That
blooming
algae
As a rower, getting anything caught in your
rudder or picking up a pile of plant mass on
your blade is extremely frustrating. When
racing, it is a significant problem which can
impact results. This plant mass can be algal
bloom and is much more than just an
annoyance to rowers. In worst cases it is an
unsightly toxic health hazard.
Algal bloom is naturally occurring, especially
in warm summer months when there is
a stratification of water temperatures.
Documentation of it happening goes back more
than 200 years including areas with little or no
human inhabitation. Algal bloom, however, can
be sped up by human activity such as pollution
runoff into waterways from factories, farming
fertiliser practices (especially the use of nitrates
and phosphates), or in urban areas from storm
water runoff and sewage overflow – anything that
increases nutrients in the water. This surplus of
nutrients causes algal bloom, or phytoplankton,
to grow at a much faster rate.
There can be benefits from algal bloom as it can
increase plant life productivity in the impacted
water way. But it can also have a negative impact
as the bloom causes oxygen depletion in the
water and thus leads to the death of fish and
other aquatic life. Ultimately, the on-going
impact of algal bloom can contribute to the
reduction of water levels.
For humans, algal bloom is often considered
unattractive and more importantly it can produce
toxic chemicals. When toxicity is measured as
too high, a ban on swimming is enforced in the
impacted areas. Above water sports, like rowing,
can also be banned at high levels of toxicity. >
Issue 18 – October 2011
