Ponsatí, Lídia; Barceló, D; Freixa, A; Guasch, H; Petrovic, M; Picó, Y; Corcoll, N; Ricart, M; Romaní, A.M; Tornés, E and Sabater, S.
Pollution in Mediterranean watersheds
• Seasonality and variability in rainfall.• Hydrology: floods and drought• High human pressures.
• Pollution for priority and emerging compounds
Epilithic biofilms:
• Epilithic biofilms are subject to river characteristics and respond veryquickly in front stress conditions.
Complex entity
Hypotheses:
Aims:
• Analyze the effects of chemical pollution in epilithic biofilms in Mediterranean watersheds.
• Understand the relevance of chemical pollution and environmental stress in structure and functioning of Mediterranean river biofilms.
• Environmental stressors explain the majors changes in biofilm structfrom headwaters to downstream.
• Chemical inputs affect efficiency in biofilm functions.
• Gradient of water quality decrease from EBRO – JÚCARGUADALQUIVIR – LLOBREGAT.
Study sites and samplig
5 sites in the main course acrochemical gradient –Autumn 20
LLOBREGATLLo3_Pont de VilomaLLo4_CastellbellLLo5_AbreraLlo6_MartorellLLo7_St Joan Despí
BRObr1_Reinosabr2_Mirandabr3_Harobr4_Mendaviabr5_Tudela
JÚCARJuc1_HúelamoJuc2_CuencaJuc4_MotillejaJuc6_AntellaJuc7_Alzira
GUADALQUIVIRGua1_MogónGua2_BaezaGua3_MarmolejoGua4_Córdoba
Physical and Chemical variables:
Pollutants analysis:
• Discharge (Q)• Conductivity (cond)• pH• Oxygen (O2 mg·L-1)• Temperature (TºC)
• Nutrient content• DIN (mg N · L-1)• TP (mg P· L-1)
• DOC (mg C · L-1)
Epilithic Biofilms:
Algal Biomass (Chl-a)Diatom composition (PCA cores)Photosynthetic efficiency
‐ Bacterial density‐ Extracellular enzymatic activity:
• Alkaline Phosphatase (AP)
St ti ti l l i
LLOBREGAT 4948.3kmLLOBREGATWater analysis: Nutrients and Conductivity
EBRO
Water analysis: Metals
Water analysis: Organic Pollutants
9166 n
Biofilm analysis
EBRO
LLOBREGAT
Biofilm analysis
GUADALQUIVIR
JÚCAR
Multivariate statistical analysis (RDA): Diatom responses
ance partitioning
3 groups
7.9%
OrganiccompoundsPhysical &
Chemical
Non explained51.9%
Explained variance48.1%
‐Pharm‐ED’s8.1%
‐Q‐Cond12.4% 4.8%
2.5%9.5%
Multivariate statistical analysis (RDA): Biological response
riance partitioning
2 groupsPhysical
and Chemical:
Organiccompounds
16.9%Non explained
38%
Explained variance 62%
-Q4.1%
-Pest-Pharm
41%
• The most polluted system was Llobregat River, for metals and organic pollutants
• In general, Biofilms response to pollution is related to watershed land uses.
• Agriculture in Júcar
• Industrial and Urban in Llobregat
• Diatoms community distribution is explained for both stressors (environmental and chemical) but mostly for discharge and conductivity (upstream to downstream).
• Biological parameters are significantly explained by organic pollutants (Pesticides and Pharmaceutics)
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