Author: Christopher LanePublisher:
ISBN:
Category : Diatoms
Languages : en
Pages : 124
Book Description
The Use of Diatoms as Biological Indicators of Water Quality in Two Coastal Dune Lakes, Northern New South Wales
Author: Christopher LanePublisher:
ISBN:
Category : Diatoms
Languages : en
Pages : 124
Book Description
Use of Diatom Algae as Biological Indicators for Assessing and Monitoring Water Quality of the Rivers in the Greater Toronto Area, Canada
Author: Natasa Zugic-DrakulicPublisher:
ISBN: 9780494218723
Category :
Languages : en
Pages : 494
Book Description
Diatom and environmental data collected from the rivers in the Greater Toronto Area (GTA) were analyzed using various multivariate ordination and weighted averaging methods. A regional calibration set was based on the 280 samples collected from 42 sites of the Humber River on a monthly basis over a one-year period. Canonical Correspondence Analysis (CCA) showed that the first two axes were correlated with specific conductivity and temperature, suggesting that both spatial and temporal patterns were important. Specific conductivity was the most important variable and a diatom inference model was developed for this variable using the simple weighted average method with inverse de-shrinking. Subsequently, diatoms from five selected sites each belonging to one of five different land use categories and sampled over a 12-month period, were analyzed for temporal variations. Each land use site supported different diatom species, some of which further showed different seasonal changes. More polluted sites exhibited more distinct seasonal patterns, while less polluted sites showed less pronounced seasonal variability. For sites where seasonal variation was pronounced, distinct differentiation was found between winter and spring samples and summer and fall samples. Therefore it can be recommended to sample more than once per year, or to develop different diatom indices depending on the season. Despite the high seasonal variation in some sites, differences in overall diatom assemblages between more polluted and less polluted sites remained distinct, indicating that diatoms can be used as a powerful biomonitoring tool. The influence of substratum type on diatom composition and abundances was also tested by comparing pairs of rock and sand samples collected from 73 monitoring stations along six watersheds of the GTA. Results show that rocks and sand samples support similar diatom assemblages, with comparable species richness and diversity as well as growth forms. Correspondence Analysis (CA) did not show any separation between diatom assemblages from the two substrata, and CCA showed that the two assemblages not only have similar patterns in diatom distribution but are also controlled by the same environmental variables, suggesting that in river stretches where a preferred substratum is not present, the second choice substratum can be used.
The Use of Diatoms as Biological Indicators of Water Quality, and for Environmental Reconstruction, in South-east Tasmania, Australia
Author: Christopher M. LanePublisher:
ISBN:
Category : Water quality biological assessment
Languages : en
Pages : 344
Book Description
Unearthing Prehistory
Author: Armand Salvador B. MijaresPublisher: British Archaeological Reports Oxford Limited
ISBN:
Category : Art
Languages : en
Pages : 164
Book Description
This study proposes a general culture history of northern Luzon from the late Pleistocene to the mid-Holocene period. Northern Luzon is an important area for reconstructing the prehistory of the Southeast Asian region, contributing to our understanding of the peopling of the Philippine Islands, from the Pleistocene foragers to the migration of the early Austronesians. This study synthesizes past and current archaeological research in the area, and presents new findings from archaeological excavations in the Peñablanca caves, which provide fresh data for reconstructing the transition from the Preceramic into the ceramic period. Recent excavations have provided the earliest dated evidence of human occupation in Luzon. Evidence from faunal identification, macrobotanical and phytolith remains show broad-spectrum subsistence strategies, and lithic analysis shows some changes from Late Pleistocene into early Holocene technology. Interaction between these foragers and the early Austronesian farmers of the Cagayan Valley was established by at least 3500 years ago.
Diatoms as Indicators of Lake Trophic Status
Author: Ching-jung YangPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Relationships between surface sediment diatom assemblages and lake trophic status were studied in 50 Canadian Precambrian Shield lakes in the Muskoka-Haliburton and southern Ontario regions. The purpose of this study was to develop mathematical regression models to infer lake trophic status from diatom assemblage data. To achieve this goal, however, additional investigations dealing with the evaluation of lake trophic status and the autecological features of key diatom species were carried out. Because a unifying index and classification for lake trophic status was not available, a new multiple index was developed in this study, by the computation of the physical, chemical and biological data from 85 south Ontario lakes. By using the new trophic parameter, the lake trophic level (TL) was determined: TL = 1.37 In[1 +(TP x Chl-a / SD)], where, TP=total phosphorus, Chl-a=chlorophyll-a and SD=Secchi depth. The boundaries between 7 lake trophic categories (Ultra-oligotrophic lakes: 0-0.24; Oligotrophic lakes: 0.241-1.8; Oligomesotrophic lakes: 1.813.0; Mesotrophic lakes: 3.01-4.20; Mesoeutrophic lakes: 4.21-5.4; Eutrophic lakes: 5.41-10 and Hyper-eutrophic lakes: above 10) were established. The new trophic parameter was more convenient for management of water quality, communication to the public and comparison with other lake trophic status indices than many of the previously published indices because the TL index attempts to Increase understanding of the characteristics of lakes and their comprehensive trophic states. It is more reasonable and clear for a unifying determination of true trophic states of lakes. Diatom specIes autecology analysis was central to this thesis. However, the autecological relationship of diatom species and lake trophic status had not previously been well documented. Based on the investigation of the diatom composition and variety of species abundance in 30 study lakes, the distribution optima of diatom species were determined. These determinations were based on a quantitative method called "weighted average" (Charles 1985). On this basis, the diatom species were classified into five trophic categories (oligotrophic, oligomesotrophic, mesotrophic, mesoeutrophic and eutrophic species groups). The resulting diatom trophic status autecological features were used in the regressIon analysis between diatom assemblages and lake trophic status. When the TL trophic level values of the 30 lakes were regressed against their fi ve corresponding diatom trophic groups, the two mathematical equations for expressing the assumed linear relationship between the diatom assemblages composition were determined by (1) uSIng a single regression technique: Trophic level of lake (TL) = 2.643 - 7.575 log (Index D) (r = 0.88 r2 = 0.77 P = 0.0001; n = 30) Where, Index D = (0% + OM% + M%)/(E% + ME% + M%); 4 (2) uSIng a' multiple regressIon technique: TL=4.285-0.076 0%- 0.055 OM% - 0.026 M% + 0.033 ME% + 0.065 E% (r=0.89, r2=0.792, P=O.OOOl, n=30) There was a significant correlation between measured and diatom inferred trophic levels both by single and multiple regressIon methods (P 0.0001, n=20), when both models were applied to another 20 test lakes. Their correlation coefficients (r2 ) were also statistically significant (r2 0.68, n=20). As such, the two transfer function models between diatoms and lake trophic status were validated. The two models obtained as noted above were developed using one group of lakes and then tested using an entirely different group of lakes. This study indicated that diatom assemblages are sensitive to lake trophic status. As indicators of lake trophic status, diatoms are especially useful in situations where no local trophic information is available and in studies of the paleotrophic history of lakes. Diatom autecological information was used to develop a theory assessing water quality and lake trophic status.
Selected Water Resources Abstracts
Author: Use of Diatom Algae as Biological Indicators for Assessing and Monitoring Water Quality of the Greater Toronto Area, Canada
Author: Natasa Zugic-DrakulicPublisher:
ISBN:
Category :
Languages : en
Pages : 494
Book Description
Diatoms as Indicators of Water Quality in the Wetlands of the Swan Coastal Plain, Western Australia
Author: Stuart K. R. HellerenPublisher:
ISBN:
Category : Diatoms
Languages : en
Pages : 438
Book Description
Diatom Communities As Indicators of Ecological Impairment in Rivers
Author: Taurai BerePublisher: LAP Lambert Academic Publishing
ISBN: 9783659121685
Category :
Languages : en
Pages : 228
Book Description
Field and laboratory studies were conducted to elucidate the confounding effects of substrate selection, eutrophication, organic pollution, ionic strength, land-use patterns, and heavy metal pollution on benthic diatom communities. Characteristics of benthic diatom communities in relation to pollution level and type were analysed through general criteria and specific criteria. Diatom communities closely reflected the pollution gradient. Diatom-based multivariate water quality assessment results based on different substrates are interchangeable. 17 diatom-based water quality indices developed in other regions proved useful in providing an indication of water quality. Hormesis was demonstrated with a Cd EC50 of 0.077 mg.L-1 being recorded. High metal accumulation capacity by periphyton was demonstrated. Pb and Cr III were shown to decrease the toxicity effects of Cd on periphyton communities. The closer the frequency and duration of the pulse is to a continuous exposure, the greater the effects of the contaminant on aquatic life. Light has a role in modulating the effects of metal toxicants on aquatic life. Diatoms are important indicators of ecological impairment.
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