鹽鹼灘，又稱鹽沼，是沿海潮間帶和陸地間的一種生態系統，海水或鹹水有規律地湧入流出地帶。這一地帶主要生長鹽土植物。[1][2]這些植物是陸生植物且耐鹽鹼。在水域食物鏈及海陸營養交換中鹽鹼灘扮演着重要的地位，此外次地帶也為一些陸地生物的生存提供了支持。同時它起著海岸保護的作用。[2]
鹽鹼灘常出現在溫帶和極地的海岸線上，[3]有穩固、形成和淹沒三種狀態。通常鹽鹼灘有河流帶來的沉積物形成的砂基或泥基，[4]且處於障壁島、路堤、河口等有遮蔽之處。熱帶和亞熱帶因有紅樹林而不易形成鹽鹼灘，因為後者的生態是以草本植物為主導的。[1]
大多數鹽鹼灘的地勢和海拔都很低，因為地帶空曠，所以常有大量人口聚集。[5]根據實際地貌的差異，鹽鹼灘又可分為三角洲、開闊海岸、海灣和溺灣等等。歐洲等河流眾多之處常見有三角洲鹽鹼灘。[2][6]
成因
潮灘隨着沉積物不斷堆積而升高，漸漸可以生長植物，[7]隨着先鋒種繁殖體的到達，此地生態開始改善。河流帶來懸浮泥沙，[4]藍綠藻可以固着沉積物，[8]加上新生的植物，[9]更使得堤岸愈來愈穩固。[10]
潮汐與植被帶
沿海鹽鹼地與普通土地最大的區別在於其每日都有潮汐沖刷，造成該地持續積水。[1]這對鹽鹼地的營養積累有着重要積極影響。[5]除去這些低沼澤外，高沼澤因為地勢較高可以減少潮汐沖刷的影響，因而鹽度較低。[1]實際上鹽鹼灘的鹽度依據氣候時間的不同也會發生變化，例如下雨可以減少鹽度而蒸發則使其增加。[1]因此根據生理適應能力的不同，該地帶會形成不同的小環境。一般來說地勢較低處的植被耐鹽鹼度較高，也可以承受水的浸泡。[11][12]
參考文獻
- ↑ 1.0 1.1 1.2 1.3 1.4 Adam, P (1990). Saltmarsh Ecology. Cambridge University Press. New York.
- ↑ 2.0 2.1 2.2 Woodroffe, CD (2002). Coasts: form, process and evolution. Cambridge University Press. New York.
- ↑ Allen, JRL, Pye, K (1992). Saltmarshes: morphodynamics, conservation, and engineering significance. Cambridge University Press. Cambridge, UK.
- ↑ 4.0 4.1 Chapman, V. J. (1974). Salt marshes and salt deserts of the world. Phyllis Claire Chapman, Germany.
- ↑ 5.0 5.1 Bromberg-Gedan, K., Silliman, B. R., and Bertness, M. D. (2009). Centuries of human driven change in salt marsh ecosystems, Annual Review of Marine Science, 1: 117-141.
- ↑ Te Ara - The Encyclopedia of New Zealand (2005-2010). Plants of the Estuary . Retrieved 15 March 2010
- ↑ Pethick, J. (1984). An introduction to coastal geomorphology. Edward Arnold, London.
- ↑ Ginsburg, R. N., and Lowenstam, H. A. (1958). The influence of marine bottom communities on the depositional environment of sediments. The Journal of Geology, 66: (3), 310-318.
- ↑ Bird, E. (2008). Coastal geomorphology: an introduction. John Wiley & Sons Ltd, West Sussex, England.
- ↑ Aspden, R. J., Vardy, S. and Paterson, D. M. (2004). Salt marsh microbial ecology: microbes, benthic mats and sediment movement. In Fagherazzi, S., Marani, M. and Blum, L. K. (Eds), The Ecogeomorphology of Tidal Marshes (pp. 115-136). American Geophysical Union, Washington, DC.
- ↑ Bertness, MD, Ewanchuk, PJ, Silliman, BR (2002). Anthropogenic modification of New England salt marsh landscapes. Proceedings of the National Academy of Sciences 99(3): 1395-1398.
- ↑ Rand, TA (2000). Seed Dispersal, Habitat Suitability and the Distribution of Halophytes across a Salt Marsh Tidal Gradient. Journal of Ecology 88(4): 608-621.
外部連結
- Friends of Famosa Slough
- Geography resource for schools
- Johnson, CY (2006). Cause sought as marshes turn into barren flats. The Boston Globe.
- Marine Nature Study Area operated by the Town of Hempstead: Dept. of Conservation & Waterways, located in Oceanside, New York, USA
- New England Sudden Wetland Dieback
- Salt Marsh Nature Center located in the Marine Park section of Brooklyn, New York, USA
