Toxic Algae Blooms
Image by Lincoln Mackenzie, Cawthron Institute
Image by Lincoln Mackenzie, Cawthron Institute
Sea
Keeper Profile: Lesley Rhodes Cawthron Institute, Nelson
Hi.. I'm Lesley Rhodes, a research scientist at the Cawthron Institute,
Nelson. I study marine toxic algal blooms.
If you come from the Hauraki Gulf or from near Caroline Bay, Timaru,
and if you are observant, you might have seen brown patches discolouring
the water during the summer. Those patches were blooms of a fish-killing
micro-alga called Heterosigma.
Occasionally I have the fun job of visiting such blooms to collect
samples, but mostly my work is based at the bench or microscope.
If the micro-algae are particularly difficult to identify then
I prepare samples for the electron microscope. This special microscope
can let me look at scales on the surface of the cells. Some of
these minute scales, less than 1/1000th of a millimetre, bear
exquisite patterning and each view is a delightful surprise.
The scales help me identify the species and that is important
to understanding exactly what forces are at work in the sea.
The ecology of these single celled plants is fascinating. They
interact with one another as well as with other organisms in the
water. They produce secretions that can actually control the ecology
of the whole area, influencing the succession of different species
of plankton throughout the seasons. Only a small proportion of
the micro-algae are actually toxic, but I have found several kinds
of poisonous ones here in New Zealand. Knowing when these species
are present is extremely useful to shellfish and fin fish farmers,
who can often predict whether a toxic bloom is likely to occur
on the basis of the micro-algae present in the water combined
with the current weather conditions.
My research keeps me incredibly busy. New Zealand's aquaculture
industry is a large and growing - and important - activity. Shellfish
eat plankton and if there are poisonous species in the water the
oysters and mussels eat them and then THEY become poisonous to
eat. That's why the people who farm the oysters and mussels need
to know as soon as possible if there are any toxic algae around.
We would not want poisonous oysters ruining our excellent reputation
overseas.
My work is totally satisfying .. new discoveries are a tremendous
buzz, the development of new methodologies is absorbing, and the
links with other researchers around the world is stimulating,
And I get paid for doing it .. who could want for more!
