page_title: Marine microorganisms
section_title: Marine microfossils
hierarchical_section_title: Marine microorganisms / Marine microfossils
caption_attribution_description: English: Map showing distribution of marine sediments. Gray: land. White: Sediments of the continental margin. Blue: glacial sediments. Orange: land-formed sediments. Brown: pelagic clay. Green: siliceous sediments. Yellow: calcareous sediments.
context_page_description: Marine microorganisms are defined by their habitat as the microorganisms living in a marine environment, that is, in the saltwater of a sea or ocean or the brackish water of a coastal estuary. A microorganism is any microscopic living organism, that is, any life form too small for the naked human eye to really see, needing a microscope. Microorganisms are very diverse. They can be single-celled or multicellular and include all bacteria and archaea and most protozoa, as well as some species of fungi, algae, and certain microscopic animals, such as rotifers and copepods. Many macroscopic animals and plants have microscopic juvenile stages. Some microbiologists also classify biologically active entities such as viruses and viroids as microorganisms, but others consider these as nonliving.
  Marine microorganisms make up about 70% of the biomass in the ocean. Taken together they form the marine microbiome. Over billions of years this microbiome has evolved many life styles and adaptations and come to participate in the global cycling of almost all chemical elements. Microorganisms are crucial to nutrient recycling in ecosystems as they act as decomposers.
context_section_description: Sediments at the bottom of the ocean have two main origins, terrigenous and biogenous. 
  Terrigenous sediments account for about 45% of the total marine sediment, and originate in the erosion of rocks on land, transported by rivers and land runoff, windborne dust, volcanoes, or grinding by glaciers.
  Biogenous sediments account for the other 55% of the total sediment, and originate in the skeletal remains of marine protists (single-celled plankton and benthos microorganisms). Much smaller amounts of precipitated minerals and meteoric dust can also be present. Ooze, in the context of a marine sediment, does not refer to the consistency of the sediment but to its biological origin. The term ooze was originally used by John Murray, the "father of modern oceanography", who proposed the term radiolarian ooze for the silica deposits of radiolarian shells brought to the surface during the Challenger Expedition. A biogenic ooze is a pelagic sediment containing at least 30 percent from the skeletal remains of marine organisms.
caption: Distribution of pelagic sediments
   Yellow: calcareous sediments
  Green: siliceous sediments
  Brown: pelagic clay
  White: sediments of the continental margin
  Blue: glacial sediments
  Orange: land-formed sediments
  For further information, see here
exif: {"Image Orientation": "Horizontal (normal)", "Image XResolution": "9/1250", "Image YResolution": "9/1250", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop Elements 5.0 Windows", "Image DateTime": "2009:08:30 06:33:38", "Image ExifOffset": "172", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "308", "Thumbnail JPEGInterchangeFormatLength": "3234", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "1000", "EXIF ExifImageLength": "752"}