A. Quesada et al., SEASONAL-VARIATIONS IN THE PHYSICAL AND CHEMICAL CHARACTERISTICS OF ASHALLOW-WATER ECOSYSTEM, THE RICEFIELDS OF VALENCIA, SPAIN, Archiv fur Hydrobiologie, 132(4), 1995, pp. 495-511
A study was made of the physical and chemical features of the ricefiel
ds from ''La Albufera'' (East Spain) with a view to improving the unde
rstanding of this complex ecosystem. The results show the association
of the measured variables in 3 factors: water mineralization, biologic
al (photosynthetically) related variables, and the nutritional factor,
including P and N concentrations. Water mineralization variables were
the most descriptive for each type of system. Calcium concentration c
an discriminate groups of water qualities in this system. Mineralizati
on variables increased through the crop. On the other hand the biologi
cal factor showed a very close relationship with photon flux density v
ariation along the crop; dissolved O-2 and pH decreased, but CO2 incre
ased. The nutritional factor indicated elevated mean values for nutrie
nts (N and P), but did not show an unique pattern of variation, indica
ting the strong influence of agricultural fertilization on the physico
chemical features.