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Particulates and the cycling of lead in Ullswater, Cumbria
Author(s) -
EVERARD MARK,
DENNY PATRICK
Publication year - 1985
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1985.tb00194.x
Subject(s) - seston , particulates , water column , littoral zone , phytoplankton , lead (geology) , environmental science , settling , hydrology (agriculture) , environmental chemistry , geology , oceanography , chemistry , ecology , environmental engineering , nutrient , biology , geomorphology , geotechnical engineering
SUMMARY.1 Ullswater has been affected by former lead mining in the catchment area. This paper investigates how lead in the lake is re‐distributed within the littoral zones. Concentrations in the lake water are low. Particulates including phytoplankton, seston and gelatinous ooze overlying lead‐enriched sediments can have values from 1.3 to >6.0 and 26 mg Pb g ‐1 dry weight respectively. 2 During turbulent conditions, contaminated phytoplankton, settled algae and some of the gelatinous ooze are brought into near‐homogenous suspension within the water column. In calm conditions, settlement of particulates occurs and a rate‐zonal distribution results such that, in a vertical column of water, the finer particles in the upper layers have lower concentrations of lead per unit volume of water than the lower layers. 3 In non‐turbulent conditions the particles which settle on all submerged surfaces form a tenuous layer termed ecton. Aufwuchs becomes coated by ecton but the latter is readily re‐suspended by disturbances. The intimate contact, and the similarity of concentrations of lead in Aufivuchs and ecton from any one sample, suggests that metal flux occurs between the two. It is concluded that the variety of particulates which comprise the ecton distribute lead during turbulence. In calm conditions the ecton settles on all submerged surfaces and provides a mechanism for transfer of lead into the littoral food web.