Post by Marie Smith on Dec 5, 2017 7:03:34 GMT
What is "Chl-a", and how does it relate to HABs?
Chlorophylly a (Chl-a) is a type of photosynthetic pigment that is found in all aquatic phytoplankton. Although we cannot see phytoplankton directly (especially from space), the Chl-a alters the light field that exits the water. The more phytoplankton in the water, the stronger this signal. As a result, Chl-a can be used as a proxy for phytoplankton biomass, and we can then relate the shape of the light field to the concentration of Chl-a (and the amount of algae) in the water.
Do all HABs present as high Chl-a, and are all high Chl-a harmful?
Not necessarily. Some diatoms, like Pseudo Nitzschia, can cause shellfish toxicity at relatively low concentrations. The very high biomass events are often caused by dinoflagellates, which may not necessarily be toxic themselves. However, they can still be harmful to marine life by causing physical damage (e.g. clogging the gills). A large bloom that persists in one area could also use up all the nutrients in the water and die off - as the bloom decomposes the bacteria could use up all the oxygen in the water, potentially leading to events such as crayfish walk-outs.
So how do I know if it's a "harmful" bloom?
That's where we come in. Our group has over 15 years worth of experience in phytoplankton physiology, marine bio-optics, and earth observation capabilities. We are using our expertise to assimilate the relevant data and provide user-friendly risk assessment reports. Furthermore we are developing techniques to differentiate between algal types, which can facilitate the appropriate mitigation steps.
So there is a bloom - what now?
Government agencies DEA and DAFF are alerted, who notify the relevant aquaculture facilities and municipalities. We cannot prevent these events, but ideally this would allow enough warning time for the appropriate mitigation steps to be taken.
Chlorophylly a (Chl-a) is a type of photosynthetic pigment that is found in all aquatic phytoplankton. Although we cannot see phytoplankton directly (especially from space), the Chl-a alters the light field that exits the water. The more phytoplankton in the water, the stronger this signal. As a result, Chl-a can be used as a proxy for phytoplankton biomass, and we can then relate the shape of the light field to the concentration of Chl-a (and the amount of algae) in the water.
Do all HABs present as high Chl-a, and are all high Chl-a harmful?
Not necessarily. Some diatoms, like Pseudo Nitzschia, can cause shellfish toxicity at relatively low concentrations. The very high biomass events are often caused by dinoflagellates, which may not necessarily be toxic themselves. However, they can still be harmful to marine life by causing physical damage (e.g. clogging the gills). A large bloom that persists in one area could also use up all the nutrients in the water and die off - as the bloom decomposes the bacteria could use up all the oxygen in the water, potentially leading to events such as crayfish walk-outs.
So how do I know if it's a "harmful" bloom?
That's where we come in. Our group has over 15 years worth of experience in phytoplankton physiology, marine bio-optics, and earth observation capabilities. We are using our expertise to assimilate the relevant data and provide user-friendly risk assessment reports. Furthermore we are developing techniques to differentiate between algal types, which can facilitate the appropriate mitigation steps.
So there is a bloom - what now?
Government agencies DEA and DAFF are alerted, who notify the relevant aquaculture facilities and municipalities. We cannot prevent these events, but ideally this would allow enough warning time for the appropriate mitigation steps to be taken.