Masoud Moradi

Red tide detection in the Strait of Hormuz (east of the Persian Gulf) using MODIS fluorescence data

A monstrous red tide appeared on October 2008 and expanded to the west on November 2008 off the Iranian coasts in the Hormuz Strait (east of the Persian Gulf). MODIS satellite data, hydrographic and bio-optical field measurements were used to detect the red tide. MODIS fluorescence line height (FLH in w m−2 μm−1 sr−1) data showed the highest correlation with near-concurrent in situ chlorophyll concentration of 0.74 (100(FLH))1.23 (r = 0.9, n = 44). In contrast, the band-ratio Chlorophyll product of MODIS showed more inconsistency with in situ chlorophyll data due to the interference of other water constituents. High FLH value patches >0.18 were confirmed to be located at the medium to high (104–106 cells l−1) concentrations of Cochlodinium polykrikoides, and also showed a chlorophyll anomaly >1 mg m−3, which means the potential of red tide occurrences. The FLH imagery also showed that the bloom started in early September along Bandar-Abbas port, and developed and moved to the west along the coastal regions. The results revealed that MODIS FLH and enhanced RGB (ERGB) imagery plus in situ data are adequate tools for red tide monitoring.

Fluctuation of Sea Surface Temperature in the Persian Gulf and its impact on coral reef communities around Kish Island

Sea Surface Temperature (SST) is a critical parameter which can affect the health of coral reef communities. The Persian Gulf consists of various types of coral reefs, especially around the islands such as Kish Island. NOAA-Pathfinder-5 provides a valuable global dataset including the SST values of the water bodies. This research focuses on the studies of fluctuations SST values of near-shore waters around the Kish Island during 1985 to 2009 using NOAA-Pathfinder-5 dataset and field observed data including direct underwater photography and photo-transecting by snorkeling. Subsequently, the results were analyzed to study the impacts of these fluctuations on main coral reef communities such as Acroporids and Faviids in the studied area. Statistical analyses on SST data showed a meaningful and positive correlation between the SST values and bleaching in coral reefs. Specifically, in August 1998 and 2007, this phenomenon was clearly observable when most of corals have been affected by the bleaching phenomenon when the SST values were ∼1.5°C higher than normal situation. Coral reefs showed their ability to recover themselves after the anomalous dates, if the SST values remained normal enough for a long period of time.

Mapping of the corals around Hendorabi Island (Persian Gulf), using WorldView-2 standard imagery coupled with field observations

High spatial resolution WorldView-2 (WV2) satellite imagery coupled with field observations have been utilized for mapping the coral reefs around Hendorabi Island in the northern Persian Gulf. In doing so, three standard multispectral bands (red, green, and blue) were selected to produce a classified map for benthic habitats. The in-situ observations were included photo-transects taken by snorkeling in water surface and manta tow technique. The satellite image has been classified using support vector machine (SVM) classifier by considering the information obtained from field measurements as both training and control points data. The results obtained from manta tow demonstrated that the mean total live hard coral coverage was 29.04% ± 2.44% around the island. Massive corals poritiids (20.70%) and branching corals acroporiids (20.33%) showed higher live coral coverage compared to other corals. Moreover, the map produced from satellite image illustrated the distribution of habitats with 78.1% of overall accuracy.