Seaweed and the Basics of Marine Algae; Dr. Mark Edwards, Ph.D.

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Seaweed and the Basics of Marine Algae


Dr. Mark Edwards, Ph.D.
Professor, Environmental Resource Management
Fulton Schools of Engineering at Arizona State University

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Introduction to Algae

Nano-sized, single-celled algae are among Earth’s earliest life forms. They have been surviving in many of Earth’s harshest environments for 3.7 billion years. Algae’s simplicity enables these plants to be incredibly robust – they not only survive but produce high-value biomass in tough environments. In good cultivation conditions, algae produce protein and energy biomass with yields that are 30 to 100 times more productive per acre than land plants.

Algae are critical to life on Earth as they produce the organic matter at the base of the food chain. The biomass is eaten by everything from the tiniest krill to the great blue whales. Algae also produce most of the oxygen needed for other aquatic life and provide about 70% of our daily atmosphere oxygen.

Algae, the Latin name for seaweed, present themselves in all shapes and sizes. Microalgae are single-celled, microscopic organisms often smaller than 5µ (microns) wide. The period at the end of this sentence is about 100µ.

Algae grow all over the Earth, including under both ice caps. Their preferred environments are in damp places or water but algae are common on land as well as in aquatic environments. Soils, rocks, trees and ice contain dried algae cells and many are still viable.

Seaweeds make up about 10% of algae and are larger species that live in marine environments such as kelps; brown seaweeds that may grow to 180 feet. Seaweeds may appear to have trunks and leaves similar to land plants but these structures are actually undifferentiated cells called pseudo-leaves. In tropical regions, coralline algae help build corals and support the formation of coral reefs and other species live in symbiosis with sponges.

Algae Classifications

Algae are living plants that break the rules for plant classification because they evolved in many different forms – cells, multicellular plants, bacteria and in nearly infinite combinations. While the various species share certain characteristics, different algae, even of the same species, display extraordinary variety in shape, size, structure, composition and color.

A single algae species may change shape, composition and color in a single day based on culture variables such as available light energy, nutrients, temperature and acidity, pH. Similar to all living organisms, when algae are stressed, they switch to survival mode, which changes the speed and composition of cellular metabolism. Stressors may cause algae to store more oil at the expense of proteins or carbohydrates, to use for energy at a later time. Some algae seem to accumulate more oil in order to rise to the top of the water column where they can harvest more solar energy.

The classification of algae into taxonomic groups follows the same rules used for the classification of land plants. Land plant classification came before algae because many nano-sized algae species could not be seen prior to advanced microscopes. The major algae groups are distinguished on the basis of pigmentation, shape, structure, cell wall composition, flagella characteristics, products stored and method of propagation. Algae display so many variations, even within each species, that they express exceptions to nearly every classification rule. Interestingly, many species can change the way they propagate based on ambient conditions. When conditions are good, they propagate sexually. When conditions degrade, they are able to use one or more asexual methods such as cell division, fragmentation or spores.

The ability to see minute differences in algae cells with the electron microscope has changed classifications substantially since the 1960s. Classification changes continue as new differentiators are discovered.

Algae are differentiated from other plants because they generally:

  • Display the ability to perform photosynthesis with the production of molecular oxygen, which is associated with the presence of chlorophyll a, b or c;
  • Do not have specialized transport tissues or organs consisting of interconnected cells that move nutrients and metabolites among different sites within the organism;
  • Reproduce sexually or asexually to produce gametes that generally are not surrounded by protective multicellular parental tissue.

Land plants evolved from algae about 500 million years ago and evolved specialized cells for absorbing and moving nutrients and for reproduction. Algae are distinguished from the higher plants by a lack of true roots, stems or leaves. Some seaweed such as kelp appear to have leaves, but they are pseudo leaves made up of the same cellular structure as the rest of the plant. Scientists believe microalgae and seaweeds developed in parallel evolution with land plants.

Algae species culture collections are available at The University of Toronto, California Academy of Sciences, University of Texas, University of Copenhagen, the Scottish Marine institute, The Chinese Academy of Sciences , the University of Pragueand the World Federation of Culture Collections. Most collections provide composition and culturing information, culture sales, descriptive details and pictures. The Algae Image Laboratory run by Dr. Rex Lowe at Bowling Green offers digital images of algae at no charge for educational purposes.

Many species are single-celled and microscopic including phytoplankton and other microalgae while others are multicellular and may grow as tall as trees such as kelp. Phycology, the study of algae, includes the study of prokaryotic forms known as blue-green algae or cyanobacteria. Some algae also live in symbiosis with lichens, corals and sponges. The basic single-celled organism, algae, has the general appearance illustrated in the figure.

Algae Cell

The green often associated with algae comes from chlorophyll but algae also contain pigments of many colors, especially cyan, red, orange, yellow, blue and brown. Some varieties are colorless. Green algae appears green because green is the only color of light it does not absorb. Red algae absorb a full spectrum of colors and reflect red. Red algae can grow deeper in the oceans than most other species because they are equipped to absorb the blue light that penetrates deep in the ocean.

Algae use pigments to capture sunlight for photosynthesis but each pigment reacts with only a narrow range of the spectrum. Therefore, algae produce a variety of pigments of different colors to capture more of the sun’s energy. Algae channels light into chlorophyll a, which converts light energy into high energy bonds of organic molecules.

About Dr. Mark Edwards

Mark Edwards graduated from the United States Naval Academy with a bachelor’s degree in mechanical engineering, oceanography and meteorology. He received his MBA and Ph.D. in Marketing and Consumer Psychology from Arizona State University in 1978.

His industrial experience includes service as Personnel Director for The Greyhound Corporation during the 1970s, then 27th among the Fortune 500. He had responsibility for executive recruiting, compensation, O.D., affirmative actions and succession planning. Mark has also consulted for over 600 organizations globally in the areas of advanced metrics, leadership assessment and development, sustainability and marketing.

Edwards has been a professor at Arizona State University since 1978. His teaching has focused on adding value through marketing, customer relationships, organizational leadership and entrepreneurship. His recent work focuses on solving world hunger and sustainable energy with green solutions. He has won numerous awards for excellence in teaching, research and service. He has taught several interdisciplinary courses in engineering, psychology, public programs and business. Edwards is well-known internationally as an executive trainer, author and innovator of metrics that help people to learn and develop faster, to take actions to improve performance and to grow human capital. He was named by Financial Times as “One of the Top 50 Executive Trainers” in 2000.

Ph.D. in Marketing and Consumer Psychology, Arizona State University, 1978
M.B.A, Arizona State University, 1973
B.S., United States Naval Academy

Representative Publications

Biowar I: Why Battles over Food and Fuel Lead to World Hunger. 2007. The unintended consequences of producing corn ethanol on U.S. and world food markets will be catastrophic for U.S. fossil water, soils, air, food exports and food prices.

Green Algae Strategy: End Oil Imports and Engineer Sustainable Food and Fuel. 2008. Algae offer solutions for sustainable and affordable food and energy because algae are the most productive biomass source on Earth.

Green Solar Gardens: Algae’s Promise to End Hunger. 2008. Algaculture in small solar gardens distributed globally will enable SAFE production, locally. Solar gardens addresses the web of poverty and hunger including affordable food, fodder, fish food, fertilizer, fire for cooking and heating and fine medicines.

Crash! The demise of Fossil Foods and the rise of Abundance. 2009. Traditional fossil agriculture sits precariously on a foundation of unsustainable fossil resources that will become unaffordable and then run out. Abundant agriculture is sustainable because it uses plentiful inputs that are cheap and will not run out.


Best Science Book of the Year, Independent Publishers Gold Medal, 2009
The Financial Times’ “One of the Top 50 Executive Trainers in the World,” 2000
Top 10 Speakers at American Compensation International Conference, 1999
Arizona Software Association Software Product of the Year, Intelligent Consensus, 1998

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For links to similar papers used to research this article, and to other ocean and marine-based white papers, including The World of Algae, please visit