| Autor: |
Hutchings, Larry, Verheye, Hans M., Huggett, Jenny A., Demarcq, Hervé, Cloete, Rudi, Barlow, Ray G., Louw, Deon, da Silva, Antonio |
| Zdroj: |
Benguela: Predicting a Large Marine Ecosystem; 2006, p91-124, 34p, 2 Diagrams, 1 Chart, 14 Graphs |
| Abstrakt: |
This article reviews the variability of plankton over time scales ranging from mesoscale upwelling events of a few days' duration to decadal scale changes in the northern and southern subsystems in the Benguela Current. It focuses on the plankton that are considered important for fish, particularly the crustacean zooplankton. The southern Benguela is strongly pulsed over periods of 4-12 days with a series of upwelling events modulated by passing cyclonic weather systems. The northern Benguela is less pulsed with short-term variability linked to continental shelf waves. Upwelling is particularly active at seven major sites in the Benguela system. Dense phytoplankton blooms develop in the cool nutrient-rich plumes, which merge and blend with surrounding waters, creating a broad band of phytoplankton-rich water over the shelf. Species succession from small to large diatoms, dinoflagellates and small flagellates occurs as the waters mature after upwelling and generally move offshore, although numerous exceptions occur, with small-celled communities occasionally dominant in nearshore waters. Much regeneration and recycling of nutrients occurs, resulting in lower than expected f-ratios. Frontal zone aggregations provide important feeding opportunities in the transport phase of ichthyoplankton between the Agulhas Bank spawning grounds and the nursery grounds on the South African West Coast. The Angola-Benguela front in the northern Benguela is also an important region for pelagic fish spawning. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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