Quick notes and Aquamats

Three agenda items here:

1. Meeting tomorrow at 11:35 at Uni High. I assume we're meeting at the usual spot.

2. We just passed 2000 hits on the Inventor's Club page. Our site has now been viewed in most states in the US, plus Canada, Mexico, Belize, Guatemala, Honduras, Costa Rica, Brazil, China, Germany, the Philippines, Thailand, Ecuador, Vietnam, Laos, Spain, India, Brunei, Malaysia, Singapore, the Cayman Islands, South Africa, Taiwan, Czechoslovakia, Turkey, Sweden, Finland and Iran. That's 28 countries so far.

Update, May 14th. 2122 hits and add Norway, Chile, Jamaica and Australia.

3. Newly acquired manufacturer information about AquaMats!

The following are facts gleaned from the Meridian Applied Technology Systems AquaMat Customer Information Manual (Nursery edition). We've already discussed much of this, but a summary may be useful here as we continue to think about our own substrates and scrapers.

AquaMats are especially recommended for nursery culture of shrimp from post larval stage 10 and up (approimately .01 to 2 grams of size). Sizes range from 2m X 1.22M to 2M X .61M. The Meridian Corporation reports up to 30% reductions in feed costs when AquaMats are used (a figure we may find useful for future calculations).

AquaMats require exposure to direct sunlight (as we have discussed).

AquaMats float. Therefore Meridian recommends that AquaMats be deployed on 2" PVC pipe frames sunk to the bottom and filled with sand. These are attached by cinching down by cable ties (those thin plastic strips used to bundle video cables).

Meridian also recommends that AquaMats be preconditioned prior to deployment. The desired colonizing organism (as we have discussed) is benthic diatoms. Diatoms are high in highly unsaturate fatty acids (HUFAs), an important nutritional item. Meridian discusses techniques that can be used to encourage the growth of specific desireable species. This is achieved by using pure cultures of these organisms and by saturating the mats in a solution of nitrate and phosphate salts (no lack of those in our sedimentation ponds) plus sodium metasilicate (silica is a limiting nutrient for diatoms) and some trace metals and vitamins.

Meridian recommends a 3 day culture time prior to introducing AquaMats as shrimp feed. This time period may vary with local conditions. As we discussed, if the mats are left in culture too long, they will acquire undesirable organisms. Each AquaMat user must determine the proper pre-conditioning time for their requirements.

Depending on the rates of algae growth and the density and growth rates of shrimp, algae films on AquaMats might continue to grow, become depleted or reach a steady-state where growth and removal become balanced.

Meridian states that AquaMats can be cleaned with a pressure hose and dried or simply returned to pre-condition tanks (effluent canals). Sterilization is generally not used, but can be used. The following sterilization methods are approved:

1. Steam sterilization @ 15 psi for 20 minutes.
2. 3% chlorate for 2 hours.
3. 10% Hydrochloric acid for 2 hours at 25 C
4. 30-50 ppm formalin for 1 hour
5. 3% acetoperoxide for 1 hour
6. Heating below 190 C

AquaMats are not recommended in systems with excessive fine clays. Secchi depths greater than 25 cm are required.

BARNACLES are a problem. Meridian recommends filtration of waters using Aquamats at 120 to 150 microns. We will have to address barnacle colonization (perhaps by scraping?).

Update and Notes: Progress and Burglaries

It's great to see the first bit of information from the substrate tests. The early phases of the project seem to be going fine.

The Lemelson-MIT grant and the UN SEED grants have been submitted and we'll find out about those soon. The farms are excited and ready to go. On Tuesday this week, I visited one of our farms with a WWF representative. We happened to bump into the pond manager there and he was excited about the project and volunteered his time on weekends to help the IHS students with the field work. I also found out that the probe WWF is installing has finally cleared customs in Honduras and will be arriving in about 2 weeks.

A couple of other things have slowed us down a bit. It will be Easter holday in Belize until Monday next week, so we lost a bit of class time at IHS. Also, I was burglarized and my computer, field notes, back-ups and underwater camera were stolen (life lesson learned: NEVER keep your computer and backups together, even if you're just carrying them in in a back pack for a bit).

So I'm taking 2 weeks in the US to do some family things and trying to recover lost data. I could make a meeting next Friday with the Uni Inventor's Club if you plan to meet.

Look for a post from me soon with information from the Aquamat manufacturer.

Experiment Update- D+3 weeks, Also Group B Minutes

Vinyl progress: not as much growth as the screens, but stays lightweight and the smooth surface makes it easy to remove material.

Fiberglass screen is a close second to the steel in amount of growth.

Rubber comes dead last in terms of growth. Material (dirt?) comes off just by touching. But its close neighbor, the steel screen, wins the prize.

Note the abscence of the weed mat. It was growing little more than the rubber, and then was removed from the PVC by the lake. I didn't rescue it.

Lessons learned from this experiment so far:

-This rubber will not work.

-A fiberglass or steel screen may encourage more growth, but they complicate removal quite a bit, since the material can't just 'slide' off.

-Vinyl is most compatible with our current removal plan (see below) but it hasn't accumulated a whole lot of biomass.

In the near future I plan to take sample material under a microscope to see what exactly we "caught".

Another order of business:

The biomass-removal group met to explore our ideas.

We briefly researched algae removal techniques and found little of use. The nets came up with a variety of lake and aquarium algae removal devices, ranging from vacuums to string algae brushes. The closest device we found to our dreamed-up device was a flexible stainless steel scraper shaped like a rake, designed for scraping algae from large glass aquarium sides.

In our meeting, EFritzch proposed his idea for the device and we critiqued/improved it. I'll have him post about this, but it basically allows for one-sweep scraping without repeatedly having to pull the scraper in and out of the boat.

And lastly, welcome IHS students! We're so glad to be able to collaborate with you on this project.

Next Meeting

Met at IHS again yesterday. We had problems with internet connections, but a few students are still getting hooked up with the blog through their own resources. We're meeting next week in an internet cafe to help other students get started.

Right now the local students are just getting grounded in the project. It appears we'll be able to make trips through May to the farms so hopefully we can post some results by the end of the school year. Fall semester will probably be the bigger push, but we're getting in good ground work now, especially these preliminary experiments with substrates.

Let us know how the substrate experiments are going and take some time to meet the new bloggers from IHS. I'll post new information on Aquamats and a couple of recent experiences from the lagoon.