Sea lavender by Denise Emmerson
Brent geese by Rob Haynes
Sunset at Blakeney by Rob Haynes
Saltmarshes and mudflats
Mudflats and saltmarshes arise where high tides occur in areas of extremely low wave energy, such as behind spits, in bays or at the top of long, flat beaches. These very low energy conditions allow seawater to deposit the tiniest, lightest clay particles. These particles cling to one another, a process known as flocculation, and once settled are first colonised by algae, such as Vaucheria, which help to stabilise the surface of the mud and make it less likely to be eroded by waves and future tides. The subsequent colonisation of samphires (glassworts) and sea aster stabilises the mud further, adds organic material and interrupts the flow of water, making further deposition more likely.
Once the marsh is well established, common sea-lavender, sea arrow-grass, annual seablite and numerous other species move in and form the area known as the middle marsh. Along the edges of creeks where more sediment is deposited by each tide, so the ground is slightly higher, characteristic strips of silver-leaved sea purslane may be seen. At the top of the marsh or on areas of raised ground, where inundation by tides is less frequent, sea beet, pungent sea wormwood and the nationally scarce shrubby seablite grow.
Both mudflats and saltmarshes are very productive habitats in terms of animal life and are rich in mud-dwelling invertebrates. These in turn are the food of huge numbers of migrant wading birds. The mudflats of the Wash are of global importance as a migratory staging ground and wintering ground for northern breeding species such as knot, dunlin, bar-tailed godwit, oystercatcher, grey plover and shelduck. The saltmarshes of Norfolk are loud in winter with the purrs of dark-bellied brent geese, visiting from the tundra of Siberia, and the breathy calls of curlew. In summer they echo to the happy, rocking songs of breeding redshank and the ceaseless melodies of skylarks.
Norfolk’s mudflats are largely concentrated in the Wash and, to a lesser extent, in Breydon Water. Saltmarshes are found along the north coast of the county between Holme and Salthouse and again around the edges of Breydon.