Question 1 Names of aquatic plant | Parts and its fuction | Water hyacinth (Eichhornia Crassipes) | The stems and leaves contain airfilled tissue which give the plant its considerablebuoyancy. | Duckweed (Lemnaceae) | Entire lower surface of fronds can absorb nutrients from the medium, and the plants can grow well under conditions which entirely prevent root elongation. | Water Primrose (Ludwigia) | The creeping and floating stems allow it to find open water and sunlight through the larger emergent plants. | Water fern (Azolla filiculoides) | The sporophytes consist of two lobed leaves and rhizomes.The lower lobes of the leaves are usually larger than the upper and so adapted for floating the plant. (Hussner, 2010). | Knotweed (Polygonum spp.) | Vigorous rhizomes helps to regenerate when buried up to depths of three feet (0.9 m). (Parkinson and Mangold, 2010) |

Question 2

The Pond Skater (Gerris lacustris) is an insect that is especially well suited to life in Wetlands. They have specialized, paddle like legs that enable the insect to "skate" over the surface of the water, riding on the surface tension that lies between the water and the air.

Migratory Fish Migratory species such as Salmon, Trout and Eel can survive all levels of salinity in their migration through River, Estuarine and Coastal Wetlands. Fish such as these that are able to adapt to varying levels of salinity are described as eurythaline.

Gator Holes Alligators in Southern Florida Wetlands excavate the "Marl" (fine-grained clay or limestone) in order to form a deep depression into which they retreat in the dry seasons. During the dry season, a multitude of animals seek refuge and food in the deep water of Gator Holes.

Question 3
In 2010, the planted paddy area in Malaysia is 667,884 hectares. Peninsular Malaysia has some 320 000 hectares of wet paddy cultivation and about 120 000 hectares are ‘deep’ paddy area which can reach water depth of 15-16cm (Rahman and Bakri, 2008).
Table 1: Recent paddy statistics in Malaysia (Alam et al., 2011). | 2003 | 2004 | 2005 | 2006 | 2007 | Paddy Parcels Area (ha)2 | 459, 702 | 459, 044 | 440, 961 | 429, 805 | 426, 224 |

Sungai Burung and Sawah Sempandan are located at Tanjung Karang, Selangor covers 14,848 acres of rice field and producing an average of 3.8 ton of rice per hectare per year (Fuad et al., 2012).
Water management: In Malaysia, about 70% of the available water resources are consumed for rice production. Due to rapidly growing population and water competition among different sectors it is imperative that the available irrigation supplies be used efficiently. 5 to 7 cm of water is probably the best for irrigated. Water management practices such as draining, flooding and alternate flooding and draining have been practiced by the farmers for many years

Weed management: Grassy weeds serve as hosts for most rice pests both in and outside the rice fields. Using of herbicides for weed control in rice. Weeds can directly serve as food sources or provide other ecosystem resources for herbivorous arthropods, and indirectly serve carnivorous (beneficial) arthropods by providing food and shelter to their prey. Weeds can serve as alternative hosts for pest and beneficial arthropods when their preferred crop host is absent. Weeds can serve as a source of increased diversity in agroecosystems. Increased diversity has been the rationale for enhancing biological control of arthropod pests through habitat management

Nutrient management: The average chemical fertilizer usage in irrigated rice is around 170 Kg/ha of NPK compared to only 32 Kg/ha in rainfed rice.

Table 2: Weed species that are in competition with paddy (Hakim et al., 2013) Scientific name | Common name | Oryza sativa complex | Weedy rice | Digitaria ischaemum (Schr.)Muhl | Smooth crabgrass | Paspalum vaginatum Sw. | Water couch grass | Fimbristylis globulosa Kunth | Globular fimbristylis | Cyperus distans L.f. | Slender cyperus | Euphorbia hirta L. | Hairy spurge | Marsilea crenata Presl. | Dwarf Four-leaf Clover |

Question 4
Periphyton is generally defined as the community of all organisms living upon the surfaces of submerged objects in water.
The importance of periphyton are: * The sensitivity of periphyton to environmental factors and biologically active substances has been well documented, thus making periphyton a favorable bioassay object (Smolar et al., 1998, Genter and Lehman, 2000 and Kinross et al., 2000). * Periphytic algae can also be successfully used for removal of excessive nutrients, metals and toxic substances, hence improving water quality (Vymazal, 1988 and Hill et al., 2000). * It serves as an important food source for invertebrates and some fish.
Periphyton is also an important indicator of water quality: * They have a naturally high number of species. * They have a fast response to changes. * They are easy to sample. * They are known for their tolerance/sensitivity to change.

References
Alam, M.M., Siwar, C., Murad, M.W. and Toriman, M.E. (2011). Farm Level Assessment of Climate Change, Agriculture and Food Security Issues in Malaysia. World Applied Science Journal, 14(3), 431-442.
Amin, M.S.M., Rowshon, M.K. and Aimrun, W., (2011). Paddy Water Management for Precision Farming of Rice, Current Issues of Water Management.
Fuad, M.J.M, Junaidi, A.B., Habibah, A., Hamzah, J., Toriman, M.E., Lyndon, N., Selvadurai, A.C.Er,S. and Azima, A.M. (2012). The Impact of Pesticide On Paddy Farmers and Ecosystem. Advance in Natural and Apllied Science, 6(1), 65-70.
Genter, R.B. and Lehman, R.M. (2000). Metal toxicity inferred from algal population density, heterotrophic substrate use and fatty acid profile in a small stream, Environ. Toxicol. Chem., 19, 869–878.
Hakim, M.A., Juraimi, A.S., Ismail, M.R., Hanafi, M.M. and Selamat, A. (2013). A Survey On Weed Diversity In Coastal Rice Fields Of Seberang Perak In Peninsular Malaysia. The Journal of Animal and Plant Sciences, 23(2), 534-542.
Hillman, W.S., The Lemnaceae or Duckweeds. A Review of Descriptive and Experimental Literature. Yale University, New Haven, Connecticu, 221-287.
Hussner, A. (2010). NOBANIS – Invasive Alien Species Fact Sheet – Azolla filiculoides. – From: Online Database of the European Network on Invasive Alien Species – NOBANIS www.nobanis.org, Date of access 18/9/2013.
Parkinson, H. and Mangold, J. (2010). Biology, Ecology and Management of the Knotweed Complex (Polygonum spp.), 8-9.
Periphyton, http://www.esd.ornl.gov/BMAP/comm_per.htm. Retrieve September 18, 2013.
Rahman, W.A. and Bakri, M. (2008). Short Communication On The Endoparasitic Fauna Of Some Paddy-Field Fishes From Kedah, Peninsular Malaysia. Journal of Bioscience, 19(2), 107-112.
Smolar, N., Vrhovsek, D. and Kosi, G. (1998). Effects of low flow on periphyton in three different types of streams in Slovenia, G Bretschko, J Helešic (Eds.), Advances in River Bottom Ecology, Backhuys Publishers, Leiden, The Netherlands, 107–116.
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Wetzel, R.G. (1983). Recommendation of Future Research of Periphyton, First International Workshop on Periphyton in Freshwater Ecosystems, 341.
Water Hyacinth Control and possible Uses. Practical Action, The Schumacher Centre for Technology and Development, http://www.solucionespracticas.org.pe/fichastecnicas/pdf/water_hyacinth_control.pdf. Retrieve September 18, 2013.
Yasumatsu, K. and Torri, T. (1968). Impact of Parasites, Predators and Diseases on Rice Pests. Ann. Rev. Entomol, 13, 295–324.