5.5.3 Seagrass light frequency reduction experiment

Description

The capacity of seagrasses to cope with episodes of light deprivation from overlying turbid waters may not only depend on the absolute quantity of light they receive during that episode, but also on how the light deprivation varies through time. For example, turbidity and therefore light reduction may be relatively constant over the episode or it may fluctuate depending on the frequency of pulsed turbidity events.

This report presents findings from a controlled mesocosm experiment that aimed to determine the responses of seagrasses to, and recovery from, differences in the pattern of the delivery of light. The study focussed on two seagrass species found in the northwest of Western Australia.

Aims

• To determine the effects of light frequency under dredge-simulated conditions on the growth and health of two seagrass species found in the northwest of Western Australia.
• Provide guidance and protocols for the application of the research outputs (e.g. light stress frequency and response relationships, recovery potential, sub-lethal and lethal bio-indicators and thresholds) to impact prediction, monitoring and/or management of dredging programs in northwest Western Australia.