RE: NANFA-- NJZ-pond scum Follow-up

Nick Zarlinga (njz_at_clevelandmetroparks.com)
Tue, 18 Nov 2003 13:19:40 -0500

My apologies for responding to this so late. I had a family emergency and
am now just catching up. Our situation seems a bit different than what you
described. We were over run with "seaweed" and floating algae mats. There
is an excess of nutrients in the system due to duck feedings, and animal
foods and excrement from the animals that are exhibited on the islands. Not
to mention that there is little water input to flush nutrients. This has
been a recurring problem for this pond, and every other pond in the world,
like it. The hardest part is to get the people in charge to think about
things in the "whole ecosystem" approach. Todays society relies so much on
quick fixes, like adding coppersulfate to the water which has been done for
years in this situation. To document the problem, we have been doing many
different water quality tests over the summers. At one point, the solution
was to fence off a 10' x 10' section (okay, maybe two sections) on the
couple acre pond and add water hycinths to suck up the nutrients. Yes,
laugh all you want, these are people that are not familiar with aquatic
systems. My mission has been to preach to them that there are two different
approaches. First, we can treat the lake like a classic closed system
aquarium (not the Crail Aquarium Concepts) and deal with the symptoms of the
problem. My analogy is that we are just putting a bandaid on the cut. The
second, and more appropriate way, is to use the Crail Aquarium Concept by
treating the system like an ecosystem. There needs to be a reasonable
amount of nutrient input and export, combined with proper floral and faunal
speceis assemblages in the form of wetland formation as filters and the
like. Well, after years of back and forth (actually back and back, not much
forth), they found a middle ground. Let's add bacteria to the system to
help nature along. I don't think that this is the best approach, but it is
a practical approach. So, after two years of bacterial additions, I have
seen a change in the system. The floral species composition has changed and
now we have a larger assortment of aquatic plants growing. The jury is
still out on this project, however I am interested in seeing the changes in
the system over the next couple of years.

Nick Zarlinga
Aquarium Biologist
Cleveland Metroparks Zoo
216.661.6500 ext 4485

><)> -----Original Message-----
><)> From: owner-nanfa_at_aquaria.net
><)> On Behalf
><)> Of john bongiovanni
><)> Sent: Saturday, November 08, 2003 10:44 AM
><)> To: nanfa_at_aquaria.net
><)> Subject: NANFA-- NJZ-pond scum Follow-up
><)>
><)>
><)> Nick,
><)>
><)> How was your pond scum problem resolved this past
><)> summer? We had a thread
><)> going at one point discussing one of the ponds at
><)> the zoo that went Green. I
><)> think you assigned the problem to one of your neophytes.
><)>
><)> I had a discussion with some locals last night
><)> with a similar problem. Late
><)> in the summer, their pond (called a tank in Texas)
><)> tuned green. It is fed by
><)> spring water, so it is not necessarily a stagnant
><)> issue. There is a hay field
><)> nearby that gets fertilized and apparently the
><)> runoff goes into the creek. I
><)> suggested growing soem floating plants such as
><)> hornwort and building a strong
><)> riparian zone. The fast growing floating plants
><)> will absorb the water born
><)> phosphates and nitrates. When they overgrow, they
><)> can be raked out of the
><)> pond ands used as mulch.
><)>
><)>
><)> john
><)> ---------------------------
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