The types of plankton Essay

Plankton is comes from the name "planktos" meaning wandering or roaming (Garrison, 2013). Plankton itself has small size body which usually cannot be seen by the naked eyes and driven by water current or swim counter to typical ocean currents. Plankton can be classified according to size and life cycle. There are two type of plankton which is phytoplankton and zooplankton. Phytoplankton is autotrophic plankton which produces glucose by photosynthesis while zooplankton is heterotrophic plankton which feed to gain glucose (Garrison, 2013). Significant autotrophic plankton includes diatoms, dinoflagellaes and coccolithophores while copepod and crustacean larvae are example of zooplankton.
Phytoplankton is plant-like organisms which mostly found in photic zone where there are enough light penetration for photosynthesis process (Chandy et al., 2014). Phytoplankton called as primary producer as they able to synthesize new organic matter or food either by photosynthesis or chemosynthesis. Phytoplanktons commonly found are phylum or group of Cynophyta, Bacillariophyta, and Dinophyta. Zooplankton or small-free living animals is a primary consumer and feed on other organism to gain nutrient or energy. They are able to swim against the current to feed or avoiding predator.
Zooplankton divided into meroplankton and holoplankton depends on length of planktonic life (Castro and Huber, 2013). Meroplankton spends only part of their lifetime as plankton and usually in larvae stage before growth into adult. For example the early stages of benthic organism, such as crustaceans or decapods have planktonic larvae or nauplius stage. Holoplankton is plankton that spends their whole lifetime as free-swim organism in the water column. For example copepods which is the most dominant group in water column (Nakajima et al., 2008). Phytoplankton and zooplankton both related in the food chain.
Plankton is microscopic organism and can be divided into 7 categories. From the smaller size which is femtoplankton (0.02mum0.2mum) follow with picoplankton (0.2mum-2mum), nanoplankton (2mum-20mum) and microplankton (20mum-200mum) which majority consists of phytoplankton. On the other hand megaplankton (20cm2m), macroplankton (2mm 20cm) and mesoplankton (200mum 2mm) majority consist of zooplankton (Castro and Huber, 2013). There is also smaller size of zooplankton which classified as microplankton for example crustacean nauplius.The size composition of plankton can be a good biological index as the ecological processes are functions of body size like growth rate, metabolic rate and prey size range(Peters,1983). Their body sizes are responsive to various environmental stresses such as introduction of non-indigenous substances into the environment. Different size classes of plankton provide information for the relationship associated with the community structure and environmental parameters (Arnott et al.,2003)
Food chain is a simple way to show relationship of organism in a habitat. Phytoplankton act as producer provide food for other organism. They are primary food for zooplankton. They gain energy by making their own food from sunlight and pass it through the tropic level. The next level in the chain is primary consumer include zooplankton and small crustaceans. Larger zooplankton, fish and mammals depends on plankton for their survival. Besides, the food chain also depends on the habitat they live on or in.