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  • 1
    Electronic Resource
    Electronic Resource
    Characteristics of softwater streams in Rhode Island. I. A comparative analysis of physical and chemical variables (1985)
    Springer
    Hydrobiologia 128 (1985), S. 97-108 
    Details
    ISSN: 1573-5117
    Keywords: Rhode Island ; streams ; lotic ; riparian shading
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Thirteen physical and chemical characteristics of five softwater streams in Rhode Island, U.S.A. were examined biweekly to monthly for seventeen months. One first-order, two second-order and two third-order streams were included in the study. The mean annual temperature ranged from 9.4 °C in the spring-fed headwater stream to 14 °C in an open, third-order stream, with seasonal fluctuations of 14.5 ° to 28.0 °C. The heavily shaded first-order stream generally received less than 30% incident light at its surface throughout the year. By contrast, the other streams either were unshaded or were associated with distinct periodicity of incident light quantity due to seasonality of the tree canopy. The mean annual current velocity ranged from 22 to 100 cm s−1 among the streams, pH ranged from 3.7 to 6.4, and specific conductance was generally less than 50 µS cm−1. The first-order stream was associated with lowest mean annual temperature, current velocity, light penetration and nitrate, as well as relatively high and constant silica concentrations. Temperature was negatively correlated with current speed in second- and third-order streams, and temperature was also negatively correlated with light in shaded streams. There was a general pattern in all streams for decreasing pH following precipitation events. Concentrations of total phophorus, nitrate-nitrogen, ammonium-nitrogen and silica were among the lowest reported for lotic systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00008729
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  • 2
    Electronic Resource
    Electronic Resource
    Characteristics of softwater streams in Rhode Island II. Composition and seasonal dynamics of macroalgal communities (1985)
    Springer
    Hydrobiologia 128 (1985), S. 109-118 
    Details
    ISSN: 1573-5117
    Keywords: Rhode Island ; streams ; lotic ; macroalgae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Forty stream segments in Rhode Island, U.S.A., were examined seasonally from June 1979 to March 1982. Thirty-nine species of macroalgae were collected, respresenting 25 genera. The composition of the lotic flora was 54% green algae, 31% red algae, 5% blue-green algae, 5% xanthophytes, 3% chrysophytes and 3% diatoms. The majority of these taxa (85%) were filamentous. From a biweekly examination of five stream segments, macroalgal communities could be grouped according to light regime. Species in unshaded streams exhibited little seasonality, whereas in streams shaded by one or more layers of riparian canopy, maxima in species numbers and abundance occurred during colder seasons. The most widespread and abundant species were the blue-green alga Phormidium retzii, the green alga Draparnaldia acuta, and the diatom Eunotia pectinalis. P. retzii and E. pectinalis were aseasonal annuals, while D. acuta was primarily a winter-spring form. It appears that pH is a major factor affecting broad geographic distribution patterns of stream macroalgae, whereas the light regime established by overhanging canopy is an important factor which influences localized abundance and seasonality of lotic macroalgal communities. Niche pre-emption appears to be a common mode of resource space division among stream macroalgae in Rhode Island. E. pectinalis is the strongly developed dominant in this drainage system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00008730
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Characteristics of softwater streams in Rhode Island. III. Distribution of macrophytic vegetation in a small drainage basin (1986)
    Springer
    Hydrobiologia 140 (1986), S. 183-191 
    Details
    ISSN: 1573-5117
    Keywords: Rhode Island ; streams ; macrophytes ; macroalgae ; watershed ; drainage ; basin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Wood River watershed, a small well-defined drainage basin in Rhode Island was monitored seasonally for all macrophytic vegetation and various physical variables. Twenty-four segments, 20 m in length were sampled. Mean stream depth, width and current velocity increased by 3 to 8 fold from 1st- to 4th-order segments. Light penetration was positively correlated with the above variables (p 〈 0.05) and increased by 11 fold from the headwaters to the mouth during September when the riparian canopy was maximum. 74 subgeneric taxa of macrophytes were collected in the Wood River basin, 36% algae, 13% bryophytes, 4% vascular cryptograms and 45% angiosperms. The highest diversity occurred in the 4th-order segments throughout the year. Species numbers were positively correlated with depth, width and light penetration (p 〈 0.05). Vascular plants dominated all orders, but their proportion doubled from 1st- to 4th-order streams. Macrophyte cover was twice as high in the 4th-order segments in June and September as in the other orders. Macrophyte abundance was positively correlated to light penetration and negatively correlated to the ratio of nonvascular: vascular plants (p 〈 0.05). Two distinct clusters were found for the predominant species. The first cluster contained mostly large angiosperms, which were rooted in sediments, while the second cluster was composed of small epilithic algae and bryophytes. The moss, Fontinalis antipyretica, was the most frequent species, occurring in 51% of the samples and in all 4 orders throughout the year.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00007573
    Location Call Number Limitation Availability
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    Paper (German National Licenses)
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