State of the Oceans Portfolio Committee 13 February

State of the Oceans Portfolio Committee 13 February 2013

Reported parameters 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 RV Algoa

Wind Speed & Direction Associated with warm and cold episodes. 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

Changes in wind strength and direction - potential big storms - amount of rainfall

• Changes in wind affect the Temperature 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

ST HELENA BAY STUDIES:

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

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

• 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. African Penguin Cape Cormorant Bank Cormorant Declines in population size: - Prey (Sardine & Anchovy; Rock Lobster) has shifted Southwards and Eastwards.

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