Agricultural and Biological Sciences: Aquatic Science
; Earth and Planetary Sciences: Oceanography
; Environmental Science: Pollution
英文摘要:
This study compared the spatio-temporal dynamics in two agriculturally-influenced South African estuaries - Gamtoos and Sundays - to investigate how contrasting hydrological alterations influence physical, chemical and biological responses. With the Gamtoos Estuary experiencing regular high flow conditions, a key difference between the two systems is the propensity for natural flushing events to occur; a mechanism largely eliminated from the highly-regulated Sundays Catchment. Phytoplankton blooms (>�20�Chl-a�μg�l−�1) were persistent and seasonal in the Sundays, inducing summer bottom-water hypoxia (<�2�mg�l−�1), whilst those in the Gamtoos were episodic and flow-dependent. Of concern in the Sundays Estuary, was the magnitude (>�550�μg�l−�1) and recurrent nature of two harmful algal bloom (HAB) species. This study provides the first account of HAB persistence and seasonal hypoxia in a South African estuary, demonstrating the possible consequences of shifting an ecosystem into a new stable state. � 2017 Elsevier Ltd
Botany Department, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth, South Africa; Council for Scientific and Industrial Research, PO Box 320, Stellenbosch, South Africa
Recommended Citation:
Lemley D.A.,Adams J.B.,Taljaard S.. Comparative assessment of two agriculturally-influenced estuaries: Similar pressure, different response[J]. Marine Pollution Bulletin,2017-01-01,117(2018-01-02)