Some biotic features would be Bristle Grass (Setaria megaphylla) or Irrawaddy Dolphins (Orcaella brevirostris). Abiotic Features would be the Precipitation, that can vary between 100mm and 1000m. Another abiotic feature is temperature. Like precipitation, estuaries are incredibly varied in temperatures. The Amazon estuary in the summer can reach 100 degrees Fahrenheit while an Alaskan estuary in the winter may be -30 degrees Fahrenheit.
