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  • macroalgae  (3)
  • Mixotroph  (1)
Publikationsart
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Erscheinungszeitraum
  • 1
    ISSN: 1573-5117
    Schlagwort(e): Rhode Island ; streams ; lotic ; macroalgae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    ISSN: 1573-5117
    Schlagwort(e): Rhode Island ; streams ; macrophytes ; macroalgae ; watershed ; drainage ; basin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: 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.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 222 (1991), S. 159-172 
    ISSN: 1573-5117
    Schlagwort(e): Benthic ; macroalgae ; macrophytes ; niche pre-emption ; riparian shading ; stream
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The seasonal distribution and abundance of benthic macrophytes were characterized from second- and third-order segments of a stream flowing over granite flatrock in the southeastern United States. Eighteen genera were identified over two annual cycles including macroalgae (60% of the total), angiosperms (30%), and bryophytes (10%). Light availability as affected by riparian shading was a major factor influencing community structure. Based on strong agreement among two-way indicator species analysis, detrended correspondence analysis and cluster analysis, we identified four communities characteristic of distinct light regimes and seasons. In shaded sites the red alga Lemanea australis was dominant during cool seasons, and the aquatic moss Fontinalis sp. was dominant during warm seasons. By contrast, in open sites L. australis and the angiosperm Podostemum ceratophyllum were co-dominant during cool seasons, and P. ceratophyllum was also dominant in warm seasons. The prolific macrophyte communities followed a pattern of broad seasonal maxima for dominant species along with rapid fluctuations in ephemerals. The community dynamics suggest that competitive interactions control space partitioning among macrophytes on the granite flatrock.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    Publikationsdatum: 2022-05-26
    Beschreibung: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Protist 167 (2016): 106–120, doi:10.1016/j.protis.2016.01.003.
    Beschreibung: Arranging organisms into functional groups aids ecological research by grouping organisms (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally have been split between photoautotrophic “phytoplankton” and phagotrophic “microzooplankton”. However, there is a growing recognition of the importance of mixotrophy in euphotic aquatic systems, where many protists often combine photoautotrophic and phagotrophic modes of nutrition. Such organisms do not align with the traditional dichotomy of phytoplankton and microzooplankton. To reflect this understanding, we propose a new functional grouping of planktonic protists in an eco-physiological context: (i) phagoheterotrophs lacking phototrophic capacity, (ii) photoautotrophs lacking phagotrophic capacity, (iii) constitutive mixotrophs (CMs) as phagotrophs with an inherent capacity for phototrophy, and (iv) non-constitutive mixotrophs (NCMs) that acquire their phototrophic capacity by ingesting specific (SNCM) or general non-specific (GNCM) prey. For the first time, we incorporate these functional groups within a foodweb structure and show, using model outputs, that there is scope for significant changes in trophic dynamics depending on the protist functional type description. Accordingly, to better reflect the role of mixotrophy, we recommend that as important tools for explanatory and predictive research, aquatic food-web and biogeochemical models need to redefine the protist groups within their frameworks.
    Beschreibung: This work was funded by grants to KJF and AM from the Leverhulme Trust (International Network Grant F00391 V) and NERC (UK) through its iMARNET programme NE/K001345/1.
    Schlagwort(e): Plankton functional types (PFTs) ; Phagotroph ; Phototroph ; Mixotroph ; Phytoplankton ; Microzooplankton
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Standort Signatur Einschränkungen Verfügbarkeit
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