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.
Hildenbrandia
The freshwater species "H. rivularis" and "H. angularis" seems to form a clade, and require an alkaline pH and hard water, preferring clean water. Unlike most other freshwater red algae (which prefer running water), "H. rivularis" prefers still water, particularly shady lakes or ponds. "H. rubra" and other marine species are found in brackish waters, but freshwater / gemma-bearing species cannot tolerate even moderate salinities.
The genus is often found in a symbiotic partnership with fungi.
"Hildenbrandia" has a remarkable tolerance to stresses including extreme temperatures, desiccation, and Ultra-violet light; it can be up and photosynthesizing near full capacity just minutes after being cooled to −17 °C or subjected to extreme salinities.