Transcript Wetland
Wetland 1. Vegetated areas that are covered with water or have very wet soils for part of the year. 2. Wet areas without vegetation, Most documents focus on vegetated areas because wetland plants provide a unique habitat and other benefits to fish that unvegetated areas do not provide. Seagrass meadow Mangrove Saltmarsh climateshifts.org Mangrove Mangroves are various kinds of trees up to medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics Distribution: mainly between latitudes 25° N and 25° S; dominate three-quarters of tropical coastlines. This habitat is characterized by a depositional coastal environments, where fine sediments , often with high organic content, collect in areas protected from high-energy wave action. ozcoasts.gov.au The saline conditions range from brackish water, through pure seawater (30 to 40 ppt), to water concentrated by evaporation to over twice the salinity of ocean seawater (up to 90 ppt; part per thousand). Mangrove (source: en.wikipedia.org) The word is used in at least three senses: (1) most broadly to refer to the habitat and entire plant assemblage or mangal for which the terms mangrove forest biome, mangrove swamp and mangrove forest are also used, (2) to refer to all trees and large shrubs in the mangrove swamp, and (3) narrowly to refer to the mangrove family of plants, the Rhizophoraceae, or even more specifically just to mangrove trees of the genus Rhizophora. The remaining mangrove forest areas of the world in 2000 was 53,190 square miles (137,760 km²) spanning 118 countries and territories. Source: Exploring Taiwan Mangrove • 在台灣符合此定義的現存紅樹林植物只有 紅樹科的水筆仔、五梨跤、使君子科的欖 李及馬鞭草科的海茄苳等四種。當然，在 台灣的濱海地區還有各種植物，包括紅樹 林的的伴生植物，例如苦林盤、黃槿、土 沈香等，另外還有禾本科之雲林莞草、鹽 地鼠尾粟、濱刺麥及林投、草海桐、鹽地 等海濱植物- • • • • • • Black Mangroves or 'Courida' (Avicennia germinans) Red Mangrove or 'Red Mango' ( Rhizophora mangle ) White Mangrove ( Laguncularia racemosa ) Source: www.mangrovesgy.org/index.php?option=com boripat.ac.th Hypocotyl: The part of the stem of an embryo or of a seedling between the radicle and the cotyledons ; cactus-art.biz 種子和發芽情況; y3c2.blogspot.com Special Type of Germination: Vivipary source: tutorvista.com In viviparous germination, the seeds germinate while still attached to the parent plant. The embryo grows out of the seed and then out of the fruit and projects from it in the form of a green seedling幼苗 displaying the root and the hypocotyl. Due to the increase in weight the seedling separates from the parent tree and falls into the water and develops lateral roots. Vivipary is seen in Rhizophora, Cercops, Kandelia and Sonneratia. Radicle:胚根; hypocotyl:下胚軸; seed or progragule en.wikipedia.org • Mangrove plants require a number of physiological adaptations to overcome the problems of anoxia, high salinity and frequent tidal inundation. Each species has its own solutions to these problems; this may be the primary reason why, on some shorelines, mangrove tree species show distinct zonation. Therefore, the mix of species is partly determined by the tolerances of individual species to physical conditions, like tidal inundation and salinity, but may also be influenced by other factors such as predation of plant seedlings by crabs. En.wikipedia.org • Once established, mangrove roots provide an oyster habitat and slow water flow, thereby enhancing sediment deposition in areas where it is already occurring. The fine, anoxic sediments under mangroves act as sinks for a variety of heavy (trace) metals which colloidal particles in the sediments scavenged from the water. Mangrove removal disturbs these underlying sediments, often creating problems of trace metal contamination of seawater and biota. En.wikipedia.org • Mangrove swamps protect coastal areas from erosion, storm surge (especially during hurricanes), and tsunamis. The mangroves' massive root systems are efficient at dissipating wave energy. Likewise, they slow down tidal water enough that its sediment is deposited as the tide comes in, leaving all except fine particles when the tide ebbs. In this way, mangroves build their own environment. Because of the uniqueness of mangrove ecosystems and the protection against erosion they provide, they are often the object of conservation programs, including national biodiversity action plans. En.wikipedia.org emeralddiving.com; bryozoan苔蘚蟲 The unique ecosystem found in the intricate mesh of mangrove roots offers a quiet marine region for young organisms. In areas where roots are permanently submerged, the organisms they host include algae, barnacles, oysters, sponges, and bryozoans, which all require a hard surface for anchoring while they filter feed. Shrimps and mud lobsters use the muddy bottoms as their home. Mangrove crabs mulch the mangrove leaves, adding nutrients to the mangal muds for other bottom feeders. In at least some cases, export of carbon fixed in mangroves is important in coastal food webs. Mangrove plantations in Vietnam, Thailand, the Philippines and India host several commercially important species of fish and crustaceans. Despite restoration efforts, developers and others have removed over half of the world's mangroves in recent times. Young lemon sharks use mangroves as a nursery area.laststands. kennedywarne.com This is the foodweb of a Mangrove Ecosystem w3.shorecrest.org This is the foodweb of a Mangrove Ecosystem w3.shorecrest.org The microbial food web. After Conover(1982); pcwww.liv.ac.uk 浮游動物 • • • • • • 箭蟲(毛頜類) 海樽 橈足類 磷蝦 水母 櫛水母 Size groups of planktons; Adapted from Sieburth et. al. 1978; msource: hpl.umces.edu 氮循環 The Nitrogen Cycle - important to fish keeprs princeton.edu fishdoc.co.uk Nitrite:NO2亞硝酸鹽; nitrate硝酸鹽: NO3; Both are anions陰離子, or io離子with a negative charge Mangrove products: timber, fuel wood and charcoal, dye, corrosion inhibitor Tannins and dyes: Bark of mangrove trees are harvested as a source of tannin for the tanning industry. High tannin content is found especially in members of the Rhizophoraceae, to increase their resistance to herbivores. With development of cheap synthetic tannic acids after World War II, the commercial exploitation of mangrove bark has dropped to practically zero. Mangrove sap is, however, still used by East Africans or Polynesians to make the black dye for tapa cloth. http://mangrove.nus.edu.sg/guidebooks/text/1022.htm Topics for discussion • Using mangrove in fish culture • Interrelationship between mangrove, seagrass meadow and coral reef ecosystem--evidence Mangrove is used in Thailand to control the water quality in fish ponds Supplementary reading • Biology of mangrove: ocw.unu.edu/...mangroves/Biology-ofmangroves.pdf