PDF Marine_Freshwat...pdf | Request a copy Full text restricted Available under University of Tasmania Standard License.

Abstract

Variation in subsurface solar radiation has been identified as a second-order factor in coral bleaching. This
study examines transmission of radiation at Heron Reef (southern Great Barrier Reef, Australia) testing the hypotheses
that spectral transmission is independent of location, season and solar zenith angle. In June and December 2004, 132
underwater irradiance profiles were collected at six ultraviolet wavelengths (305, 313, 320, 340, 380, 395 nm) and
photosynthetically-active radiation (PAR) to estimate spectral diffuse attenuation coefficients Kd(l). Mean Kd(l)
decreased through the ultraviolet spectrum (0.435m
1 at 305 nm to 0.115m
1 at 395 nm) whereas mean Kd(PAR) was
0.129m
1. Ultraviolet Kd(l) values were highly correlated with each other, but less well correlated with Kd(PAR). Kd(l)
values were larger inside than outside Heron Lagoon, both across all wavelengths and at individual wavelengths.
Similarly, Kd(l) values were significantly larger in December than June. These results are consistent with greater
resuspension and transport of particulates in Heron Lagoon at higher wind speeds. Kd(l) values were not dependent on
solar zenith angle. The implications are that location and season must be accounted for when setting Kd(l) values to
calculate spectral irradiances affecting corals at Heron Reef

Item Type:	Article
Authors/Creators:	Nunez, M and Michael, KJ and Veal, C
Journal or Publication Title:	Marine and Freshwater Research
ISSN:	1323-1650
DOI / ID Number:	10.1071/MF11106
Additional Information:	Copyright 2011 CSIRO
Item Statistics:	View statistics for this item

Actions (login required)

Item Control Page