Nitroadoras
Nitroadoras are a genus of photosynthetic nitrogen fixers. They have developed a modified form of their chloroplasts which function like the heterocyst forms of some Terran nitrogen-fixing cyanobacteria; essentially, these modified chloroplasts lack the oxygen-generating step of photosynthesis. Instead, the hydrogen they obtain from the water is combined with dissolved or atmospheric nitrogen to form ammonia, which they can then use to form compounds necessary for their survival. The development of this ability allows them to thrive in environments with less usable nitrogen available. Nitroadoras are mainly found in aquatic environments, including saltwater and freshwater variants, though they can also thrive on the surface of mud. Like their ancestor, if conditions get especially bad they can still enter a dormant state for weeks at a time until conditions change for the better.
Different species of Nitroadora are fairly similar to one another, in that they have a pair of long fore-flagella and a pair of short, thick hind-flagella. However, they can come in a variety of blobby shapes ranging from long and worm-like to almost perfectly spherical. Polar species can usually go dormant for much longer than other species, as is necessary during dark winters. Like their ancestor, they have light-sensitive organelles which they use to navigate to better light. As is the case with many Terran microbes, it is difficult to distinguish between species without examining their genomes.