A Short Lesson on Algae

posted Feb 24, 2017, 8:57 AM by Joseph Bickard

February 13, 2017 - Naples-Say the word “algae” and most people have a negative reaction: they conjure up images of slimy rocks, smelly, pea-soup colored water, and closed beaches. While all of these scenarios can be the result of excess algae growth, the real cause of algae blooms is often human impact. When you realize how important algae are to life on earth, and how beautiful and varied they are in all their shapes and designs, I hope you will gain a new appreciation for them. 

All lakes (in fact, all waters) contain algae. Cyanobacteria, the algae often to blame for water quality problems in lakes with high nutrient levels, are descended from the first complex cells. These early photosynthetic bacteria are responsible for creating our oxygenated atmosphere over a billion years ago. Algae (mainly in our oceans) also produce about 70% of the atmosphere’s oxygen every year (although trees usually get the credit!). 

The group of organisms called “algae” are very diverse, and not all algae are closely related. The one common trait they share is their ability to perform photosynthesis, the process of using sunlight and carbon dioxide to produce oxygen. Most algae are considered to be plants by scientists, with groups such as Charophyta even sharing a common ancestor with terrestrial plants. The cyanobacteria, as previously mentioned, are genetically more closely related to bacteria than plants.

No matter their origin, algae are the foundation of the aquatic food web, filling the same role that plants do in terrestrial habitats. Without algae there would be no fish or indeed much other life in our lakes, rivers, and oceans. Algae use sunlight and nutrients present in the water (most notably nitrogen and phosphorus) to grow. They are eaten by tiny zooplankton (microscopic animals) that are eaten by small fish, which in turn are eaten by larger fish. Therefore, algae are essential to a well-functioning lake ecosystem.

Knowing the amount of algae in a lake is essential to understanding and managing it. Most lake managers, including LEA, use chlorophyll-a (the green pigment common in all algae) as a way to measure algae concentrations. While this provides a convenient and comparable number with which to monitor algae populations, it leaves out a lot of useful information like diversity of species.

This is why LEA began its algae monitoring program in 2015. This program is an effort to count and identify algae from area lakes once a month from May to September. Monthly sampling allows us to see seasonal changes and patterns in algae populations. Identifying and counting the algae to genus level (one step above species) allows us to pinpoint the most common types and get an idea of the distribution of algae in each lake. 

This sort of information can be used to determine general lake water quality status, climate, seasonal flux, nutrient availability, and can be an early warning sign of water quality problems. For an element that has such a huge impact on lake water quality, algae are often neglected, only becoming important when a bloom occurs. One reason for this is the time and knowledge it takes to assess algae populations. Samples can take two to three hours each to be analyzed under a microscope, and the analyst needs to have a good understanding of algae taxonomy (identification). 

With funding from an anonymous family foundation, the LEA membership annual appeal and local lake associations, LEA was able to expand Staff Researcher hours to accommodate algae analysis. After a couple of years of self-teaching, I went to Michigan in July of 2016 to attend a week-long algae taxonomy and ecology course at PhycoTech, Inc. with algae expert Ann St. Amand. The Norcross Foundation, The Kendal C. and Anna Ham Charitable Foundation and an anonymous family foundation provided funds for microscopes, settling chambers, and other essential equipment. 

The results of our algae studies show that our lake algae populations are consistent with Northern latitude, low-to-moderate nutrient systems. There are several common algae types, however they often occur at very different concentrations from lake to lake. These differences occur for a variety of reasons. A greater understanding of the causes and consequences of the differences is a key goal of LEA’s algae monitoring program. Sudden changes in normal algae dynamics can be a sign of pending water quality problems and something we will be Tabellaria watching for with this new program.

Amanda Pratt, LEA Lakes News, Winter 2017