| Feature | Aquatic ecosystems | Terrestrial ecosystems |
| Prevalence of aquatic medium | Greater | Lower |
| Phyletic diversity (a and b) | Greater | Lower |
| Interpopulation genetic diversity | Lower | Higher |
| Dimensions of species distribution | Three-dimensional | Two-dimensional |
| Degree of domestication | Lower | Higher |
| Effective population size | Larger | Smaller |
| Spatial structure of populations | More open | Less open |
| Spatial scale of gene flow | Larger | Smaller |
| Openness of local environment (i.e., rates of import and export) | Greater | Lower |
| Strength of natural forces | Tides, currents and waves may vary | Wind and rain vary with depth |
| Availability of shelter and space | Not required for all organisms; substrate, rocks, vegetation and coral reefs provide shelter; space is important for animal requiring territory | Most animals require shelter; some plants require shelter; space is important for organisms requiring territory, shelter or nesting sites |
| Scale of chemical and material transport | Greater | Smaller |
| Rate of response to environmental variability | Faster | Slower |
| Sensitivity to large-scale environmental variability | Higher | Lower |
| Reliance on external sources of recruitment | Higher | Lower |
| Importance of pollination syndromes | Minimal | Great |
| Spatial scale of propagules transport | Greater | Smaller |
| Likelihood of local self replenishment | Low | High |
| Habitat destruction | Spatially focused | Widespread |
| Sensitivity to habitat fragmentation | Lesser | Greater |
| Loss of biogenic habitat structure | Spatially focused | Widespread |
| Sensitivity to smaller scale perturbations | Lesser | Greater |
| Temporal response to large-scale events | Higher (decades) | Slower (centuries) |
| Temperature variation | Low; less variation in big waterbodies; decreases with depth; heats up and cools down more slowly than air; heat loss and gain is not usually a problem | High; very varied both as we move through the seasons and through latitude and altitude; temperature varies more than in water; daily and seasonal variations may be great |
| Light availability and penetration | Affects availability of plants in water; intensity and wavelength decreases with depth of the water | Very important for plant growth; dense plant growth can affect light; plenty of light readily available |
| Pressure variation | Few organisms live at great depths; greatly increases with increasing depth | Little effect on most organisms; decreases with altitude |
| Water and ions | Readily available | Vary greatly from deserts to swamps; some soils are rich others, poor |
| Gases (oxygen and carbon dioxide) | Oxygen availability is low and gas solubility decreases with an increase in temperature | No shortage of gases; availability decreases with altitude |
| Viscosity | Higher | Lower, less than water |