Marine life live in the water column of large bodies of water and that cannot swim against a current. They provide a crucial source of food to many large aquatic organisms, such as fish and whales. These organisms include drifting or floating bacteria, archaea, algae, protozoa and animals that inhabit, for example, the pelagic zone of oceans, seas, or bodies of fresh water. Essentially, plankton are defined by their ecological niche rather than any phylogenetic or taxonomic classification. Though many planktonic species are microscopic in size, "plankton" includes organisms covering a wide range of sizes, including large organisms such as jellyfish. The
Microscopic colitis of 7.1 per 100,000 person-years and 12.6 per 100,000 person-years for collagenous colitis for lymphocytic colitis, respectively. Prevalence has been estimated as 103 cases per 100,000 persons. People who develop microscopic colitis are characteristically, though not exclusively, middle-aged females. The average age of diagnosis is 65 but 25% of cases are diagnosed below the age of 45. The condition of microscopic colitis was first described as such in 1982. Lymphocytic colitis was described in 1989. Collagenous colitis was recognised earlier, in 1976. Microscopic colitis Microscopic colitis refers to two related medical conditions which cause diarrhea: collagenous colitis and lymphocytic colitis.