A. Basset et al., Water transparency and health of coastal salt marshes: simple enclosure experiments on nutrient dynamics, AQUAT CONS, 11(4), 2001, pp. 273-279
Citations number
13
Categorie Soggetti
Aquatic Sciences
Journal title
AQUATIC CONSERVATION-MARINE AND FRESHWATER ECOSYSTEMS
1. In many coastal salt marshes. water transparency is decreased by the res
uspension of sediments. We analyse the influence of suspended not-photosynt
hetic matter on the regulation of phosphorus (P) dynamics in the water colu
mn., compared with the role of phytoplankton and sediments.
2. Field surveys and manipulative experiments of P enrichment in light and
dark enclosures, open and closed at their bottom, were performed in the bra
ckish Lake Alimini Grande (Otranto, LE, Italy).
3. Water transparency in Alimini Grande was inversely related to seston org
anic mass. 98.8% of which was composed of dead organic matter and heterotro
phic organisms.
4. P enrichment experiments showed an increase of the phytoplankton biomass
with time from the beginning of the manipulation (4.9 times) in the light
enclosures. but also an exponential decrease of P concentration in all the
enclosures, even in the dark one closed at the bottom.
5. The rate of P removal from the water column was not significantly affect
ed by phytoplankton activity, even though P concentration was always lower
in light than in dark enclosures, or by the activity of sediments.
6. Dead suspended organic matter with associated micro-organisms seemed to
remove nutrients very efficiently from the water column in Lake Alimini Gra
nde, contributing significantly to control the potential risk of lake eutro
phication. Copyright (C) 2001 John Wiley & Sons, Ltd.