Geology Reference
In-Depth Information
Figure 7 Characteristic reactions involving phosphorus in the sediments of Toolik Lake,
Alaska. The primary processes controlling porewater phosphorus concentrations
are adsorption to and desorption from iron oxyhydroxides and the precipitation
of authigenic vivianite
(Reprinted with permission from ref 142,
r
E. Schweizerbart'sche Verlags-
buchhandlung, 1987)
water column), the phosphate from previously deposited sediments
would stream off into the water column and promote eutrophication.
This process is called internal loading of phosphorus.
Redox control may not be the only process affecting release of
phosphorus from sediments. During the enhanced photosynthesis of
algal blooms, the pH of lake water increases as CO
2
is used up and
HCO
3
increases. Thus, in summer, both Lough Neagh
143
in N. Ireland
and Lake Glanningen
144
in Sweden have shown an increase in water
