Coastal Lagoons of East Anglia, U.K.

Abstract

Twenty-six remaining coastal lagoons in East Anglia, U.K., fall into six distinct categories on the basis of their origin, physiography, hydrography, and sedimentology, all six either created or heavily influenced by man: (1) pits or other excavations within shingle formations in to which water percolates; (2) depressions remaining in reclaimed salt marshes in to which springs discharge water retained within adjacent sand dunes; (3) shallow pools floored by clay and filled by water issuing to landwards from out of longshore shingle ridges; (4) streams or small rivers ponded back by low-lying barrier beaches; (5) short-circuited former estuaries; and (6) relict bodies of brackish water. From a world viewpoint, all but category (4) are aberrant in having neither any freshwater inflow (other than rainfall) nor any direct influx of sea water; in common with other northern Atlantic lagoons, all are further atypical in being confined behind barriers composed largely of shingle. Their rather limited macrofaunas and macrofloras, however, are characteristically lagoonal, although there is a wide variation in species from lagoon to lagoon, even between geographically adjacent systems. The precise species found in any given lagoon appear largely to be the result of stochiastic processes, there being no correlation of biotas with physiographic category or environmental type, with the partial exception of lagoonal salinity.