Plankton

The plankton embraces organisms that have such limited powers of locomotion that they are at mercy of the prevailing water movement. There are two types of plankton that is phytoplankton and zooplankton. Phytoplankton are the tiny minute plants of the pelagic environment that are supported by water and are drift near the water surface where the light intensity are great enough for photosynthesis. Besides, there are two types of phytoplankton which is epiphytic and epilithic. Epiphytic is the plankton that growing attached to other algae or other plants but not parasitizing them. While, epilithic is the one living on the surfaces of hard substrate like stone and rock. While, zooplankton are the various free-floating animals. Zooplankton movement is largely the consequence of currents and are not directed swimming activities.(Pace et al.,2006). Zooplankton commonly famous with diel vertical migration where they move vertically in the water column. It must swimming in vertically position and not in horizontally to avoid from predator and to move out from area with depletion of food source.

phytoplankton

zooplankton

Methodology:

The water samples was collected in order to sampling the plankton that is zooplankton and phytoplankton that present in the water column. The instrument used is the plankton net with the size of 63 µm and 120 µm. The net was pull three times in the water with different distance depend on the people that operate it.  Moreover, another types of phytoplankton, epilithic was sampling through the collection of substrate like rocks and dead coral. The substrate was brushed by using old toothbrush in order to collected the phytoplankton which attach to it. All the samples then were preserving in formalin before the further analysis.For the laboratory analysis, the plankton was observed under microscope where up to 300 organisms need to be observed and identify. The calculation of phytoplankton cell density per ml was done by using the Lackey’s method. Then the density of the phytoplankton per m3 was calculate by using the following formula

Density, no. of cells/ mL =    (  C x A_t )  /  ( A_s x S x V)
Where:     
C        = Number of organisms counted
At      = Area of cover slip (22mm x 22mm)                    
As      = Area of one strip (22mm x 1mm)                   
S       = Number of strips counted                  
V      = Volume of sample under the cover slip (0.05ml)

While, for the zooplankton it density was measured by using formula of:
Density   =    Number of zooplankton /  Volume filtered seawater (m³)
For the both zooplankton and phytoplankton, the percentage abundance was calculate by using formula:
Percentage  abundance =  (No of plankton individuals / Total number of plankton individuals) x 100%              

Results and Discussion:

1.0  Phytoplankton

                                1.1 Percentage abundance

Figure 1.1.1 percentage abundance for 63 µm net.

Figure 1.1.2 percentage abundance for 120 µm net.

Figure 1.1.3 percentage abundance for epilithic.

                        The three figure above shows the percentage abundance for the phytoplankton present in the water sample and on the substrate at the Kapas Island. All the samples which is the phytoplankton collected by 63 µm and 120 µm plankton net and epilithic which the phytoplankton on substrate shows the highest percentage abundance of class Bacillariophyceae with the value of 91% for 63 µm net, 96% for 120 µm net and 74% for epilithic.

                        Bacillariophyceae is of the periphyton which dominate different habitat including ocean. Under division Bacillariophyceae, there is diatom. Diatoms are unicellular, microalgae with membrane-bound cell organelles and which have a siliceous cell wall or frustules which made up of two valves. Diatom can be divided into two major groups that is pinnate and centric diatom. Epiphytic and epilithic diatom is the diatoms which found as benthic forms growing on sediments, rocks and plants. 

                        While the least abundance of phytoplankton collected by the three different instrument is different where class Trebouxiophyceae lowest in 63 µm net (1%), Ulvophyceae lowest in 120 µm net (1%) and chlorophyceae lowest for epilithic (6 %)

.

1.2 Density 

Figure 1.1.1 Density for 63 µm net.

Figure 1.1.2 Density for 120 µm net.

Figure 1.1.3 Density for epilithic. 

                       For the density, it can be note from graph of density in the three figure above that the density of class Bacillariophyceae also were highest in all three instrument used. The density of Bacillariophyceae collected  is 2779.55 m³ by 63 µm net, 1036.14 m³ by 120 µm net and 236777.43 m³ for epilithic.

                         2.0  Zooplankton 

                                                                     2.1 Percentage abundance

Figure 2.1.1 percentage abundance for 63 µm net.

Figure 2.1.2 percentage abundance for 120 µm net.

                       The percentage abundance of zooplankton collected by two different mesh size of plankton net shows that the highest group of copepod was collected in both size make it appear as the dominant zooplankton in the Kapas Island water. The percentage is more highest in 120 µm net (73%) while less in 63 µm net (17%). Copepode are belong to the phylum Arthropoda. Copepods have cylindrical body and distintly segmented. The body is divide into a cephalothorax bearing appendages with a without appendages abdomen. There are three group of copepode that is Calanoid, Harpacticoid and Cyclopoid which all with different body structure. 

2.2 Density

Figure 2.2.1 Density for 63 µm net.

Figure 2.2.2 Density for 120 µm net.

                    While for density, the three highest density collected by 63 µm net (Figure 2.2.1) is copepode followed by Oikopleura and then Nauplius. The density for copepode is 75.44 m³. Besides, the three highest density collected by 120 µm net (Figure 2.2.) is copepode followed by Water flea and then Nauplius with the density of copepod is 289.98 m^3.

                        Conclusion:

                       In conclusion, the most dominant phytoplankton collected by all three instrument which  is 63  µm net, 120 µm net and toothbrush for epilithic is class Bacillariophyceae while for the zooplankton, the dominant class is copepode.