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Anthropogenic activities on land will affect the carbon system in coastal waters. This condition will affect the role of coastal waters as a source or sink of carbon. This research will examine the distribution of carbonate systems and estimate CO2 fluxes. Water samples were taken at 30 stations as well as measuring in situ water parameters including pH, temperature, salinity, and pressure. Alkalinity was analysed based on the titration method, chl-a using the fluorometer method, and carbonate system parameters (pCO2(sea) and DIC) calculated using CO2SYS.xlsm. The pCO2(atm) value is calculated based on atmospheric data from satellite data, including the saturation vapour pressure of sea air in the atmosphere, fraction mol of CO2, and sea level pressure. Pearson correlation analysis was used to see the correlation between the measured parameters and CO2 flux. Carbon flux is determined based on the difference between atmospheric and oceanic pCO2. The DIC calculation result was in the range of 1,946.09 µmol/kg - 2,061.65 µmol/kg and the total alkalinity was 2,156.86 µmol/kg - 2,264.71 µmol/kg. Based on this value, Jepara coastal waters have pCO2(sea) of 573,800 micro-atmospheric (µatm) which is higher than pCO2(atm) (i.e., 386,772 µatm). The input of organic/inorganic carbon resulting from anthropogenic processes on land has influenced Jepara coastal waters which act as a source of CO2 into the atmosphere amounting to 103,799 mmol/m2/day. The results of this research can be used as a reference for managing coastal areas to achieve low carbon emissions. [ABSTRACT FROM AUTHOR]

The seas of Southern Java are located at the eastern equatorial Indian Ocean and therefore, they are strongly influenced by the Indian Ocean Dipole (IOD). Strong negative IOD occurred in 2016. However, none of the previous studies investigated its effect on the seas of Southern Java. This study aims to reveal the influence of the strong negative IOD in 2016 on the upwelling intensity along the seas of Southern Java as represented by surface temperature and chlorophyll-a. This research was conducted using satellite-based data and the analysis was based on climatology, and anomaly for 15 years (2007-2021). The data used includes sea surface temperature (OISST), wind (ASCAT), IOD index (DMI), chlorophyll-a (OC-CCI), and sea level anomaly (altimetry). The findings show that the strong negative IOD in 2016 had a significant impact on sea surface temperatures which made these waters warmer. The most visible impact is through the sea surface temperature anomaly map where in 2016 throughout the year it experienced a positive anomaly with a value of 2°C higher than the climatological average. The value of chlorophyll-a in these waters has also dropped drastically which, when viewed from the anomaly map, has a value of 0.2 mg/m³ lower than the climatological average, especially during the upwelling month. This means that, strong negative IOD in 2016 reduced the upwelling intensity along the seas of Southern Java. We also found the propagation of downwelling Kelvin waves from the Indian Ocean to the Southern Java waters which bring warm temperatures and cause downwelling events during the strong negative IOD in 2016 that hampers coastal upwelling along the seas of Southern Java. [ABSTRACT FROM AUTHOR]

Indonesia as a region located in the tropics gets a greater heat distribution than the other hemisphere and has an important role in the phenomenon of atmospheric and ocean interactions in the Indo-Pacific region. The heat exchange between the ocean and the atmosphere affects the dynamics of both. The southern coast of Java is known as the upwelling area which is driven by the variability of Ekman transport and Ekman pumping. The present study aims to investigate the effect of heat flux variability on sea surface temperature variability and chlorophyll-a in surface upwelling areas along the Southern coast of Java which was less observed in the previous study. The study was conducted with a quantitative descriptive approach through climatological spatial and temporal data processing for 10 years from 2007 - 2016. The data used are Shortwave Radiation, Longwave Radiation, Latent Heat Flux, Sensible Heat Flux, Sea Surface Temperature, Chlorophyll-a, Surface Wind, and Mixed Layer Depth. The results show that the Southern coast of Java receives an average heat of 547.8 W/m2 per year. Net Heat Flux fluctuations are dominated by heat intake by Shortwave Radiation and heat release by Latent Heat Flux. Net Heat Flux has a very strong relationship with sea surface temperature with the best correlation of 0.84 and 0.83 at lag+2 and lag+3 months indicating that Net Heat Flux plays an important role in modulating changes in sea surface temperature in the next 2-3 months. A significant increase in chlorophyll-a occurred after the Net Heat Flux was positive or there was ocean heating which caused the shoaling of Mixed Layer Depth, resulting in primary productivity in the east monsoon along with nutrient rich entrainment to the surface by EMT and EPV. [ABSTRACT FROM AUTHOR]

Chlorophyll-a (chl-a) and Sea Surface Temperature (SST) are important indicators of air-sea interaction and primary productivity. It has been widely known that the variability of chl-a and SST in the waters of Central Java Province (CJP) is influenced by the monsoonal cycle. Previous studies did not clearly describe the variability of chl-a and SST when compared to other cycles. This present study investigated the variability of chl-a and SST influenced by monsoonal cycles, IOD, and ENSO in both CJP waters. Our analysis is based on satellite observations and uses daily data to compile climatological data. The analysis found differences between the variability of chl-a and SST during the monsoonal cycle and ENSO-IOD extreme conditions. During the monsoonal cycle, the maximum (minimum) chla (SST) in northern CJP is 0.7 mg.L-1 (28.5°C) is observed in the West Monsoon, and in the southern CJP is 1.5 mg.L-1 (25.5°C) is observed in the East Monsoon. In addition, the analysis reveals that the ENSO and IOD extremes do not clearly alter the variability of chl-a and SST in the northern CJP. However, ENSO and IOD extremes have clearly altered the variability of chl-a and SST in the southern CJP. The highest impact to variability of chl-a and SST occurred during IOD+ extreme (2019), where the range of value chl-a (SST) in south CJP is 0,35-4,57 mg.L-1 (23,29 - 30,49°C). The value of chl-a (SST) is greater than 4 mg.L-1 (less than 24°C) are observed in the east monsoon. It is caused by the intensity of lifting the mass of water from deeper waters to the sea surface, which possibly supplies the nutrients in the surface waters. The result of the investigation showed that the increasing of chl-a and decreasing of SST in the northern CJP dominant by monsoonal cycle and southern CJP dominant by monsoonal cycle and ENSO - IOD. [ABSTRACT FROM AUTHOR]

Arafura Sea is one of the waters in the eastern region of Indonesia that is rich in marine and fisheries potentials because of its fertile conditions which is suitable for fishing ground. One of the fish resources which have important economic value at the Arafura Sea is big pelagic fish such as Mackerel. Thus this study aims to determine the spatial and temporal distribution of Mackerel in the Arafura Sea based on fishing boat coordinate data, to know the distribution of chlorophyll-a concentration and SST from MODIS satellite data in the Arafura Sea and to determine the correlation of chlorophyll-a and SST to the Mackerel catch distribution. This study was conducted in December 2016 until February 2017 in the Arafura Sea, image data analysis of MODIS level-3 conducted at the Laboratory of Oceanography FPIK UNDIP. The data used are Mackerel catch data, the Chlorophyll-a data and SST from MODIS satellite from June to August 2015. The results of this study showed that the distribution of Mackerel catch from June to August more were caught in August a total of 62.2 tons for 19 trips. While the chlorophyll-a between June and August ranged from 0.30 to 8.04 mg/m3 and SST in June-August ranged from 24.6 °C - 28.4 °C. The correlation between chlorophyll-a and Mackerel catch results showed very strong correlation (correlation coefficient (r) 0.934). While the correlation between SST with the Mackerel catch showed a strong correlation (correlation coefficient (r) 0.664).

We investigate the distribution of various fractions phosphorus (P) in sediments at the coastal area of Semarang City. Samples were collected from thirteen locations at the Banjir Kanal Barat, port and Banjir Kanal Timur. Sedimentary parameters such as sand, silt, clay, and organic carbon were analysed in order to find out their relation with various P fractions. The sediment types are predominantly sandy and silty with low clay content. Among all fractions (loosely bound/Ads-P), bound calcium/Ca-P), iron bound/Fe-P), and organic fraction/OP), Ca-P fractions constitute the largest portion (71.2 %) followed by iron-bound (17.0 %), organic fraction (10.4 %) and loosely bound (1.4 %). The bioavailable P fractions range from 20.2 % to 42.0 % of the total P (TP) content with average 28.8 %. Relatively high Ads-P content is observed in offshore locations with comparatively high mud percentage as compared with the near-shore locations. The order of abundance of the main forms of P in the Semarang coastal surface sediments is as follows: Ca-P > Fe-P > OP > Ads-P. The concentration of this fraction causes the abundance of chlorophyll-a from 9.09 to 21.09 mg/m3. [ABSTRACT FROM AUTHOR]

The Red Sea has a special geographical feature because it is situated in the tropical and subtropical zones. The uniqueness of the Red Sea makes a variability of oceanography data (Chlorophyll-a (Chla), current, Salinity, etc.) and meteorological data (Precipitation, Wind Speed, etc.). However, investigations of differences interaction of oceanography and meteorology are less studied in of the Red Sea. Satellites and modeling make it possible to observe oceanographic and meteorological data over a long period of time. This study first demonstrates that there are three major areas along the Red Sea that represent the different Chl-a concentrations during the rainy season. The month of July has the highest Chl-a concentration in the south (1.3 mg/m³) and the lowest Chl-a concentration in the north (0.18 mg/m³). The southern part of the Red Sea has a different generation mechanism from the northern part of the Red Sea in terms of increasing and decreasing Chl-a concentrations. The existence of surface runoff in this area may result in the supply of anthropogenic organic compounds and fresh water to coastal waters. This may increase the supply of nutrients at the peak of the rainy season, and finally increase the concentration of Chl-a in the southern part. In the middle part, the variability of Chl-a is mainly affected by wind speed. Meanwhile, the high salinity in the northern part may limit the growth of phytoplankton and keep the Chl-a concentration low. [ABSTRACT FROM AUTHOR]

The southern coast of South Sulawesi-Indonesia is known as an upwelling area occurring during dry season, which peaks in August. This upwelling area is indicated by high chlorophyll-a (Chl-a) concentrations due to a strong easterly wind-induced upwelling. However, the investigation of Chl-a variability is less studied along the western coast of South Sulawesi. By taking advantages of remote sensing data of Chl-a, sea surface temperature, surface wind, and precipitation, the present study firstly shows that along the western coast of South Sulawesi, there are two areas, which have high primary productivity occurring during the rainy season. The first area is at 119.0° E–119.5° E; 3.5° S–4.0° S, while the second area is at 119.0° E–119.5° E; 3.5° S–4.0° S. The maximum primary productivity in the first (second) area occurs in April (January). The generating mechanism of the high primary productivity along the western coast of South Sulawesi is different from its southern coast. The presence of river runoff in these two areas may bring anthropogenic organic compounds during the peak of rainy season, resulting in increased Chl-a concentration. [ABSTRACT FROM AUTHOR]

A rare event known as Fujiwhara effect occurred in the southeastern tropical Indian Ocean when tropical cyclones (TCs) Seroja and Odette were co-existed, interacted each other, and merged into one TC in April 2021. Here, remotely sensed data (surface winds, sea surface temperature, chlorophyll-a concentration, and surface currents) were analyzed to determine the impact of Fujiwhara effect on the ocean biophysical variables in the region. Ekman pumping velocity were computed to determine the upwelling/downwelling process. During the entire development of the TCs to the merging, the TCs induced sea surface temperature (SST) cooling and raising sea surface chlorophyll-a. Ekman pumping and inertial pumping may serve as the primary driving force for the observed negative SST anomaly and positive anomaly in chl-a concentration associated with TCs. This rare event adds the complexity of ocean and climate dynamics of the region as an exit gate of the Indonesian throughflow to the Indian Ocean and may have implications to circulation and climate in the Indian Ocean and beyond. The present research likely represents the first scientific documentation of oceanic responses to a Fujiwhara effect in the region. • TC Odette and TC Seroja merged in the southeastern tropical Indian Ocean. • The Fujiwhara effect influences the ocean biophysical parameters. • The Ekman and inertial pumping partly affect the ocean biophysical parameters. [ABSTRACT FROM AUTHOR]