Red Sea large marine ecosystem
Contributing Author; C. Michael Hogan
Contents
Location and General Description
The Red Sea Large Marine Ecosystem (LME) is characterized by its tropical climate. This semi-enclosed large marine ecosystem (LME) is situated between the continents of Africa and Asia, and it links tediterranean Sea and the Indian Ocean. Its width varies from 30 to 280 kilometres (km). The Global Environment Facility (GEF) is supporting a project aimed at protecting the unique coral reefs of this LME, and sustaining its valuable Me coastal and marine resources. LME book chapters and articles pertaining to this marine ecosystem include Baars et al, 1998, and Getahun, 1998.
Productivity
The LME’s narrow elongated shape, its semi-enclosed character and its circulation patterns protect the coastal areas from storms (Tropical weather and hurricanes). Its complex reef ecosystem, the most northern on earth, provides habitats for a wide range of marine species including endemic species (see Baars et al, 1998). For information on the LME’s coral reefs, see UNEP's Coral Reef site. Formed as a result of the expansion of the Mediterranean Sea, the Red Sea received its first biota from the Mediterranean Sea but now its biota (phytoplankton, zooplankton and fish fauna) bears more similarity to the Indian Ocean. For more information on the relationship between the Red Sea and the Indian Ocean in terms of geophysical, chemical and biologic phenomena, see Getahun, 1998. The Red Sea LME is considered a Class II, moderately productive (150-300 grams of Carbon per square meter per year (gC/m2-yr)), ecosystem based on SeaWiFS global primary productivity estimates. As a result of the wind system, surface currents flow from the Indian Ocean into the Red Sea during winter and reverse themselves in the summer. Meanwhile, the nutrient-rich bottom and mid-level currents flow in the opposite direction, resulting in a net outflow of nutrients from the Red Sea LME during the winter and its enrichment during the summer. For information on nutrient supply in the winter and summer, see Beckmann (1984). For information regarding a “monsoons and pelagic systems” project, see Baars et al, 1998. Water temperature and salinity increase from the Indian Ocean to the Red Sea. In spring and summer the Red Sea is oligotrophic (see Baars et al, 1998). Generally, there is a decrease of productivity from South to North (see Getahun, 1998).
Fish and Fisheries
(Source: NOAA) The greater marine biodiversity of this tropical region is reflected in the catch composition. Among species found in the LME are Raja fullonica, Sciaena aquila, and Syngnathus algeriensis. Endemic species include Sphyrna mokarran, Torpedo panthera, and Terapon jarbua (see Botros, 1971). The FAO (Food and Agriculture Organization (FAO)) 10-year trend shows an increase from 50,000 tons in 1990 to more than 80,000 tons in 1999 (see FAO, 2003, appendix figure 19). The bulk of the catch consists of miscellaneous coastal fishes and pelagic fishes. The catch of tunas, bonitos and billfishes is increasing, as is the catch of herrings, sardines and anchovies. A Red Sea Strategic Action Programme (SAP), PERSGA, a Regional Organization for the Conservation of the Environment of the Red Sea and Gulf of Aden. The University of British Columbia has detailed fish catch statistics for this LME. Click on the graph below for the FAO data. was initiated in 1995. There is a paucity of reliable data. Unregulated fishing is a threat to ecosystem health. One commercial species is lobster. A positive move is the replacement of gillnets with lobster traps, which will enable fishermen to release egg-bearing female lobsters. See information on PERSGA, a Regional Organization for the Conservation of the Environment of the Red Sea and Gulf of Aden. The University of British Columbia has detailed fish catch statistics for this LME. Click on the graph below for the FAO data.
Pollution and Ecosystem Health
(Source: NOAA) Due to its relatively small size, limited oceanographic circulation and high endemism, the Red Sea is particularly vulnerable to water pollution, loss of species, and reduction in ecosystem productivity. The key environmental threats are unregulated fishing, uncontrolled development, and nutrient addition from surface runoff and sewage disposal. When controls were added in about 1990 to limit nutrient inputs, coral reef health began to improve; however intensive pen-fishing began and again the reef health declined.(Kolb,2004)
There is a pollution hotspot in the LME’s Gulf of Aqaba. Tankers make their way into this LME through the Suez Canal. It is a high-risk area in terms of navigation, and it requires the establishment of official traffic lanes and separation schemes for the heavy flow of traffic. The World Bank/GEF/PERGSA Strategic Action Programme (SAP) for the Red Sea aims to improve coastal and marine environments by reducing navigation risks, and preventing and controlling maritime pollution. Surveys have been completed to locate hazardous rocks. The LME’s extensive coral reefs, seagrass beds, and mangroves suffer from the excesses of tourism, pollution discharges and industrial development. There is a need to establish more marine protected areas, to serve as havens for fish and for repopulation purposes. A marine park has been established by Israel and Jordan.
Tangent Terrestrial Ecoregions
Terrestrial ecoregions that adjoin the Red Sea are:
- Along the northeast coast of the Red Sea is the Red Sea Nubo-Sindian tropical desert and semi-desert
- Along the northwest coast of the Red Sea is the Sahara Desert
Red Sea Nubo-Sindian tropical desert and semi-desert
The vegetation in the Red Sea Nubo-Sindian tropical desert and semi-desert ecoregion is sometimes referred to as a pseudo-savanna. The spaces between the scattered trees and larger shrubs are occupied by smaller shrubs and herbs; grass-cover may sometimes appear, but only after a plentiful rainfall. The wadis and gullies tend to support most of the vegetation, due to generally higher soil moisture levels in such ravines. Common plants include species of Vachellia or Acacia, notably Umbrella Thorn (Vachellia tortilis), Red Thorn (V. gerrardii), Acacia tortilis raddiana, as well as Christ's Thorn Jujube (Ziziyphus spina-christi), Desert Date (Balanites aegyptiacus), Toothbrush Tree (Salvadora persica), Moringa peregrina, Karira (Capparis decidua), Cordia gharaf, Giant Milkweed (Calotropis procera) and many other plant taxa. On Oman's central plains, common trees are Vachellia tortilis and A. ehrenbergiana, with Prosopis cineraria in areas of deeper sand accumulation. The most widespread and abundant grasses are within the genus Stipograstis.
Sahara Desert
The Sahara is located in a climatic divide, with the Intercontinental Convergence Zone moving up from the south, but stopping before the center of the Sahara, and consequently hardly carries any rain. Similarly, the winter rainfall of North Africa does not reach far south enough to regularly bring rain to the central Sahara. Consequently, the rainfall, albeit extremely rare, can fall in any season. The annual rainfall is below 25 millimetres (mm), and in the eastern part of the desert it is less than five mm per annum. The scarcity of rainfall in this ecoregion is aggravated by its irregularity, as no rain may occur for many y in some areas, followed by a single intense thunderstorm.
The Sahara is one of the hottest regions in the world, with mean annual temperatures exceeding 30°C. earsIn the hottest months, temperatures can rise over 50°C, and temperatures can fall below freezing in the winter. A single daily variation of -0.5°C to 37.5°C has been recorded. The Sahara is also extremely windy. Hot, dust-filled winds create dust devils which can make the temperatures seem even hotter.
The extreme aridity of this area is a relatively recent feature. Much larger areas of the Sahara had adequate water only 5000 to 8000 years ago. It is not clear how much of this ecoregion was covered with vegetation, but in other parts of the Sahara the vegetation was closer to the savanna woodlands of eastern and southern Africa. Currently the ecoregion is in a "hyper arid" phase, with high summer temperatures, lower winter temperatures and rainfall between 0 and 25 mm per annum. There are two theories of the formation of the Sahara, but in any case its formation is recent, beginning circa 8000 to 4000 years before present. One theory relates to subtle natural changes in the Earth orbit, leading to dramatically reduced rainfall in the region. The second theory, supported by extensive archaeological and plant record data, indicates Holocene man engaged in steadily expanding pastoralism, leading to overgrazing and corresponding changes in land cover and albedo.
Socio-Economic Conditions
(Source: NOAA) The coast offers opportunities for economic development in the area of fisheries, [../156679/index.html trade, petroleum, and tourism. Tourism (marine recreation, diving and snorkeling) attracts thousands of tourists each year and provides valuable foreign exchange. Local fisheries have for centuries provided food and employment to the people of the Red Sea. But the potential for fishing is being eroded in some coastal areas due to the degradation of the environment caused by pollution associated with industrial and urban development. The sustainable use of the important local resources requires a reduction in current pollution inputs.
Governance
The countries bordering the Red Sea LME are Egypt, Sudan, Eritrea, Djibuti, Yemen, Saudi Arabia, Israel and Jordan. Information is available on the GEF-supported projects in the Red Sea. The process of formulating a Transboundary Diagnostic Analysis (TDA) and a Strategic Action Programme (SAP) has played an important role in uniting the approach taken by the coastal countries bordering this LME. In 1982, they had signed the Jeddah Convention, which provides the legal framework for cooperation in marine issues. A Regional Organization for the Conservation of the Environment of the Red Sea and Gulf of Aden (PERSGA) was established. The SAP identifies actions needed to protect the uniquely fragile coral reefs, sea grass beds and mangroves of the Red Sea coast. Its aim is to improve coastal and marine environments by supporting integrated [[coastal] zone] management and identifying the institutional and legal impediments to further regional cooperation. Egypt, Sudan, Saudi Arabia and Yemen are creating marine protected areas that will provide sanctuaries for valuable species. There is a need to raise public awareness of the value of the marine environment through education.
References
- Baars, M.A., Schalk, P.H. and M.J.W. Veldhuis, 1998. Seasonal fluctuations in plankton biomass and productivity in the ecosystems of the Somali Current, Gulf of Aden, and Southern Red Sea. In Sherman, et al., (eds.), Large Marine Ecosystems of the Indian Ocean: Assessment, Sustainability, and Management, (Oxford: Blackwell Science). pp. 143-174. ISBN: 0632043180 (Red Sea large marine ecosystem) .
- FAO, 2003. Trends in oceanic captures and clustering of large marine ecosystems—2 studies based on the FAO capture database. FAO fisheries technical paper 435. 71 pages.
- Getahun, Abebe, 1998. "The Red Sea as an Extension of the Indian Ocean", in Sherman, et al., (eds.), Large Marine Ecosystems of the Indian Ocean: Assessment, Sustainability, and Management, (Oxford: Blackwell Science). pp. 277-283. ISBN: 0632043180
- Beckmann, W. 1984. "Mesozooplankton Distribution on a Transect from the Gulf of Aden to the Central Red Sea During the Winter Monsoon". Oceanolog. Acta. 7:87-102.
- Botros, G. A. 1971. "Fishes of the Red Sea". Oceanogr. Mar. Biol. Annual Review. 9: 221-348.
- Halim, Y., 1984. Plankton of the Red Sea and the Arabian Gulf. Deep-Sea Res 31:969-982.
- Kotb, M., M. Abdulaziz, Z. Al-Agwan, K. Alshaikh, H. Al-Yami, A. Banajah, L. Devantier, M. Eisinger, M. Eltayeb, M. Hassan, G. Heiss, S. Howe, J. Kemp, R. Klaus, F. Krupp, N. Mohamed, T. Rouphael, J. Turner and U. Zajonz , 2004 , Status of Coral Reefs in the Red Sea and Gulf of Aden in 2004. . p: 137-154 in C. Wilkinson (ed.). Status of coral reefs of the world: 2004. Volume 1. Australian Institute of Marine Science, Townsville, Queensland, Australia. 301 p.
- Seriy, V. V. 1968. "To the Problem of the Water Exchange Between the Red Sea and the Gulf of Aden". Okeanol. Issled 19: 195-200.
Citation
U.S. National Oceanic and Atmospheric Administration, C. Michael Hogan (2008) Red Sea large marine ecosystem. Encyclopedia of Earth. National Council for Science and Environment. Washington DC. Updated 2019. Retrieved from http://editors.eol.org/eoearth/wiki/Red_Sea_large_marine_ecosystem| Disclaimer: This article contains some information that was originally published by the National Oceanic and Atmospheric Administration (NOAA). Topic editors and authors for the Encyclopedia of Earth have edited its content and added new information. The use of information from the National Oceanic and Atmospheric Administration (NOAA) should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content. |
