The Sources And Variation Of Particulate Organic Matter And Their Relationship With The Carbon Fixation In The Frequent Harmful Algal Blooms Areas Of The East China Sea

The ocean is a large carbon sink. The most important question in the research of ocean carbon flux is to answer how is the ability of the ocean to adjust the CO2 in the atmosphere. And the Marginal Seas takes an important role in this research. Particulate Organic Carbon affects the carbon fixation obviously. Thus, this article uses the data of ten full-scale marine surveys, nine partial marine surveys, one day and night sequent pointing research, one trap experiments of sediment particulate matters and two Mesocosm experiments and focuses on the influence of the carbon fixation in the East China Sea-the most important Marginal Seas in China-by the abnormal ecological phenomenon red tide through the variation and concentration of Particulate Organic Carbon in the Frequent Harmful Algal Blooms Areas of the East China Sea.At first, the article analyses the distribution of Particulate Organic Matter of the samples of the cruise 2005 and 2006 in the Frequent Harmful Algal Blooms Areas of the East China Sea deeply, then uses the Regression Analysis, Cluster Analysis and Correlate Analysis to explain and testify the results. The main results are as following: 1. The largest concentration of POC in field is 5998.92μg?dm-3, which is much larger than the none harmful algal Blooms period and is 100 folds of the average concentration of the open sea; 2. the linear coefficient between POC and chlorophyll-a of all the samples (n=1011, P<0.0001) is 0.81, and the ratio between POC and chlorophyll-a is 62.89; 3. The linear coefficient between POC and PON of all the samples (n=1020, P<0.0001) is 0.87, and the average C:N in the organic matters are 6.97, which is closed to the Redfield ratio; 4. In the R type Cluster Analysis, POC, PON, POP, chlorophyll-a and Phaeopigments are divided as the same kind separately while are much further from other parameters; 5. In the Correlate Analysis , the C, N and P in the particulate organic matters have obvious positive correlation with the chlorophyll-a and Phaeopigments (confidence measure: 99%), while the relationship is not obvious with other parameters; 6. The partial correlation coefficient between POC and salinity in the samples near estuary is very small. Thus, the POC and salinity do not have any relationship except other factors. All these results testify that during spring and summer, the main factor of the concentration of POC is the growing and increasing of the phytoplankton and the red tide. The source of the POC is single. The POC in research area in spring and summer is mainly directly or indirectly contributed by the photosynthesis of phytoplankton, and the concentration of carbon can represent the total concentration of inorganic carbon absorbed by photosynthesis in this area. Although the input of the Changjiang River contributes large particulate matters to the East China Sea, the organic part is too small to count comparing to the contribution of the red tide. The contribution of bottom resuspension process by upwelling is too small to count either. We can also conclude that the organic matters which are produced by the photosynthesis of phytoplankton concentrate in the top layer of the column. After the death of the phytoplankton, parts of the dead particulate matters can pass through the density layer to deposit to the bottom and become a part of the sediment and this process is the burials of particulate matters which is produced by the phytoplankton and finally fix the carbon. On the base of the static analyze, this article analyses the variation and characteristic of particulate organic matters by the analyzing of POC. The result is that because of the mobilization of the column the analyse of the variation of POC in small scale area can not obtain the initial law. In the larger area, the law of the concentration of POC in the column during the time change is obvious. And when the research area covers all the Frequent Harmful Algal Blooms Areas of the East China Sea, the variation of POC average integral value during time is according with the Logistic phytoplankton growth model, which the coefficient is 0.870. Through the analyse of the process of the producing and decomposing of POC, the process of the producing and decomposing of POC is similar to the Logistic model. This testifies that it is reasonable to use Logistic model to explain the variation of average concentration of POC, and the data of mesocosm experiments also testifies this conclusion. We also found that the POC congregate in the column but not decomposing and recycling during the evanescing of the red tide. And the same phenomenon is found during the analyse of field data of the variation of POC and chlorophyll-a with temperature and salinity and mesocosm experiments.The upwards results show us the quality and half quantity relationship between Harmful Algal Blooms and carbon fixation. We can conclude that the variation of the concentration of POC in Harmful Algal Blooms water column have the same adjusting mechanism with the mesocosm experiments and have the same initial law. On this condition, this article analyzes the total carbon fixation value of the research area and uses many methods to calculate the net output value of total value of POC and the value of POC which are produced by photosynthesis in spring and summer in HABs period in research area. The results show that the total value of POC which is produced by photosynthesis during HABs period in research area is 337×104 t, in which about 50.72×104 t is output from the euphotic zone at the end. And that results in the value of carbon in the research area which only takes 2.9% of the East China Sea takes nearly 11.8% of the carbon concentration in the whole East China Sea per year, which testify that the large scale Harmful Algal Blooms do affect the carbon sink value of the research area and even the carbon sink value of the East China Sea. In the process of using different principals and methods to calculate the total production and net input value during HABs period, this article develops a method which is different from the past to calculate the total seawater carbon fixation value via the concentration and variation of POC in column. The principal of this method is to use the following formula tocalculate the mass of POC in research area, and then multiply by different revisingcoefficient to get the total production of POC or net output value. To get exactrevising coefficient, this article uses the data of mesocosm experiments, the trapexperiments of sediment particulate and day and night sequent experiments separatelyand get the independent results. So these coefficients are credible. This article uses0.133 as the average revising coefficient in the calculation to count the totalproduction, and uses 0.020 to calculate the net output value. This method can be usedto the areas which have obvious Harmful Algal Blooms and POC accumulation.At last, this article argues the reason why the carbon fixation ability in research area isquite strong according to the C: N ratio is increasing during the Harmful AlgalBlooms process in mesocosm experiments. And this article points out that on the baseof rich nutrient supplement the nutrient have much larger ability of recycling, and which makes the research area can fix more carbon than the expectation by Redfield ratio. And the phenomenon is that few nutrients can input the carbon from the atmosphere to the bottom of the sea, and then the carbon fixation ability in the Harmful Algal Blooms area takes an important role in the whole East China Sea.