Dogs Breakfast event
Less Toxic Algae Risk
Cyanobacteria Action Plan
A series of ‘dogs breakfast’ events were held next to the Maitai River to pass on information about toxic algae to dog owners. About 60 dogs and their owners were there and people even travelled in from Tasman to attend, so hopefully the word is getting out about the risks and what to look for. Remember the Maitai is generally safe to swim in (except after heavy rain), but dog owners and swimmers should know how to recognise toxic algae so they can keep away from it.
We’ve posted this video by Cawthron to our website to further educate people on what to look out for.
Cawthron research students in the Maitai River
Toxic algae experimental set up
The Cawthron research projects on toxic algae have been completed with some interesting results. Previous research has shown that slightly raised nitrogen, low phosphorus and stable periods of low flow provide good conditions for toxic algae blooms. Toxic algae has an advantage in low phosphorous conditions because it can extract phosphorous from sediment trapped in its mats.
This summer, toxic algae blooms (over 20% cover) were only recorded in the lower and mid reaches at Avon Terrace, Dennes Hole and the Maitai Camp, and only in November and December. The new research has noted that toxic algae blooms in the river could be affected by the blooms of other algae, in particular the green filamentous algae that bloomed strongly last year in spring. In low nitrate conditions it is likely they compete with each other for nutrients. In higher nitrate conditions it seems that the toxic algae is outcompeted by the green, so toxic algae blooms may be a result of biological activity as well as chemical and physical conditions.
The results also indicated that toxic algae blooms may be affected by unstable or variable river flows which though not strong enough to wash it all away, may disrupt the algal colonies.
Thanks to the Cawthron Institute, Dr Susie Wood and summer research students Alice Kilner and Dom Eardly from University of Birmingham in the UK for all their great work.