The Occurrence of "Green Tides" - a Review
2S
nitrogen from seawater offers some potential for the use of these "green
tide" components in waste water treatment. Particularly noteworthy in this
respect are the studies of Langton et al. (1977), Chan et al. (1982), Lehnberg
and Schramm (1984), Krom et al. (1989), Vandermeulen and Gordin (1990)
and Neori et al. (1991).
A number of workers have drawn attention to the morphology of many
of the "green tide" components and the role this might play in nutrient
absorption. They suggest that the frequently recorded filamentous,
sheet-like, tubular and ball-like nature of their thalli produces a high ratio
of surface to volume which ensures maximum nutrient uptake (Espinoza
and Chapman 1983; Rosenberg and Ramus 1984; Wallentinus 1984, 1991).
Indeed, Parker (1981) suggests that algal shape, water motion and nutrient
content all interact in controlling nutrient uptake and growth patterns.
Certainly it is known that the water velocity can determine nutrient uptake
and supply to algal thalli (Harlin and Thorne-Miller 1981; Norton and
Mathieson 1983) and it is perhaps not surprising that the morphological
features of macro algae can playa major influencial role in this process by
creating turbulence at the thallus surface, thereby increasing nutrient
availability (as shown for Macrocystis integrifolia and Nereocystis
leutkeana by Hurd et al. (1993). By hanging as vertical sheets (as reported
for the Venice Lagoon), it was further suggested that Ulva can increase its
potential exchange surface with passing water (Welsh 1980). Not unrelated
to this discussion was the observation that filamentous algae tend to have
very high specific carbon fixation rates (Leskinen et al. 1992). Finally, it is
possible that nutrient ecotypes have developed for "green tide" algae in
response to the high ambient nutrient levels in some eutrophicated coastal
waters similar to that reported for Laminaria longicruris in Nova Scotia
(Espinoza and Chapman 1983).
The effect of nutrients on benthic community structure was particularly
well demonstrated by Harlin and Thorne-Miller (1981) who treated
seagrass beds with nutrients. Additions of NH4 and N0 3 resulted in
the occurrence of dense beds of free-floating Enteromorpha plumosa and
Ulva lactuca plants. In general, they also noted that low nutrient
concentrations favoured vascular plants and that N0 3 may even be toxic to
Zostera. Raymont (1947) also observed that the addition of nitrate and
phosphate fertilizer to a Scottish sea loch encouraged an extremely heavy
growth of algae.
2S
nitrogen from seawater offers some potential for the use of these "green
tide" components in waste water treatment. Particularly noteworthy in this
respect are the studies of Langton et al. (1977), Chan et al. (1982), Lehnberg
and Schramm (1984), Krom et al. (1989), Vandermeulen and Gordin (1990)
and Neori et al. (1991).
A number of workers have drawn attention to the morphology of many
of the "green tide" components and the role this might play in nutrient
absorption. They suggest that the frequently recorded filamentous,
sheet-like, tubular and ball-like nature of their thalli produces a high ratio
of surface to volume which ensures maximum nutrient uptake (Espinoza
and Chapman 1983; Rosenberg and Ramus 1984; Wallentinus 1984, 1991).
Indeed, Parker (1981) suggests that algal shape, water motion and nutrient
content all interact in controlling nutrient uptake and growth patterns.
Certainly it is known that the water velocity can determine nutrient uptake
and supply to algal thalli (Harlin and Thorne-Miller 1981; Norton and
Mathieson 1983) and it is perhaps not surprising that the morphological
features of macro algae can playa major influencial role in this process by
creating turbulence at the thallus surface, thereby increasing nutrient
availability (as shown for Macrocystis integrifolia and Nereocystis
leutkeana by Hurd et al. (1993). By hanging as vertical sheets (as reported
for the Venice Lagoon), it was further suggested that Ulva can increase its
potential exchange surface with passing water (Welsh 1980). Not unrelated
to this discussion was the observation that filamentous algae tend to have
very high specific carbon fixation rates (Leskinen et al. 1992). Finally, it is
possible that nutrient ecotypes have developed for "green tide" algae in
response to the high ambient nutrient levels in some eutrophicated coastal
waters similar to that reported for Laminaria longicruris in Nova Scotia
(Espinoza and Chapman 1983).
The effect of nutrients on benthic community structure was particularly
well demonstrated by Harlin and Thorne-Miller (1981) who treated
seagrass beds with nutrients. Additions of NH4 and N0 3 resulted in
the occurrence of dense beds of free-floating Enteromorpha plumosa and
Ulva lactuca plants. In general, they also noted that low nutrient
concentrations favoured vascular plants and that N0 3 may even be toxic to
Zostera. Raymont (1947) also observed that the addition of nitrate and
phosphate fertilizer to a Scottish sea loch encouraged an extremely heavy
growth of algae.