Herawati E. Y., Khasanah R. I., Ambarwati M., Sofarini D., 2020 The
Total Page:16
File Type:pdf, Size:1020Kb
The effect of hydro-oceanographic factors on the community structure of plankton in natural and artificial coral reefs in Paiton waters 1Endang Y. Herawati, 2,3Ruly I. Khasanah, 3Muliyana Ambarwati, 2,4Dini Sofarini 1 Faculty of Fisheries and Marine Sciences, Universitas Brawijaya, Malang, Indonesia; 2 Post Graduate Program of Fisheries and Marine Sciences, Faculty of Fisheries and Marine Sciences, Universitas Brawijaya, Malang, Indonesia; 3 Program Study of Marine Science, Faculty of Science and Technology, Universitas Islam Negeri Sunan Ampel, Surabaya, Indonesia; 4 Department of Aquatic Resource Management, University of Lambung Mangkurat, Jl. Brigadir H. Hasan Basry, Banjarmasin 70123, Indonesia. Corresponding author: R. I. Khasanah, [email protected] Abstract. Hydrooceanographic factors influence the plankton occurrence. These are aquatic environmental parameters that take important role in plankton community structure. This study was aimed at knowing the effect of the hydro-oceanographic factors on the abundance and the diversity of plankton in the natural coral reef ecosystem and the artificial reef in the waters of Steam-Based-Electric Power Plant (SBEPP), Paiton. It employed quantitative analysis and Principle Component Analysis (PCA) method. Results showed that the phytoplankton abundance in the natural coral reef ecosystem ranged from 3,209 to 5,589 cells L-1 and in the artificial reef from 598 to 856 cells L-1. Zooplankton abundance in the natural coral reef and the artificial reef were 48-70 ind L-1 and 23-36 ind L-1 respectively. Phytoplankton abundance in both localities was more than 500 cells L-1 reflected high fertility category of the waters, while plankton diversity of both localities of 2.19-3.25 indicated moderate diversity. PCA analysis showed that water brightness and pH were moderately correlated with plankton abundance and diversity. Water salinity, dissolved oxygen (DO), and phophate were very strongly positively correlated with plankton abundance and diversity, while water temperature and nitrate were very strongly negatively correlated with plankton abundance and diversity. The latter in the natural coral reef is indicated with increased plakton abundance in low nitrate and phosphate concentrations, while in the artificial reef, the plankton abundance was low in the high nitrate and phosphate concentrations. Key Words: plankton, coral reef, abundance, diversity, Paiton. Introduction. Indonesia seawater is rich in various living resources. One of them whose presence is very important is plankton. According to Nontji (2008), plankton is microscopic organisms floating in the water or on the surface whose movement is influenced by currents. In general, plankton is distinguised into phytoplankton and zooplankton. Plankton occurrence highly influences life in aquatic ecosystem because it is an aquatic organism that plays important role as primary producer in marine food chain (Cheng 1997). This role can come from its ability to produce organic matters in the ocean (Rissik 2009). Thus, plankton can be considered as fertility bioindicator of the waters. Water fertility can be based on the abundance and the composition or the diversity of the plankton in the waters. Plankton abundance above 500 ind L-1 indicates high fertility level of the waters (Odum 1996). Although plankton can be considered as the fertility bioindicator of the water, there are also limiting factors that affect its occurrence. These are physical and chemical factors that are important variables for the plankton density in the waters. Plankton have strong correlation with coastal and marine ecosystem, one of which is coral reef ecosystem. According to Guntur (2011), coral reef ecosystem is a very complex AACL Bioflux, 2020, Volume 13, Issue 1. 71 http://www.bioflux.com.ro/aacl ecosystem with high biodiversity. One of the main roles of coral reef is as habitat for various marine biota. In coral reef ecosystem, one of the plankton function is coloration of the coral reef ecosystem (Wibisono 2011). Some coral animals live as meroplankton, being plankton at the larval stage and coral organisms at the adult stage (Guntur 2011). In the Steam-Based-Electric Power Plant (SBEPP) waters, Paiton, Probolinggo, there are natural coral reef and artificial reef ecosystems. The presence of artificial reef ecosystem can increase the water fertility quality around the SBEPP Paiton waters. Since plankton have strong relationship with coral reef ecosystem, it is necessary to value the water fertility around the SBEPP Paiton waters, Probolinggo. This study was intended to know the plankton abundance and diversity in the natural coral reef and the artificial reef and factors that can affect their growth. Material and Method Study site and period. Measurements of the physical and chemical parameters and sample collection were carried out in the SBEPP Paiton waters, Probolinggo (Figire 1) in April 2019. Figure 1. Study site. Study site determination. Sampling station determination used cluster random sampling method. Based on this method, 2 areas were selected, natural coral reef and artificial reef each of which had 3 sampling points randomly selected, TS 1a, TS 2a, and TS 3a in the natural coral reef and TS 1b, TS 2b, and TS 3b in the artificial reef (Table 1). Data collection. Physical parameters measured were water brightness and temperature, while the chemical parameters included pH, salinity, dissolved oxygen (DO), nitrate (NO3), and phosphate (PO4). The measurement methods are presented in Table 2. AACL Bioflux, 2020, Volume 13, Issue 1. 72 http://www.bioflux.com.ro/aacl Table 1 The geographic coordinates of the study site Station Latitude Longitude Natural coral reefs Sampling point 1 (TS 1a) 07o 42' 3.00 S 113o 34' 25.00 E Sampling point 2 (TS 2a) 07o 42' 0.29 S 113o 34' 20.57 E Sampling point 3 (TS 3a) 07o 42' 1.36 S 113o 34' 27.70 E Artificial reefs Sampling point 1 (TS 1b) 07o 42' 51.00 S 113o 35' 41.00 E Sampling point 2 (TS 2b) 07o 42' 51.32 S 113o 35' 41.69 E Sampling point 3 (TS 3b) 07o 42' 50.66 S 113o 35' 40.57 E Table 2 Tools and methods used Parameter Unit Tools Method Brightness m Secchi disc In situ Temperature oC DO meter In situ pH - pH paper In situ Salinity ppt Refractometer In situ DO mg L-1 DO meter In situ Nitrate mg L-1 Spectrophotometer Laboratory Phosphate mg L-1 Spectrophotometer Laboratory Plankton sampling. Plankton sample collection used vertical hauling method, in which the plankton net was set down vertically from the boat at a position down to the desired depth and then pulled back on board. Before sampling, the water depth was taken into account in order to estimate the water volume filtered through the plankton net. The seawater collected in the cod-end of the plankton net was then removed into the labelled sample bottle (Rachman et al 2018). In this study, 12 bottles of samples were obtained and then preserved. Lugol solution was added to the water sample as needed up to the seawater color turn red. For 100 mL of water sample, as much as 3 drops of 4% lugol solution were used (Rachman et al 2018). The plankton samples were observed and analyzed in the Integrated Laboratory of UIN Sunan Ampel Surabaya. Plankton sample analysis. Plankton observations adopted Sedgewick-rafter Counting Cell (SRCC) under the microscope to know the genus and the number of cells. Identification followed Shirota (1966), Newell & Newell (1977), Yamaji (1984), and Tomas (1997). After obtaining the number of cells of plankton, the abundance and the diversity were estimated. Plankton abundance (N). Plankton abundance value is used to know the number of plankton in each water volume (cells L-1). Plankton abundance (N) analysis was calculated using the formula of APHA (1998) as follows: [1] where: N = number of cells per liter (cells L-1); Oi = area of cover glass (mm2); Op = area of a view space (mm2); Vr = volume of filtered water (mL); Vo = volume of sample under the cover glass (mL); Vs = volume of filtered seawater sample (L); n = number of phytoplankton cells in entire view space (cells); p = number of spaces observed (mm2). AACL Bioflux, 2020, Volume 13, Issue 1. 73 http://www.bioflux.com.ro/aacl According to Odum (1996), phytoplankton abundance can reflect the fertility in the waters. The phytoplankton abundance-based water fertility category is as follows: N > 500 cells L-1 = highly fertile; N < 500 cells L-1 = moderately fertile. Plankton diversity (H’). This analysis was applied to know the diversity of the biota in the water. The present study used Shanon-Wiener’s diversity index (Odum 1993): [2] where: H’ = diversity index; Pi = ni/N; ni = number of individuals i; N = total number of individuals. Principle Component Analysis (PCA). This correlation analysis is used to examine the relationship between the physical and chemical parameters with plankton abundance. Those cover water temperature, brightness, DO, salinity, pH, nitrate, and phosphate. The physico-chemical parameter data were analyzed using Microsoft Excel in the form of tables and graphs, then the correlation between the physico-chemical parameters and plankton abundance and diversity was estimated to gain the matrix value. The matrix value of the PCA analysis to know the correlation between the physico-chemical parameters and the plankton abundance is presented in Table 3 (Khasanah et al 2013). Table 3 Correlation level between variables Interval coefficient Correlation level 0.00-0.199 Very low 0.20-0.399 Weak 0.40-0.599 Moderate 0.60-0.799 Strong 0.80-1.00 Very strong Results and Discussion Physico-chemical water parameters. The water physical and chemical parameters measured in situ are temperature, salinity, brightness, DO and pH, while phosphate and nitrate were examined in the Laboratory of Living Environmental Board of East Java Province. The parameters measured are given in Table 4.