Was there evidence of that happening at Waldo?
That’s right. Goldman published a paper in the 1960’s about that very thing. It is where I got my idea about energy efficiency for my doctoral thesis (40). Goldman may have gotten this idea from someone else, but in lakes like Crater Lake and Waldo Lake, the phytoplankton species are generally small-bodied organisms. They are highly efficient at taking up nutrients. In other words they devote most of their entire mass to surface area in order to maximize nutrient uptake because the nutrients are so scarce. Concentrations of phytoplankton are relatively low and if you look at the phytoplankton in Crater Lake and in Waldo Lake, they generally are small-bodied organisms with a high surface area to volume ratio to maximize nutrient uptake. This is an adaptation.
As lakes become more eutrophic, more nutrient rich, the organisms become more wasteful because nutrients are readily available. They don’t have to be as highly efficient in obtaining them because nutrients are abundant. You generally find more blue-green algae in eutrophic lakes like Klamath, large bodied organisms whose energy efficiency or nutrient uptake efficiency is less. In oligotrophic lakes, the phytoplankton are sensitive to slight nutrient increases, as you would expect. They’re going to respond to these slight nutrient increases even though the amount of nutrients that went in to the lake were infinitesimally small and probably insignificant in terms of volume. Yet this amount of nutrient may have been sufficiently large to stimulate a significant response from the algae. I remember reading about prisoners of war from the Pacific after World War 11. Men who had been starved came back weighing 80 – 90 pounds. It didn’t take but a matter of weeks and they were back to their normal weight. That probably has nothing to do with phytoplankton, but illustrates that these organisms are really nutrient starved. Given even a slight increase in nutrients, they may really take off. That is what I suggested at Crater Lake and for other lakes like it. Managers who are responsible for the lakes may assume that small, incremental increases in nutrients are insignificant and really aren’t sufficient to change or add to the lake’s eutrophication rate, but that’s wrong. Goldman had mentioned this in an earlier paper about how these organisms are highly adapted for lower nutrient conditions but could have a significant increase in productivity resulting from a seemingly insignificant increase in nutrient availability. That’s my argument–that these lakes can’t be treated like any lake as far as their potential to become more eutrophic.
By the same token, fish could have a negative long-term effect in terms of adding nutrients to the lake.
Absolutely. This is the case in Waldo Lake, though it has never been proved. They’ve banned fish stocking as of 1990 in Waldo. One of the arguments, though I’m not sure I agree with it, is that the fish were adding nutrients through defecation. There’s another problem with fish stocking in Waldo that’s not related to their nutrient loading. Anyway, next question.
