Environmental Engineering Reference
In-Depth Information
Figure 4.2.
Habrophlebia fusca, showing evidence of iron hydroxide deposits on its
appendages.
See colour plate section
.
1. Clogging of gills and feeding structures (e.g., Cordone & Kelley
1961
; Hynes
1970
; Gerhardt
1992
). Physical damage was shown to cause inhibition of
sediment inhabitation of Hydropsyche orientalis and Cheumatopsyche brevili-
neata (Sasaki et al.
2005
) and to lead to chronic lethal effects in hydropsy-
chid caddisflies (DeNicol & Stapleton
2002
).
2. Limitation of food resources. Suspended solids can reduce the growth of
mosses and other plants which act as attachment sites for periphyton
and also accumulate fine debris which can act as a food supply for
collector-gatherers (Suren & Winterbourn
1992
). Grazers can also be
affected in terms of reduced uptake of sediment contaminated periphyton
by the presence of suspended solids (Newcombe & MacDonald
1991
; Broe-
khuizen et al.
2001
). Ochre may cover leaves preventing access for shredders
(Nelson
2000
).
3. Lowering primary production. Suspended solids reduce the amount of
light penetrating the water column and therefore reduce the growth of
algae (Bilotta & Brazier
2008
) potentially disrupting the food web.
4. Loss of habitat. The precipitation of significant quantities of hydroxides on
the beds of rivers which is characteristic of iron contamination (Younger
et al.
2002
) can destroy potential habitat for a wide variety of benthic
organisms (e.g., Gray
1996a
,
b
).
5. Damage to organisms. Langer (
1980
) has also shown that suspended solids
can scour and abrade benthic organisms damaging respiratory organs.
