Definitions


Component Class Definition
Temperature Frozen/superchilled water Temperature 0 degrees and below.
Temperature Very cold water Temperature 0 to < 5 degrees (liquid).
Temperature Cold water Temperature 5 to < 10 degrees.
Temperature Cool water Temperature 10 to < 15 degrees.
Temperature Moderate water Temperature 15 to < 20 degrees.
Temperature Warm water Temperature 20 to < 25 degrees.
Temperature Very warm water Temperature 25 to < 30 degrees.
Temperature Hot water Temperature 30 to < 35 degrees.
Temperature Very hot water Temperature > 35 degrees.
Salinity Oligohaline water Salinity < 5 PSU.
Salinity Mesohaline water Low. Salinity 5 to < 18 PSU.
Salinity Lower polyhaline water Variable / reduced. Salinity 18 to < 25 PSU.
Salinity Upper polyhaline water Variable / reduced. Salinity 25 to < 30 PSU.
Salinity Euhaline water Fully marine. Salinity 30 to < 40 PSU.
Salinity Hyperhaline water Salinity above 40 PSU.
Depth band littoral Intertidal zone
Depth band 0-5 0-5 m
Depth band 5-10 5-10 m
Depth band 10-15 10-15 m
Depth band 15-20 15-20 m
Depth band 20-30 20-30 m
Depth band 30-40 30-40 m
Depth band 40-50 40-50 m
Depth band 50-60 50-60 m
Depth band 60-80 60-80 m
Depth band 80-100 80-100 m
Depth band 100-150 100-150 m
Depth band 150-200 150-200 m
Tidal streams Very strong > 6 knots.
Tidal streams Strong 3-6 knots.
Tidal streams Moderately strong 1-3 knots.
Tidal streams Weak < 1 knot.
Tidal streams Very weak Negligible.
Wave exposure Extremely exposed Open coastline facing into prevailiing wind and receive oceanic swell without any offshore breaks. deep water occurs close to shore.
Wave exposure Very exposed Exposure less than extreme but strong winds and swells often occur.
Wave exposure Exposed Not facing prevailing wind and swell directions but subject to non-prevailing winds and swells.
Wave exposure Moderately exposed Open coasts facing away from prevailing winds and/or without a very long fetch. Sheltered from direct swell waves but may be subject to swell surge from highly diffracted waves.
Wave exposure Sheltered Negligible.
Wave exposure Very sheltered Fetch less than 20 km.
Wave exposure Extremely sheltered Fully enclosed with fetch no greater than 3 km.
Wave exposure Ultra sheltered Fetch of a few tens or 100s of metres.
Layer Estuarine coastal surface layer Estuarine waters between the shore and the 6 m depth contour at the surface to a depth of a few centimetres.
Layer Estuarine coastal upper water column Estuarine waters above the pycnocline (or the mid-depth) between the shore and the 6 metre depth contour.
Layer Estuarine coastal pycnocline Estuarine waters within the pycnocline, between the shore and the 6 metre depth contour.
Layer Estuarine coastal lower water column Estuarine waters below the pycnocline (or the mid-depth) and between the shore and the 6 metre depth contour.
Layer Estuarine open water surface Estuarine waters at the surface, at or beyond the 6 m depth contour.
Layer Estuarine open water upper water column Estuarine waters above the pycnocline (or mid-depth), at or beyond the 6 m depth contour.
Layer Estuarine open water pycnocline Estuarine waters within the pycnocline, at or beyond the 6 m depth contour.
Layer Estuarine open water lower water column Estuarine waters below the pycnocline (or mid-depth), at or beyond the 6 m depth contour.
Layer Estuarine tidal riverine coastal surface layer Tidal fresh waters at the surface, between the shore and the 6 m depth contour.
Layer Estuarine tidal riverine coastal upper water column Tidal fresh waters above the pycnocline (or mid-depth), from the shore to the 6 m depth contour.
Layer Estuarine tidal riverine coastal pycnocline Tidal fresh waters within the pycnocline, between the shore and the 6 m depth contour.
Layer Estuarine tidal riverine coastal lower water column Tidal fresh waters below the pycnocline (or mid-depth), between the shore and the 6 m depth contour.
Layer Estuarine tidal riverine open water surface layer Tidal fresh waters at the surface, at or beyond the 6 m depth contour.
Layer Estuarine tidal riverine open water upper water column Tidal fresh waters above the pycnocline (or mid-depth), at or beyond the 6 m depth contour.
Layer Estuarine tidal riverine open water pycnocline Tidal fresh waters within the pycnocline, at or beyond the 6 m depth contour.
Layer Estuarine tidal riverine open water lower water column Tidal fresh waters below the pycnocline (or mid-depth), at or beyond the 6 m depth contour.
Layer Marine nearshore surface layer Marine waters at the surface, from the shore to the 30 m depth contour.
Layer Marine nearshore upper water column Marine waters above the pycnocline (or mid-depth), from the shore to the 30 m depth contour.
Layer Marine nearshore pycnocline Marine waters at the pycnocline, from the shore to the 30 m depth contour.
Layer Marine nearshore lower water column Marine waters below the pycnocline (or mid-depth), from the shore to the 30 m depth contour.
Layer Marine offshore surface layer Marine waters at the surface, between the 30 m depth contour and the shelf break.
Layer Marine offshore upper water column Marine waters above the pycnocline (or mid-depth), between the 30 m depth contour and the shelf break.
Layer Marine offshore pycnocline Marine waters at the pycnocline, between the 30 m depth contour and the shelf break.
Layer Marine offshore lower water column Marine waters below the pycnocline (or mid-depth), between the 30 m depth contour and the shelf break.
Layer Marine oceanic surface layer The interface between the atmosphere and the water column, extending to a depth of several centimetres.
Layer Marine oceanic epipelagic upper layer Region between the surface and the epipelagic pycnocline, or 100 m depth if the pycnocline is not present.
Layer Marine oceanic epipelagic pycnocline Zone of maximum vertical change within the epipelagic layer (upper 200 m).
Layer Marine oceanic epipelagic lower layer Region between the epipleagic pycnocline (or 100 m depth if not present) and 200 m depth.
Layer Marine oceanic mesopelagic layer Region between 200 and 1000 m depth where light is attenuated to below the level required for photosynthesis and oxygen declines to a minimum.
Layer Marine oceanic bathypelagic layer Region where light does not penetrate, from 1000 to 4000 m depth. typified by cold bottom currents and foodwebs are reliant on organic detritus.
Layer Marine oceanic abyssopelagic layer Region that is generally in contact with the abyssal seafloor, except trenches and basins, from 4000 to 6000 m depth. Food webs are based on chemoautotrophic processes, hydrothermal vents, decomposition of organic matter and bacterial production.
Layer Marine oceanic hadalpelagic layer Deepest waters of the globe below 6000 m depth. there is a high degree of techtonic and thermal activity in these areas. Characteristic features include immense pressure, strong currents, accumulation of sediments and organic material.
Hydroform 1 Boundary current The portion of an ocean gyre that moves along the continental boundary
Hydroform 1 Eastern boundary current The eastern portion of great ocean gyres against the west continental coasts.
Hydroform 1 Western boundary current The western portion of great ocean gyres against the east continental coasts
Hydroform 2 Current meander A current that deviates from a striaght line flow. Meanders can pinch off fromt he main current flow and form rings.
Hydroform 1 Deep boundary current A current that connects high latitude ocean waters with upwelling regions.
Hydroform 2 Mesoscale eddy A rotational feature that breaks off an ocean gyre or large current and perisist autonomously for some period (from days to months) at sizes of 20-500 km.
Hydroform 3 Tidal flow Advective flow resulting from tidal movement, often amplified in velocity when moving through an inlet, pass or channel or around a promontory.
Hydroform 4 Longshore current Advective flow resulting from tidal movement, often amplified in velocity when moving through an inlet, pass or channel or around a promontory.
Hydroform 4 Surf zone Zone with incipient wave breaks, extending from the seaward boundary of the wave breaks to the limit of the wave uprush.
Hydroform 4 Hydrothermal plume A discharge of hot fluids from sea-bottom vents associated with colcanic or tectonic activity.
Hydroform 5 Detatched hydrothermal plume A parcel of hot, mineral rich water that has become detached from it source and forms a persistent lens within the water column.