|Liow, Pui sze|
Submitted to: Journal of Freshwater Ecology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/4/2011
Publication Date: 9/1/2011
Citation: Spencer, D.F., Liow, P., Lembi, C.A. 2011. Growth response to temperature and irradiance in Nostoc spongiaeforme. Journal of Freshwater Ecology. Vol 26 Page 357-363. Interpretive Summary: Bluegreen algae grow in California rice fields where they form large mats that may smoother seedlings or cause them to dislodge, resulting in yield loss. The most troublesome species is Nostoc spongiaeforme. There is very little information on the growth requirements for this organism. We grew it in a defined medium at 24 combinations of light and temperature. Optimum growth occurred at 26 C and 227 'M m-2 s-1. Thus, N. spongiaeforme grows well at warm water temperatures and low light levels, similar to those measured in rice fields during the critical thirty days following initial flooding and rice seeding. Mathematical equations derived from these results are a first step toward predicting when Nostoc spongiaeforme will be most abundant in rice fields and in developing integrated management approaches that can used by rice growers.
Technical Abstract: California water-seeded rice fields are typically shallow and have high nutrient levels, which are ideal growing conditions for algae and cyanobacteria. Nostoc spongiaeforme is problematic in California rice fields because floating mats may dislodge seedlings or smother them when the mats accumulate in windward areas. There is very little published information on growth requirements for N. spongiaeforme. We grew N. spongiaeforme in BG-11 medium at 24 combinations of light (22, 87, 162, and 400 'M m-2 s-1) and temperature (10, 15, 20, 25, 30, and 35 C). Results indicate that optimal growth occurred at 26 C and 227 'M m-2 s-1. The data indicate that N. spongiaeforme grows well at warm water temperatures and low irradiances, similar to those measured in rice fields during the critical thirty days following initial flooding and rice seeding. The resulting quadratic equation relating light and temperature to growth can be used in ecological models.