How Does Iron Affect the Growth of Harmful Algae?

Methods

Summary

We will fill the bottles with lake water from three different lakes in OK, USA, each with differing starting nutrient concentration. These bottled will have either N, P, Fe, N+P, N+Fe, P+Fe, or N+P+Fe added to each and then placed in the lake (See below for a representation). We will then measure the amount of algal growth in general and BGA in particular, as well as the nutrient concentrations after 4 days. This will be done by measure of biomass of filtered seston, chlorophyll a measurements, and counts of particular algal genera. Additionally, nutrient measurements will be taken for N, P, and Fe in each treatment to determine how each nutrient is used in conjunction with the others.

Challenges

Performing any experiment outside of a controlled laboratory setting increases the risk of outside factors influencing the findings, but the risks are worth the potential results. The main challenge posed is dealing with the starting nutrient concentrations in these lakes. It is possible that during the time of this study, the lakes may have an over abundance of one or more nutrients, and are therefor unresponsive to our addition tests. It is also possible for an algal bloom to form during our tests, again making it difficult to determine how changing nutrients influenced algal abundance.

We hope to mitigate these problems by performing several replications of these experiments over several months so that if at one instance starting conditions of nutrients or algae are high, we have other sources of data to use.