The water at Zeekoevlei is incredibly clear at the moment, probably clearer than it has been in years! This is linked to the dry summer we have had.
If you have a chance today, go and treat yourself with a look!
The water at Zeekoevlei is incredibly clear at the moment, probably clearer than it has been in years! This is linked to the dry summer we have had.
If you have a chance today, go and treat yourself with a look!
Hi Jocelyn
Is there actual recent water quality data for the current situation to compare with historical data? What is the proposed mechanism behind the link between water quality and the summer conditions? Thanks Justine
that is awesome, long may it stay that way.
Yes, also on the south side of the Peninsula, we can see the bottom coming into the gap in our Reeds – more than a meter 🙂
True. I can see all the below water plants and activities in the Otters Creek side of the lake.
The water usually IS clear just after draw-up, when algal growth is slow because of cold temperatures, and what does grow is eaten by zooplankton – the millions of tiny critters you see scooting about in the water column). As the water warms up and is light for longer, the algae grows faster (lots of nutrients!) and usually by early summer is so dense it has outweighed any effect of grazing by zooplankton, and the vlei is its usual green self. The algal cells / colonies may also get too big to be eatable by the tiny zooplankton. Last year something different happened – zooplankton were around in huge quantities and seemed to keep the water clear throughout most of summer. There might have been more because of the summer drought, which acts as a cue for them to hatch when they are submerged in water again. Will be interesting to see what happens this year …
Thank you for the explanation Liz, it will be interesting to see if it is a similar situation this year!
Hi Justine, the last quarterly water samples were taken on the 19th of May 2016 and the next sample date is set for the 18th of August 2016. I currently don’t have my hands on the data, but I will get the results and provide a brief update.
Hi Thanks for the interesting discussion – and it will be great to see the water chemistry results and to watch what happens to the “Zeethroughvlei” later in the season 🙂 Something else that adds to the normal greenness that Liz was explaining is the strong summer south easter that causes the surface water to move in the direction of the wind and allows mixing of the bottom sediments into the water (and thus even more nutrients for the phytoplankton/algae). So it would also be interesting to look at what happens when the south-easter picks up…
Can we please get the city to conduct tests on a far more regular basis. All results should be made public, perhaps a page here where we can post and analyse the data
For your perusal, please find a number of water quality results under the “Zeekoevlei” drop-down tab, titled “Zeekoevlei Water Test Results”.
Thanks for the comments. Although we have expected seasonal fluctuations in these ecosystem dynamics, it would be interesting to monitor ANNUAL differences in water level, water chemistry, as well as phytoplankton, and macroinvertebrate abundance to determine exactly what might drive these differences. I have also noticed an increase in bird life and I wondered if this is linked to a) the lack of wader habitat in a regional context due to the drought or b) more food (invertebrates) in the system, c) a combination or d) other. i.e. are we seeing better processing of nutrients in this system?????
Lots of thoughts but we need to monitor!!! Some nice ideas for a research project anyone??
Hi all,
For your perusal, please find a number of water quality results under the “Zeekoevlei” drop-down tab, titled “Zeekoevlei Water Test Results”.
These results will be updated regularly.
Excellent thanks
Hi Jocelyn,
I am a third year Geo-environmental student at Stellenbosch University and I am doing a group project on Zeekovlei’s pollution levels. Could you please assist us by sending me a link to the most recent data of Zeekovlei’s water pollution levels. We would really appreciate a detailed dataset of the pollution types, possible pollution subtypes and then the quantities. Thank you so much!
Jessica
I will forward this on to the manager of Zeekoevlei.