The Varadero Reef is located south-west of the Cartagena Bay close to the southern strait that connects the Bay to the Caribbean Sea in Colombia (10\u00b018\u201923.3\u201dN, 75\u00b035\u201908.0\u201dW). The Bay is a receiving estuary from the Magdalena River through the Canal del Dique, a man-made channel whose construction and operation dates back almost a century. Three study sites with contrasting light regimes were considered in order to evaluate the role of the light-environment perturbation associated with the Dique channel freshwater plume on the photosynthetic performance of corals from Varadero: 1) Varadero reef at 3.5m depth close to the Dique channel mouth (10\u00b018\u201923.3\u201dN, 75\u00b035\u201908.0\u201dW), 2) Rosario reef at 12m depth as clear-control site 21 km southwest from Varadero (10\u00b011'12.1\"N, 75\u00b044'43.0\"W), and 3) Cartagena Bay at 3m depth, the closest\u00a0 site to the Dique channel mouth and most turbid among the three sites (10\u00b018'5.80\"N, 75\u00b034'37.10\"W).
\nThe values of the photosynthetic efficiency (alpha) are expressed in umol O2 umol quanta-1, the compensating irradiance (Ec) in umol quanta m-2 s-1, the saturating irradiance (Ek) in umol quanta m-2 s-1, the average respiration rate (R-avg) as well as the respiration pre- and post-illumination (R0 and Rf) are expressed in umol O2 m-2 s-1, and the net and gross maximum photosynthesis rates (Pmax(n) and Pmax(gross)) are expressed in umoles O2 m-2 s-1.
\nPhotosynthetic parameters of corals were obtained from PE (photosynthesis vs. irradiance) curves conducted under laboratory conditions. A custom-made water-jacket acrylic chamber with four independent hermetic compartments (~650 ml each) was used to run the PE curves, maintaining a constant temperature of 28 \u00b0C, close to natural conditions, with an external circulating water bath (Isotemp, Fisher Scientific). During each incubation, corals were submerged on filtered seawater (0.45 \u00b5m) under constant agitation by magnetic stirrers. Ten levels of irradiance between 0 and ~1400 \u00b5mol quanta m-2 s-1 were supplied at 10-min intervals with four 26 W LED bulbs (UL PAR38, LED Wholesalers Inc, USA). The light intensity was controlled with a custom-made software. The LEDs were operated in continuous mode with a multifunction I/O card (USB-6001, National Instruments Corp., USA) to avoid potential artefacts related to the effect of different pulsating frequencies on photosynthesis. Oxygen concentrations inside the compartments within the chamber were measured with a 4-channel fiber optical oxygen meter system (FireSting, Pyroscience, Germany). The photosynthetic efficiency (\u03b1), compensating irradiance (Ec), saturating irradiance (Ek), respiration rates (Rd), and maximum photosynthetic rates (Pmax), were calculated from the light-limited and light-saturated regions of the PE curves. Chlorophyll a (Chl a) content per unit of coral surface area was determined after obtaining coral tissue slurries with the help of an air gun connected to a scuba tank. Pigment extraction was performed in acetone/dimethyl sulfoxide (95:5 vol/vol) after homogenizing the slurries with a Tissue-Tearor Homogenizer (BioSpec Inc, USA). Chl a density was estimated spectrophotometrically with a modular spectrometer (Flame-T-UV-VIS, Ocean Optics Inc., USA). The specific absorption coefficient of Chl a (a*Chl a) was calculated using the equation: a*Chl a = (D675/\u03c1) \u00b7 ln(10), where D675 is the estimated absorbance value of corals at 675 nm, calculated from reflectance (R) measurements as [D675 = log (1/R675)], and \u03c1 is the pigment content per projected surface area (mg Chl a m-2).
\nThe software Pyro Oxygen Logger was used to operate the fiber optical oxygen meter system. The software OceanView was used to operate there modular spectrometer.
This file contains the primary data of the photosynthetic parameters from coral fragments of the species Orbicella faveolata used in a reciprocal transplant experiment. Data from three study sites are reported: Varadero at 3.5m depth; Rosario at 12m depth; and Cartagena Bay at 3m depth. Both Varadero and Rosario were used as source and destination sites; while Cartagena Bay was only used as destination site for the transplant experiment. The file has one spreadsheet: Photosynthetic parameters, which contains the primary data of several photosynthetic parameters. These parameters were measured on two time points with different groups of corals: before transplantation on October of 2016 (T1) and seven months after transplantation on May of 2017 (T2).
\nThese data were used in the manuscripts:
\n\"Degradation of the underwater light environment: physiological and ecological consequences for reef corals\u201d submitted to the Journal Nature Communications Biology. [under review, 2019-12-28]
\nand
\n\u201cSurviving marginalized reefs: assessing the implications of the microbiome on coral physiology and survivorship\u201d, submitted to the journal Coral Reefs, special issue \"Coral\u00a0Reefs in a Changing World: Insights from Extremes\".
Related Reference:
\nPizarro V, Rodr\u00edguez SC, L\u00f3pez-Victoria M, Zapata FA, Zea S, Galindo-Mart\u00ednez CT, Iglesias-Prieto R, Pollock J, Medina M. (2017) Unraveling the structure and composition of Varadero Reef, an improbable and imperiled coral reef in the Colombian Caribbean. PeerJ 5:e4119 https://doi.org/10.7717/peerj.4119
BCO-DMO Processing Notes:
\n- added conventional header with dataset name, PI name, version date
\n- modified parameter names to conform with BCO-DMO naming conventions