Benguela Current
Introduction
The Benguela Current is a major oceanic current that flows along the southwestern coast of Africa. It is a significant component of the Atlantic Ocean's circulation system and plays a crucial role in the regional climate, marine biodiversity, and the economy of the surrounding coastal nations. Originating from the Southern Ocean, the Benguela Current flows northward along the coast of Namibia and South Africa, extending up to the Angola-Benguela Front near the Angola-Namibia border. This current is part of the larger South Atlantic Gyre and is characterized by its cold, nutrient-rich waters, which support one of the world's most productive marine ecosystems.
Oceanographic Characteristics
The Benguela Current is driven by the prevailing south-easterly trade winds, which induce coastal upwelling—a process that brings cold, nutrient-rich water from the depths to the surface. This upwelling is most intense off the coast of Namibia and the western coast of South Africa, where the continental shelf is narrow. The current is relatively shallow, with its core flow occurring within the upper 300 meters of the ocean.
The current's temperature ranges from 10°C to 20°C, depending on the season and location. The salinity of the Benguela Current is relatively low compared to other ocean currents, primarily due to the influence of the cold, upwelled waters. The current's flow rate is variable, with speeds ranging from 0.1 to 0.5 meters per second. The Benguela Current is also subject to seasonal and interannual variability, influenced by factors such as the El Niño-Southern Oscillation (ENSO) and the Southern Annular Mode (SAM).
Ecological Significance
The Benguela Current is renowned for its high biological productivity, which supports a diverse array of marine life. The upwelling of nutrient-rich waters fuels the growth of phytoplankton, forming the base of the marine food web. This, in turn, supports large populations of zooplankton, fish, seabirds, and marine mammals.
The region is home to several commercially important fish species, including sardines, anchovies, and hake. These species are vital to the local fishing industry and contribute significantly to the economies of Namibia and South Africa. The Benguela Current also supports a variety of seabirds, such as the African penguin and Cape gannet, as well as marine mammals like the Cape fur seal and various species of whales and dolphins.
Climate Influence
The Benguela Current plays a crucial role in moderating the climate of the southwestern coast of Africa. The cold waters of the current contribute to the arid conditions of the Namib Desert by reducing the amount of moisture available for precipitation. The current also influences the regional wind patterns, which can affect weather conditions such as fog formation and coastal breezes.
Furthermore, the Benguela Current interacts with other oceanic and atmospheric systems, such as the Agulhas Current, which flows along the southeastern coast of Africa. The exchange of water between these currents can impact the larger-scale circulation patterns of the South Atlantic Ocean and influence global climate systems.
Human Impact and Management
The Benguela Current region is subject to various human activities, including fishing, shipping, and oil and gas exploration. Overfishing and habitat degradation pose significant threats to the marine ecosystem, leading to declines in fish stocks and biodiversity. To address these challenges, the Benguela Current Commission (BCC) was established in 2007 as a cooperative initiative between Angola, Namibia, and South Africa. The BCC aims to promote sustainable management of the Benguela Current Large Marine Ecosystem (BCLME) through research, monitoring, and policy development.
Efforts to mitigate the impact of climate change on the Benguela Current region are also underway. These include initiatives to reduce greenhouse gas emissions, enhance coastal resilience, and improve the management of marine resources.