Impact of Climate Change on the Agulhas Bank, South Africa ― a 100 year projection with consequences for the squid fishery

2020 ◽  
Author(s):  
Sarah Asdar ◽  
Michael J. Roberts ◽  
Zoe Jacobs ◽  
Ekaterina Popova
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Water Retention ◽  
East Coast ◽  
Surface Current ◽  
Economic Importance ◽  
Economic Consequences ◽  
Local Circulation ◽  
Agulhas Current ◽  
Ocean Biogeochemistry

<p>The South and East coast of South Africa is strongly influenced by the warm, fast-flowing Agulhas Current. The Agulhas Bank, a shallow shelf on the southern tip of Southern Africa, is a crucial area for productivity which support fisheries of high economic importance for South Africa.  In this context of climate change, perturbations of this diverse, complex and highly variable marine environment could affect the productivity and lead to dramatic social and economic consequences for the region. To predict potential changes over the eastern and central Bank, we employ a high-resolution global coupled ocean-biogeochemistry model, NEMO-MEDUSA, simulated to year 2099. We find that even though the Agulhas Bank is warming over the next century, primary production does not experience a significant decrease. Additionally, we show that the Agulhas Current might shift its position, with intensification surface current velocity on the Bank hence reducing water retention over the Bank. This change in local circulation over the Bank could have a serious impact on the ecosystem of the region.</p>

scholarly journals Ocean Gliders Ride the Research Wave in the Agulhas Current

Eos ◽  
2018 ◽  
Vol 99 ◽  
Author(s):  
Marjolaine Krug ◽  
Sebastiaan Swart ◽  
Juliet Hermes
Keyword(s):  
South Africa ◽  
East Coast ◽  
Agulhas Current

Off the east coast of South Africa, robotic ocean gliders deployed in the Agulhas Current capture new data that help us better understand how energy dissipates in the ocean.

scholarly journals Seasonal and diurnal variation of lightning activity over southern Africa and correlation with European whistler observations

2006 ◽  
Vol 24 (2) ◽  
pp. 529-542 ◽  
Author(s):  
A. B. Collier ◽  
A. R. W. Hughes ◽  
J. Lichtenberger ◽  
P. Steinbach
Keyword(s):  
South Africa ◽  
Diurnal Variation ◽  
Southern Africa ◽  
Seasonal Variations ◽  
East Coast ◽  
Lightning Activity ◽  
Agulhas Current ◽  
Statistical Pattern ◽  
Seasonal And Diurnal Variation ◽  
Imaging Sensor

Abstract. Lightning Imaging Sensor (LIS) data have been analysed to ascertain the statistical pattern of lightning occurrence over southern Africa. The diurnal and seasonal variations are mapped in detail. The highest flash rates (107.2 km-2 y-1) occur close to the equator but maxima are also found over Madagascar (32.1 km-2 y-1) and South Africa (26.4 km-2 y-1). A feature of the statistics is a relatively steady contribution from over the ocean off the east coast of South Africa that appears to be associated with the Agulhas current. Lightning statistics are of intrinsic meteorological interest but they also relate to the occurrence of whistlers in the conjugate region. Whistler observations are made at Tihany, Hungary. Statistics reveal that the period of most frequent whistler occurrence does not correspond to the maximum in lightning activity in the conjugate region but is strongly influenced by ionospheric illumination and other factors. The whistler/flash ratio, R, shows remarkable variations during the year and has a peak that is narrowly confined to February and March.

Occurrence of tuna and mackerel larvae (Family: Scombridae) off the east coast of South Africa

2000 ◽  
Vol 51 (8) ◽  
pp. 777 ◽  
Author(s):  
Lynnath E. Beckley ◽  
Jeff M. Leis
Keyword(s):  
South Africa ◽  
East Coast ◽  
Temporal Distribution ◽  
Western Indian Ocean ◽  
Distribution Patterns ◽  
Agulhas Current ◽  
The North ◽  
Scomberomorus Commerson ◽  
Euthynnus Affinis ◽  
King Mackerel

Spatial and temporal distribution patterns of scombrid larvae along the east coast of South Africa were investigated from ichthyoplankton collections made during May–June 1990 (winter), October 1990 (spring) and February 1991 (summer). Results were analysed in relation to oceanographic conditions and known spawning localities of tuna and mackerels in the western Indian Ocean. In total, eight species were represented in the samples, with highest diversity in February and lowest numbers in May–June. Larvae of the temperate chub mackerel Scomber japonicus were most abundant at shelf stations during October. Larvae of neritic tunas Auxis sp. and Euthynnus affinis occurred in shelf stations off KwaZulu–Natal in February and extended southward in a plume along the shelf edge. Larvae of skipjack tunaKatsuwonus pelamis were most abundant in the Agulhas Current during February. Only a few larvae of oceanic tunas Thunnus spp., wahoo Acanthocybium solandri and king mackerel Scomberomorus commerson were collected in the Agulhas Current in the north of the study area during February when there was an intrusion of warm Tropical Surface Water. This indicates that spawning of these species probably does not occur off the east coast of South Africa.

scholarly journals Marine climate change over the eastern Agulhas Bank of South Africa

Ocean Science ◽  
2020 ◽  
Vol 16 (6) ◽  
pp. 1529-1544
Author(s):  
Mark R. Jury
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Large Scale ◽  
Time Span ◽  
Rate Of Change ◽  
Sea Surface ◽  
Ensemble Model ◽  
Agulhas Current ◽  
Marine Climate ◽  
Subtropical Ridge

Abstract. The rate of change in the marine environment over the eastern Agulhas Bank along the south coast of South Africa (32–37∘ S, 20–30∘ E) is studied using reanalysis observations for 1900–2015 and coupled ensemble model projections for 1980–2100. Outcomes are influenced by resolution and time span: ∼ 1∘ datasets covering the whole period capture large-scale changes, while ∼ 0.5∘ datasets in the satellite era better distinguish the cross-shelf gradients. Although sea surface temperatures offshore are warming rapidly (0.05 ∘C yr−1 since 1980), a trend toward easterly winds and a locally stronger Agulhas Current have intensified nearshore upwelling (−0.03 ∘C yr−1). The subtropical ridge is gradually moving poleward, leading to a drier climate.

scholarly journals TIDAL AND INERTIAL CURRENTS AROUND SOUTH AFRICA

1982 ◽  
Vol 1 (18) ◽  
pp. 155 ◽  
Author(s):  
E.H. Schumann ◽  
L.A. Perrins
Keyword(s):  
South Africa ◽  
Energy Spectrum ◽  
West Coast ◽  
Vertical Structure ◽  
East Coast ◽  
Coastal Ocean ◽  
Limited Information ◽  
The West ◽  
Agulhas Current ◽  
Inertial Currents

Limited information is available on currents in the semi-diurnal and diurnal frequency bands for the coastal ocean areas around Southern Africa. However, recently mooring data have become available from sites on the east, south and west coasts, and this paper analyses these results in an attempt to assess the importance of tidal and inertial currents. It is clear that on the narrow shelf on the east coast the Agulhas Current dominates the energy spectrum, and tidal currents should be relatively unimportant at such sites. In the south on the Agulhas Bank the Current is still important, but comparable energy resides in inertial and tidal fluctuations. Modal analysis indicates the tides are primarily barotropic, with the inertial fluctuations mainly baroclinic. In the absence of a major current on the west coast, most of the current variance occurs in the tidal and inertial bands; a complex vertical structure is also found. It is therefore clear that there are regions where such currents cannot be ignored.

The World Economic Forum Principles on "Climate Governance on Corporate Boards": can soft law help to face climate change around the world?

2020 ◽  
pp. 37-55
Author(s):  
Sabrina Bruno
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Comparative Analysis ◽  
Boards Of Directors ◽  
Soft Law ◽  
Corporate Boards ◽  
World Economic Forum ◽  
Financial Factor ◽  
The World ◽  
World Economic

Climate change is a financial factor that carries with it risks and opportunities for companies. To support boards of directors of companies belonging to all jurisdictions, the World Economic Forum issued in January 2019 eight Principlescontaining both theoretical and practical provisions on: climate accountability, competence, governance, management, disclosure and dialogue. The paper analyses each Principle to understand scope and managerial consequences for boards and to evaluate whether the legal distinctions, among the various jurisdictions, may undermine the application of the Principles or, by contrast, despite the differences the Principles may be a useful and effective guidance to drive boards' of directors' conduct around the world in handling climate change challenges. Five jurisdictions are taken into consideration for this comparative analysis: Europe (and UK), US, Australia, South Africa and Canada. The conclusion is that the WEF Principles, as soft law, is the best possible instrument to address boards of directors of worldwide companies, harmonise their conduct and effectively help facing such global emergency.

Evaluating government's communication strategy of the 16 Days of Activism campaign for No Violence Against Women and Children in South Africa

2020 ◽  
Vol 9 (4) ◽  
pp. 219-241
Author(s):  
Mutambuli J. Hadji
Keyword(s):  
South Africa ◽  
Violence Against Women ◽  
Diffusion Of Innovation ◽  
School Curriculum ◽  
Economic Consequences ◽  
Communication Strategy ◽  
Survey Method ◽  
Gender Based Violence ◽  
Women And Children ◽  
Gender Based

This article aims to evaluate government's communication strategy and citizens' awareness of the 16 Days of Activism for No Violence against Women and Children campaign in Soshanguve, South Africa. The study applied the diffusion of innovation theory because of its ability to assess how communities receive communication about the campaign from various media. Survey method was used to collect data, which was analysed using descriptive statistics. It was found out that mass media and other communication channels were main sources of campaign messages, which help the community to know how to address gender-based violence issues. Notably, this study found that females were more likely to know about the campaign than males. This article recommends that this campaign should be visible throughout the year and there should be more campaigns targeting men, and school curriculum, which educate pupils about the social and economic consequences of GBV.

BIOGENIC OPAL PRODUCTION IN THE AGULHAS CURRENT AND ITS CONNECTION TO ARIDIFICATION IN SOUTH AFRICA DURING THE MID-PLEISTOCENE

2018 ◽  
Author(s):  
Eduardo Ruiz Marin ◽  
◽  
Jason Coenen ◽  
Reed P. Scherer ◽  
Nathan D. Stansell ◽  
...  
Keyword(s):  
South Africa ◽  
Agulhas Current ◽  
Biogenic Opal

The Biology of Mediterranean-Type Ecosystems

2018 ◽  
Author(s):  
Karen J. Esler ◽  
Anna L. Jacobsen ◽  
R. Brandon Pratt
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Invasive Species ◽  
Habitat Loss ◽  
Endemic Species ◽  
Geographic Area ◽  
Cutting Edge ◽  
Wide Range ◽  
The Mediterranean ◽  
Mediterranean Type Ecosystems

The world’s mediterranean-type climate regions (including areas within the Mediterranean, South Africa, Australia, California, and Chile) have long been of interest to biologists by virtue of their extraordinary biodiversity and the appearance of evolutionary convergence between these disparate regions. Comparisons between mediterranean-type climate regions have provided important insights into questions at the cutting edge of ecological, ecophysiological and evolutionary research. These regions, dominated by evergreen shrubland communities, contain many rare and endemic species. Their mild climate makes them appealing places to live and visit and this has resulted in numerous threats to the species and communities that occupy them. Threats include a wide range of factors such as habitat loss due to development and agriculture, disturbance, invasive species, and climate change. As a result, they continue to attract far more attention than their limited geographic area might suggest. This book provides a concise but comprehensive introduction to mediterranean-type ecosystems. As with other books in the Biology of Habitats Series, the emphasis in this book is on the organisms that dominate these regions although their management, conservation, and restoration are also considered.

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