Search results
Results from the WOW.Com Content Network
In a reversal of the pattern on land, in the oceans, almost all photosynthesis is performed by algae and cyanobacteria, with a small fraction contributed by vascular plants and other groups. Algae encompass a diverse range of organisms, ranging from single floating cells to attached seaweeds. They include photoautotrophs from a variety of groups.
Microalgae, capable of performing photosynthesis, are important for life on earth; they produce approximately half of the atmospheric oxygen [2] and use the greenhouse gas carbon dioxide to grow photoautotrophically. "Marine photosynthesis is dominated by microalgae, which together with cyanobacteria, are collectively called phytoplankton."
Since iron is necessary for phytoplankton growth, the auto-reduction of reactive oxygen species may be a way for algae to get usable iron from free or organically bound ferric iron. [73] For instance, Cakman et al. [ 74 ] showed that ROS may increase the amount of iron available through extracellular ferric reduction.
Microorganisms have key roles in carbon and nutrient cycling, animal (including human) and plant health, agriculture and the global food web. Microorganisms live in all environments on Earth that are occupied by macroscopic organisms, and they are the sole life forms in other environments, such as the deep subsurface and ‘extreme’ environments.
Marine algae can be divided into six groups: green, red and brown algae, euglenophytes, dinoflagellates and diatoms. Dinoflagellates and diatoms are important components of marine algae and have their own sections below. Euglenophytes are a phylum of unicellular flagellates with only a few marine members. Not all algae are microscopic.
Sponges (phylum Porifera) have a large diversity of photosymbiote associations. Photosymbiosis is found in four classes of Porifera (Demospongiae, Hexactinellida, Homoscleromorpha, and Calcarea), and known photosynthetic partners are cyanobacteria, chloroflexi, dinoflagellates, and red and green (Chlorophyta) algae.
In 2000 it was discovered that if C. reinhardtii algae are deprived of sulfur they will switch from the production of oxygen, as in normal photosynthesis, to the production of hydrogen. [15] [16] [17] Green algae express [FeFe] hydrogenases, being some of them considered the most efficient hydrogenases with turnover rates superior to 10 4 s −1.
Dunaliella is a single-celled, photosynthetic green alga, that is characteristic for its ability to outcompete other organisms and thrive in hypersaline environments. [1] It is mostly a marine organism, though there are a few freshwater species that tend to be more rare. [2]