Air-Sea Flux of Co2 in the Waters of Karimunjawa Island, Indonesia

Abstract

The purpose of this study was to determine the distribution of CO2 flux in Karimunjawa in the east monsoon. The variables in this study were temperature; pH; salinity; DO; CO2 atm was measured using a CO2 meter; chlorophyll-a, phosphate, silicate were measured spectrophotometric method. Total Alkalinity / TA was measured using the titration method with the principle of changing pH; DIC (Dissolved Inorganic Carbon) was measured using CO2sys software. The partial pressure of seawater carbon dioxide calculated using formula: pCO2sea = 6.31T2 + 61,9 Chla2 – 365.85T – 94.41 Chl-a +5715.94, the partial pressure of atmospheric carbon dioxide calculated using formula: pCO2atm = xCO2atm (pb - pH2O). The calculation of the estimated CO2 flux using the formula: Flux CO2 = Kh x kwa x (∆pCO2) , if the CO2 flux has a positive value water acts as a CO2 source, and if it is negative, the waters act as a CO2 sink.. CO2 flux in Karimunjawa waters during east monsoon (represented by August 2018) showed that in Karimunjawa waters with normal pH 7.2-7.4 were dominated by bicarbonate ion HCO3-with an average value of DIC 1847.24 µmol/kg dan TA 1912.51 µmol/kg. The partial pressure of seawater CO2 is higher than the partial pressure of atmospheric CO2 this indicates that the role of Karimunjawa waters as a source of CO2 where there is release of carbon dioxide into the atmosphere with CO2 flux values ranging from 8.549 – 13.272 mmol m-2 day-1. The variables that affect the flux of CO2 were the pCO2sea and ΔpCO2 with a very strong and positive correlation. These two variables were influenced by sea water temperature, salinity, chlorophyll-a, phosphate and silicate.

Mangrove Above-Ground Biomass and Carbon Stock in the Karimunjawa-Kemujan Islands Estimated from Unmanned Aerial Vehicle-Imagery

“…This huge amount of carbon stored in the mangrove above ground biomass indicates the role of mangrove ecosystem in the Karimunjawa-Kemujan Islands in absorbing the atmospheric CO 2 which is naturally released by the Java Sea. As an illustration, Latifah et al [12] stated that the CO 2 release by the seas surrounding Karimunjawa Islands ranges from 8.549 to 13.272 mmol/m 2 /day with a mean value of about 10 mmol/m 2 /day. This mean value is equal to 3.2 g C/m 2 /day.…”

“…The releasing carbon to the atmosphere occurs at maximum during the first transition season (April-May). Focusing on the seas of the Karimunjawa Islands, which was left blank by Kartadikaria et al [10] and Wirasatriya et al [11], Latifah et al [12] also found that the seas of the Karimunjawa Island act as a carbon source by conducting in-situ CO 2 measurement. Thus, it is crucial to investigate the role of the mangrove ecosystems in the Karimunjawa Islands as a contra role of the Java Sea in releasing carbon for a future possibility of the calculating carbon budget in the region.…”

The Partial Pressure of CO2 and Fluxes of CO2 in Semarang Bay, Indonesia

“…At high latitudes with cold waters, the solubility of CO2 is high which can increase the dissolution of gas into seawater causing CO2 absorption (sink CO2) to occur. This is supported by other studies which conclude that high-latitude seas/oceans with four seasons and relatively cold temperatures function as CO2 absorbers (Takahashi et al, 1997;Takahashi et al, 2002;Cai et al, 2006;Yasunaka et al, 2016;Arnone et al, 2017;Ito et al, 2018;Tian et al, 2020) while low latitudes seas function as a source of CO2 due to warm waters (Fitranti et al, 2013;Kartadikaria et al, 2015;Afdal, 2016;Yan et al, 2018;Latifah et al, 2020). Several studies in Indonesia, however, show that the sea can function as sinks of CO2 (Fachri et al, 2015;Latifah et al, 2019).…”

“…Water quality variables that affect CO2 Flux Previous studies (Takahashi et al, 1997;Takahashi et al, 2002;Cai et al, 2006;Takahashi et al, 2009;Otero et al, 2013;Yasunaka et al, 2016;Arnone et al, 2017;Ito et al, 2018;Tian et al, 2020) showed that in waters in middle and high latitudes with low temperatures, the oceans acted as CO2 sinks. While studies conducted at low latitudes with high (warm) temperatures (Fitranti et al, 2013;Kartadikaria et al, 2015;Afdal, 2016;Yan et al, 2018;Latifah et al, 2020) showed that the oceans served as a source of CO2. Warm surface water causes CO2 to be returned to the atmosphere by the oceans (outgassing of CO2).…”

Analysis of the CO2 Content in the PIM (Mangrove Information Center) Area in Pekalongan City, Central Java Province

“…The CO 2 system in waters is in the form of gas (CO 2 ), bicarbonic acid, bicarbonate ions and carbonate ions. The total amount of all forms of the CO 2 system is called the total CO 2 concentration [∑CO 2 ] and is often called dissolved inorganic carbon (DIC) (Latifah et al, 2020). The presence of inorganic carbon plays an important role in chemical reactions in waters.…”