Meeting Abstract
P1.81 Thursday, Jan. 3 In situ UVB radiation delays development of purple sea urchins Stronglyocentrotus purpuratus DAUGHERTY, M.J.*; KERSHNER, J.M.; CAMPANALE, J.P.; ADAMS, N.L.; California Polytechnic State University, San Luis Obispo nadams@calpoly.edu
Exposure to ultraviolet radiation (UVR, 280-400 nm) can harm developing organisms. Stratospheric ozone depletion has caused increases in damaging lower UVB (280-320 nm) wavelengths from polar to temperate regions. We tested effects of specific wavebands and doses of solar UVR that penetrate into seawater on sea urchin embryos, Stronglyocentrotus purpuratus. We exposed sea urchin embryos to three different treatments: (1) Control = No UVR= photosynthetically active radiation (PAR 400-700 nm) only, (2) UVA+ PAR (320-700 nm), and (3) UVB+UVA+PAR (280-700 nm) at two ocean depths (surface and 1 meter) in San Luis Obispo Bay, California. We then calculated the delays in divisionexperinced by embryos exposed to UVA + PAR or UVB + UVA + PAR compared to control treatment (PAR). Embryos exposed to full UVR (UVB+UVA+PAR) experienced a significantly longer delay in mean percent cleavage delay than embryos exposed to PAR + UVA (P<0.0001 (2-way ANOVA)). As expected, embryos at the surface experienced a greater UV-induced delay than embryos held at 1 meter (P=0.02). There was no significant interaction between light and depth (P=0.56). Percent cleavage delay across experiments ranged from 13.7% � 2.1 at the surface and 9.3% � 2.9 at 1 m depth for embryos exposed to full UVR (n=4) and 4.7% � 0.2 at surface and 3.1% � 1.6 at 1 m depth) for embryos exposed to PAR + UVA only (n=3). Multiple linear regression analysis comparing cleavage delay and UV dose among PAR, UVA and UVB wavebands demonstrated UVB caused a significant delay in development (P=0.136), whereas UVA or PAR caused no significant delays in development (P=0.72 and 0.91 respectively). These results indicate that natural UVB radiation in shallow temperate coastal waters delays development of sea urchin embryos in a depth-dependent fashion (to at least 1m), whereas solar UVA and PAR have little to no negative effect on development.
