Environmental Engineering Reference
In-Depth Information
littoral macrophyte) revealed very little in terms of
attached algae.
Glass slides in holder
Float
Experimental procedures
Studies on epiphytic algae typically involve collec-
tion of host material, removal of algae and then exper-
imental or taxonomic analysis.
Attachment
points
Current flow
Current deflector
Collection of host material
Where algae
attached to macrophytes are being sampled, the
situation is often complicated by the diversity of
higher plants in the ecosystem. Studies by Sheldon
and Boylen (1975) on the contribution of epiphytic
algae to the primary productivity of an oligotrophic
freshwater lake, for example, encountered over 40
species of rooted macrophytes. These authors sim-
plified the investigation by carrying out experiments
on algal assemblages taken from a single macro-
phyte species (
Potamogeton amplifolius
), which was
Figure 2.27
Floating periphyton sampler - with
upstream deflecting baffle and slide rack holding eight
microscope slides. The rack can also be directly anchored
to suitable substrate (without floats) and slides can be
mounted both vertically and horizontally.
stems invariably showed periphyton development.
Differences clearly exist between macrophytes in
relation to their attached algae, since scrapings from
submerged stems of
Iris pseudacorus
(another major
Figure 2.28
Chained and sessile
diatom epiphytes on a macroalga:
Low-power view of
Cladophora
,
with numerous attached diatom
chains. Left inset: Zigzag chain
of epiphytic
Tabellaria
, attached to
by a mucilaginous plug (arrow).
Right inset: Two cells of the sessile
diatom
Cocconeis
attached to a dead
algal filament. The
Cladophora
was
attached to a buoy in the centre of
a eutrophic lake. Formaldehyde-fixed
preparation.
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