Efraín Rodríguez-Rubio

This paper presents the results of the integration, commissioning, and in-orbit calibration of the ARGUS 2000 SWIR wavelength spectrometer onboard the Colombian FACSAT-2 satellite, Colombia’s first satellite used for the measurement of greenhouse gases (GHG). The satellite has been in orbit for approximately one year, gathering spectral signatures in order to characterize the data and perform calibration. The calibration represents a certain behavior following a second-order adjustment. For data analysis, retrieval algorithms have been developed to obtain synthetic spectra using the Genspect 1.2 software code. These synthetic spectra were obtained from the spectroscopic data associated with atmospheric gases (H₂O, O₂, CO, and CO₂), which are stored in the HITRAN database. Attempting to achieve a more accurate simulation of the experimental spectrum, certain instrumental parameters have been incorporated into the synthetic spectrum, including the resolution of the spectrometer, the field of view (FOV) angle of observation, the limited quantum efficiency of detection, and the slit function. As a result, six slit functions were tested, with the Gaussian and the diffraction functions proving to be the most effective. Finally, a profile of Total Carbon Column Observing Network (TCCON) concentrations was used for comparison with a spectral signature acquired by FACSAT-2, resulting in a close match between the synthetic spectrum and the measured spectrum.

Summary: Anaerobic ammonium oxidizers contribute to the removal of fixed nitrogen in oxygen‐deficient marine ecosystems such as oxygen minimum zones ( OMZ ). Here we surveyed for the first time the occurrence and diversity of anammox bacteria in the C olombian P acific, a transition area between the prominent S outh and N orth P acific OMZs . Anammox bacteria were detected in the coastal and oceanic areas of the C olombian P acific in low oxygen (< 22 μM), high nitrate (25–35 μM) and low nitrite (< 0.07 μM), and ammonium (< 1 μM) waters. In these waters, anammox bacteria were rich [∼ 7 operational taxonomic units ( OTUs ), 98% cut‐off) and microdiverse ( S hannon index H ′ < 1.24), in comparison with the observed at the prominent OMZ of the E astern T ropical S outh P acific, A rabian S ea and B lack S ea. Anammox bacteria‐like sequences from the C olombian P acific were grouped together with sequences retrieved from the distinct OMZ 's marine subclusters ( P eru, N orthern C hile and A rabian S ea) within C andidatus ‘ S calindua spp’. Moreover, some anammox bacteria OTUs shared a low similarity with environmental phylotypes (86–94%). Our results indicated that a microdiverse anammox community inhabits the C olombian P acific, generating new questions about the ecological and biogeochemical differences influencing its community structure.

Indices of the interannual and interdecadal variability at Tumaco Island (2° N; 79° W; Colombia), based on time series of sea surface temperature (SST), air temperature (AT) and precipitation (P) from a coastal station, are presented regarding the period 1960–2010. These indices are derived from the first two EOF (empirical orthogonal function) modes of the normalized time series, which grasp 84% of the explained variance. The first EOF represents the interannual variability closely correlated with the ENSO-related SST variability of region Niño 1+2 (r = 0.74; lag = 1), Niño 3 (r = 0.71; lag = 1), and the well-known period band 2–8 yr. Furthermore, the first EOF also accounts for the extreme warm events in the eastern equatorial Pacific due to them being well correlated with the E index (r = 0.70). The second EOF represents a much longer variability dominated by the ENSO-like mode or Pacific Decadal Oscillation (PDO), represented by two interdecadal modes (8–16 yr and 20–30 yr), and may account also with moderate warm events and cool events, being more sensitive to cool events.

Seasonal circulation and three‐dimensional thermohaline structure within the Panama Bight are examined by employing satellite‐derived sea surface winds and dense in‐situ hydrographic datasets. The northerly Panama wind jet, associated with a dipole structure of wind stress curl that is positive (negative) on its eastern (western) flank, dominates the bight in winter. This wind jet generates a cyclonic eddy with mean geostrophic velocities of 60 cm s⁻¹, including the poleward flowing coastal Colombia Current, and induces a well pronounced thermocline dome. As a result, temperature (salinity) in the bight is much colder (saltier) than in its surrounding waters. Winds blow from southwesterly directions in summer and the bight is dominated by an anticyclonic eddy associated with a thermocline bowl. Mean geostrophic velocities are on the order of 40 cm s⁻¹ and the Colombia Current is not observed. Temperature (salinity) in the bight is much warmer (fresher) than in its surrounding waters.

The near shore zone of Gorgona Island is a protected marine area located in the Eastern Tropical Pacific (ETP) of Colombia. Although this is home to one of the most developed coral reefs in the ETP, the characteristics of the local oceanographic conditions at the surface and their spatial and temporal variability have been poorly studied. In order to increase the information on temperature and salinity variability off Gorgona Island, systematic records of these variables were made during four periods (September 2005, December 2005, March 2006, June 2006). Furthermore, continuous record temperature senors were installed at 15 m depth on the eastern and western sides of the island and the local surface circulation pattern was monitored in June 2006 and February 2007 using a current profiler (AWAC-ADCP). Two contrasting periods were identified in the oceanographic conditions of the surface layer (0-50 m): a warmer and low salinity period between May and December (thermocline depth 47 m), and a colder and high salinity period between January and April (thermocline depth 7.5 m). Local upwelling events were not observed and the results suggest a strong influence of mesoscale processes (Panama bight upwelling) on the temporal variability of the coastal oceanographic conditions in the study area. Furthermore, the spatial variability seems to be more associated with regional climatic processes (precipitation patterns) and the proximity of Gorgona Island to the Patía-Sanquianga River delta.

According to the relative sea level (RSL) data series from Tumaco 1953-2006, the positive sea-leve! anomalies show a good coherence with the Southern Oscillation lndex (SOi). The variability of the SOi explains 61 % of the seasonal variability in the water level data (r2 = 0.61, < 0.05). Maximum peaks appear in the 1982-1983 and 1997-1998 El Nino years, which were approximately 30 cm above the interannual monthly mean. The long term sea-leve! trend was decreasing at 0.60 mm/yr. Two subgroups of sea-level data with changing trends were identified: first (1953-1979), a decreasing trend of 4.7 mm/yr; second, an increasing trend rising ata rate of 4 .7 mm/yr. The break of the series coincides with the occurrence of the 1979 great Tumaco earthquake (Mw = 8.2). That rate of change in the RSL subgroups could be explained through the theoretical dislocation model of strain accumulation and release at a subduction zone. Moreover, anomalies in water discharge of the Mira River (1981 -2002) show an incrementally higher discharge in the drainage river basin between 1981 and 1987 and a diminishing trend in the discharge between 1988 and 2002. Recent delta dynamics show a continuous progradation proceeding between 1958 and 1987. After the 1979 earthquake, relative sea leve! rise, the 1982-1983 El Nino events and decreased river input may explain the change to a slow coastal erosion stage at the delta front. De acuerdo con el análisis de la serie del nivel relativo del mar (NRM) de Tumaco entre 1953 y 2006, las anomalías positivas del NRM muestran una buena coherencia con la curva del indice de Oscilación del Sur (IOS) en el periodo de 54 años. Las variaciones en el IOS explican 61 % de la variabilidad estacional en el nivel del agua (r1= 0,61, p < 0,05); los picos de mayor anomalía ocurrieron en los años El Niño d~ 1982-1983 y 1997-1 998, alcanzando hasta 30 cm por encima de los promedios mensuales interanuales. También se estimó la tasa general de descenso del NRM en 0,60 mm afio, y se identificaron dos subgrupos de datos con altas tasas de cambio y tendencias diferentes: el primero entre 1953 y 1979, con descenso de 4,7 mm año·'; el segundo, d~ ascenso, entre 1984 y 2006, con 4,7 mm año·'. El punto de quiebre de la serie coincide con ocurrencia del terremoto de Tumaco de 1979 (Mw = 8,2), por lo que este cambio en la tendencia del NRM se explicó mediante el modelo teórico de dislocación para la acumulación y liberación de la deformación en zonas de subducción. Las variaciones en la curva de diferencias integrales (COI) para la serie del caudal del río Mira 1981-2002 sugieren el paso de un incremento de la humedad en la cuenca fluvial (1981-1987) a otro que corresponde a una disminución en la capacidad hidrofógica (1988-2002). La dinámica reciente del delta mostró un proceso continuo de progradación entre 1958 y 1987. Después del sismo de 1979, el ascenso del nivel relativo del mar, los eventos El Niño de 1982 y 1983, y la inflexión de la curva de aporte fluvial pueden explicar el cambio a una fase de erosión marina lenta en el frente deltaico.