Economic viability of proactive harmful algal bloom mitigation through attached algal growth

Abstract

Harmful algal blooms (HABs) affect fresh and saltwater bodies around the world, causing a variety of damages to the surrounding communities. The primary driver of HABs is nutrient pollution. One novel HAB mitigation solution is to employ large-scale attached algal growth systems that consume nutrients from the water and prevent downstream nutrient accumulation and large scale HAB events. The feasibility of technology deployment is dependent on the economic viability. A model was created to estimate HAB-related economic damages, with or without non-point source nutrient reduction solutions, using Lake Erie as a case study. In the model, HAB severity is predicted based on nutrient loads and is tied to economic indicators to estimate the HAB-related economic losses. Results show that on average, Lake Erie communities lose $142 M (± $29 M) year−1 from HABs without mitigation technology. Use of attached algal systems show an average net savings ranging between $29–42 M year−1 from HAB mitigation depending on the system configuration. Attached algal systems show greater positive cash flows when compared to farm-based best management practices, thus warranting additional testing and consideration as a potential HAB mitigation strategy. Additional considerations included stochastic uncertainty and increasing dissolved reactive phosphorus concentrations, which increased the effectiveness of attached algal systems.