Current conditions. Nice and warm – between 25 and 28 deg daytime maximums with about 18 deg minimums. Water is currently 23 deg and the visibility is about 10m. Long weekend and Sodwana Shootout are now behind us. Two huge cold fronts came through during this period. We normally have a strong North Easterly blowing in front of the cold front and then a strong South Westerly behind the cold front as it passes over. The swell is changing a lot too, from 1m to 3-4 all in a week.
The strong North Easterly often brings a “cold upwelling” with it. This is due to an interaction between wind and current and is explained in depth at http://en.wikipedia.org/wiki/Upwelling. This upwelling brings colder and murkier water as it is full of phytoplankton (plant plankton) and zooplankton (animal plankton). The green water is often accompanied by small jellyfish and comb jellies. Comb jellies are so named as they propel themselves with fine hairs. A lot of them are also able to give off light and these lights can be seen running up and down their bodies. See http://www.ucmp.berkeley.edu/cnidaria/ctenophora.html for more details and pictures. The biggest advantage of the green water is that the plankton and jellies attracts the manta rays and we have seen numerous mantas over the last week.