| Term |
Description |
| m |
Metre. |
| m3 |
Cubic metres. |
| Macrophyte |
A member of the macroscopic plant life, especially of a water body. |
| Macroscopic |
Large enough to be observed by the naked eye. |
| Macro-tidal |
An area with a high tidal range. |
| Magaripple |
Underwater sand dunes with a wavelength (spacing) of 3-30 m. |
| Maintenance dredging |
Dredging concerned with the preservation of navigational channels and berths. |
| Mean range of tide (Mn) |
The difference in height between mean high water and mean low water. |
| Meteorological tides |
Tidal constituents having their origin in the daily or seasonal variations in weather conditions which may occur with some degree of periodicity. |
| mgl-1 |
Milligrams of substance (dry weight) per litre of water. |
| MHW |
Mean High Water |
| MHWM |
Mean High Water Mark |
| MHWN |
Mean High Water Neaps |
| MHWS |
Mean High Water Springs |
| MHWST |
Mean High Water Spring Tide |
| MLR |
Mean Tidal Range |
| MLW |
Mean low water |
| MLW |
Mean low water |
| MLWM |
Mean Low Water Mark |
| MLWN |
Mean Low Water Neaps |
| MLWS |
Mean Low Water Springs |
| mm |
Millimetres 1,000 mm = 1 m. |
| Modelling |
A representation of a real system in terms of the structural organisation and functioning. Numerical models are a specific type of model where the components are capable of being represented mathematically |
| Morphology |
The structure and form of the land. |
| MSL |
Mean Sea Level |
| Mudflats |
Expanses of mud which are periodically exposed at low tide often found adjacent to saltmarshes. |
