LIGHTS FOR ALGAE GROWTH
From: Dave Straus dstraus@spa.ars.usda.gov
To: aqua-l@killick.mi.mun.ca
Sent: 28 March 2003
Question:
We're setting up an indoor study in a controlled
environment; we're
using pond water and we want to maintain the algae from the pond. We
used some daylight bulbs (Sylvania Daylight Deluxe, 40 watt, 5000 Kelvin) in
the first trial, but the algae only lived for about 4 days in the first
trial. What are the best type of fluorescent lights to use in this
situation? The study will last for about 20 days and we'd like to keep
the algae alive!
David L. Straus, Ph.D., Aquatic Toxicologist
USDA - ARS - Southern Plains Area
Harry K. Dupree - Stuttgart National Aquaculture Research Center
P.O. Box 1050, 2955 Hwy 130 East
Stuttgart, AR 72160, USA
Tel: (870) 673-4483 Fax:
(870) 673-7710
Email: dstraus@spa.ars.usda.gov
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COMMENTS 1:
Try lights that are 6500K, one of the researchers
found that light
intensity and colour make a difference in fish eye physiology. 6500K
is closer to natural light.
Gerry Horne
Office of VP Research – ACU Aquatics
PO Box 1700 STN CSC
University of Victoria
Victoria, BC V8W 2Y2 Canada
Tel: 250-721-7139 (Office) or 250-888-0030 (Cell)
Fax: 250-721-7120
E-mail: gehorne@uvic.ca
URL: www.research.Uvic.ca
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COMMENTS 2:
Is it planktonic green water algae that you are working with?
The Kelvin rating of artificial light does not appear to be of particular
significance when marine diatoms and flagellates are being cultured for
aquaculture and this will most likely be the case for freshwater single
celled algae.
If you suspect light is a problem with your particular situation then you
could trial the algae in a container outside.
I suspect it is more likely that other conditions are not suitable. That is
nutrients, or a bacterial bloom or too many algal harvesting organisms [eg
protozoans, rotifers] etc, etc.
Colin Anderson
e-mail: colin.Anderson@xtra.co.nz
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COMMENTS 3:
Many people contend that grow-lux type lamps do best
and are in fact required. Just as many other people contend that
standard fluorescent lamps do just as well and offer significant savings
with regard to the grow-lux type lamps. The intensity of either being
a key consideration.
Across the boad, metal halide lamps offer the best light in terms of
intensity and a bright white, broad spectrum light source for algae growth.
My guess is your culture crashed due to bacterial contamination.
Paul Hundley
RMF-Applied Aquatics, Inc.
e-mail: AAquatics@rmf.com
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COMMENTS 4:
We are using typical freshwater pond water which is
aerated to keep the algae in suspension. We want to simulate the pond
environment, so, the water has not been filtered to remove zooplankton; this
brings up a good point and I will have the water looked at to determine the
algae types present.
What I've decided to do. We have available a local supplier who
handles Philips Agro fluorescent lights and the company tells me that
these are designed for such an application. The room has 4 rows of 8
standard 2-bulb fixtures and these are suspended 5 feet above the tanks.
We don't want to go to the expense to change the fixtures so we will
give these a try.
Dave Straus
e-mail: dstraus@spa.ars.usda.gov