Algal and other fossil evidence for major changes in Strumpshaw Broad, Norfolk, England in the last two centuries

Late Holocene diatoms in Lake Poukawa: Effects of airfall tephra and changes in depth

“…However, Lake Rotomahana is a deep lake whereas Lake Poukawa is very shallow. In shallow lakes, such as Strumshaw Broad, Norfolk, England, partial elimination of waterweeds lets wind-created waves lift sediment into the water column (Moss 1979). The nutrient-rich sediment makes the water both turbid and eutrophic, stimulating extra planktonic growth (Wetzel 1979), but macrophyte growth is inhibited as the plants become coated with silt (Manny et al 1978).…”

Eutrophication of Freshwaters

“…Although we have no detailed information of the ecology of these lakes prior to the 1960s it is clear from naturalists' records that during the early part of the nineteenth century they contained clear water and diverse submerged vegetation dominated by Chara, Najas and other plant genera characteristic of naturally rich lowland lakes. Evidence that these communities were widespread comes from examinations of sediment cores where remains of Chara have been found from numerous broadland sites (Moss, 1979b;Moss, 1980;Moss et al, 1979a). This community was described in Barton Broad around 1903 (Nicholson, 1900) and a very similar flora could be found at Hickling Broad until the 1960s (Phillips, 1963 (pallis, 1911) (Fig.…”

The composition and ecology of periphyton communities in freshwaters. II. Inter-relationships between water chemistry, phytoplankton populations and periphyton populations in a shallow lake and associated experimental reservoirs (‘Lund tubes’)

“…To a large extent the relative lack of epiphytes on their surfaces, controlled (see below) by the lack of available nitrogen, must have compensated for the high phytoplankton shading. A feature of the progressive disappearance of submerged macrophytes from the Norfolk Broads as a result of eutrophication has been the initial increased shading by periphyton which has in all cases, studied Moss, 1978Moss, , 1979Osborne & Moss, 1977;Moss, Forrest and Phillips, 1979) preceded a phytoplankton increase in the water. Where the environment is "reset" by winter flushing and other such events (Round, 1971) for the phytoplankton, or, for macrophytes, a particularly hard winter, or mechanical disturbance, and its immediate past history is obliterated, then events may proceed very differently from those where no such resetting takes place even if the previous physico-chemical environment is essentially reestablished.…”