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CRP El Niño member - Mr. Saber Al-Rousan

Mr. Saber Al-Rousan

Marine Science Station
Aqaba, Jordan



Scientific Background


To understand recent and future climatic changes, whether as a consequence of human activities or of natural variability, it is necessary to document how climates have varied in the past, i.e., the space-and time-scales of natural climate variability. Some records of this natural variability were deduced from instrumental observations, which were poor before the age of satellite remote sensing, and restricted to the last 150 years. Long term high-quality records are needed to expand the instrumental records and provide a more complete picture of natural climate changes over decades, multidecades or even centuries time scales.


Massive hermatypic coral skeletons have proven to provide high quality records of climatic and environmental changes from tropical and subtropical oceans on a seasonal to century time-scales (e.g., Pätzold, 1984; 1986; McConnaughey, 1989; Crowley et al., 1997; Felis et al., 2000). These records are in some cases equivalent in quality and resolution to those derived from instrumental data.


Records from long-lived corals have shown the presence of decadal patterns of ENSO-like variability from the tropical Pacific that is unrecognizable from existing instrumental data (e.g., Carriquiry et al., 1994; 1998; Wellington and Dunbar, 1995). High-resolution trace elements and stable isotopes coral records were used to reconstruct climatic and environmental parameters such as sea surface temperature, salinity, rainfall, nutrient and river inputs (e.g. Shen et al., 1987; McConnaughey, 1989; Cole and Fairbanks, 1990). Also it has been used to study some environmental changes caused by human activities, such as industrial and sewage pollutions (Dodge et al., 1984; Shen and Boyle, 1988), nuclear testing (Knuston et al., 1972) and anthropogenic CO2 increase (Nozaki et al., 1978). Thus, coral records can be used to assess long-term climate trends as well as the range of natural variability in the tropical-subtropical environment.


The applicability of corals as high-resolution climate proxies from earlier studies in the Gulf of Aqaba (e.g., Klein et al., 1992; Heiss, 1996; Heiss et al., 1999; Felis et al., 2000; Moustafa et al., 2000; Al-Rousan et al., 2002; 2003) encourage for further investigations to be carried out on fossil corals, as this can offer a unique source of information on tropical climate variability throughout the late Quaternary (e.g., Beck et al., 1997; 1994; McCulloch et al., 1999). Recent coral-based studies in the area have provided important informations on past climate and ocean variability (Moustafa et al., 2000, Felis etal., 2000).


In tropical pacific, climate constructions from coral skeletons have been developed in order to study ENSO phenomena (Wellington and Dunbar 1995; Carriquiry et al., 1988, 1994; 1998). Felis et al. (2000) and Rimbu et al. (2001) found that the northern Red Sea is a sensitive region to mid and high latitude climatic modes with strong continental influence and it captures variability associated with ENSO phenomena of tropical Pacific origin. Recent research indicates that some climatic phenomena such as El Niño Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) have an impact on the Middle East climate (e.g., Charles et al., 1997). These phenomena have been recently identified from a 245-year long oxygen isotopic coral record from the northern Red Sea (Felis et al., 2000; Rimbu et al., 2001). Furthermore, Mid-Holocene corals d18O records from the northern Red Sea indicate higher seasonality in temperature and/or seasonal changes in the hydrological balance during that period in the region (Moustafa et al., 2000).

Current activities related to CRP

  • Deployment of under water temperature loggers (StowAway TidbiT) in a depth transect in front of the Marine Science Station in Aqaba (29°27' N and 34°90' E). The transect was laid out on the reef between the reef flat and the deep fore reef down to 42 m These temperature loggers were deployed in April 2004 and recorded hourly resolution measurements of the seawater temperature. This new records will continue the older records from the same depths since 1999.
  • Small massive Porites colonies (20-30 cm diameter) along the depth profile have been chosen where the temperature loggers where deployed. The temperature loggers were fixed next to these colonies. Colonies depth profile was 42, 29, 1.9, and 7 m deep.
  • Collection of several huge (Porites spp.) fossil corals from the southern beach. The site is located near the Royal Navy Forces (AQB-17), where a new construction work is taking place. The corals were collected from a submerged reef terraces from about 3 m underwater deep and the colonies are about 1 m in diameter.
  • Survey of big massive coral colonies along the Jordanian coast of the Gulf of Aqaba from the north to the south. The modern corals in the living reefs chosen for the paleoclimatic studies were from the massive type mainly Porites sp. This was chosen for different reasons: first, because it is considered to be the most important reef builders in the area and second due to their ubiquity and ability to secrete huge massive colony and also display most clear density bands which enable measurement of annual extension rates. The colonies have smooth surfaces and were not from the branching or finger like types in order to provide continues records with no gaps in information recovered from its materials. The larger the size (vertical diameter) of the colony is the best to get more information of the past several centuries.
  • Collection of oceanographic parameters records from the study area and carried out a continuous record. The monthly seawater temperature and salinity records from Aqaba were started in 1997 (Dr. Riyad Manasreh). The measurements were performed in front of the Marine Science Station at Aqaba, using a Conductivity-Temperature-Depth sensor (OS200 CTD) instrument. The precision of the CTD is better than ± 0.001°C and ± 0.003‰ for temperature and salinity respectively.
  • Collection of climatic parameters records from the study area from the weather station near to the sea within the Marine Science Station. The weekly averaged records of air temperature, wind speed and wind direction is collected.

Publications

  • Al-Rousan, S., Al-Shloul, R., Al-Horani, F., Abu-Hilal. A. (2007) Heavy metal contents in growth bands of Porites corals: Record of anthropogenic and human developments from the Jordanian Gulf of Aqaba. Marine Pollution Bulletin 54 (12): 1912-1922.
  • Al-Rousan, S., Felis, T., Manasrah R., Al-Horani F. (2007). Seasonal variations in the stable oxygen isotopic composition in Porites corals from the northern Gulf of Aqaba, Red Sea. Geochemical Journal 41 (5): 333-340.
  • Al-Horani, F.A., Al-Rousan S.A., Manasrah R.S. and Rasheed M.Y. (2205) Coral Calcification: Use of radioactive isotopes and metabolic inhibitors to study the interactions with photosynthesis and respiration. Journal of Chemistry and Ecology 21 (5): 325-335.
  • Felis, T., G. Lohmann, H. Kuhnert, S. J. Lorenz, D. Scholz, J. Patzold, S. A. Al-Rousan, S. M. and Al-Moghrabi. Increased seasonality in Middle East temperatures during the last interglacial period, Nature 429 (2004) 164-168.
  • Al-Rousan S., Al-Moghrabi S., Patzold J. and Wefer G. Stable oxygen isotopes in Porites corals monitor weekly temperature variations in the northern Gulf of Aqaba, Red Sea. Coral Reefs 22, 4 (2003) 346-356.
  • Al-Rousan S., Al-Moghrabi S., Patzold J., Wefer G. (2002) Environmental and biological effects on the stable oxygen isotope records of corals in the northern Gulf of Aqaba, Red Sea. Marine Ecology Progress Series 239: 301-310.
  • Al-Rousan, S., Patzold J., Al-Moghrabi S. and Wefer G. Invasion of anthropogenic CO2 recorded in planktonic foraminifera from the northern Gulf of Aqaba. International Journal of Earth Sciences 93, 6 (2004) 1066-1076.