Is it a plant? Is it an animal? Algae are very unusual! Algae are microscopic organisms, and are usually considered to be just simple aquatic plants. Pond scum, really. But it may surprise you to learn that some algae display characteristics we would normally associate with an animal. Characteristics like motility and a cell structure more like bacteria than plants. Algae can come in a variety of sizes from microscopic to dramatically large. As well, algae are not just water-based. Algae also live in soil, snow, fungus, and animals. But water based Algae, which is what we're looking at today, can be found in both fresh and marine waters. There are many types of water-based algae, so we will quickly review just a few of them here so you know the difference. The algae that grows on rocks or plants in the water is one kind. Another kind is more commonly referred to as seaweed because it grows into the water but is attached to a larger stem-like structure. Water-based algae, in many cases, are also called "phytoplankton", and it is one of the key ingredients that take carbon dioxide out of the air and replace it with oxygen! We need water-based algae (phytoplankton) to live, and they account for a lot of the carbon dioxide/oxygen replacement in the world today. Often, algae are referred to by colour. Plank tonic algae, like the kind described above, are called green algae. There are other kinds, too, referred to as blue green algae. Blue-green algae is a type of bacteria, even though it has plant-like characteristics as well, and they grow everywhere, including dams, rivers, creeks, and hot springs. Okay, so you've probably read more than you wanted to about algae. And there's a lot more that you probably don't need to know. Essentially know this: Phytoplankton is a type of algae that we want lots of in the world to help scrub our atmosphere of greenhouse gases. Blue-green algae, although it also releases oxygen, also has a different effect. Blue-green algae grow and rise to the surface where it accumulates into a large bloom. These blooms take on other colours, including brown and red. And as a result of this bacteria blooming in the water, bad things happen. In fact, the term "red tide" when referring to water-based algae blooms, is never a good thing. Because blue-green algae are bacteria, it tends to grow where bacteria would typically grow: in areas with high nutrient levels, slow rivers, low wind, and warmer temperatures. When this happens, bad water can result. While usually people think of algae as being a plant that grows, you might think of blue-green algae and the resultant bloom as bacteria that fester. At a very basic level, blue-green algae can create unpleasant water. For example, it can leave water with an unpleasant odour and taste; it can clog machinery filters; it can fluctuate the pH balance in water, turning alkaline water acidic and acidic water alkaline; it can pull the oxygen out of the water and both fish and humans need water with oxygen in it to live! While those are unpleasant and sometimes dangerous results of algae blooms in the water, there are other potential risks as well. Algae blooms can create Hepatoxins which attack the liver and other internal organs and promote cancer. Algae blooms can create Neurotoxins which can lead to respiratory arrest. Algae blooms can create Endotoxins which irritate the skin and also cause stomach cramps, nausea, fever and headaches if consumed. So how bad can algae blooms get? Why can't we just swim around them or scoop them up? Because they can grow tremendously huge! One algae bloom in 1991 was reported to be over 600 miles long! What causes blue-green algae to become so dangerous? There are a few things. The first suggestion is the use of fertilizers and sewage that eventually works its way back into the water system. (Sure we use it on the soil, but we live in an interconnected Geo-system that has rainfall soaking the ground, draining off the land into the water, and getting evaporated into the sky. On the way, it picks up all the bad things we leave in the ground). Another problem that allows blue-green algae to bloom is called thermal stratification. This is a distinct difference in the layers in a river, where a quickly flowing surface does not actually mix with a slower moving bottom layer. These two distinctly different layers of water allow algae to grow in large proportions, but remain in one layer; however when a temperature changes as the result of seasonal fluctuations, the algae mixes and moves, and blooms can develop. So how does global warming affect, or get affected by, algae blooms? Algae blooms can have a negative impact on the delicate ecosystem that requires balance to thrive. This is because blooms can virtually kill water, reducing its impact on scrubbing carbon dioxide. And, because temperature changes often act as a catalyst for algae blooms, our warming planet may exacerbate more blooms! Also, the more we use fertilizers or allow sewage to seep back into our water systems, the more we'll see the proliferation of algae blooms over time. So what's the answer? It's easy to simply say "don't use fertilizer" or "don't let sewage get into the water system", but it's quite another thing to manage it. After all, reverse thinking suggests that a greater amount of fertilizer will theoretically grow more plants which will feed more people. So you might think of it this way: more well-fed scientists can spend time thinking how to reduce algae blooms, than a few poorly fed scientists can spend time thinking how to grow plants without using fertilizer. And, as our understanding of DNA structure develops, scientists may be able to develop a super-phytoplankton that uses elements of good green phytoplankton that currently scrubs our atmosphere with the aggressive and migratory nature of blue-green algae to create a phytoplankton that can respond to atmospheric changes and congregate where it is needed most.