Dear Dana, Joe and Paul:

This is to bring you (tardily) up to date, I hope in time for your

next meeting. Last fall I had done all of the analyses except for

phosphate. That was not only the most tedious, but to do it required

boiling chips to avoid "bumping"--explosive overboiling. I tried

without them, and it simply didn't work. So I left all of the

analysis kits with Dana, except for the phosphate one. I finally got

around to ordering the boiling chips--they are so essential that I

cannot think why they weren't included to begin with--and I have now

completed the phosphate analyses.

I believe I reported orally on all results except the phosphate at the

September meeting, and the final report is displayed in the

attachment. It requires some comment.

The pH results are to be expected. The soils around the pond are

generally acidic, and the pond is slightly so. The sample from in

front of our cottage is neutral doubtless because of the ground

limestone I've used in a futile attempt to encourage grass and

discourage moss.

When I get a "none detected" result, I always want to make sure the

analytical method is working, and that requires a "positive control."

For the nitrate positive control, I added a trace of soluble

fertilizer to a pint of water in one sample, and somewhat more in a

second. The results show that the method works. The results for

nitrite were all negative. One should not ordinarily expect much in

open water, and I didn't have any to make a positive control.

The phosphate is surprisingly low but still high enough to support

algal blooms, from what I have read. Total inorganic phosphate

include both meta- and poly-phosphate, the latter being common in

detergents. Obviously there is only enough to be barely able to detect.

No detergent detected, good, and again a positive control.

The dissolved oxygen in the surface waters samples was far over the

range of the test kit. We'll need to consider whether it's worthwhile

to be able to test the actual range. I think we should plan to sample

some deeper water, where we might indeed find dead zones.

While we should repeat these analyses early this summer, the overall

results certainly show no large amounts of free plant nutrients

(nitrogen and phosphorus). But we have lots of algae. The conclusion

is obvious; there is plenty of nitrogen and phosphorus there, but it

has all been gobbled up by the algae. Aside from any actual runoff,

there is always some leaching from the soil of these nutrients, and a

thunderstorm adds a bit of nitrogen. While we should always try to

reduce nitrogen and phosphorus inputs into the pond, that will not

provide algal reduction anytime soon, and the nutrient levels are

already low. So what can we do?

There is a possible solution, but it is one that I suspect would not

be highly popular and it is far from certain. Consider the food

chain. It begins with algae which range from tiny unicellular

organisms through tiny multicellular colonies or thread-like masses up

to very large plants. Much, even most of it, is the smaller organisms

and they are responsible for loss of water clarity. Every organism

has predators, and the predators of the smaller algae are zooplankton,

tiny multicellular animals. The eat mostly algae. There is no

question that high zooplankton levels nearly always reduce

phytoplankton (tiny plants, including algae). So we should try to

have some count of zooplankton population to see where we stand. What

follows seems logical, and in some reports, it has worked. But the

actual situation is apparently often more complex, and results are

mixed.

The zooplankton have predators, too. Theirs are the small fish,

sunnies, and the larvae (immature) of larger fish. The more small

fish, the fewer zooplankton, the more algae. The fewer small fish,

the more zooplankton, the less algae. The small fish have their

predators--the larger fish--trout, bass, and all the others everyone

likes to catch. The more big fish, the fewer small fish, the more

zooplankton, the less algae. The fewer big fish, the more small fish,

the less zooplankton, the more algae. You can see where this heads.

By this very logical, and sometimes valid scheme, only if one

restricts the catching and removal of big fish, does the balance tip

in favor of zooplankton and less algae.

While I've read a fair amount on this, I'm certainly no expert.

Perhaps we should try to get someone from U of M, or the state

Department of Natural Resources, if that's the name, to tell us more

about how to tackle this. One possible solution, helpful elsewhere,

is to introduce zooplankton that like our phytoplankton, if we don't

now have the right kind. If we pursue this further, and have some

expert advice that recommends it, we could then try to persuade the

town to mandate "catch and release" fishing only (good luck!).

This is about as far as I have been able to carry it. I'll be

interested in your reactions and comments. We'll arrive in Franklin

probably June 8th for the summer.

All the best!