Journal ArticleDOI
A trophic state index for lakes1
TLDR
A numerical trophic state index for lakes has been developed that incorporates most lakes in a scale of 0 to 100, which represents a doubling in algal biomass as well as various measures of biomass or production.Abstract:
A numerical trophic state index for lakes has been developed that incorporates most lakes in a scale of 0 to 100. Each major division ( 10, 20, 30, etc. ) represents a doubling in algal biomass. The index number can bc calculated from any of several parameters, including Secchi disk transparency, chlorophyll, and total phosphorus. My purpose here is to present a new approach to the trophic classification of lakes. This new approach was developed because of frustration in communicating to the public both the current nature or status of lakes and their future condition after restoration when the traditional trophic classification system is used. The system presented hcrc, termed a trophic state index (TSI), involves new methods both of defining trophic status and of determining that status in lakes. All trophic classification is based on the division of the trophic continuum, howcvcr this is defined, into a series of classes termed trophic states. Traditional systems divide the continuum into three classes: oligotrophic, mesotrophic, and cutrophic. There is often no clear delineation of these divisions. Determinations of trophic state are made from examination of several diverse criteria, such as shape of the oxygen curve, species composition of the bottom fauna or of the phytoplankton, conccntrations of nutrients, and various measures of biomass or production. Although each changes from oligotrophy to eutrophy, the changes do not occur at sharply defined places, nor do they all occur at the same place or at the same rate. Some lakes may be considered oligotrophic by one criterion and eutrophic by another; this problem isread more
Citations
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Primary productivity, nutrients, and transparency during the early onset of eutrophication in ultra-oligotrophic Lake Tahoe, Califomia-Nevada1
TL;DR: In this article, the early stages of cultural eutrophication of Lake Tahoe have been studied and the relationship between the primary productivity and transparency has been analyzed, showing that a gradual increase in the N:P may be a general evolutionary characteristic of oligotrophic lakes during the earliest stages of eutrophic evolution.
Journal ArticleDOI
Nutrient Enrichment and Grazer Effects on Phytoplankton in Lakes
TL;DR: Algal carrying capacity, as quantified by TP, explains much of the variation in Daphnia effects on total algal biomass across lakes, and the success of biomanipulation in eutrophic lakes should critically depend upon the effective- ness of strategies aimed at reducing zooplanktivory.
Journal ArticleDOI
The Trophic Response of Ciliated Protozoans in Freshwater Lakes
John R. Beaver,Thomas L. Crisman +1 more
TL;DR: Analysis of planktonic ciliated protozoans in Florida lakes during 1979 found that small-bodied ciliates are reduced in oligotrophic lakes where bacterial concentrations arc limiting and are replaced by those largerbodied taxa able to ingest nannoplanktonic algae in addition to bacteria.
Journal ArticleDOI
Secchi disk depth: A new theory and mechanistic model for underwater visibility
Zhongping Lee,Shaoling Shang,Chuanmin Hu,Keping Du,Alan Weidemann,Weilin Hou,Junfang Lin,Gong Lin +7 more
TL;DR: In this article, the authors show that the Secchi disk depth (Z SD) may not exactly represent the sighting of a Secchi disc by a human eye. And they develop a new theoretical model to interpret Z SD, which relies only on the diffuse attenuation coefficient at a wavelength corresponding to the maximum transparency.
Journal ArticleDOI
Regional water temperature characteristics of lakes subjected to climate change
Midhat Hondzo,Heinz G. Stefan +1 more
TL;DR: A deterministic, validated, one-dimensional, unsteady-state lake water quality model was linked to a daily weather data base to simulate daily water temperature profiles in lakes over a period of twenty-five (1955−79) years as mentioned in this paper.
References
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Journal ArticleDOI
The phosphorus‐chlorophyll relationship in lakes1,2
P. J. Dillon,F. H. Rigler +1 more
TL;DR: In this article, data for summer chlorophyll and spring total phosphorus concentration were collected from 19 lakes in southern Ontario and combined with data reported in the literature for other North American lakes to produce a regression line that can be used to predict the average summer CHP from a single measurement of phosphorus concentration at spring overturn.
Journal ArticleDOI
Environmental control of photosynthesis in the sea
TL;DR: In this article, a theoretical equation for the photosynthesis-light relation is developed which includes the effects of inhibition in intense light, assuming that phytoplankton adapts to seasonal light changes and that nutrient deficiency affects the carbon:chlorophyll ratio of natural phyto-ankton populations.
Journal Article
Primary production by phytoplankton community in some Japanese lakes and its dependence on lake depth
Journal ArticleDOI
Phosphorus, Nitrogen, and Algae in Lake Washington after Diversion of Sewage
TL;DR: After diversion of sewage effluent from Lake Washington, winter concentrations of phosphate and nitrate decreased at different rates, but nitrate remained at more than 80 percent of the 1963 value and free carbon dioxide and alkalinity remained relatively high.