Estimation of the annual primary production of stream epilithic biofilms based on photosynthesisirradiance relations
Guasch, Helena; Sabater, Sergi
Archiv für Hydrobiologie Volume 141 Number 4 (1998), p. 469 - 481
published: Mar 24, 1998
ArtNo. ESP141014104006, Price: 29.00 €
The main objective of this study was to estimate annual primary production in two undisturbed streams: La Solana (LS) and Riera Major (RM). Using hourly values of irradiance, community-specific photosynthesis irradiance relations (P-I) measured in the laboratory were used to estimate areal net and gross primary production over an annual cycle. The model (referred to as P-I model), showed good agreement (r2= 0.53 and r2= 0.62, p <0.001 for ls and rm, respectively) between estimated values and those measured in the field. the p-i model was also applied to estimate annual primary production after nutrient enrichment. annual primary production was 50 gc m-2y-1 for RM and 157 gC m-2y-1 for LS before nutrient addition, but increased to 440 gC m-2y-1 after nutrient addition. Light conversion efficiency (Ef) was higher for RM (0.25 %) than for LS (0.16%) and it was significantly enhanced after nutrient additions (0.55 %). A comparison between the annual primary production values obtained in this study with those from other lotic systems in different climatic zones indicated that stream order, nutrient concentration and light availability are probably more important than climate type in determining annual values of primary production in fluvial systems.