Browsing by Author "Saldarriaga, Maritza S."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Restricted Hydrological controls on the biogeochemical dynamics in a Peruvian mangrove forest(Springer Verlag, 2017) Pérez Segovia, Alexander; Gutiérrez, Dimitri; Saldarriaga, Maritza S.; Sanders, Cristian J.A tropical mangrove forest in Northern Peru was studied to determine if physical and biogeochemical characteristics of creek water and subtidal sediments are related to the seasonal hydrological regimes. The results showed that during the dry season, there were greater reducing conditions (Eh) and greater fine particle content (silt and clay) in the subtidal sediments. In contrast, the wet season showed greater dissolved oxygen concentrations in creek water as well as lower total organic matter and chlorophyll-a contents in the subtidal sediments. Carbohydrate and protein concentrations indicated remobilization and degradation of sedimentary organic matter, which were higher during the dry season than in the wet season. The results presented here indicate that changes in the hydrological regime affect the biogeochemical dynamics of mangroves, modulating the sediment redistribution as well as the organic matter deposition and degradation. This research provides insight to the biogeochemical dynamics in Peruvian mangrove sediments which are sensitive to extreme El Niño-Southern Oscillation events and the potential effects of climate change.Item Restricted Tidally driven sulfidic conditions in Peruvian mangrove sediments(Springer, 2018-09) Pérez Segovia, Alexander; Gutiérrez, Dimitri; Saldarriaga, Maritza S.; Sanders, Christian J.The seasonal influence of tidal regimes on sulfidic conditions was studied in intertidal environments from a mangrove estuary in Northern Peru. Along two sampling stations, creek water and sediment cores were collected during the dry and wet seasons at all tidal phases (ebb, low, flow, and high tides). Physical-chemical parameters were measured in the creek water (temperature, salinity, pH, Eh, and DO), whereas pH, redox potential (Eh), and total organic matter contents were obtained from the sediment cores. In addition, total dissolved sulfide content ∑ (H2S, HS−, H2−) was measured from sediment pore water. During the dry and wet seasons, the creek water pH, Eh, and dissolved oxygen were lowest in low tide, whereas oxygenated conditions and higher pH and Eh values prevailed in high tide. The total organic matter content in sediments was higher during the dry season, with the highest contents observed in the seaward station. Higher average ∑H2S (landward station, 243.1 ± 234.9 μM L−1; seaward station, 544.9 ± 174.4 μM L−1) were noted during wet season compared to dry season (landward station, 5.3 ± 4.5 μM L−1; seaward station, 430.2 ± 435.1 μM L−1). These ∑H2S contents increased towards the bottom of the sediment column, reflecting the anaerobic decomposition of the organic matter and sulfate reduction. This study provides insight to the geochemical dynamics of intertidal mangrove sediments that are sensitive to fluctuating reducing and sulfidic conditions, oscillating at time scales of minutes to hours.