Mangrove ecosystem


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Mangrove ecosystem

  1. 1. Suguru Taga<br />IB Biology HL 2, P4<br />Mr. Stantus<br />January 19, 2011<br />Mangrove Ecosystems At Kung Kraben Bay<br />Introduction:<br />This lab report is about the study of mangrove ecosystem at Chantaburi (Kung Kraben Bay), Thailand. The data was collected at mangrove at night, using quadrants by making a 25 meters straight line towards the sea and within that line at every 5 meters, both biotic and abiotic data were collected.<br />Data Collection:<br />Picture 1: This is a picture at the mangrove. As from the picture, the site is muddy and the white mangrove’s roots sticking out of the mud. <br />Picture 2: This picture shows how the data collection was done. As from the picture, four quadrants were used for data collection and the organisms that were seen in the quadrants were recorded.<br />Organisms and Abiotic Factors<br />Table 1: This table shows both organisms observed at the mangrove and abiotic factors. As from the table the pH and the temperature has not changed, but the number of organisms increased as it moved towards that sea.<br />Qualitative Data:<br />At the mangroves two different types of mangroves were observed, one with roots shooting out from the ground like a needle (pencil roots) and one with root that has several branched roots (prop roots). The mud (ground) was mostly gray and dry, but when the foot was taken out of the ground redish brown color soil with water coming from the ground was observed. The place was very dark that without the flash light, it is hard to even see. The organisms were usually in the mud than out in the surface so not many organisms were observed as from table 1. Also, there were only little organisms and not big ones like fish or lobster. While the observations there were poping sound like pop corn and according to the rangers it was the sound of shrimp jumping. While walking on the board walk the mangroves were densely close to each other, but towards the sea the number of mangroves got less dense. <br />Data Processing and Presentation:<br />Graph 1: This graph shows the average number of organisms that were observed during data collection. As from the graph almost none of crabs were observed but many crab holes were founded about 27 in an average. Also almost none of the worms were found either. Lastly, in an average about 4 of snails were found.<br />Calculations (Mangrove):<br />D=N(N-1)n(n-1)<br />D=Simpson’s Index<br />N=total number of organisms<br />n=number of organisms of a species<br />From Table 1:<br />N=((total # of crabs)+ (total # of crab holes)+(total # of snails)+(total # of worms))<br /> =1+136+20+1<br /> =158<br />N(N-1)=158(158-1)<br /> =158(157)<br /> =24806<br />Crabs:<br />n= (0 meter) + (5 meters) + (10 meters) + (15 meters) + (20 meters)<br /> = 1+0+0+0+0<br /> = 1<br />n(n-1) =1(1-1)<br /> =1(0)<br /> =0<br />Crab Holes:<br />n= (0 meter) + (5 meters) + (10 meters) + (15 meters) + (20 meters)<br /> = 22+27+20+47+20<br /> = 136<br />n(n-1)= 136(136-1)<br /> = 136(135)<br /> = 18360<br />Snails:<br />n= (0 meter) + (5 meters) + (10 meters) + (15 meters) + (20 meters)<br /> = 0+2+0+8+10<br /> = 20<br />n(n-1)= 20(20-1)<br /> = 20(19)<br /> = 380<br />Worms:<br />n= (0 meter) + (5 meters) + (10 meters) + (15 meters) + (20 meters)<br /> =0+0+0+0+1<br /> =1<br />n(n-1)= 1(1-1)<br /> = 1(0)<br /> = 0<br />Simpson Index (Mangrove):<br />D=N(N-1)n(n-1)<br />D = 248060+18360+380+0<br />D= 2480618740<br />D= 1.323692636<br />D≈1.32<br />Simpson Index of other group (Rocky Shore):<br />D=4.60687<br />D≈4.61<br />Conclusion and Evaluation:<br />This lab is about the data collected at mangrove. As from table 1, only one crab, 136 crab holes, 20 snails, and only one worm were observed during the data collection. It is surprising that 136 crab holes were found but only one crab was found. Also, pH of 7.5 and 25 ℃ were constant along the 20 meters. There were not any connections between the biotic factors and the abiotic factors found. However, since the data collection took place at night, most of the organisms were sleeping and not many organisms were found. The Simpson index for mangrove was about 1.32 and the Simpson index for rocky shore was about 4.61. These two numbers shows that at the rocky shore, more organisms were found and fewer organisms were found at the mangrove. The time of the data collection made the difference in Simpsons because at the rocky shore the data collection was during the day time but the data collection at the mangrove took place at night. So, the organisms at mangrove might have been asleep and hiding.<br />The weaknesses during the data collection were the time of the data collection and the data was collected at a place where the mud was ruined by human. The data at the mangrove was at night so the organisms were not active like in the day time so not many organisms were found. Therefore, the data collection should have been taken at around the same period of time during day time so that most of the organisms are active and found more easily. Lastly, when other groups got off to the mud and walking around, the ground became ruined and many holes were made which might have destroyed the number of the crab holes. Also, because the ground was ruined, the organisms might have got scared and went away. For improvement, the data could be collected where people have not stepped on the ground so that the more accurate number of organisms could be recoreded. <br />