Hypoxia in a pristine stratified estuary (Krka, Adriatic Sea)
| Autor: | Tarzan Legović, D Petricioli, V Ẑutić |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
geography
geography.geographical_feature_category Freshwater inflow 010504 meteorology & atmospheric sciences Hypoxia (environmental) Halocline Estuary General Chemistry 010501 environmental sciences Oceanography 01 natural sciences 6. Clean water Water column 13. Climate action Benthic zone Phytoplankton dissolved oxygen benthic mortality Mediterranean Sea Environmental Chemistry Environmental science Seawater 14. Life underwater 0105 earth and related environmental sciences Water Science and Technology |
| Zdroj: | Marine Chemistry. 32:347-359 |
| ISSN: | 0304-4203 |
| Popis: | The occurrence of hypoxia in October 1988 in the Krka estuary is described, with special reference to the Prokljan Lake. Hypoxia develops near the bottom in autumn in response to the temperature maximum that appears this time of the year. The decomposition rate of naturally present organic matter increases, creating higher biological oxygen demand. As the water column is stratified by salinity and temperature, mixing of seawater near the bottom with oxygen-supersaturated water which resides closer to the surface is very slow. When an extensive marine phytoplankton bloom appears below the halocline in the Prokljan Lake, then, because of the sinking and degradation of phytoplankton near the bottom, the dissolved oxygen concentration decreases further. The hypoxia becomes so severe that it causes massive mortality of benthic macrofauna. The decomposition of the macrofauna further decreases the dissolved oxygen concentration. The hypoxia may persist until an increase in the freshwater inflow occurs, which forces the arrival of colder marine water near the bottom via a compensating flow. In the absence of autumn rains, the hypoxia may be recorded throughout winter. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|