Marine BioGroups
From Microcosm Aquarium Explorer
Arothron mappa, Map Puffer. Scott W. Michael
Marine: A Definition
Marine is defined "of or pertaining to the ocean or sea," while saltwater is more narrowly defined by aquarists.
The classification of different waters by their salt content, as measured by Specific Gravity (relative density, the most-common measure among aquarists) is:
- Marine or Saltwater 1.022 – 1.035
- Brackishwater 1.05 – 1.010
- Freshwater 1.0
Salinity or salt content is measured as parts per million (ppm) or mg/L:
- Marine or Saltwater: 3-5% or 30,000-50,000 ppm
- Brackishwater 0.05-3% or 500-30,000 ppm
- Freshwater <0.05% or <500 ppm
Marine BioGroups:
Specific Gravity of Different Marine Regions
- Tropical Indo-Pacific 1.022 – 1.025
- Caribbean 1.023 – 1.026
- Red Sea 1.028 – 1.035
Chemical Composition of Seawater
Reference: The Conscientious Marine Aquarist