Precision Measurements of UVB global irradiance in 5‐nm‐wide spectral bands centered from 290 to 320 nm were made continuously from September 1975 through December 1990. The spectral radiometer was calibrated at roughly monthly intervals. Annual maximum monthly means for total daily radiation, radiation at solar noon, and clear sky radiation at small secants all were observed to be significantly higher during the period from 1983 through 1989. The maximum monthly mean of integrated 295–320 nm total daily radiation in 1986 was 29% above the long‐term mean, 47% above the maximum in 1982, and 54% above the mean maxima for 1979–1982. These interannual changes were largest for the shorter wavelengths but were significant for all spectral bands. Interannual variations in clear sky radiation were largest at small secants. For maximum monthly means of integrated 295–320 nm flux, the secant 1.2 maximum in 1989 was 19% above the long‐term mean and the average of the maxima during 1983–1989 was 13% above the long‐term mean.
A laboratory method is presented for studying zooplankton swimming behaviors such as phototaxis and photokinesis . The method attempts to standardize laboratory conditions and to minimize the effects of several phenomena which modify zooplankton behavior . The role of angular light distribution in zooplankton behavior is discussed, and an apparatus which simulates a natural underwater light environment is described . The procedure minimizes the fluctuations in zooplankton swimming speed and vertical distribution that are caused by large light stimuli, noise, food deprivation, endogenous rhythms, and other factors . The experimental animals were viewed remotely with the aid of a light amplifier and video camera . A mathematical equation and computer program for calculating three-dimensional swimming speeds of zooplankton from video recordings are described in detail .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.