Why are harmful algal blooms dangerous and how do we keep track of their spread?
In recent decades, harmful algal blooms have become more and more common due to increasing temperatures and increased incidents of natural disasters. This impact on communities ranges from inconveniences, such as beach closures, to health hazards.
While algae can develop into a harmful algal bloom almost anywhere where the conditions are right, one area that has encountered many issues with algal blooms in the Great Lakes and surrounding bodies of water. Specifically, Lake Erie has struggled to keep algal blooms at bay.
The lighter coloration in this image shows the algal blooms in Lake Erie.
What are harmful algal blooms (HABs)?
Algal blooms are the overgrowth of bacteria or algae in water over a short period of time. This can happen in any type of water, fresh or salt, and usually blooms are the most productive in warmer months of the year. Harmful algal blooms, abbreviated as HABs, is when algae or bacteria grow out of control while producing toxins that can result in negative impacts on humans. Cyanobacteria, or more commonly known as blue-green algae, is a common bacteria that develops into HABs.
What are the risks associated with algal blooms?
There are toxins that are present in the algae or bacteria which can infiltrate food sources that are living in the body of water that the HAB is present in, such as fish or shellfish, which can cause humans or animals that consume them to become sick. Furthermore, coming into contact with HABs in a recreational context, swimming for example, can cause a number of nasty symptoms, including skin rashes and diarrhea. These same toxins can become airborne as well, causing issues for those with asthma.
How are algal blooms tracked?
In order to understand where the blooms are most dense, and therefore dangerous, there are a number of ways that algal blooms can be illustrated. Recently, the most efficient and immediate method of figuring out how large a space of an algal bloom is and the intensity of the spread is through the use of aerial imaging techniques. This is then illustrated through hyperspectral imaging.
Hyperspectral imaging is an application of spectroscopy, which takes many images of the same area at many different wavelengths. In the case of using hyperspectral imaging for algal blooms, it can create an image that colors the spread and intensity of the cyanobacteria.
As seen in the images below, the NASA-Glenn Research Center and the NOAA/GLERL groups developed slightly different methods of showing this hyperspectral imagery. Ultimately they both show similar information about the density of the algal blooms. Knowing what areas are impacted by HABs allows local authorities and community members to take steps in order to avoid health hazards and negative impacts on local industries.
These figures show another hyperspectral method used by NOAA/GLERL looking at the density of the cyanobacteria.
Harmful algal blooms are a very current and relevant issue that must be dealt with in order to protect the health of our communities. This can be done with the help of technologies such as hyperspectral imaging. On an individual level, harmful algal blooms can be fought through reducing the use of fertilizers on properties as well as ensuring any sort of septic systems are sound and will not leak. On a broader scale, fighting climate change, and reducing its impacts on the environment, will help to reduce the incidents of harmful algal blooms.
By Anna Cerosaletti
Sources:
Center for Disease Control. “Protect Yourself and Your Pets | Harmful Algal Blooms.” CDC, https://www.cdc.gov/habs/prevention-control.html. Accessed 13 November 2022.
Denchack, Melissa, and Melanie Sturm. “Freshwater Harmful Algal Blooms 101.” NRDC, 28 August 2019, https://www.nrdc.org/stories/freshwater-harmful-algal-blooms-101. Accessed 13 November 2022.
Konica Minolta Sensing Singapore Pte Ltd. “Understanding Hyperspectral Imaging (HSI) - Konica Minolta Color, Light, and Display Measuring Instruments.” Konica Minolta Sensing, 23 June 2021, https://sensing.konicaminolta.asia/understanding-hyperspectral-imaging-hsi/. Accessed 13 November 2022.
Lekki, John, et al. “Airborne hyperspectral and satellite imaging of harmful algal blooms in the Great Lakes Region: Successes in sensing algal blooms.” Journal of Great Lakes Research, vol. 45, no. 3, 2019, Pages 405-412. Elsevier, https://www.sciencedirect.com/science/article/pii/S0380133019300723. Accessed 13 November 2022.
National Centers for Coastal Ocean Science. “Lake Erie Harmful Algal Bloom FAQs.” National Centers for Coastal Ocean Science, https://coastalscience.noaa.gov/research/stressor-impacts-mitigation/hab-forecasts/lake-erie/faqs/. Accessed 13 November 2022.
National Oceanic and Atmospheric Administration. “Why do harmful algal blooms occur?” National Ocean Service, 1 June 2022, https://oceanservice.noaa.gov/facts/why_habs.html. Accessed 13 November 2022.
NIREOS. “What Is Hyperspectral Imaging?” NIREOS, https://www.nireos.com/hyperspectral-imaging/. Accessed 13 November 2022
You do a really great job of explaining algal blooms, how they occur, and their effects on humans. I love the pictures and graphs you used to help visualize this issue, and just the overall format of this page. It makes for an easy but sophisticated read. After reading it, I wonder how algal blooms affect other species and their habitats. It could be interesting to look into this and emphasize the indirect effects that humans can have on countless species through pollution and climate change.
ReplyDeleteAwesome article! Being from Florida, algae blooms have been a reoccurring problem for years, and I know it's only gonna get worse as climate change continues to worsen. I feel that algae blooms as a consequence of climate change doesn't get enough attention, and some of its wider effects are still unknown. I really hope some sort of solution or tactic can be discovered to negate or lessen the frequency/ severity of algae blooms.
ReplyDeleteI have encountered algal blooms a couple times in my life, so it was interesting to learn more about the ways in which they are harmful as well as how they are managed. At the end of the piece, I was left wondering how climate change can impact incidents of harmful algal blooms. Additionally, I want to learn more about how HABs produce toxins. And how do bacteria develop into HABs? Your piece left me with a lot of questions so great job establishing a tone of importance!
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