Assessment Of Trophic Status Research Articles

Eutrophication assessment of Lake Manzala, Egypt using geographical information systems (GIS) techniques

Lake Manzala is in grave danger of suffering pollution from the drainage of industries, agriculture and urban sewage that affects the physio-chemical and biological parameters in the lake. A geographical information system (GIS)-based method of lake trophic status assessment was undertaken to study the spatial distribution of eutrophic conditions of Lake Manzala. In the present study, tabular data supported by field checks have been analyzed by GIS functions and operations to assess, monitor and model the environmental conditions of the lake. A representation of the spatial distribution was developed using the inverse distance weighted (IDW) interpolation method. The eutrophic state index was calculated to describe the state of the lake's environment. A GIS overlay technique was applied to synthesize the information into a final map illustrating the spatial distribution of eutrophication conditions within the study area. The different levels associated with trophic status classification using GIS were then discussed in relation to environmental change and external loading from tributary inflows. The study revealed that the lake changed to eutrophic freshwater. This change is due to the increase of freshwater inputs and nutrient loading associated with agricultural land reclamation and urban waste disposal.

NUTRIENT CONCENTRATION CRITERIA AND CHARACTERIZATION OF PATTERNS IN TROPHIC STATE FOR RIVERS IN HETEROGENEOUS LANDSCAPES1

ABSTRACT: A method is demonstrated for the development of nutrient concentration criteria and large scale assessment of trophic state in environmentally heterogeneous landscapes. The method uses the River Environment Classification (REC) as a spatial framework to partition rivers according to differences in processes that control the accrual and loss of algae biomass. The method is then applied to gravel bed rivers with natural flow regimes that drain hilly watersheds in New Zealand's South Island. An existing model is used to characterize trophic state (in terms of chlorophyll a as a measure of maximum biomass) using nutrient concentration, which controls the rate of biomass accrual, and flood frequency, which controls biomass loss. Variation in flood frequency was partitioned into three classes, and flow data measured at 68 sites was used to show that the classes differ with respect to flood frequency. Variation in nutrient concentration was partitioned at smaller spatial scales by subdivision of higher level classes into seven classes. The median of flood frequency in each of the three higher level classes was used as a control variable in the model to provide spatially explicit nutrient concentration criteria by setting maximum chlorophyll a to reflect a desired trophic state. The median of mean monthly soluble reactive phosphorus and soluble inorganic nitrogen measured at 68 water quality monitoring sites were then used to characterize the trophic state of each of the seven lower level classes. The method models biomass and therefore allows variation in this response variable to provide options for trophic state and the associated nutrient concentrations to achieve these. Thus it is less deterministic than using reference site water quality. The choice from among these options is a sociopolitical decision, which reflects the management objectives rather than purely technical considerations.

An integrated methodology for assessment of estuarine trophic status

This paper describes an integrated methodology for the Assessment of Estuarine Trophic Status (ASSETS), which may be applied comparatively to rank the eutrophication status of estuaries and coastal areas, and to address management options. It includes quantitative and semi-quantitative components, and uses field data, models and expert knowledge to provide Pressure-State-Response (PSR) indicators. A substantial part of the concepts underlying the approach were developed as the United States National Estuarine Eutrophication Assessment (NEEA), which was applied to 138 estuaries in the continental United States. The core methodology relies on three diagnostic tools: a heuristic index of pressure ( Overall Human Influence), a symptoms-based evaluation of state ( Overall Eutrophic Conditions), and an indicator of management response ( Definition of Future Outlook). Recently, the methodology has been extended and refined in its application to European estuaries, and a more quantitative approach to some of the metrics has been implemented. In particular, the assessment of pressure is carried out by means of simple modeling techniques, comparing anthropogenic nutrient loading with natural background concentrations, and the quantitative criteria for classification of system state based on different symptoms have been refined to improve comparability. The present approach has been intercalibrated with the original NEEA work, for five widely different U.S. estuaries (Long Island Sound, Neuse River, Savannah River, Florida Bay and West Mississippi Sound) with good results. ASSETS additionally aims to contribute to the EU Water Framework Directive classification system, as regards a subset of water quality and ecological parameters in transitional and coastal waters.

Water quality trends and trophic state assessment of Laguna de Bay, Philippines

Monitoring of key water quality parameters in Laguna de Bay was carried out from 1986 to 1996 to determine trends in water quality and the trophic state of the lake. Monthly sampling and field analyses were made at randomly selected sites of the lake. Three-year trend analysis of the annual mean values of some key water quality parameters showed the worsening condition of the lake. Ammonia-nitrogen, nitrate-nitrogen, ortho-phosphate, total phosphorus, chemical oxygen demand, turbidity, conductivity, and chlorides increased while alkalinity, clarity, and dissolved oxygen decreased. The lake is judged to be extremely trophic or dystrophic. Uses of the lake as a fishery resource and as a source of domestic water supply are briefly discussed.

Diagnosing reservoir water quality using self-organizing maps and fuzzy theory

Since trophic status assessment of water quality is very important for the water resources management, the assessment results obtained from using only one parameter may easily mislead or bias the decision makers or managers. Even when using a multivariable index, how to determine the weights of all factors is debatable. In this research, one complementary evaluation method, self-organizing map (SOM), for diagnosing water quality has been used to develop a trophic state classifier and is illustrated with a case study of trophic status assessment for Fei-Tsui Reservoir in Taiwan. The historical database was collected from the management agency of Fei-Tsui Reservoir from 1987 to 1995. The results of SOM are compared with those of the Carlson index and Fuzzy synthetic evaluation, showing that the inconsistent records can be mapped to the conflicting data zone of the SOM output map. In addition, SOM creates a diagnostic axis on the map to express the trophic status of the water body. As long as the SOM model is well-trained, new records can be assessed and classified as either one of three trophic levels or special cases. If special water quality conditions are expressed on the SOM output, those data can reveal that either total phosphorus (TP) or chlorophyll A (chl a) is higher than usual.

Classification, assessment and trophic reconstruction of Danish lakes using chironomids

1. Surface‐sediment assemblages of subfossil chironomid head capsules from fifty‐four primarily shallow and nutrient‐rich Danish lakes were analysed using multivariate numerical techniques. The species data, comprising forty‐one chironomid taxa, were compared to environmental monitoring data in order to establish a relationship between chironomid faunal composition and lake trophic state.2. The subfossil assemblages were compared to the chironomid bathymetric distributions along transects from four lakes. Correspondence analysis and similarity coefficients showed that the subfossil assemblages, sampled in the lake centre, reflect the chironomid communities in the littoral at a depth of 2–7 m.3. Two‐way indicator species analysis (TWINSPAN) was used to classify the Danish lakes into five groups defined by trophic state, lake depth and pH. Eighteen chironomid taxa showed significant differences in abundance among the five groups. Canonical correspondence analysis (CCA) showed the chlorophyll a concentration ([Chl a]) and Secchi depth to be the variables best correlated to the faunal data, and fourteen taxa were significantly correlated to [Chl a].4. The strong correlation between chironomid data and the ln‐transformed ([Chl a]) was used to create a weighted averaging (WA) model to infer lake trophic state. Several models were tested by cross validation (leave‐one‐out jack‐knifing), and a simple WA model using inverse de‐shrinking had a RMSEPjack of 0.65 (ln units) and a r2jack of 0.67.5. The results can be used in the assessment and reconstruction of lake trophic state for long‐term monitoring and palaeoecological investigations of shallow, temperate lakes in the mesotrophic to hypertrophic nutrient range.

Analysis of reservoir water quality using fuzzy synthetic evaluation

A general methodology for fuzzy synthetic evaluation is developed and illustrated with a case study of trophic status assessment for Fei-Tsui Reservoir in Taiwan. The historical data base was collected from the management agency of Fei-Tsui Reservoir from 1987 to 1996. In fuzzy synthetic evaluation, the classification is determined by a matrix operation of the weighted vector with the fuzzy evaluation matrix. After all individual membership functions of evaluated factors have been determined, the fuzzy evaluation matrix can be established. The weighted vector is determined by the analytic hierarchy process method (AHP). The results of this investigation show that the long-term change of water quality and the overturn phenomena cannot be observed with the Carlson index from 1987 to 1992 but is expressed by fuzzy synthetic evaluation. Fuzzy synthetic evaluation is better suited than the Carlson index to rating the trophic status of self-sustaining lakes. Interpretation of the results can provide valuable information to decision makers and aid reservoir management.

Comparative ecosystem trophic structure of three U.S. mid-Atlantic estuaries

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 161:239-254 (1997) - doi:10.3354/meps161239 Comparative ecosystem trophic structure of three U.S. mid-Atlantic estuaries Mark E. Monaco1,*, Robert E. Ulanowicz2 1NOAA - N/ORCA 1, 1305 East-West Highway, Silver Spring, Maryland 20910-3281, USA 2University of Maryland, Chesapeake Biological Laboratory, Box 38, Solomons, Maryland 20688, USA *E-mail: mark.monaco@noaa.gov Quantitative networks of trophic exchanges offer the potential to compare food webs from neighboring ecosystems in order to ascertain whether large differences and similarities exist in trophic structure and function. Network analysis was invoked to compare the exchanges of carbon in 3 mid-Atlantic estuaries on the eastern U.S. coast: the Narragansett, Delaware, and Chesapeake Bays. Narragansett Bay exhibited the highest average annual rate of net primary production, followed by Delaware and Chesapeake Bays. Taken in combination, the analyses of cycling structures (magnitude of flows, average carbon cycle lengths), organization of carbon flows, system production:biomass ratios, and harvest rates all indicated that the Delaware and Chesapeake Bay ecosystems are more stressed than that of Narragansett Bay. To differentiate between the former two, a combination of measures of system efficiency, cycling structure, and food web connectivity was employed. The results indicated that Delaware Bay is currently less impacted and has potentially more ability to mitigate perturbations to its food web than does Chesapeake Bay. Overall, network analysis proved to be a suitable methodology for making inter-estuarine ecosystem comparisons, and for providing useful insights to natural resource managers in the assessment of estuarine trophic structure and status. Network analysis · Food webs · Carbon flows · Estuaries Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 161. Publication date: December 31, 1997 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1997 Inter-Research.

Trophic State Evaluation of Jackson Lake in Grand Teton National Park

This study is the continuation of an evaluation of the trophic state of lakes located in Grand Teton National Park, Wyoming. The original 1995 study was motivated by concern that the water quality of the lakes within the Park may be declining due to increased human usage over the past several years. A trophic state evaluation, featuring nutrient and chlorophyll-a analyses, was chosen because it is believed to be a sound indicator of the lakes' overall water quality. In this 1996 study, a thorough evaluation was made of Jackson Lake. This summary is taken from the complete 100 page report which is available from Woodruff Miller at Brigham Young University or Hank Harlow at the University of Wyoming. In most cases water samples were taken four times during the summer of 1996, in June, July, August, and October. Jackson Lake was sampled at eight different locations on thesurface and at depths near the bottom. The lake inlet and outlet were also sampled four times. Jackson Lake was sampled from a motor boat which also provided a means to measure the lake transparency and depth. The chlorophyll-a and nutrient concentrations were analyzed by the Utah State Health Department, Division of Laboratory Services. Jackson Lake was evaluated using the models of Carlson, Vollenweider, and Larsen­Mercier. The nature of the Larsen-Mercier and Vollenweider models, based on system inflow and outflow data, is such that they yield one trophic state assessment of the lake per inflow and outflow sample set. The Carlson Trophic State Indices (TSI), on the other hand, are based on in situ properties of the water at any point in the lake. Consequently, while there are four Vollenweider and four Larsen-Mercier evaluations for Jackson Lake, individual Carlson evaluations were made for the eight sample sites around the lake at the surface and at depth, and an evaluation for the lake as a whole was constructed using averages taken from the site evaluations. This allowed us to examine the relative water quality of different portions of the lake at different time periods.

Trophic State Evaluation of Jackson Lake in Grand Teton National Park

This study is the continuation of an evaluation of the trophic state of lakes located in Grand Teton National Park, Wyoming. The original 1995 study was motivated by concern that the water quality of the lakes within the Park may be declining due to increased human usage over the past several years. A trophic state evaluation, featuring nutrient and chlorophyll-a analyses, was chosen because it is believed to be a sound indicator of the lakes' overall water quality. In this 1996 study, a thorough evaluation was made of Jackson Lake. This summary is taken from the complete 100 page report which is available from Woodruff Miller at Brigham Young University or Hank Harlow at the University of Wyoming. In most cases water samples were taken four times during the summer of 1996, in June, July, August, and October. Jackson Lake was sampled at eight different locations on the surface and at depths near the bottom. The lake inlet and outlet were also sampled four times. Jackson Lake was sampled from a motor boat which also provided a means to measure the lake transparency and depth. The chlorophyll-a and nutrient concentrations were analyzed by the Utah State Health Department, Division of Laboratory Services. Jackson Lake was evaluated using the models of Carlson, Vollenweider, and Larsen-Mercier. The nature of the Larsen-Mercier and Vollenweider models, based on system inflow and outflow data, is such that they yield one trophic state assessment of the lake per inflow and outflow sample set. The Carlson Trophic State Indices (TSI), on the other hand, are based on in situ properties of the water at any point in the lake. Consequently, while there are four Vollenweider and four Larsen-Mercier evaluations for Jackson Lake, individual Carlson evaluations were made for the eight sample sites around the lake at the surface and at depth, and an evaluation for the lake as a whole was constructed using averages taken from the site evaluations. This allowed us to examine the relative water quality of different portions of the lake at different time periods.

An assessment of the sources of error in estimations of bulk sedimentary pigment concentrations and its implications for trophic status assessment

Pigment concentrations in surface sediments in two lakes were analysed on ten occasions over a year. Statistical analysis showed that mean concentrations varied through the year and the relative contribution of several sources of variability (analytical, spatial, temporal) to the total was estimated. Using this information, the relative cost-effectiveness of several alternative sampling strategies was investigated. Measurement of sedimentary pigment concentrations on single cores on two or three different occasions would reduce the standard error of the mean by 30% and 42% respectively and is very cost effective. However replicate cores taken on a single occasion appeared to be a workable compromise. The data also allowed a comparison of the ability of the different pigment determinands to resolve two lakes of very different trophic status. Total carotenoid concentrations were found to be the most effective.

A classification of freshwater Louisiana lakes based on water quality and user perception data

An index system developed for Louisiana lakes was based on correlations between measurable water quality parameters and perceived lake quality. Support data was provided by an extensive monitoring program of 30 lakes coordinated with opinion surveys undertaken during summer 1984. Lakes included in the survey ranged from 4 to 735 km(2) in surface area with mean depths ranging from 0.5 to 8.0 m. Water quality data indicated most of these lakes are eutrophic, although many have productive fisheries and are considered recreational assets. Perception ratings of fishing quality and its associated water quality were obtained by distributing approximately 1200 surveys to Louisiana Bass Club Associaton members. The ability of Secchi disc transparency, total organic carbon, total Kjeldahl nitrogen, total phosphorus, and chlorophyll a to discriminate between perception classes was examined using probability distributions and multivariate analyses. Secchi disc and total organic carbon best reflected perceived lake conditions; however, these parameters did not provide the discrimination necessary for developing a quantitative risk assessment of lake trophic state. Consequently, an interim lakes index system was developed based on total organic carbon and perceived lake conditions. The developed index system will aid State officials in interpretating and evaluating regularly collected lake quality data, recognizing potential problem areas, and identifying proper management policies for protecting fisheries usage within the State.

Methods of Assessing the Trophic State of Lakes and Reservoirs

A review is undertaken of various methods of assessment of trophic state in lakes and reservoirs. Input-output models, multi-layer models and trophic state indices are evaluated. Future development of multi-layer models and the use of biological indicators as contributors to compound trophic state indices is advocated.

A Chlorophyll a Trophic Status Classification System for South African Impoundments

AbstractChlorophyll a data from 24 South African impoundments were examined with the objective of developing a trophic status classification system. For the combined data set, standard deviation of the mean annual chlorophyll a concentration displayed an almost 1:1 linear relationship to the mean, indicating a wide annual variation in chlorophyll a for most impoundments. There appeared to be no common seasonal pattern to the occurrence of chlorophyll a maxima and minima, leading to the conclusion that trophic status was best described by a statistical parameter based on annual data (notably the mean value). Statistically significant empirical formulae that relate both the maximum value and the frequency of occurrence of specific chlorophyll a ranges to the mean annual value were established, and their potential use in the assessment of trophic status and impoundment management is described.

Assessment of Trophic State of Lakes: A Case of Mansi Ganga Lake in India

Due to rapid growth of population coupled with urbanization, the water bodies, especially, rivers, lakes, ponds, reservoirs etc are deteriorating due to heavy pollutational stresses resulting in the scarcity of drinking water resources. The present paper attempts to review the work done on the development of TSI for assessment of trophic state of lakes and applicability of most important TSI methods for Indian lakes. The paper also deals with the revival of Mansi Ganga Lake in Mathura, especially, assessment of its trophic state based on the data collected for 2006-09. The results indicated that the lake was oligotrophic during 2006 which has become mesotrophic in the year 2008 showing increase in pollution. After the chemical treatment for the removal of algae, the lake water was drained and results of sampling done in 2009 (pre-monsoon) indicated it to be eutrophic. These calls for its immediate revival and accordingly, the conservation measure are suggested.Key words: Eutrophication; Trophic State Index (TSI); Total Phosphorus (TP); Secchi depth (SD); Chlorophyll ‘a’ (Chl’a’)DOI: 10.3126/hn.v6i0.4198Hydro Nepal Journal of Water, Energy and Environment Vol. 6, January 2010Page: 65-72Uploaded Date: 24 January, 2011

PLANKTONIC ALGAE AS INDICATORS OF LAKE TYPES, WITH SPECIAL REFERENCE TO THE DESMIDIACEAE

The biological classification of lakes is briefly reviewed and the value and limitations of phytoplankton quotients for the assessment of trophic status are discussed. Comparisons are made between quotient determinations and the characterization of lakes in terms of their dominant phytoplankton species. The sensitivity of algal plankton to changes in water chemistry is examined in the light of experiments with mineral fertilizers and observations of natural or seminatural eutrophication. Special attention is paid to the use of desmids as indicators of trophic status. Studies of the British freshwater plankton have shown that many taxa of this supposedly oligotrophic algal group are most frequently associated with eutrophic waters.