Littérature scientifique sur le sujet « Trophic index TRIX »

Abstract. The main scope of the Marine Strategy Framework Directive is to achieve good environmental status (GES) of the EU's marine waters by 2020, in order to protect the marine environment more effectively. The trophic index (TRIX) was developed by Vollenweider in 1998 for the coastal area of Emilia-Romagna (northern Adriatic Sea) and was used by the Italian legislation to characterize the trophic state of coastal waters. We compared the TRIX index calculated from in situ data (“in situ TRIX”) with the corresponding index simulated with a coupled physics and biogeochemical numerical model (“model TRIX”) implemented in the overall Adriatic Sea. The comparison between in situ and simulated data was carried out for a data time series on the Emilia-Romagna coastal strip. This study shows the compatibility of the model with the in situ TRIX and the importance of the length of the time series in order to get robust index estimates. The model TRIX is finally calculated for the whole Adriatic Sea, showing trophic index differences across the Adriatic coastal areas.

EUTROPHICATION ASSESSMENT METHOD FOR COASTAL WATER USING TROPHIC INDEX (TRIX). Eutrophication, a process in which water bodies experience excessive growth of aquatic plants due to accumulation of land-originated nutrients especially phosphorus and nitrogen, has become a worldwide coastal environmental problem. Its negative impacts have been well known including oxygen depletion, harmful algal blooms, biodiversity reduction and ecosystem degradation. Unfortunately, the occurrence of those impacts is often not well anticipated as the instruments for assessing the quality of coastal and marine environment are weak and hardly available. Therefore, there has been a growing concern in developing appropriate methods for assessing coastal and marine eutrophication. One of the most widely used methods is trophic index (TRIX) due to its good efficacy. However, it is still questionable whether TRIX is a universal index of eutrophication or the scaling of TRIX should be region specific.

Abstract Salas, F., Teixeira, H., Marcos, C., Marques, J. C., and Pérez-Ruzafa, A. 2008. Applicability of the trophic index TRIX in two transitional ecosystems: the Mar Menor lagoon (Spain) and the Mondego estuary (Portugal). – ICES Journal of Marine Science, 65: 1442–1448. Ecological indicators are commonly used to provide synoptic information about the state of ecosystems. Their main attribute is that they combine a range of environmental factors in a single value, which is thought useful for management and for making ecological-quality concepts easily understandable by the general public. In some European countries, the trophic state of marine and coastal waters is characterized using the trophic index TRIX. We used TRIX in the studies of the Mar Menor coastal lagoon (southeast Spain) and the Mondego estuary (northwest Portugal). These areas are under environmental stress, and eutrophication processes have been monitored in recent years. The results demonstrate the inefficacy of TRIX as a trustworthy tool to classify eutrophication status in estuarine waters. The causes of the malfunction of the index are discussed, and we suggest that, if the index is to be applied over wide areas, the classification criteria will have to be adapted to specific environments.

Eutrophication of littoral seawater is estimated to be one of the main threats to marine biota. Therefore, continuous monitoring is necessary to define areas of potential risk. Our work is an essay to explore the possibility of applying the trophic state index (TRIX) to assess the state of eutrophication along the eastern coast of the Moroccan Mediterranean (Ras Kabdana-Saïdia) in concert with a number of hydro chemical parameters and nutrients descriptors aimed at selection of relevant indicators of marine coastal area ecological quality. Seawater samples were studied monthly during 2018. The following environmental parameters have been considered: temperature, salinity, pH, suspended matter, turbidity, dissolved oxygen, saturation levels, nitrite, nitrate, and orthophosphate. Principal Component Analysis was applied in order to figure out and score the most relevant combination of parameters to discriminate between sites and select representative descriptors (pressure/state) of eutrophication. The following variables are defined as relevant descriptors for classification of the sites: nutrients (N, P) and their molar ratios (N/P), the capacity of the system to produce and sustain organic matter (chlorophyll a), and the trophic state index (TRIX). The results show TRIX values below 4, the eutrophication range indicated that there is no ecological risk. The Ras Kabdana-Saïdia is located in an oligotrophic state.

This paper provides evidence of the effects of urban wastewater discharges on the trophic state and environmental quality of a coastal water body in a semiarid subtropical region in the Gulf of California. The concentrations of dissolved inorganic nutrients and organic matter from urban wastewater primary treatment were estimated. La Salada Cove was the receiving water body and parameters measured during an annual cycle were temperature, salinity, dissolved oxygen, nitrite, nitrate, ammonia, orthophosphate, and chlorophylla. The effects of sewage inputs were determined by using Trophic State Index (TRIX) and the Arid Zone Coastal Water Quality Index (AZCI). It was observed that urban wastewater of the city of Guaymas provided 1,237 ton Nyr−1and 811 ton Pyr−1and TRIX indicated that the receiving water body showed symptoms of eutrophication from an oligotrophic state to a mesotrophic state; AZCI also indicated that the environmental quality of the water body was poor. The effects of urban wastewater supply with insufficient treatment resulted in symptoms of eutrophication and loss of ecological functions and services of the coastal ecosystem in La Salada Cove.

The present paper is an attempt to test the applicability of the trophic state index (TRIX) for scaling the eutrophication along the Bulgarian Black Sea coastal zone in concert with a number of chemical and biological descriptors aimed at selection of relevant indicators of marine coastal area ecological quality. The following environmental parameters have been considered: to, salinity, nutrients - inorganic P, N and dissolved Si, dissolved oxygen and oxygen saturation, phytoplankton - taxonomic structure, abundance and biomass, chlorophyll a, zooplankton - taxonomic structure, abundance and biomass. Principal Component Analysis was applied in order to figure out and score the most relevant combination of parameters to discriminate between sites and select representative descriptors (pressure/state) of eutrophication. The following variables are defined as relevant descriptors for classification of the sites: nutrients (N, P, Si) and their molar ratios (N:P and Si:P), the capacity of the system to produce and sustain organic matter (chlorophyll a, phytoplankton biomass), phytoplankton taxonomic dominance (Bacilariophyceae:Dinophyceae biomass ratio), grazing pressure (phytoplankton:zooplankton biomass, Bacilariophyceae:Copepoda), plankton diversity index (Hb and Ha) and the trophic state index (TRIX). The investigated sites under a different anthropogenic impact are classified according to selected descriptors and their water quality state.

Implementation of Trophic Status Index in Brackish Water Quality Assessment of Baltic Coastal Waters The assessment of the trophic state of marine coastal waters is one of the leading initiatives declared in the European Water Framework Directive (WFD). The Baltic Sea is a semi-enclosed ecosystem which consists of subregions with wide salinity and seasonality gradients. Anthropogenic impact results in eutrophication processes on different scales. Efficient eutrophication control and environmental management in the Baltic Sea, according to WFD, requires a prerequisite of common and sensitive indicators for the European coastal waters including the Baltic Sea. In this article the Trophic Status Index TRIX, recently succcesfully implemented in Mediterranean and Northern European sea coastal waters as a holistic approach indicator, was implemented for the Gulf of Rīga and Latvian Baltic Sea coastal water quality assessment between 1999 and 2005.

Tujuan dari penelitian ini adalah untuk mengetahui tingkat kesuburan perairan berdasarkan indeks TRIX (Trophic Index), serta kondisi perairan fisika, kimia dan biologi di Perairan Kampung Madong Kelurahan Kampung Bugis Kota Tanjungpinang. Penelitian ini dilakukan dengan metode survei sebanyak 15 titik sampling pada saat surut dan 15 titik sampling pada saat pasang pada titik koordinat yang sama. Hasil penelitian ini menunjukkan kualitas perairan Kampung Madong baik parameter fisika maupun kimia pada saat pasang dan surut masih berada pada kriteria sesuai menurut KEPMEN LH No. 51 Tahun 2004 tentang baku mutu air laut untuk biota, namun untuk parameter Nitrat dan Fosfat tidak memenuhi baku mutu. Nilai tingkat kesuburan Perairan Kampung Madong berdasarkan nilai indeks TRIX yaitu pada saat pasang terdapat nilai 4,74 yang tergolong sedang (mesotrofik), sedangkan tingkat kesuburan di Perairan Kampung Madong pada saat surut terdapat nilai indeks TRIX 5,18 yang tergolong tinggi (eutrofik).

Le aree costiere sono sottoposte a pressioni antropogeniche e ai cambiamenti climatici. Negli ultimi venti anni, il concetto di gestione integrata della zona costiera ben presente nelle diverse azioni politiche, manca degli strumenti a supporto degli sforzi di pianificazione e gestione, specialmente nelle aree di estuario dove gli effetti dei bacini fluviali sulle zone costiere sono poco evidenziati nella maggior parte delle implementazioni. Gli ambienti costieri costituiscono un ambiente dinamico influenzato da input continentali sia naturali che antropogenici e controllato da fattori idrodinamici e climatici. Alcune zone costiere sono, con la loro geografia e geomorfologia, un recettore in cui sono presenti corpi idrici carichi di minerali esogeni e / o di materia organica derivanti dall'attività antropica. Il tempo di permanenza di questi corpi idrici è legato all'intensità delle correnti marine che controlla la distribuzione e la diluizione delle sostanze disciolte che possono influenzare l'ecosistema. Al fine di valutare lo stato trofico delle acque marine costiere del Mediterraneo, la Direttiva Quadro sulle Acque (DQA) richiedeva il monitoraggio della concentrazione di Clorofilla-a (Simboura et al., 2005) e l'indice trofico TRIX proposto da Vollenweider et al. (1998), che tiene conto delle sostanze nutritive complessive, della clorofilla e dell'ossigeno disciolto nell'ambiente. I nostri risultati hanno fornito la classificazione dello stato di qualità ecologica (EQS) dei tre siti Sonactere, Cheliff e Sokhra rispettivamente come stato Scadente, in base alla concentrazione di clorofilla, e come Cattivo, secondo l'indice trofico (TRIX). Le acque costiere di Mostaganem nell'Algeria occidentale mostrano una situazione di grave eutrofizzazione. Tuttavia, per capire meglio lo stato dell'ecosistema, è essenziale esplorare l'intera area costiera di Mostaganem per un lungo periodo. Gli indici Chl-a e TRIX sono stati sviluppati per le regioni del Mediterraneo, ma dovrebbero essere adattati alle condizioni locali in modo che siano pertinenti e più affidabili e rappresentativi, dato l'aspetto eterogeneo delle zone costiere del Mediterraneo.
Coastal areas are under anthropogenic and climate change pressures. During the last twenty years, the concept of Integrated Coastal Zone Management, as provides the overall policy frames, but tools supporting the planning and management efforts are almost lacking, especially in the estuary areas where the effects of river basins on coastal zones are nearly absent in most implementations. Coastal environments constitute a dynamic environment influenced by both natural and anthropogenic continental inputs and controlled by hydrodynamic and climatic factors. Some coastal zones are, by their geography and geomorphology, a receptor where are trapped water bodies loaded with exogenous mineral and /or organic matter resulting from the anthropic activity. The residence time of these water bodies is related to the sea currents intensity which controls the distribution and dilution of dissolved substances that can unbalance the ecosystem. In order to assess the trophic status of coastal Mediterranean marine waters, the Water Framework Directive (WFD) required the monitoring of the Chlorophyll-a concentration (Simboura et al., 2005) and the trophic index TRIX proposed by Vollenweider et al. (1998), which takes into account the overall nutrients, chlorophyll-a, and dissolved oxygen in the environment. Our results highlighted the ranking of the ecological quality status (EQS) of the three sites Sonactere, Cheliff, and Sokhra as bad according to the Chlorophyll concentration and as Poor status according to trophic index (TRIX). The coastal waters of Mostaganem in western Algeria have proved to be in a situation of severe eutrophication. However, to better understand the state of the ecosystem, it is essential to explore the entire coastal area of Mostaganem over a long period. The Chl-a and TRIX index were developed for Mediterranean regions but it should be adapted to local conditions so that it is relevant and more reliable and representative, given the heterogeneous aspect of the Mediterranean coastal zones.