Abstract The nesting characteristics (number of nests and eggs, time of year, nesting initiation, and nesting length) of leatherback (Dermochelys coriacea) and hawksbill (Eretmochelys imbricata) sea turtles of the southern Caribbean Sea (specifically in the Gulf of Paria in Venezuela), were examined in association with weekly precipitation averages and number of rainy days per week during the period between 2009 and 2018. We hypothesized about the influence of rainfall intensity and patterns as the main abiotic factor for sea turtle nesting. On average, leatherbacks preferred nesting during the drier season of each year (March, April, and May), while hawksbills nested during the rainy season (June to September). For both species, we found few significant correlations between the number of nests or clutch size (number of eggs per nest) and weekly averages of seasonal precipitation rates in the region. Average hawksbill clutch sizes were not correlated with average precipitation rates but were positively correlated with the number of rainy days per week (r=0.66, P≤0.05). Average hawksbill clutch sizes decreased each year on average (-3.3 eggs/year, r=-0.88, P≤0.001), which coincided with a negative long-term trend in the number of rainy days (-0.11 rainy days/week, r=-0.69, P≤0.05). During the study period, nesting activities for both leatherback and hawksbills started progressively later (0.9 and 0.6 weeks/year, respectively p≤0.05) and were shorter (-0.9 and -0.8 weeks /year, P≤0.1 and P≤0.05, respectively).

For more than ten years, the CARIACO Time-Series Program has studied seasonal patterns and interannual variability at the Cariaco Basin. Monthly core physical and biogeochemical observations have been collected since November 1995 at the CARIACO Time-Series station (10º 30' N, 64º 40' W). A region with suboxic conditions (oxygen and sulfide concentrations <1 µM) is found at intermediate waters at the station. The characteristics of this region show time and space variability, depending on the dynamics of the water. In general, ammonium, nitrate and nitrite disappeared within the suboxic region, although there is a steep ammonium concentration increase with depth after the oxic-anoxic interface suggesting its consumption at this boundary. Our data shows that intrusions are a major factor in affecting the chemical characteristics of the water column.

Por más de diez años, el Programa Serie de Tiempo CARIACO ha estudiado los patrones estacionales y la variabilidad interanual en la Fosa de Cariaco. Observaciones de los principales parámetros físicos y biogeoquímicos se han obtenido mensualmente desde noviembre de 1995 en la estación Serie de Tiempo CARIACO ubicada a 10º 30' N, 64º 40' W. Una región con condiciones subóxicas (concentraciones de oxígeno y sulfuro <1 µM) se encuentran presentes en las aguas intermedias de la fosa. Las características de esta región muestran una variabilidad temporal y espacial que depende de la dinámica de las aguas. En general, los niveles de amonio, nitrito y nitrato son prácticamente indetectables en esta región, aunque se observa un incremento marcado del amonio después de la interfaz lo que sugiere que está siendo consumido en esta zona. Nuestros datos muestran que las intrusiones son un factor importante en alterar las condiciones químicas de la columna de agua.