In the quest to find cheap and abundant sources of energy, many companies and research organizations have turned to algae. Much of their research has been focused on maximizing algal growth. However, increased algal growth can often become harmful if in a natural setting. One algae company, Algaeventure Systems, is actually looking at ways to lessen the effects of these “harmful algal blooms” (HABs) in the environment. Dr. Stephanie Smith is the lead scientist at Algaeventure and answered the following questions about HABs.
1. What are the main causes of harmful algal blooms (HABs)?
The causes vary from site to site, and there are typically multiple factors that converge at the same time to contribute to a bloom. It boils down to this: why didn’t the algae bloom before, or why don’t they always bloom? In other words, there are natural checks and balances on algal populations (all populations, really), and when those checks and balances are disrupted it can lead to a bloom.
In the case of many inland lakes, the thing that keeps algae that cause HABs in check is often nutrients, especially phosphorus and nitrogen. Typically those nutrients are not in high enough concentrations in a lake to allow the HAB algae to flourish, but a variety of things can lead to nutrient-rich conditions (agricultural runoff is often blamed, albeit not always fairly). And if the nitrogen goes away but the phosphorus is still high, the dominant algae continue to thrive because they are able to take nitrogen out of the air rather than the water.
Another major factor is temperature. These nitrogen-fixing algae, which are actually cyanobacteria sometimes called “blue-green algae,” are insidious under condition of high phosphorus, low nitrogen, and warm temperatures. Grand Lake-St. Marys (GLSM) is an immense, but shallow lake that easily warms in the late summer. Therefore, with the right nutrients, it is perfect for a HAB.
Another factor is competition. Could other algae, like a group of algae called diatoms, use those nutrients, and grow when it’s warm? They probably can, but then maybe something else is keeping their populations in check. Last summer, AVS proposed that a key factor limiting diatoms could be silica, which they require for growth, and which in the past has been added to other systems to stimulate their growth.
This is an overly simplistic answer to the “causes” question, but it is widely agreed among scientists that nutrients and temperature are among the biggest drivers that cause HABs.
2. Can you explain how a company who is focused on growing algae would be able to help with stopping harmful algal blooms?
Well, for clarity, we don’t think we can stop HABs, without some restoration of the checks and balances such as those mentioned above. No single approach is going to end this problem. A variety of approaches are going to have to be implemented, and different combinations of technologies will be required at different sites, in order to stop a HAB. Frankly, that’s going to require a lot of continued research, as well as development of new technologies and methodologies.
AVS does know a thing or two about growing algae, and what they like, and what they don’t like, and we know more than almost anyone about how to harvest algae. As we and all other algal companies can tell you, growing algae at large scale is not a trivial process. But when you look at HABs, it happens “at scale” all the time. So a company like ours sees that at GLSM, there are a lot of algae floating up on the shores and into the back yards of beautiful lakeshore homes. Can we use our harvesting technologies to help ameliorate some of those effects, and maybe even put the recovered algal biomass to use somehow? While prevention of HABs should always be strived for, we thus think it is worth investigating whether more can be done when a bloom is in progress, and if it cannot be fully remediated, can positive outcomes be realized through some other means?
3. Algaeventure Systems is currently working with harmful algal blooms in Grand Lake St. Marys. How has your pilot program of adding silica to a certain area of the lake turned out?
The premise of this program was that if we could encourage the growth of diatoms, the diatoms might be able to outcompete the cyanobacteria. In the end, our amendment with silica did not have any adverse effects, but neither did it have the desired effect. That exercise was very important, because it has led to a better understanding of what is going on at GLSM. At the time we did our amendment, nobody had any data regarding silica concentrations in that lake, and there was little known about the biological profile of the types of algae in the system. We’ve since implemented our own monitoring program, and have learned that the silica concentrations are probably not low enough to limit diatom growth at GLSM. That, combined with the very hot temperatures last year, makes the outcome not surprising in hindsight. Our monitoring program has also made us aware of other algal species at GLSM that could potentially have a better chance at outcompeting the cyanobacteria. It would be a very involved research project to see if they can be stimulated, but one we might pursue in the future.
4. Do you think that large scale commercial production of algae could lead to the risk of more harmful algal blooms?
Like all industries and agricultural activities, commercial production of algae needs to include monitoring and waste management. The same nutrients that we use to deliberately grow algae can stimulate an algal bloom if they are recklessly dumped into a municipal system, stream, or water body. Because of our involvement at GLSM and interest in HABs, our company is more acutely aware of this than most. We work very closely with our municipal water officials, and monitor and meter our waste. There are some interesting possibilities here, too. For example, could our “spent” media used to grow algae be repurposed to fertilize a garden, or a field of corn? We are investigating such options, because of our commitment to operate an environmentally sustainable business.
5. An Algaeventure Systems representative recently testified at a Congressional hearing on algal blooms. What was the outcome of these hearings?
The legislation (HABHCRA) is still in review and is expected to be passed during this congressional session. HABHRCA has been in place for years, and funds most of the HAB research that is conducted at our coastal areas (e.g., Chesapeake Bay) and the Great Lakes (e.g., Lake Erie). The renewal of the legislation is in progress, as is the decision process regarding how much funding will be allocated to it. The significance of the hearings was to make sure that expert opinion was entered into the congressional record, so that it would be considered in the legislative and funding process. Points our company aimed to emphasize at the hearing were that the legislation neglects inland lakes like GLSM, and that very little is done in the area of remediation.
Dr. Stephanie Smith