{"id":825,"date":"2014-11-11T11:24:16","date_gmt":"2014-11-11T16:24:16","guid":{"rendered":"http:\/\/blogs.nicholas.duke.edu\/fuelforthought\/?p=825"},"modified":"2014-11-11T11:24:16","modified_gmt":"2014-11-11T16:24:16","slug":"algae-farming","status":"publish","type":"post","link":"https:\/\/blogs.nicholas.duke.edu\/fuelforthought\/algae-farming\/","title":{"rendered":"Algae Farming"},"content":{"rendered":"

Crops.<\/p>\n

Although this word may have just\u00a0conjured up\u00a0images of corn and wheat fields, a lesser-known\u00a0crop was the subject of an international summit held in San Diego last month. Algae, from microscopic cells to seaweeds, are crops that can supply numerous products such as nutrient supplements, omega-3 fatty acids, animal feeds, natural dyes, and, potentially, fuels like biodiesel and ethanol.<\/p>\n

The Algae Biomass Summit is an annual event that draws in key players<\/a> in the algae business, including researchers, companies, government representatives, and more. While we are still researching how\u00a0to successfully mass-produce\u00a0algal biofuels, other companies have been profiting from algae\u00a0nutrient supplements (mostly Spirulina<\/em>). These include companies such as Earthrise Nutrionals in California (read about how they grow algae here<\/a>) and Cyanotech<\/a> in Hawaii. A\u00a0sample package of Spirulina tablets I received while touring the Earthrise farm is below.<\/p>\n

\"IMG_2761\"<\/p>\n

Algae\u00a0products like nutrient powder are\u00a0currently more profitable than algae\u00a0fuels. To make algae a viable energy source, researchers are working to\u00a0decrease the\u00a0costs and energy requirements of\u00a0growing algae, harvesting them and converting them into fuel. One strategy for reducing costs in the growth stage\u00a0is applying\u00a0lessons we’ve already learned from\u00a0agriculture.<\/strong><\/p>\n

Earlier this year, ecologists Val Smith (see\u00a0previous post<\/a>) and Timothy Crews published a paper <\/a>in which they compared commercial agriculture\u00a0and large-scale microalgae cultivation. The same problems and potential solutions that are applicable to agriculture are applicable to growing microscopic algae for various products from fuels to feeds.<\/p>\n

Algae grown outdoors (see the raceway pond at 1:34 in the video below) are susceptible to predators, weeds, and parasites just like terrestrial crops are. With\u00a0algae, ‘weeds’ are\u00a0algae strains that aren’t desirable for biofuels, and predators include grazers such as zooplankton. One\u00a0commercial-scale agricultural solution to predators is pesticides. Smith and Crews note that while pesticide application in open algae ponds is an option, it faces similar problems as terrestrial crops: predators can become resistant to pesticides due to selection pressures. The authors instead promote biological control methods, where beneficial\u00a0organisms are added to either consume or deter\u00a0pests and predators. Alternatively, Earthrise farms uses a high pH in their algae ponds\u00a0so that only Spirulina<\/em> can grow, since most other microorganisms cannot tolerate the alkaline conditions.<\/p>\n

Creating resistant crops through genetic engineering is another route to prevent disease and predation. When all individuals in a crop are genetically the same, however, they could quickly be wiped out by a pathogen they are not resistant to. Genetic diversity offers protection because some individuals may be susceptible while\u00a0others survive. This safety net is one advantage of growing polycultures, which contain different crops\u00a0that coexist because of different growth requirements.<\/p>\n

Growing polycultures can\u00a0also increase the long-term sustainability, resilience, and productivity of crops, though terrestrial polycultures are usually grown on small farms\u00a0and do not always work in reality. Crops grown together could\u00a0use resources more efficiently, and could benefit from the metabolic products or protective features\u00a0of the other crops. Aquatic ecologists have recently been\u00a0experimenting with algae polycultures, and some have shown<\/a> that certain algae strains grown together can create more biomass than any of the strains grown individually. This does not work for all of the algae mixtures, but is a step forward in thinking about how to improve the stability and productivity of algae cultures grown for biofuels.<\/p>\n

While researchers have been experimenting with growing algae for biofuels for over 50 years, algae have been grown as crops for much longer. Attending the Algae Biomass Summit reminded me of the direct connection between algae and agriculture, and how we can apply existing principles of crop science to improve productivity of this lesser-known crop.<\/p>\n

Below is an arrangement of\u00a0photos and clips from\u00a0my trip to San Diego for the Algae Biomass Summit. Enjoy!<\/p>\n