Early blooming algae; discoloured water nothing to worry
about
18th March 2011
Plymouth Marine Laboratory scientists
have detected two large algal blooms; one off the coast of Ireland
and the other closer to home covering an area from the Lizard, in
Cornwall, to Salcombe, in Devon.
When such blooms occur scientists from a range
of disciplines are brought together to identify the plankton
responsible and establish whether there is any threat to people or
other marine life. In this case the bloom, which is likely to
discolour the sea, consists of vast numbers of a harmless
microscopic plant called Skeletonema and poses no
threat.
“Skeletonema is a beautiful
microscopic plant that given the right conditions reproduces
rapidly to cover large areas of coastal seas”, says PML’s Earth
Observation scientist, Dr Peter Miller. “Over the winter nutrients
have built up in the sea and the windy weather we have experienced
recently has stirred them up to the surface. Combined with the now
calmer conditions and bright sunny days everything slotted into
place to enable this plant to reproduce and form a large
bloom.”
Claire Widdicombe, a plankton ecologist also
at PML, identified the plant from samples collected out near the
Eddystone off Plymouth, so confirming the suspicions that the bloom
was not harmful. “What is interesting is the timing of the bloom”,
said Widdicombe, “we would normally expect the spring bloom to be a
few weeks later than this, although there is some variation and it
all depends on being in the right place at the right time. A
further point of interest is that this species all but disappeared
from Plymouth Sound for many years and its early appearance this
year is all the more unusual.”
Long term monitoring of natural events like
plankton blooms is a key part of nationwide programmes to
understand and predict how our seas may be changing. Using
satellites to detect the timing of such blooms is one way of trying
to discover how the oceans are being affected by climate change and
other environmental factors, for example.
Peter Miller and his team are continuing to
watch the bloom grow after analysing data beamed down from the
satellite as part of an EU funded research programme involving
partners across Europe.
The AquaMar project aims to use satellites to
detect algal blooms that might pose a risk to humans, fisheries and
shellfisheries. By combining satellite data with a variety of
techniques such as realtime sampling at sea using automated buoys
and analysis using high power microscopy and flow cytometry to
identify and count plankton cells, the Plymouth team and their
European colleagues are refining methods of identifying the tiny
plants that cause the bloom. The idea is to ensure that any
analysis from space is reliable and as precise as possible, so
acting as an early warning system in the case of a Harmful Algal
Bloom (HAB), or to put minds at rest if the bloom is harmless, or
indeed beneficial.