Oceanography in Mossel Bay, South Africa

Since November 2010 Oceans Research has been performing Conductivity, Temperature and Depth (CTD) scans focusing in the general vicinity of Seal Island.  CTD is an essential tool that is utilized by Oceanographers to gather data on specific parameters within the Oceans’ water column.  In this instance Oceans Research was most concerned with Mossel Bay’s water quality in relationship to how the new Petrol SA Desalination Plant would affect the complex ecosystem surround Seal Island.

Through the Seal Island project Oceans Research has been able to perform a preliminary base line data set; collected scans during construction of the Desalination Plant; and Oceans is continuing to collect scans while the plant is operational.  Oceans Research hopes to complete the cycle of data collection with scans being performed after the Desalination Plant is dormant.  With the data sets collected Oceans Research should be able to show what effects, if any the plant had on Mossel Bay’s oceanography and depending on how long the CTD scans continue after the plant is offline, Oceans Research should be able project if the Bay will return to a homeostasis state that was witnessed prior to the plant.

Petro SA’s Desalination Plant was projected to go online in 2014 but due to years of drought that wrecked havoc on all of South Africa this project was fast tracked ahead of schedule.  In 2011 the construction of the plant was underway.  During this phase Oceans’ Cetacean’s monitoring program, headed by University of Pretoria’s Master Student Bridget James, noticed a behavioral change in the vulnerable humpback dolphin (Sousa chinensis) population which moves throughout Mossel Bay.  Humpback Dolphins are regularly found foraging on the Westerly facing side of Seal Island in Mossel Bay due to a shallow reef system that is inhabited by shoals of reef fish.  During construction the Humpback Dolphins where noticeably absent from this common feeding ground.  Mrs. James suspects that during construction there was a sediment influx into this part of the bay since the construction of the plant was directly in line with this reef system.  Construction was completed in mid-2011and Mrs. James was happy to report her observations of the return of the Humpback Dolphins to this feeding ground.  Petro SA’s Desalination Plant is striving to be one of the Greenest Desalination Plants in South Africa and wanted to set the standards for future plants.  With events such as the return of the Humpback Dolphins and Oceans Research constantly monitoring Seal Island, Oceans Research hopes to prove Petrol SA correct in their assumption of Greenness.  Through monitoring this area of the bay Oceans Research wants to be able to realize changes in the bay’s oceanography and be able to work with local government to improve the bay’s health. 

For more information on Petro SA’s Desalination plant visit www.pertosa.co.za .

-Renae Logston