SPATIAL-TEMPORAL DISTRIBUTION OF CHLOROPHYLL-A IN SOUTHERN PART OF THE MAKASSAR STRAIT

Surface chlorophyll-a (Chl-a) distribution have been analyzed with seasonal variation during southeast monsoon in southern part of Makassar Strait and Flores Sea. Satellite data of Landsat-8 is applied to this study to formulate the distribution of chlorophyll concentration during monsoonal wind period. The distribution of chlorophyll concentration was normally peaked condition in August during southeast monsoon. Satellite data showed that a slowdown in the rise of the distribution of chlorophyll in September with a lower concentration than normal is likely due to a weakening the strength of southeast trade winds during June – July – August 2016. Further analysis shows that the southern part of the Makassar strait is likely occurrence of upwelling characterized by increase in surface chlorophyll concentrations were identified as the potential area of fishing ground.


INTRODUCTION
The southern part of the Makassar Strait is one of the relatively more fertile waters because it is suspected that there is an increase in the mass of water in to the local and temporary surface layers in a narrow area.The fertile waters of the Makassar Strait occur throughout the year not only in the west season but also in the east seasons.In the western season, fertility occurs due to the run off of the mainland of Borneo and Sulawesi in large numbers due to high rainfall, while in the east season the fertility occurs due to the increase in water mass (upwelling) in the southern Makassar Strait.Nababan et al., (2009) revealed that high concentrations of chlorophyll-a surface are strongly suspected of upwelling in the eastern seasons until the start of the transition season (July-September) in the southern waters of the Makassar Strait indicated by cold temperatures and relatively high chlorophyll-a concentration.Kurniawati, et al., 2015 revealed that the distribution of chlorophyll-a concentration in the ocean varies according to geographical location as well as depth of water.This variation is caused by the differences in the intensity of sunlight and the concentration of nutrients contained in the waters.Distribution of achlorophyll concentration is higher in coastal and coastal waters, as well as low chlorophyll-a concentration in offshore waters.
The rise of the inner layer water to the surface layers in the southern waters of the Makassar Strait was not only due to the circulatory impact of Indonesia's cross currents but the strong role of southeastern airflow (Samad, et al, 2015) and the influence of dipole modes from the Indian Ocean (Susanto et al., 2006Curie et al., 2013).High water 1 Department of Marine Science, Hasanuddin University Jl.Perintis Kemerdekaan Km. 10, Makassar 90245, Indonesia * Wasir Samad Daming Email: acilws@gmail.comproductivity is identified by the high concentration of chlorophyll-a in these waters (Rashid, 2010).
Chlorophyll-a concentration is one of the parameters that determine primary productivity at sea.. Spreading and high chlorophyll concentration is strongly associated with oceanic conditions Distribution of chlorophyll-a concentrations is generally high in coastal waters as a result of high nutrient supplies derived from land via river runoff, and low in offshore waters.However, high chlorophyll-a concentrations can also be found in offshore waters, due to the mass water circulation process (Sukoraharjo, 2012;Syahdan et al., 2014).
In addition, the exchange of water masses with the Pacific Ocean through the Sulawesi Sea, Flores Sea and Java Sea affects the primary productivity level in the southern waters of the Makassar Strait (Inaku, 2015, Kurniawati et al., 2015) to become one of the causes of the southern waters of the Makassar Strait to be highly dynamic which is closely related to the potential area of fisheries caused by the enrichment of nutrients in the area.This paper discusses the spatial dynamics of temporal distribution of chlorophyll-a southern waters of the Makassar Strait in relation to the potential location of fishing.

MATERIAL AND METHOD
The materials used in this research are Landsat

Sea Surface Temperature
The thermal band data can be converted from spectral radiance to brightness temperature by using the thermal constants provided in image"s metadata files (USGS, 2013):

East Wind Pattern
The wind blowing in the east-season period is identified when entering April -October especially in the southern waters of the Makassar Strait.The wind that blows in the period of the east season is the result of the sun in the northern hemisphere, causing a difference of pressure between the continent of Asia and the continent of Australia, as the impact of the Australian continent faster cooling and high pressure compared to the warmer and lower-pressure Asia continent.In the period of east seasons, the southern waters of the Makassar Strait are influenced by east winds.This east wind is the southeast wind (east season) has a role to the formation of surface water circulation in the southern waters of the Makassar Strait.The pattern of east-east wind circulation over the waters of the Makassar Strait can affect the distribution of surface temperatures as they are with the circulation of wind-induced surface currents.The circulation of the inner water mass to the surface layer is the role of the southeast wind blowing force, the stronger the wind blow the greater the effect on the temperature distribution and the surface chlorophyll.
The pattern of east wind circulation can be seen in Figure 1.
Based on wind data at the study site, in May the dominant wind direction comes from south to southeast to north to northwest with a speed of 1.0-4.0m / s.In July-August wind direction is still dominant from southeast to east to west and northwest with speeds between 2-8 m / s.Then in Sep-Oct the wind direction is more dominant from east to west with speeds between 2-7 m / s.
Although it has entered the transition season (transition) precisely wind direction is uncertain.of South Sulawesi covering the southern waters of the Makassar Strait including the Java Sea and Flores Sea.Syahdan et al., (2014) revealed that the surface chlorophyll-a in the Makassar strait varies tends to increase toward the coast and vice versa decreases towards offshore.The high concentration of chlorophyll is one factor due to the high intensity of solar radiation that can cause blooming chlorophyll can form around the surface.This phenomenon is also reinforced by Rahardjo (2012) and Rashid (2010) which explains that oceanic oceanic conditions greatly affect the high-low concentration of chlorophyll on the surface.Distribution of this chlorophyll is generally concentrated more near sea level along the offshore of South Sulawesi from the west to the south of the coastal plains of South Sulawesi.It should be noted, however, that surface chlorophyll concentrations are inseparable from the dynamics of vertical water mass motions that tend to carry nutrients that can be identified as highly potential locations for pelagic fisheries.The fish response to fluctuations in chlorophyll-a which tends to be stable due to the nutrient availability required by phytoplankton is always available so that it impacts the chlorophyll-a concentration in the waters as shown in Figure 2.This condition will cause the fish to respond to other environmental factors suspected availability of stable chlorophyll-a, so it remains within tolerable limits, consequently small pelagic fish will tend to respond to fluctuations of other oceanographic factors, such as temperature, density and current.Different concentrations of chlorophyll-a each month in the southern waters of the Makassar Strait provide an indication that the presence of fish also fluctuates.

Distribution of Sea Surface Temperature (SST)
The (g) (h) 0,9-1,0 0,8-0,9 0,7-0,8 0,6-0,7 0,5-0,6 0,4-0,5 0,3-0,4 0,2-0,3 0,1-0,2 0,0-0,1 (e) (f) (g) (h) (mg/m 3 ) Wasir Samad Daming chlorophyll concentration so that there was time lag between SST and chlorophyll-a.In contrast, Rasyid, (2010) revealed that increased chlorophyll concentrations are characterized along with decreasing sea surface temperatures.This phenomenon gives the assumption that the decrease of SST value is not necessarily followed by the increase of chlorophyll concentration.This study should be more comprehensive because it may be that the cause of the rise of the inner surface water mass to the surface is not the main cause of increased concentration of chlorophyll on the surface but there is a possibility of the influence of river runoff from the mainland, the internal sea due to the throughflow of Indonesia as well as the effect of eddy currents, so it needs a more in-depth study.
Sea surface temperatures when associated with estimation of fishing areas tend to fluctuate, in Rasyid, (2010) revealed that the tendency of small pelagic fish has the ability to adapt to the temperature range of measurement results ie 28 o C -30 o C.However, the optimum trend of catching is in the temperature range of 29oC -30oC.Furthermore, it is said that fish have the ability to recognize and select a certain temperature range that provides the opportunity to perform activities to the maximum and ultimately affect the abundance and distribution.Upwelling and Catching Areas The strength of the southeastern wind causes the mass transfer of the inner layer water to the surface.This displacement is followed by the motion of water particles that bring the life source to the ecosystem to grow and multiply.
Areas indicated by upwelling are closely related to the catchment area.Upwelling area is not only fertile but is a fish area for foraging.Rasyid, et al., (2010) explains that the presence of fish in tropical waters is related to monsoon variations of the marine environment.The influence of daytime long monsoon variations and the temperature of the tropical waters is not very influential when compared with equatorial regions.In the tropics wind and monsoon variations are more influential on marine ecosystems; where monsoon variations will affect the availability of quantities and types of food that directly affect the presence of fish in tropical marine ecosystems.In the southern part of Makassar Strait area identified upwelling occurs because during the period of east season in these waters have below normal surface temperatures ranging from 26 o C -28 o C found in July -September.
Figure 4 shows the monthly average of sea surface temperature and chlorophyll-a in the southern waters of the Makassar Strait, SST tends to decrease from June until October, while in May-October the chlorophyll concentration fluctuates.In July the concentration of chlorophyll increased but not  significant compared to the previous month, but in October it increased sharply to exceed 1 mg / m 3 .It is suspected that there is an impact of the massive increase of Makassar Strait water mass by the flow of Indonesian traffic.Strengthened by Sukoraharjo (2012) and Susanto, et.al. (2006) revealing that the role of Indonesia's cross-currents could trigger upwelling in the east season, so this area is highly potential for fish catching areas.

Figure 1 .
Figure 1.Profile of wind intensification during east season period (June-July-August) Distribution of Chlorophyll-a To investigate the evolution of 16-daily chlorophylla by using spatial and temporal analysis during the east-season period of Landsat-8 imagery shows the presence of surface chlorophyll concentration fluctuations.Figure 2 shows the distribution of 16daily chlorophyll-a concentrations in the southern waters of the Straits of Makassar that on May 21, June 22, August 9 and September 26 the surface chlorophyll concentrations showed higher values compared to chlorophyll-a concentrations on June 6, July 24, September 10 and October 12 with an almost uniform distribution of concentration from the central waters to the southern part of the waters Figure 2. Map of Landsat-8 satellite imagery of surface chlorophyll-a concentration (mg / m3) in east season 2016; (a) May 21, (b) June 6, (c) June 22, (d) July 24, (e) August 9, (f) Sept 10, (g) Sept 26, (h) October 12 range at 29.5 o C -30.0 o C, which then increases in the first week of June (June 6, 2016) in the range 30.0 o C -30.5 o C. Entering the third week (June) again decreased in the range 29.0 o C -29.5 o C.However, at the end of July the sea surface temperature significantly changed, in the southern part of mainland of South Sulawesi tends to decrease in the range 28.0 o C -28,5 o C and this phenomenon has been strongly suspected the influence of southeast wind that has been very intensive blowing from the southeast.While in the north just in the range 30.0 o C -30.5 o C. The presence of temperature fluctuations is possible by the influence of rivér inputs, and declining rainfall conditions This phenomenon becomes interesting, because the results of imaging on July 24 showed a decrease of SST in southern of South Sulawesi did not increase

Figure 4 .
Figure 4. Graph between SST and Chlorophyll-a in the southern waters of Makassar Strait.