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Definition of saline lagoons
Definition Biodiversity Action Plan
Lagoons in the UK are essentially bodies, natural or artificial, of saline
water partially separated from the adjacent sea. They retain a proportion of
their sea water at low tide and may develop as brackish, full saline or hyper-saline
water bodies. The largest lagoon in the UK is in excess of 800 ha (Loch of Stenness)
although the rest are much smaller and some may be less than 1 ha. Lagoons can
contain a variety of substrata, often soft sediments which in turn may support
tasselweeds and stoneworts as well as filamentous green and brown algae. In
addition lagoons contain invertebrates rarely found elsewhere. They also provide
important habitat for waterfowl, marshland birds and seabirds. The flora and
invertebrate fauna present can be divided into three main components: those
that are essentially freshwater in origin, those that are marine/brackish species
and those that are more specialist lagoonal species. The presence of certain
indigenous and specialist plants and animals make this habitat important to
the UK's overall biodiversity.
Other definitions
"Lagoons. The sometimes extensive lagoons, which may be associated with
deltas and barrier island coasts, are a special form of wetland and defined
as being:
'shallow enclosed or semi-enclosed bodies of sea water with a narrow entrance
to an adjacent sea.' (Doody 2001)
The Saline
Lagoon Guide (Section 2.2) defines them as:
"Areas of typically (but not exclusively) shallow, coastal saline water,
wholly or partially separated from the sea by sandbanks, shingle or, less frequently,
rocks or other hard substrata. They retain a proportion of their water at low
tide and may develop as brackish, fully saline or hyper-saline water bodies.
As a distinct habitat, the essence of saline lagoons is their tidally restricted
or tideless state ("low hydrodynamics"), and as such they are distinct
from estuaries or from littoral pools."
References
Doody, J.P.
2001.
Coastal Conservation and Management: an Ecological Perspective. Kluwer, Academic Publishers, Boston, USA, 306 pp.
Conservation Biology Series, 13
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