Washed up algae has a silver lining

TOPAlgaereefLEAD

Recent rough weather over the past
week has had a smelly impact on the pristine white sands of Seven Mile Beach,
but the news is not all bad.

Nearly the entire stretch of beach
received a thick coating of puffy algae balls, which in some places was piled
over a foot deep. The stinky mess, accompanied by additional flotsam and
jetsam, was causing a cleanup headache for condos and hotels along the beach.

“This happens quite frequently when
we experience heavy wave actions,” says Department of Environment Deputy
Director Tim Austin.

He says the algae washing up is a
completely natural process and actually spells good news
for Cayman’s reefs.

Mr. Austin says that when the water
is clear and calm for extended periods, the algae grow abundantly on coral
reefs.

“These are a myriad of different
algae species, which were growing on the reef over the summer; when the first
stormy wave action happens at around this time, they get pulled off,” he said.

The reefs benefit from this natural
cleansing process, since too much algae choke the delicate corals and can cause
major damage.

Mr. Austin notes that water quality
has an impact on algae growth, as higher nutrient levels caused by water
pollution act as fertiliser for the algae. “In recent years with water quality
levels dropping, the algae would be growing faster,” he said.

While some properties along the
beach are busily cleaning up the massive piles of seaweed, Mr. Austin says a
few days of sun and dry weather will dry it up. It will turn to dust and blow
away or get worked into the beach.

“The algae will turn the sand brown
for a little while, and the water will turn brown, but it quickly takes care of
itself, and the sun will bleach it out quickly,” he says.

Mr. Austin says that at present,
because most of Seven Mile Beach is private down to the high water mark, there
is no clear policy on who is responsible for cleaning up these occasional algae
messes.

“We are trying to get a policy
together for when events like this happen,” he said.

“In my opinion Seven Mile Beach is
such a national asset, we should have something in place.”

 

Constantly in flux

The stormy weather has also caused
parts of the beach to almost disappear south of the Royal Palms. At high tide,
the seawalls of two homes now extend right into the water, temporarily
curtailing the efforts of strollers to go from one section of the beach to
another.

“The beach in the area flexes
continuously and with sustained southerly winds, such as Cayman was
experiencing over the past few days, the sand on Seven Mile Beach gets pushed
northward,” said Mr. Austin.

“Right now the cold front will
shift the wind to the northwest and it will help in remaking the beach.”

He predicts some of the missing
sand will come back, but in places it might need a little help.

“Some spots could use what we call
opportunistic nourishment, as the beach will not get built up by volume but by
the fact there is already some sand there,” he explained.

“Sand needs other sand to settle,
so when for example waves are washing up against a seawall and rocks, the water
just get churned up and sand will not get deposited,” he continued.

“Once you put some sand there it
will start to build up on its own, we have done that in the past in some
areas.”

TOPAlgaereefSTORY

A small hole dug in the sands of Seven Mile Beach shows how algae which washed up is being covered up by a new layer of sand.
Photo: Basia Pioro McGuire

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