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Titre du document / Document title

Physical and chemical conditions surrounding the diurnal vertical migration of Cryptomonas spp. (Cryptophyceae) in a seasonally stratified MidwesternReservior (USA)

Auteur(s) / Author(s)

KNAPP Charles W. ; DENOYELLES Frank ; GRAHAM David W. ; BERLIN Sean ;

Résumé / Abstract

Cross Reservoir, a small mesotrophic reservoir located at the University of Kansas Ecological Reserves (Kansas, USA), contained a dense metalimnetic community of algae and photosynthetic bacteria between early July and late October 1997-1999. Within this community, various Cryptomonas species, primarily C. erosa (Ehrenberg), C. erosa var. reflexa (Marsson), and C. rostratisformis (Skuja), diurnally migrated as indicated by in situ fluorescence monitoring and direct phytoplankton enumeration. The Cryptomonas spp. typically resided near the oxic-anoxic boundary of the water column; however, they actively migrated upward during the day and descended to lower anoxic locations at night, apparently responding to diurnal changes in their local habitat. Their nocturnal environment had moderate levels of sulfide, elevated secondary nutrients, and a community of anoxygenic phototrophic bacteria, whereas their daytime environment had higher light, lower nutrients, and no local photosynthetic bacteria. Monitoring indicated that the Cryptomonas spp. migration was generally linked to daily variations in absolute light intensity (e.g. sunny vs. cloudy days) and the level of other potentially growth-limiting resources, particularly nitrogen and phosphorus. However, further analyses showed that the primary factor that determined whether the Cryptomonas spp. migrated or not on a given day was the slope of the light gradient immediately above the Cryptomonas spp. peak.

Revue / Journal Title

Journal of phycology    ISSN  0022-3646   CODEN JPYLAJ 

Source / Source

2003, vol. 39, no5, pp. 855-861 [7 page(s) (article)]

Langue / Language

Anglais

Editeur / Publisher

Blackwell, Malden, MA, ETATS-UNIS  (1965) (Revue)

Localisation / Location

INIST-CNRS, Cote INIST : 12833, 35400011330058.0040

Nº notice refdoc (ud4) : 15199119



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