2SO4. Chlorophyll a concentrations and cell densities in the periphytic algal communities were used to measure differences in biomass accumulations between the 2 streams over a 42-d, spring colonization period. Relative abundances of algal genera and Stander's similarity index (SIMI) were used to examine compositional differences between the control and acidified periphytic algal communities. These algal communities exhibited pronounced differences in their total biomasses and compositions indicating periphytic algal communities inhabiting low-order, softwater streams, such as those of the Upper Peninsula of Michigan, are vulnerable to acidic deposition. Decreased biomass accumulation under acidified conditions was believed to result primarily from decreased nutrient availability, and possibly secondarily from elevated aluminum and/or iron concentrations. The shift in community compositions was interpreted to be a more direct response to the lowered pH as acidophils and acid tolerant genera became favored, and thus more abundant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00191385
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  • 9
    Electronic Resource
    Electronic Resource
    Artificial substrates which release nutrients: Effects on periphyton and invertebrate succession (1984)
    Springer
    Hydrobiologia 114 (1984), S. 29-37 
    Details
    ISSN: 1573-5117
    Keywords: periphyton ; artificial substrate ; phosphate ; nitrate ; chlorophyll ; succession
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nutrient-diffusing substrates for periphyton were made from clay flower pots (O.D. = 8.8 cm), sealed with plastic petri dishes, and filled with 2% agar and specified nutrients. When placed in water, the nutrients slowly diffuse through the agar and clay walls of the pots, becoming available to organisms colonizing the outer surface. Forty-eight pots, 16 containing 0.1 M KH2PO4, 16 with 0.1 M NaNO3, and 16 with no added nutrients, were placed at 0.5 m depth in Douglas Lake, Michigan. Four pots of each nutrient treatment were sampled for algal periphyton and invertebrates after 7, 14, 25, and 36 days. A total of 72 algal species were enumerated. Of these, Epithemia adnata (Kütz.) Bréb., Rhopalodia gibba (Ehr.) O. Müll, and Anabaena sp. experienced strong growth stimulation in response to phosphate addition. No significant effects of nitrate addition were noted. Measures of algal community structure also reflected the impact of phosphate addition. Final algal biomass was enhanced 10-fold, successional change was prolonged, and species diversity declined relative to nitrate and control pots. Chironomids, chydorid Cladocera, and gastropods dominated the invertebrate fauna found on the pots. Densities of the small, algivorous chironomid Corynoneura nr. lobata Edwards were highest on phosphate pots at the end of the study, in apparent response to the increase in periphyton biomass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00016599
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  • 10
    Electronic Resource
    Electronic Resource
    Primary productivity and spatial structure of phytolithic growth in streams in the Great Smoky Mountains National Park, Tennessee (1985)
    Springer
    Hydrobiologia 123 (1985), S. 59-67 
    Details
    ISSN: 1573-5117
    Keywords: algae ; community structure ; diatoms ; incubation chamber ; periphyton ; phytolithon ; primary productivity ; scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The purpose of this study was to examine the primary production rates of phytolithic communities found in the major different habitats of streams and determine the effects of physical and chemical parameters associated with each habitat on periphyton community spatial structure. The project was designed to study natural, intact communities within stream systems. A comparative analysis was made of phytolithic communities found in Camel Hump and Husky Branch streams in the Great Smoky Mountains National Park. Camel Hump flows through virgin forest area and Husky Branch flows through an area logged approximately 60 y ago. The effects of logging on Husky Branch stream and the surrounding watershed are discussed. Seasonal data were collected from July, 1981 through May, 1982 from fast flow, slow flow and pool areas within each stream. An incubation chamber designed for use in lotic systems was used for in situ measurements of 14C uptake. Rock samples collected at each site were used as substrates for community structure observations utilizing a scanning electron microscope. The algal communities of Camel Hump and Husky Branch streams were found to be predominantly composed of diatoms. The dominant genera in the fast, slow and pool areas included Achnanthes, Eunotia, Meridion, Navicula and Gomphonema. Fast flow areas were dominated by diatom species growing in a prostrate position. Slow flow areas were more densely populated by diatoms than the fast flow areas. Diatoms in the slow flow areas appeared mainly in prostrate position with a few stalked forms present. Pool area communities were less densely packed than slow flow areas and contained stalked and chain formations of diatoms. Results indicate that the physical and chemical parameters associated with each habitat affect the primary production rates and community structure found at the experimental sites. Measurements of carbon assimilation and chlorophyll a concentration were significantly greater in habitats of higher current velocity and light availability. Cell densities tend to increase with a decrease in current velocity. Habitats of high density showed a decrease in diversity and evenness. Correlations between productivity in the various habitats of each stream and other parameters measured in the study are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00006615
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