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Average nutrient and chlorophyll distributions in the western Mediterranean : RADMED Project

García-Martínez María del Carmen, Vargas-Yáñez Manuel, Moya Francina, Santiago Rocío, Muñoz María, Reul Andreas, Ramírez Teodoro, Balbín Rosa

Oceanologia

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2019

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No. 61 (1)

143--169

EN

Because of its reduced dimensions and its location, surrounded by three continents, the Mediterranean Sea could be especially vulnerable to climate change effects. An increase of the water column stratification could inhibit winter mixing and reduce the frequency and intensity of convection processes which inject nutrients into the photic layer and are responsible for the ventilation of deep waters. In this context, the long-term monitoring of the Mediterranean waters is a basic task. The RADMED project is a monitoring program that covers the waters from the eastern side of the Gibraltar Strait to the Catalan and Balearic Seas. This project was initiated in 2007, merging some previous programs, some of them initiated in 1992. The main objective of this project is to establish average distributions, ranges of variability and long-term trends for physical, and biochemical variables which could be considered as indicative of the environment al state of the sea. The present work analyses nutrient, chlorophyll and oxygen time series from 2007 to 2015 in some cases and from 1992 in other cases. The current analyses show a clear trop hic gradient in the RADMED area. Nutrient and chlorophyll concentrations and the intensity of the deep chlorophyll maximum decrease northeastward. The deep chlorophyll maximum depth increases to the northeast. The Balearic and Catalan Seas show a clear seasonal pattern with maximum surface concentrations for nutrients and chlorophyll in winter/spring, associated with winter mixing. On the contrary, the Alboran Sea does not show such a clear seasonal cycle, probably because of the existence of permanent upwelling processes acting along the whole year. The Atlantic Water occupying the upper part of the water column shows a Redfield N:P ratio close to or lower than 16, indicating no phosphorus limitation. Finally, chlorophyll concentrations seem to have increased from 1992 to 2015 in the Alboran Sea, while no long term changes could be established for the rest of the variables and geographical areas.

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Skuteczność koagulacji kontaktowej w usuwaniu substancji biogennych z wody

Świderska-Bróż M., Wolska M.

Ochrona Środowiska

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2010

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Vol. 32, nr 2

3-7

PL

Jednym z głównych warunków, jakie należy spełnić, aby zapobiec wtórnemu rozwojowi mikroorganizmów (głównie bakterii) w sieci wodociągowej jest zapewnienie stabilności biologicznej wody wprowadzanej do systemu dystrybucji. W tym celu z oczyszczanej wody muszą być usunięte w jak największym stopniu nieorganiczne związki azotu i fosforu oraz biodegradowalne rozpuszczone substancje organiczne (BRWO), a głównie ich frakcje przyswajalne przez mikroorganizmy (PWO). W artykule przedstawiono wyniki badań nad skutecznością procesu koagulacji kontaktowej w usuwaniu organicznych i nieorganicznych substancji biogennych z mieszaniny wody podziemnej (po napowietrzaniu) i powierzchniowej (po mikrocedzeniu). Stwierdzono, że koagulacja kontaktowa siarczanem żelaza(III) przyczyniła się do znacznego usunięcia fosforanów z wody. Nieorganiczne związki azotu były w tym procesie usuwanie w znacznie mniejszym stopniu. Jednocześnie najmniej skutecznie usuwana była z wody biodegradowalna frakcja związków organicznych, a najskuteczniej nierozpuszczony i rozpuszczony węgiel organiczny. Wykazano, że proces koagulacji kontaktowej w analizowanym przypadku nie zapewnił usunięcia substancji biogennych do wartości zapewniających stabilność biologiczną wody oczyszczonej.

EN

An essential prerequisite for preventing the regrowth of microorganisms (specifically bacteria) in the water-pipe network is the biological stability of the water supplied to the distribution system. To achieve this goal, it is necessary to aim at the highest possible removal of inorganic nitrogen compounds, inorganic phosphorus compounds and biodegradable dissolved organic carbon (BDOC) - particularly their fractions assimilable for microorganisms (AOC) - from the water being treated. In this work, contact coagulation was investigated for efficiency in removing biogenic substances from a mixture of groundwater (after aeration) and surface water (after microfiltration). The study produced the following results. Contact coagulation with iron(III) sulfate provided noticeable removal of phosphates, and much lower removal of inorganic nitrogen compounds. At the same time, the lowest removal efficiency was obtained for the biodegradable fraction of organic compounds, and the highest extent of removal for insoluble organic carbon. It has been demonstrated that in the case under analysis the contact coagulation process failed to provide a reduction in biogenic substances to such a value that would guarantee a biological stability of the treated water.

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Phytoplankton based biomonitoring on Hungarian Upper-Tisa

Imre A.

Oceanological and Hydrobiological Studies

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2004

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Vol. 33, No. 2

57--62

EN

Phytoplankton based biomonitoring in Hungary actually includes its numbers, also saprobiological investigation and measurement of chlorophyll-a. Saprobiological analyses showed us 199 different described planktonic forms (including Ciliata, Bacteria, Flagellata apochromatica and Mycophyta), which were dominated usually by Diatoms. Other periods are characterised by equalized domination between phylla of algae. The highest numbers of algae were registered usually in summer season and the chlorophylla’s level showed explicit correlation with it. Classification on the content of chlorophyll-a must be corrected by a seasonal factor, according to changeable light conditions. Saprobity at every sampling places in all sampling time was showed the second or the third class of water quality, with only one exception at Záhony.