Environmental Engineering Reference
In-Depth Information
Figure 14.6.
Annual average secchi depth in Basin 7 (St Louis Basin).
development of macrophyte stands (
Fig. 14.6
). Macrophyte biomass is pro-
foundly influenced by photic depth as it influences photosynthesis (Moss
1980
; Carvalho et al.
2002
). During a survey in 2007 (a combination of visual
assessment, bathyscope surveys and grapnel samples across a grid system)
seven macrophyte species and four filamentous algal species were recorded
(APEM
2008b
). Percentage frequency analysis revealed the community to be
dominated by Nutall's water-weed (Elodea nuttallii) and to a lesser extent rigid
hornwort (Ceratophyllum demersum). A nationally scarce charophyte (Nitella mucro-
nata) was also identified for a second year. Although N. mucronata is nationally
scarce, the species seems to be increasing in canal systems and in particular
favours restored canals (Nick Stewart
4
personal communication). Management
of the plant community is essential to optimise the recreational potential
of the Quays, and the annual weed cutting programme also aims to protect
N. mucronata from competition and excessive growth of other more prolific
species such as E. nuttallii and C. demersum.
Revitalising the MSC Turning Basin
Concurrently with the developments under way at Salford Quays initiated by
SCC, regeneration of the upper MSC was also being considered by the Mersey
Basin Campaign (MBC). The MBC was launched in 1985 and is coordinated by
the Department of the Environment, Transport and the Regions (DETR) (MBC
4
Nick Stewart - UK charophyte referee for the Botanical Society of the British Isles and
author of the Red Data Book on stoneworts.
