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Redalyc.Impact of Upwelling Events on the Sea Water Carbonate Chemistry Revista de Biología Tropical ISSN: 0034-7744 [email protected] Universidad de Costa Rica Costa Rica Rixen, Tim; Jiménez, Carlos; Cortés, Jorge Impact of upwelling events on the sea water carbonate chemistry and dissolved oxygen concentration in the Gulf of Papagayo (Culebra Bay), Costa Rica: Implications for coral reefs Revista de Biología Tropical, vol. 60, núm. 2, abril, 2012, pp. 187-195 Universidad de Costa Rica San Pedro de Montes de Oca, Costa Rica Available in: http://www.redalyc.org/articulo.oa?id=44923906013 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Impact of upwelling events on the sea water carbonate chemistry and dissolved oxygen concentration in the Gulf of Papagayo (Culebra Bay), Costa Rica: Implications for coral reefs Tim Rixen1, Carlos Jiménez2,3 & Jorge Cortés3 1. Leibniz Center for Tropical Marine Ecology (ZMT), Fahrenheitstr. 6, D-28359 Bremen, Germany 2. Oceanography Center, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus 3. Centro de Investigación en Ciencias del Mar y Limnologías (CIMAR), Ciudad de la Investigación, Universidad de Costa Rica, San Pedro, 11501-2060 San José, Costa Rica. Received 05-VIII-2011. Corrected 04-X-2011. Accepted 15-II-2012. Abstract. The Gulf of Papagayo, Pacific coast of Costa Rica, is one of the three seasonal upwelling areas of Mesoamerica. In April 2009, a 29-hour experiment was carried out at the pier of the Marina Papagayo, Culebra Bay. We determined sea surface temperature (SST), dissolved oxygen concentration, salinity, pH, and the partial pressure of CO2 (pCO2). The aragonite saturation state (Ωa) as well as the other parameters of the marine carbon- ate system such as the total dissolved inorganic carbon (DIC) and the total alkalinity (TA) were calculated based on the measured pH and the pCO2. The entrainment of subsurface waters raised the pCO2 up to 645 µatm. SSTs, -1 dissolved oxygen concentrations decreased form 26.4 to 23.7°C and from 228 to 144 µmol l . Ωa dropped down to values of 2.1. Although these changes are assumed to reduce the coral growth, the main reef building coral species within the region (Pocillopora spp. and Pavona clavus) reveal growth rates exceeding those measured at other sites in the eastern tropical Pacific. This implies that the negative impact of upwelling on coral growth might be overcompensated by an enhanced energy supply caused by the high density of food and nutrients and more favorable condition for coral growth during the non-upwelling season. Rev. Biol. Trop. 60 (Suppl. 2): 187-195. Epub 2012 April 01. Key words: pCO2, dissolved oxygen, upwelling, Gulf of Papagayo, aragonite saturation state, Costa Rica, corals. The eastern tropical Pacific (ETP) con- coral reefs (Kleypas et al. 2006). A tripling tains one of the most pronounced and largest of the pre-industrial CO2 concentration from mid-water oxygen minimum zones (OMZ) in 280 to 840 µatm which is predicted to occur the world’s oceans (Conkright et al. 2002). within the forthcoming 100 years (Meehl Along the Californian coast, upwelling is et al. 2007) could decrease Ωa from 3.44 to known to carry oxygen-depleted and carbon- 1.81 and calcification of specific corals spe- enriched subsurface waters into the surface cies by up to 85% (Kleypas et al. 2006). In layers, which leads to pCO2’s of ~ 1000 µatm order to study possible effects of upwelling and Ωa of < 1 (Feely et al. 2008). Experi- on reef forming corals in Culebra Bay within ments have shown that calcification of many the Gulf of Papagayo, SST, salinity, dissolved scleractinian corals decline with decreasing oxygen concentration, pH, and pCO2 were Ωa. Accordingly ocean acidification caused measured during upwelling events triggered by the rising CO2 concentration in the atmo- by the Papagayo winds at the end of April sphere is assumed to be a significant threat to 2009 (Fig. 1). Rev. Biol. Trop. (Int. J. Trop. Biol. ISSN-0034-7744) Vol. 60 (Suppl. 2): 187-195, April 2012 187 up south and north of the axis of the Papagayo A Nicaragua Jet leading to upwelling of subsurface waters 11º0’0” N 11º0’0” along the Nicaraguan coast and in the Gulf of Caribbean Papagayo (McCreary et al. 1989, Ballestero & Sea Costa Rica Coen 2004, Kessler 2006). The cyclonic eddies 10º0’0” N 10º0’0” south of the Papagayo Jet intensify the shoaling of the thermocline within the Costa Rica Dome region, which is connected to the coast between 9º0’0” N 9º0’0” March and April (Fiedler 2002, Fiedler & Tal- Pacic Panama Ocean ley 2006). Due to upwelling and wind mixing the SST can drop by up to 10°C within hours within the Gulf of Papagayo (Jiménez 2001, 8º0’0” N 8º0’0” 0 75 150 300 km Alfaro & Cortés 2011). The coral habitats of 86º0’0” W 85º0’0” W 84º0’0” W 83º0’0” W the Gulf of Papagayo are of special interest due to the high abundance of large reefs built 20 B almost entirely by Pavona clavus and Pocil- ) -1 15 lopora spp. and the presence of rare or endan- gered coral species with restricted distributions 10 (Cortés & Jiménez 2003, Jiménez et al. 2010). Wind speed (m s Wind 5 Methods: The SST and the mole fraction 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 of CO2 (xCO2) was measured by an underway April 2009 pCO2 system (SUNDANS) at a water-depth of ~ 3 m. The system was set up on April 24th at Fig. 1. A. Sampling site (black arrow). B. Daily wind speeds measured at the meteorological station Liberia, 1:00 am at one of the outer piers of the Marina Costa Rica. The grey bar indicates the sampling period. Papagayo (85°39’21.41”W; 10°32’32.89”N) in order to reduced impacts from the Marina at our sampling site. However, during the MATERIAL AND METHODS sampling period there was no ship traffic and the pier moved up and down with the tide so Study site: The Papagayo wind is a strong that water-depth from which we pumped the north-easterly jet blowing through low eleva- water remained constant throughout the experi- tion gaps of the Central American cordillera in ment. SUNDANS was developed by “Marine southern Nicaragua and northern Costa Rica. Analytics and Data” (MARIANDA, Germany, The jet is driven by the sea level pressure dif- www.marianda.com) according to the recom- ference between the Caribbean Sea and the mendations of the 2002 underway pCO2 sys- eastern tropical Pacific (ETP) which develops tem workshop in Miami, Florida (NOAA & during the boreal winter and the associated AOML 2002). It was equipped with a shower south-eastward migration of the subtropical type equilibrator, an open pre-equilibrator and Azores-Bermuda high (Clarke 1988, Amador a non-dispersive dual cell infrared gas analyzer et al. 2006, Romero-Centeno et al. 2007). (LI-7000). The LI-7000 was calibrated by using Outbreaks of cold air masses from the North nitrogen gas (zero CO2) and a standard gas for American continent into the Caribbean occa- CO2. The CO2 standard gases were checked sionally increase the sea level pressure differ- against the standard gases provided by NOAA ence between the two oceans and intensify the (CA07600 and CC311968) at the Institute for Papagayo winds (Clarke 1988, Alfaro & Cortés Baltic Sea Research in Warnemünde, Germany. 2011). During such wind events, offshore- The accuracy of the measured xCO2 was ±1.6 advecting cyclonic and anticyclonic eddies spin ppm. The xCO2 data were recorded every six 188 Rev. Biol. Trop. (Int. J. Trop. Biol. ISSN-0034-7744) Vol. 60 (Suppl. 2): 187-195, April 2012 seconds and subsequently averaged minute by the sampling period was characterized by an minute. xCO2 was converted into pCO2 and the intensification of the Papagayo winds (Fig. 1). fugacity of CO2 (ƒCO2) according to equations provided by Zeebe and Wolf-Gladrow (2001). DISCUSSION The SSTs were measured within the equilibra- tor. The atmospheric pressure and the wind The simultaneous drop of SST, dissolved speed were obtained from the meteorological oxygen, and pH indicate that oxygen-deplet- station in Liberia approximately 30 km east ed and CO2-enriched subsurface waters were of the sampling site (NCDC 2011). Salinity entrained into the surface layer in the early and the dissolved oxygen concentrations were morning hours on April 24th (Fig. 2). The determined by using WTW probes (Cond3310 observed SST drop of 2.3°C was associated and Multi 340i). The pH was measured using with a decrease in the oxygen concentration of an Orion ROSS electrode and an Orion StarTM. 84 µmol l-1 corresponding to a 37% reduction The Orion ROSS electrode was calibrated by of the dissolved oxygen concentration. During using NBS standards and re-calibrated by using the second upwelling event the decrease in oxy- the RCM standards (Batch 82: http://andrew. gen concentration and pH was less pronounced but reveal as the data obtained during the first ucsd.edu/co2qc/). Ωa, DIC, and TA were cal- upwelling event and elsewhere (Feely et al. culated based on the ƒCO2 and the pH. In order remove effects caused by temperature 2008, Manzello et al. 2008, Manzello 2010b), changes, DIC and TA were used to compute that wind-driven upwelling events in the ETP can deliver oxygen-poor, acidic waters to the the ƒCO2(DIC/TA) using a constant salinity and temperature of 34.51 and 25.01°C.
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