Article

Ecotoxicology

, Volume 18, Issue 8, pp 1087-1094

First online:

Intracellular and extracellular ammonium (NH4 +) uptake and its toxic effects on the aquatic biomonitor Fontinalis antipyretica

  • Ana Rute VieiraAffiliated withFaculty of Sciences, Centre for Environmental Biology (CBA), University of Lisbon
  • , Carla GonzalezAffiliated withFaculty of Sciences, Centre for Environmental Biology (CBA), University of LisbonCENSE-ECOMAN—Centre for Environmental and Sustainability Research, Ecological Economics and Environmental Management Group, Faculty of Sciences and Technology, New University of Lisbon, Edifício Departamental
  • , Maria Amélia Martins-LouçãoAffiliated withFaculty of Sciences, Centre for Environmental Biology (CBA), University of LisbonBotanical Garden, Natural History Museum, University of Lisbon
  • , Cristina BranquinhoAffiliated withFaculty of Sciences, Centre for Environmental Biology (CBA), University of Lisbon Email author 

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Abstract

The objective of this work is to validate the use of the aquatic moss Fontinalis antipyretica as biomonitor of NH4 + aquatic pollution. In order to achieve this objective we needed to understand the pattern of uptake of NH4 + by the moss and evaluate the impact of high concentrations on its physiological performance. The cellular location of NH4 + in the moss is crucial for understanding its monitoring capacity. We were able to show that a sequential elution technique, based on the use of NiCl2 as an efficient displacing agent, allowed the quantification of the cellular location of NH4 +. This was done along a concentration gradient and time of exposure. The extracellular and intracellular NH4 + concentrations that caused significant physiological impact in membrane permeability of F. antipyretica were the same that caused significant decreasing in the photosynthetic capacity of the same moss. The former NH4 + concentration thresholds were shown to decrease with increasing exposure time. These results are important since under natural conditions lower concentration of NH4 + are present in waters but for very long periods of time. The importance of applying this knowledge in biomonitoring studies to fulfil the requirements of the Water Framework Directive is discussed.

Keywords

Water pollution Mosses Eutrophication Mediterranean streams Cellular location Fluorescence of chlorophyll a