IMIS

Publications | Institutes | Persons | Datasets | Projects | Maps
[ report an error in this record ]basket (0): add | show Print this page

Effects of dredging activities on growth of Laminaria saccharina
Lyngby, J.E.; Mortensen, S.M. (1996). Effects of dredging activities on growth of Laminaria saccharina, in: Dworschak, P.C. et al. (1996). Influences of organisms on their Environment, the role of episodic events: Proceedings of the 29th European Marine Biology Symposium Vienna, 29 August-2 September 1994. Marine Ecology (Berlin), 17(1-3): pp. 345-354
In: Dworschak, P.C.; Stachowitsch, M.; Ott, J.A. (Ed.) (1996). Influences of organisms on their environment, the role of episodic events: Proceedings of the 29th European Marine Biology Symposium Vienna, 29 August-2 September 1994. European Marine Biology Symposia, 29. Marine Ecology (Berlin), 17(1-3). 568 pp., more
In: European Marine Biology Symposia., more

Available in  Authors 
Document type: Conference paper

Keywords
    Chemical reactions > Photochemical reactions > Photosynthesis
    Dredging
    Population functions > Growth
    Sedimentation
    Laminaria saccharina (Linnaeus) J.V.Lamouroux, 1813 [WoRMS]
    Marine/Coastal

Authors  Top 
  • Lyngby, J.E.
  • Mortensen, S.M.

Abstract
    The possible effects of fine-grained deposits on the photosynthesis, growth, and nutrient uptake of Laminaria have been studied in field and laboratory experiments. Some of the plants were treated with fine-grained material for two hours and then transplanted in rows together with untreated plants. At two-week intervals the treatment was repeated and samples collected. The macroalgae were analyzed for growth as well as chlorophyll a, nitrogen, and phosphorus content. In the laboratory experiments, plants of a uniform size were incubated in Plexiglas containers after leaf-marking and treatment in a sediment suspension. At weekly intervals, photosynthesis, growth, chlorophyll a, and nutrients were analyzed.

    The field study showed that Laminaria growth was significantly affected by the fine-grained material. The growth in the control experiment was 20% higher than in the treated plants. The chlorophyll a concentrations in the treated plants were significantly lower than in the control experiment, and the results indicated a reduced nutrient uptake in the treated plants. In the laboratory experiments the growth of the treated plants was only 30% of the controls, but no differences in photosynthetic capacities were detected. Nitrogen uptake was reduced in the treated plants, but no effects were observed on phosphorus uptake. Thick layers of fine-grained material caused direct harmful effects and rotting.

    The results are discussed in relation to dredging activities; it is concluded that in heavy sedimentation areas, Laminaria growth may be significantly reduced beyond the indirect effect of shading from suspended material in the water.


All data in the Integrated Marine Information System (IMIS) is subject to the VLIZ privacy policy Top | Authors