by Mark Edwards
lgae are aquatic microscopic plants with chlorophyll-a and a single-cell body not differentiated into roots, stems or leaves. Algae include some photosynthetic bacteria, the cyanobacteria. Algae’s photosynthetic mechanism is similar to land-based plants, except they are far more efficient in converting solar energy into biomass. Algae has a very simple cellular structure, live in an aqueous environment where they have efficient access to water, CO2 and other nutrients, and an extraordinary capacity to adapt.
Terrestrial algae have adapted to live on land and exhibit robust growth in moist environments. Algae crusts cover global deserts and get their moisture from morning dew. Algae grow on any surface, alive or not, and grow on and in the bark of trees and the roots of plants. Legumes use algae in root nodules to harvest nitrogen from the air. Algae and fungi are symbionts in lichen. Algae supplies the pigments and food, as well as sugars, while the fungi grow on the outside and protect the algae from desiccation in the sun. Algae also grow in symbiosis with moss, coral, sponges and many aquatic animals.
The energy available to each cell constrains growth, for both single and multicellular organisms. Available nutrition dictates how much energy an organism can make using cellular metabolism to either use immediately or to store. Multicellular organisms expend roughly 85% of their energy on non-growth functions. Therefore, they have only a tiny energy reservoir, and only modest energy for growth and development.
Many unicellular organisms reproduce asexually, which can take the form of binary fusion, fragmentation or spores. They do not have to waste energy and resources on a sexual apparatus, but many can reproduce both asexually and sexually. Avoiding a sexual apparatus saves 35% of the energy over multicellular plants. Asexual reproduction allows single-celled organisms to multiply at very high rates. Corn plants create 640 seeds in its one-year of life. (Actually, corn matures in about 120 days, but grows only during the summer growing season each year). Algae can double, triple and even quadruple its biomass in a single day.
Unicellular organisms have the ability to absorb energy and nutrients by diffusion or osmosis. Almost anything makes a potential food source for a unicellular organism. This eliminates the necessity for roots, which consumes about 30% of the energy for land plants. Single-celled organisms do not waste energy finding digestible food or expending their energy on a digestive system.
Terrestrial crops such as food grains must build structures that can withstand the harsh effects of wind and rain, which saps another 10% of their energy. Unicellular organisms also have no need for circulatory or excretory systems, saving another 10% of their cellular energy.
Algae sustain a substantial competitive growth advantage over terrestrial plants. Algae cells waste no energy on functions that are vital to land plants, which retains all their energy for growth. In addition, nearly the entire algae biomass contains valuable nutrients.
Grain farmers must invest enormous resources to grow food grains that are more than 90% non-digestible cellulose in roots, stem, leaves and husks. Farmers harvest the fruit of the vine, typically the seeds, which is often less than 10% of the plant. In contrast, microfarmers harvest algae that is nearly 90% food. Ash, the only non-nutritional residual in algae, accounts for less than 10% of the dry biomass.
Many macro and microalgae are asexual and divide by multiple fission. Most share one common feature: under optimal growth conditions, they can divide into two or more daughter cells. The number of daughter cells, also known as the division number, is relatively stable for most species, and ranges from 4 to 16. Light, nutrients and temperature dictate the number of daughter cells. Cells normally divide twice or three times during a single cell cycle. Cell-cycle progression starts with a period of growth, the G1 phase.
During this phase, the cells increase their volume until they roughly double the volume of the daughter cell, coenobia. A coenobia is a colony of algal cells, where the cells are arranged in a constant form and number and are surrounded by a gelatinous matrix.
When the cells have doubled their volume, the cell cycle approaches the commitment point (CP). When the CP is reached, the cell commits to triggering and then terminating the DNA replication–division sequence, followed by mitosis and cell division.
Scientists are actively studying the CP with the plan to trigger quicker cell cycles. Another production strategy involves finding a pathway to increase the division number and create more than 16 daughter cells in each cycle. Both strategies have the potential to significantly increase algae productivity.
Most species can adapt to various microclimates, but typically thrive in the area where their ancestors have lived for millennia. Algae grow in many shapes, sizes and colors.
Algae’s tiny cell size create the ideal nutrient delivery system for plants and animals. Each tiny algae cell packages the essential nutrients for multi-cellular life – plants, animals and humans. The algae nutrient packets are so small the algae nutrients are immediately bioavailable to the plant or animal.
A food grain such as corn grows primarily in one direction, up towards the sun. Algae grow in all directions, 360°, which allows considerably more freedom to multiply quickly. Terrestrial plants are locked by their roots to one location. If the nutrients available to its roots are plentiful, the plant grows. If nutrients are not within reach, the plant dies. If moisture is not within reach, the plant dies. Moisture is necessary to dissolve the nutrients for biosorption. Food crops also need microorganisms, such as algae, to break down chemical fertilizer to make the nutrients bioavailable.
Algae displays extreme biodiversity. A handful of dirt may contain several million algae cells and several hundred-different species. A cup of pond water will contain even more algae cells and more species. Marine algae grow in highly saline ocean water and may be macro, sea vegetables, or microalgae.
Terrestrial algae thrive on land when moisture is available. They go dormant during dry times, then re-energize with rain or irrigation. Each cultivar evolved locally over eons and adapted to the unique characteristics of the in-situ microclimate.
