|Etude des migrations nycthémérales du zooplankton dans un milieu marin peu profond|
Daro, M.H. (1974). Etude des migrations nycthémérales du zooplankton dans un milieu marin peu profond, in: IZWO Coll. Rep. 4(1974). IZWO Collected Reprints, 4: pp. chapter 17
In: (1974). IZWO Coll. Rep. 4(1974). IZWO Collected Reprints, 4[s.n.][s.l.], more
In: IZWO Collected Reprints. Instituut voor Zeewetenschappelijk Onderzoek: Bredene. ISSN 0772-1250, more
|Also published as |
- Daro, M.H. (1974). Etude des migrations nycthémérales du zooplankton dans un milieu marin peu profond. Hydrobiologia 44(1-2): 149-160, more
Migrations; Nyctimeral rhythms; Shallow water; Zooplankton; ANE, Belgium, Oostende, Sluice Dock [Marine Regions]; Marine; Brackish water
The Sluice-dock of Ostend, a shallow (1.5 m) marine biotope of 86 ha stays closed during some 6-7 months of the year and is not influenced by the tides. During 24 h cycles the nycthemeral migrations of the zooplankton at 5 depths in a watercolumn of 1 meter were studied in relation to several environmental factors: water temperature, dissolved oxygen, pH and chlorophyll content. The photosynthesis shows a minimum during the night and shows a maximum during the late afternoon, at which time the water-temperature is also maximal. Holo- and meroplanktonic organisms migrate towards the surface around 3-5 o'clock a.m., at which time the chlorophyll content is minimal, hence our hypothesis of nocturnal grazing, this phenomenon perhaps combined with a nocturnal division of phytoplankton cells. Each observed species has its own characteristic behaviour in relation to its negative diurnal phototropism and its own diurnal bottomward migration speed.