Implications of rapid changes in chlorophyll-<Emphasis Type="Italic">a</Emphasis> of plankton,epipelon, and epiphyton in a Pampean shallow lake: an interpretation in terms of a conceptual model |
| |
Authors: | M G Cano M A Casco L C Solari M E Mac Donagh N A Gabellone M C Claps |
| |
Institution: | (1) D.C. Ficología Facultad de Ciencias Naturales y Museo, UNLP, Paseo del Bosque s/n 1900, La Plata, Argentina;(2) CONICET, Buenos Aires, Argentina;(3) Instituto de Limnología “Dr. R.A. Ringuelet”, Av. Calchaquí km 23.5 1888, Fcio. Varela, Argentina |
| |
Abstract: | Biomass assessments of algae in wetlands usually include only the phytoplankton community without considering the contribution
of other algal associations to total algal biomass. This omission prevents an accurate evaluation of the phytoplankton community
as an integral part of the total ecosystem. In the present work, the biomass contributions (expressed as chlorophyll-a content per m2 of lake) of phytoplankton, epiphyton on both submerged and emergent macrophytes, and epipelon were measured in Lacombe Lake,
Argentina, for the purpose of (1) establishing the relative importance of the phytoplankton and (2) evaluating the entire
contribution of algal biomass within the context of the Goldsborough & Robinson conceptual model. Our sampling was carried
out monthly for a year in sites representative of different conditions with respect to water depth and type of macrophytes.
Physicochemical analyses of water were performed following standard methods. Plankton was collected in a five-level profile
at deeper stations and in subsurface samples at the shallow one. Samples of sediment obtained with corers were collected for
epipelon sampling and segments of plants were cut at different levels, so as to obtain the epiphytes by scraping. Pigment
was extracted with aqueous acetone and calculations were made by means of the Lorenzen equation. According to the Goldsborough
& Robinson model, a Lake State developed here during the winter (phytoplankton maxima: 150 mg chlorophyll-a per m2). Then, through the subsequent growth of the submerged macrophytes, an Open State was observed, characterized by a maximum
epiphyton biomass (at 3,502 mg chlorophyll-a per m2) along with lower levels of phytoplankton biomass. The epiphytic algae on the emergent macrophytes were always present but
attained only relatively low biomass values (maximum: 120 mg of chlorophyll-a per m2 in February). The epipelon biomass varied between 50 and 252 mg chlorophyll-a per m2, registering a considerable contribution of settled algae from the water column (phytoplankton). This study contributes to
our knowledge of wetland dynamics through its assessment of the rapid changes in the relative contributions of both planktonic
and attached algae to the total algal biomass within the context of specific environmental factors.
Guest editors: U. M. Azeiteiro, I. Jenkinson & M. J. Pereira
Plankton Studies |
| |
Keywords: | Biomass Algal communities Goldsborough & Robinson conceptual model Wetland Argentina |
本文献已被 SpringerLink 等数据库收录! |
|