State of the OceansPortfolio Committee

13 February 2013

Reported parameters

RV Algoa 1. OCEAN PHYSICS – Warm and cold episodes

– Temperature

– Ocean Currents

2. ATMOSPHERIC MEASUREMENTS– Wind speed, direction

– Air pressure

3. OCEAN CHEMISTRY– Oxygen

– Heavy Metal Pollution

– Nutrients

4. OCEAN BIOLOGY– Plankton

– Biodiversity

– Protected species (birds, whales, sharks, etc)

Annual Cycles and Long-term trends

Weaker summer southeasterly winds – warm episodes - hence less upwelling.

Stronger summer southeasterly winds – cold episodes- Hence more upwelling.

• Warm & Cold episodes approx every 3-4 yrs

Wind Speed & DirectionAssociated with warm and cold episodes.

Changes in wind strength and direction - potential big storms

- amount of rainfall

Sea Surface Temperature (SST) - satellite data – over large scale - changes in SST indicates intensity of upwelling. - varies from season to season. - changes in the SST

• SST above average: Summer 2009/10 (except January 2010)

Cold summer SST – strong easterly winds – intense upwelling

Upwelling:-cold bottom water pushed to surface.-West Coast – cold nutrient rich water to surface.-Stimulates the food chain

• Changes in wind affect the Temperature

ST HELENA BAY STUDIES:

Nutrients

Nitrates: most important - phytoplankton.Silicates: 2nd most important.

• Moving offshore – nutrient content decreases with warmer water.• Nitrates and Phosphates: - steady increase since 1978 and declining since 1990’s.

If nutrients decrease - overall reduction in phytoplankton. - overall reduction in zooplankton. - eventually reduction in fish.

What we do not understand is what causes the changes in the nutrient content.

Oxygen

Low Oxygen concentration at bottom.Low Oxygen nearer to the shore.

2006-2008:: low concentrations extended 140-170 km offshore. - coincided with cool SSTs, relatively high upwelling and high chlorophyll concentrations (lots of phytoplankton). - decay(rotting) of phytoplankton consumes Oxygen lead to low Oxygen conditions - Rock Lobster walkout. (Lobster breathe Oxygen. Under low Oxygen conditions they suffocate and die in tonnes).

1951 – 2010:•Long-term, 100-fold increase in zooplankton abundance, but decrease since mid-1990s.

•Change in composition of species.

•Shift from large-species to small-species dominance: Know from other areas – associated with ocean warming.

•Geographic shift in species such as sardine & anchovy to South-East – factories stranded on West Coast.

Zooplankton(Microscopic organisms)

• Pollution monitoring

- Lead, Cadmium, Zink, Copper, Iron, Manganese, Mercury.

- Important elements for pollution status.

- Use mussels as an indicator species in that it grows in one place and it filters sea water around it.

Data collected – needs analysis and interpretation.

Seabirds

- indicators of marine ecosystem health.

Declines in population size:

-Prey (Sardine & Anchovy; Rock Lobster) has shifted Southwards and Eastwards.

African Penguin Cape CormorantBank Cormorant

In Summary:

• Increase in wind speed and direction (southeaster) – more intense upwelling – more nutrients – more phytoplankton / zooplankton and fish.

• Increase in intensity of winds – increase in storminess.

• Decline in Seabirds as a result of decrease in food availability – associated with environmental change.

Thank You