Upwelling
The major upwellings in the ocean are associated with the divergence of currents that bring deeper, colder, nutrient rich waters to the surface. There are at least five types of upwelling: coastal upwelling, large-scale wind-driven upwelling in the ocean interior, upwelling associated with eddies, topographically-associated upwelling, and broad-diffusive upwelling in the ocean interior.
Neobodo
Bodonid flagellates (class Kinetoplastea) are abundant, free-living bacterivores that occur in a wide variety of environments including freshwater, soil and marine habitats ranging from the tropics to the Arctic. Neobodo is one of the most common flagellates in freshwater environments, but can also tolerate marine environments with low salinities of 3-4 ppt. Strains of "Neobodo" species isolated from different environments fall exclusively into marine and freshwater lineages. Studies show that "Neobodo" is a complex and ancient species with a major marine clade nested among older freshwater clades. This suggests that these lineages were constrained physiologically from moving between these environments for most of their long history. Their broad physiological tolerance enables them to easily interchange between marine and freshwater environments, which gives them a cosmopolitan characteristic and a wide ecological tolerance. Recent evidence for "Neobodo designis" suggested notable divergence between freshwater and marine strains and all strains exhibited extensive genetic diversity. Epifluorescent microscopy studies reported the abundance of several HNF (heterotrophic nanoflagellate) groups (including bodonids) in the euphotic zone of different marine areas. Areas include the Mediterranean Sea, Norwegian Sea, the Indian Ocean and around the Antarctic Peninsula. Throughout the numerous oceans, large fractions of small heterotrophic flagellates with few morphological features remain unidentified. Therefore there is a high possibility that there are many bodonids among the unidentified that have not yet been studied.