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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Journal ArticleDOI
Depth colonization of eelgrass (Zostera marina) and macroalgae as determined by water transparency in Danish coastal waters
TL;DR: In this article, the authors present a comparative analysis of lower depth limits for growth of eelgrass, large brown algae and other macroalgae measured by SCUBA-diving along 162 transects in 27 Danish fjords and coastal waters, coupled to 1,400 data series of water chemistry (especially nitrogen) and Secchi depth transparency collected between March and October.
Journal ArticleDOI
Expanding the concept of trophic state in aquatic ecosystems: It’s not just the autotrophs
Walter K. Dodds,Jonathan J. Cole +1 more
TL;DR: It is made the case here that both primary production and key heterotrophic processes are needed to evaluate trophic state, and autotrophic andheterotrophic states are proposed by rates of photosynthetic and respiratory C fluxes respectively, and both be used to characterize ecosystems.
Journal ArticleDOI
Application of Landsat imagery to regional-scale assessments of lake clarity.
TL;DR: Analysis of long-term trends shows that in spite of the large land-use changes within the region over the study period, only 49 of assessed lakes in the region showed significant temporal trends in SDT over the period, and more lakes had increasing SDT than decreasing SDT.
Journal ArticleDOI
Lake ecosystem health assessment: indicators and methods.
TL;DR: A direct measurement method (DMM) and an ecological modeling method (EMM) for lake ecosystem health assessment provided similar results which corresponded with the lake's actual trophic state.
Journal ArticleDOI
Mapping amyotrophic lateral sclerosis lake risk factors across northern New England
TL;DR: It is found that poorer lake water quality was significantly associated with increased odds of belonging to an ALS cluster in the region, and this findings support the hypothesis that sporadic ALS can be triggered by environmental water-quality indicators and lake conditions that promote harmful algal blooms.
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.