Seagrass Ecology PDF

EKOSISTEM LAMUN BIOLOGI TUMBUHAN AKUATIK Departemen Perikanan, Fakultas Pertanian Universitas Gadjah Mada Seagrass  A division of higher plants, flowering plant  Grow in the shallow coastal waters of most continents  Can form vast aggregations, or meadows, which alter the flow of wat...

EKOSISTEM LAMUN BIOLOGI TUMBUHAN AKUATIK Departemen Perikanan, Fakultas Pertanian Universitas Gadjah Mada Seagrass  A division of higher plants, flowering plant  Grow in the shallow coastal waters of most continents  Can form vast aggregations, or meadows, which alter the flow of water, nutrient cycling and food web structure of the local environment  Four families (Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae)  Reproduction; - Sexually  gametes mix in the water, hydophilous pollination - Asexually  extending and branching the rhizomes Seagrass morphology Root : differences of anatomy and morphology  key for taxonomic Stem and rhizome Leaf: various in shape, size and number  important key for taxonomic SEAGRASS SPECIES CODES McKenzie, L.J., 2003  Plants produce flowers and transfer pollen from the male flower to the ovary of the female flower.  Most sea grass species produce flowers of a single sex on each individual, so there are separate male and female plants.  A few sea grass species complete their lifecycle within one year and are known as ‘annuals’. These annuals produce seeds that can remain dormant in large ‘seed banks’ for several months.  Seed banks ensure that the species can survive until conditions return to stimulate the seeds to germinate. A.Lamun B.Bunga C.Buah D.Biji  Seagrass distribution  Broadly distributed in most of the world’s oceans and seas, found mostly along the coastline, covering an estimated global area of 300,000-600,000 km2  Intertidal-sub tidal, tropic-sub tropic, soft sediment- rocky substrate, mostly shallow water.  Center of seagrass geographical distribution: Indo- Pacific and Karibia (Tomascik dkk, 1997). Seagrass Distribution Importance of seagrass Seagrass meadows provide numerous ecological services, acting as essential habitat (e.g. spawning, nursery, refuge and foraging areas) for many animals, including commercially and recreationally important fish species Providing a major source of food for a range of large herbivores such as the green sea turtle (Chelonia mydas)*, and dugongs and manatees** Have rooting structures which allow them to withstand the movement of water  sediment stabilization * = endangered, ** = vulnerable  The benefits provided by a healthy seagrass meadow extends beyond the local area, through exporting key nutrients (e.g. nitrogen and phosphate) and organic carbon to other parts of the oceans, including some to the deep-sea where they provide a critical supply of organic matter in an extremely food-limited environment Much of the excess organic carbon produced is buried within the sea grass sediments, making sea grass habitat an important blue carbon habitat Seagrass Biology Growth  Thalassia blades can grow as much as 1 cm/day  Growth is slowed by cooler temperatures  Extremes in temperatures (hot or cold) can kill leaf blades  Optimal temperature range 20-30° C  Optimal salinity range 24-35 ppt  Extensive sea grass beds not found deeper than 10-15 m (light and pressure are both factors) Role of seagrass beds  Primary producer - Food for grazers; produce detritus  Habitat - Nursery grounds - Permanent home for many species  Sediment stabilization 17 Fungsi sebagai produsen primer Company Logo Generalized Food Web in a Seagrass Community Associates seagrass  Benthic macrophyte (Gracillaria, dll)  Seagrass epiphytes, epifauna, infauna  Fauna (fishes, mollusks, etc) Habitat requirement  Transparency  high intensity for photosynthesis  Temperature  spread widely geographically, in the tropics of low tolerance to temperature changes, (28-30 optimum)  Salinity  each species has different for each species tolerance, most have wide tolerance (10-40 ppt), optimal 35 ppt  Substrate  inhabit in a wide variety of sediments, substrate depths  Protection from wave action  Nutrient supply and recycling  Water current seagrass productivity influenced by water current. Turtlegras  maximum standing crop at 0,5 m / sec. Thalassia testudinum Mampu terkubur 25cm dalam sediment Paling bahyak di Laut Karibia dan Teluk Meksiko Productivity Variations across species and localities For Thalassia, range of 0.9 – 16 grams C/m²/day 10 g C/m²/day = 3.65 kg C/m²/year Measurements usually include associated plants (macroalgae, epiphytes)… Highly productive ecosystems Important food source, for grazers and as detritus Zonation 1. Halodule grows in shallowest water and has highest tolerance to exposure 2. Thalassia : most dominant; forms large meadows in waters up to 10-12 m deep 3. Syringodium forms meadows in deep water (up to 15 m) 4. Halodule and Halophila can grow in even deeper water, but sparsely Seagrasses disturbances  Physical damage (dredging, propeller damage and boat groundings)  Storms (“blowouts”)  Eutrophication  Industrial effluent  Oil Pollution  Aquaculture  Salinity stress  Temperature stress 29% of the world’s seagrass meadows have died off in the past century, with 1.5% more disappearing each year. Indonesian seagrass Four families (Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae)  Hydrocharitaceae - Thalassia sp. (turtle grass) - Halophila sp. - Enhalus sp.  Cymodoceaceae - Syringodium sp. - Cymodocea sp. - Halodule sp. - Thalasodendron sp. Thalassia  Flat/tipis  Daun seperti mata pisau, lebar4-2 mm, panjang 10-35 cm  2-5 daun/tangkai  Membentuk padang rumput luas Halodule  Koloni pertama daerah yang terganggu atau terlalu dalam/dangkal bagi lamun  Toleransi yang luas terhadap suhu dan salinitas  Daun pipih, lebar 1-3 mm dan panjang 10-20 cm Syringodium  Daun silindris (seperti spagethi), diameter 1-1,5 mm dan panjang bervariasi dan dapat mencapai 50 cm  Umumnya ditemukan bercampur dengan seagrass lain  Jenis-jenis Lamun di Indonesia No Jenis Lamun Deskripsi 1 Cymodocea rotundata Spesies pionir, dominan di daerah intertidal Tumbuh hanya di daerah yang berbatasan dengan 2 Cymodocea serrulata mangrove 3 Enhalus acoroides Tumbuh di substrat pasir berlumpur 4 Halodule pinifolia Spesies pionir, dominan di daerah intertidal 5 Halodule uninervis Tumbuh pada rataan terumbu karang yang rusak 6 Halophila minor Tumbuh pada substrat berlumpur Tumbuh di daerah yang intensitas cahayanya 7 Halophila ovalis kurang 8 Halophila decipiens Tumbuh pada substrat berlumpur 9 Halophila spinulosa Tumbuh pada rataan terumbu karang yang rusak 10 Syringodium isoetifolium Tumbuh pada substrat lumpur yang dangkal Tumbuh pada substrat pasir berlumpur dan 11 Thalassia hemprichii pecahan karang 12 Thalassodendron ciliatum Tumbuh pada daerah subtidal Sumber : Bengen (2004), Dahuri (2003)  Penentuan Status Padang Lamun Keputusan Menteri Kependudukan dan Lingkungan Hidup nomor 200/ 2004 KONDISI LAMUN INDONESIA SEBARAN LAMUN DI INDONESIA  RESTORASI LAMUN Keberhasilan dipengaruhi oleh 1. Riwayat lokasi penanaman 2. Pemilihan lokasi penanaman 3. Jenis lamun yang akan ditanam 4. Lokasi pengambilan bibit lamun 5. Waktu penanaman 6. Kondisi perairan. Cymodocea rotundata dan Thallasia hemprichii TERIMAKASIH