Oddities and Curiosities in the Algal World

Abstract

assemblage, of O 2 -evolving, photosynthetic organisms. The profound diversity of size, shape, habitat, metabolic traits and growth strategies makes this heterogeneous assemblage of both prokaryotic and eukaryotic species an almost unlimited source of curious and unusual features. Algae display an incredible adaptability to most environments, and provide an excellent system for testing hypotheses concerning the evolution of ecological tolerance. In fact, they are not limited to temperate waters, but can survive at very low depth and very low irradiance, and thrive beneath polar ice sheets. Upon adaptation to life on land, algae have colonized such surprising places, as catacombs, tree trunks, hot springs, and can also resist desiccation in the desert regions of the world. Moreover, relations between them and other organisms, which include competition within and between species for space, light, nutrient or any limiting source, are based on a variety of associations, which includes epiphytism, parasitism, and symbiosis. Algae can share their life with animals, growing on sloth hair, inside the jelly capsule of amphibian eggs, upon the carapaces of turtles or shells of mollusks, camouflaging the dorsal scute of harvestmen. They can also light up the sea at night, and cause infections in animals and humans.______ *To whom correspondence should be addressed. Paolo Gualtieri, Istituto di Biofisica C.N.R., Area della Ricerca di Pisa, Via Moruzzi 1, 56124, Pisa, Italy. Email: paolo.gualtieri@pi.ibf.cnr.it 353 Abstract: The term algae refers to a polyphyletic, non-cohesive and artificial

Potential for green microalgae to produce hydrogen, pharmaceuticals and other high value products in a combined process

“…Many algae have the ability to survive harsh environmental conditions due to different adaptation strategies (Barsanti et al , 2008; Seckbach, 2007). Many mechanisms for adaptation lead to changes in the algae’s physiology, and as a consequence, the algae will produce different secondary metabolites as part of their adaptation strategies.…”

“…These conditions require the cells to develop defense mechanisms against damaging effects of irradiant stress (Barsanti et al , 2008). Photodamage of the photosynthetic systems is a continuous process that occurs during light conditions in all photosynthetic eukaryotes.…”

“…Thermotolerant green algae are highly uncommon; photosynthetic organisms in hot springs are usually dominated by prokaryotes (Barsanti et al , 2008). However, some green algae have tolerance to temperatures up to 42°C, like Chlorella sorokiniana (de-Bashan et al , 2008; Sakai et al , 1995).…”

“…Algae represent a highly diverse group of organisms, which are able to grow under a variety of different conditions. Algae are found at low and high temperatures, low and high light intensities, different pH, high salt concentration, in water bodies or in desert crusts, or in symbiosis with animals (Barsanti et al , 2008). …”

Symbioses between salamander embryos and green algae

“…The associations between vertebrates and algae span several different categories of symbiosis (Barsanti et al 2008). These include commensalisms, such as algae living inside the guard hairs of captive polar bears (Lewin and Robinson 1979), where neither partner benefits nor is harmed.…”