ISSN:
1573-5117
Keywords:
Daphnia
;
digestibility
;
grazing
;
nutrient limitation
;
phytoplankton
;
UV-B
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Daphnia magna was fed the green alga Selenastrum capricornutum, cultured under four different growth conditions: (1) phosphorus limitation, (2) nitrogen limitation, (3) UV-B irradiation, and (4) no nutrient limitation, no UV-B irradiation. Contrary to non-limited algal cells, nutrient-limited cells were not efficiently assimilated. Especially, P-limited cells passed through the gut mostly intact, while N-limited cells were partly assimilated. Also, algae exposed to moderate doses of UV-B radiation (0.3 mW cm−2 of UV312) were less efficiently assimilated after being grazed. Digestibility of the algae decreased with increased UV-B exposure time. Nutrient-limited and UV-B stressed algal cells increased in volume and became granular in appearance. These changes in the algal cells, combined with changed cell wall properties, most probably reduced their digestibility.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00032006
Permalink
