Premium
ULTRAVIOLET‐B RADIATION EFFECTS ON INORGANIC NITROGEN UPTAKE BY NATURAL ASSEMBLAGES OF OCEANIC PLANKTON 1
Author(s) -
Behrenfeld Michael J.,
Lean David R. S.,
Lee Henry
Publication year - 1995
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.0022-3646.1995.00025.x
Subject(s) - ammonium , plankton , biology , action spectrum , nitrogen , environmental chemistry , ultraviolet , nitrate , incubation , photosynthesis , botany , zoology , ecology , chemistry , biochemistry , materials science , optoelectronics , organic chemistry
Ultraviolet‐B radiation (UVBR: 290‐320 nm) inhibited ammonium uptake (p NH4 ) and nitrate uptake (p NO3 ) in natural plankton assemblages collected during a transect from 37° N to 55° N in the Pacific Ocean. Comparison of responses in p NH4 to ambient solar‐ and lamp‐enhanced UVBR spectra allowed calculation of an action spectrum for p NH4 inhibition. The slope of the action spectrum for Pnh 4 is half as steep as action spectra for UVBR inhibition of photosynthetic carbon uptake. Consequently, WBR‐induced photoinhibition of p NH4 extends to greater depths than inhibition of carbon fixation due to the greater relative effect of longer UVBR wavelengths. Inhibition of p NH4 was dependent upon UVBR dose when doses were weighted by the p NH4 action spectrum. Dependence of WBR inhibition of p NH4 on dose rate was not apparent. We found that near‐surface p NH4 and p NO3 can be overestimated in excess of 50% when measured using standard incubation vessels made of UVBR‐absorbing materials such as polycarbonate .