Wednesday, 26 July 2017
SQU-TRC project to unravel the mystery behind regime shifts in ecosystem

Muscat Daily Staff Writer , November 21, 2010

A project funded by The Research Council (TRC) in partnership with the Ministry of Fisheries and Sultan Qaboos University (SQU) is analysing the concept of regime shifts in our ecosystem.

As part of this project, intermittent changes of physical and chemical characteristics of water mass, species abundance and diversity over 15 years (1997- 2012) will be analysed. It has been found that red tides, often used to describe harmful algal blooms (HABs) in marine coastal areas, are red or brown and tint the sea water to a reddish colour due to the presence of marine organisms.

However, in this region as a whole and Oman in particular, red tides are not red, but green. This interesting fact is unknown to people, according to Dr Sergey Piontkovski, associate professor, department of marine sciences and fisheries at SQU.

Speaking to Muscat Daily, Piontkovski said, “This is because Noctiluca scintillans, the most abundant algal species causing red tide, has plenty of green organic pigments in its cells.” He said that due to the colour and amount of pigments in the phytoplankton bloom, the red tides are supposed to be red or brownish in colour.

“In this region, it is mostly green, and is different from that in other parts of the world,” he said. However, in some cases, due to the switch of species dominance, different colours of bloom are visible.

The ministry holds long-term records of all blooms along the coastal areas of the country. “According to the data, blooms are most likely visible in February through March, and the second peak season is in August through September,” he said. This seasonal pattern is associated with the mode of monsoon winds. “So in terms of predictions, we can know the dangerous period for the fisheries sector, as blooms cause massive fish kills,” he said.

However, some blooms are not predictable, due to the other factors influencing them. “In 2008, we had the most dramatic bloom ever recorded in this region over the past 50 years,” said Piontkovski, adding that it was caused by Cochlodinium polykrikoides, a species new to the region, which had possibly penetrated into the waters here with the ballast water of ships.

He said that the species that caused the bloom in October- November 2008 and also in March this year is a mystery which the research scientists are trying to unravel.

Elaborating on the phenomenon, he said that a team of oceanographers studying the Arabian Sea have noticed that different kinds of phytoplanktons present during the northeast (winter) monsoon seem to be changing too.

“Among the changes is the increasingly frequent and widespread appearance of Noctiluca miliaris, a dinoflagellate species.” Why phytoplankton species change their dominance over time is yet to be understood, he said.

For this reason, a number of collaborative projects linking biologists from the ministry and SQU have been developed to tackle the problem, said Piontkovski, who is also the principal investigator of the project funded by TRC.

“Our hypothesis suggests such a regime shift occurred in the Oman Sea during 2005-8, marking a switch from predominance of the diatom dominating phytoplankton species to the dinoflagellate community,” he said.

Moreover, satellite remote sensing images of ocean colour, have helped in providing a unique view of the marine ecosystem.

© Muscat Daily


General contact:   Prof. Sergey Piontkovski
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