Biogeochemistry

Icacos Groundwater Monitoring

Project Description: 

A sample of data from three groundwater monitoring locations in the Icacos / Rio Blanco watershed are included here. Requests for a complete dataset will be considered, please email leonmi@sas.upenn.edu with an explanation of what you would like to do with the data. A complete dataset will be released to the public at a later date.

Research Location: 
Core Area(s) and/or Keywords: 

groundwater, pH, Nitrate, Dissolved Oxygen, Specific Conductance

Soil organic matter quantity, quality and microbial activity in deep soil profiles

Project Description: 

1) How does the quantity and quality of soil organic matter change as a function of soil profile depth:
-in old, highly weathered oxisol profiles versus younger, granitic inceptisol profiles?
-in three different forest types: Tabunuco, Colorado and sierra palm?
2) How do soil microbial community structure and functional characteristics change with depth across contrasting parent materials and forest types?
3) Can we relate microbial community characteristics to SOM quantity and quality?

Research Location: 
Core Area(s) and/or Keywords: 

Microbial ecology, biogeochemistry, rhizosphere

Elemental inputs and outputs from volcaniclastic and granitic terrains

Project Description: 

Measure elemental inputs in rain, and outputs in streams. Weekly sampling from two bedrock types, with analysis of sediments, particulate carbon and nitrogen, and dissolved nutrients, organic matter, Si, major cations, and major anions. Quarterly sampling of dissolved organic matter quality (fluorescence excitation-emission scans). Sites specific to the CZO project include rain chemistry at East Peak, and stream chemistry in Icacos and Guaba.

Research Location: 
Core Area(s) and/or Keywords: 

rain stream chemistry biogeochemistry input output export

Linkages between redox processes and surface soil carbon cycling

Project Description: 

Humid tropical soils are characterized by fluctuating oxygen (O2) concentrations and periodic anaerobosis caused by high soil moisture and biological O2 demand. Iron (Fe) oxides provide an abundant electron acceptor for microbial metabolism under anaerobic conditions. Here, we explored interactions between Fe redox cycling and carbon (C) pools and fluxes.
Key Questions:
1. Does spatial and temporal variation in moisture, O2 availability, and Fe reduction control soil C pools?
2. Does O2 limitation constrain organic matter decomposition via microbial enzymes?

Research Location: 
Core Area(s) and/or Keywords: 

redox, carbon dioxide, methane, nitrous oxide, extracellular enzyme, iron, sulfur, manganese, nitrogen, soil moisture,

Parent Material and Topography Determine Soil Phosphorus Status in the Luquillo Mountains of Puerto Rico

Project Description: 

We collected soils from both Icacos and Bisley, in different topographic positions, and analyzed them for phosphorus content.

Abstract from the paper listed below Mage & Porder 2013.

Research Location: 
Core Area(s) and/or Keywords: 

Soil, phosphorus, topography, rock type, granodiorite, volcaniclastic, nutrients, parent material

Relevant Tools, Models or Publication Downloads: 

The reconstruction of Holocene sea level and paleoenvironmental change

Project Description: 

Sea-level changes on the time-scale of decades to millennia are driven, predominantly, by changes in climate. The recent transition of the earth system from a glacial to interglacial state produced a dramatic global sea-level response. Puerto Rico is distant from the major glaciation centers, thus is characterized by a sea-level rise of ~120 m since the Last Glacial Maximum due, largely, to the influx of glacial meltwater to the oceans.

Research Location: 
Core Area(s) and/or Keywords: 

Coastal
Biogeochemistry

Stabilization of soil organic matter in contrasting parent materials

Project Description: 

Critical zone processes contributing to soil development over the contrasting bedrock parent materials in the Luquillo Mountains has resulted in significant differences important to organic C quantity and soil organic matter (SOM) quality. Similar vegetation cover at sites on contrasting slope positions or underlying lithology will likely generate similar surface litter. Once this litter enters the soil, however, we ask: 1) will the resultant SOM be chemically distinct or is it simply protected differently?

Core Area(s) and/or Keywords: 

soil, litter, soil organic matter, organic carbon, carbon, parent material

Data Sets: 

Nutrient fluxes for rainfall and throughfall in the Bisley watersheds

Project Description: 

Nutrient fluxes in rainfall and throughfall have been measured weekly in a mature
subtropical wet forest in NE Puerto Rico for over a 15-year period that included the effects
of 10 named tropical storms, several prolonged dry periods, and volcanic activity in the
region. During the first 15 years mean annual rainfall and throughfall were 3482 and 2131 mm/yr, respectively. Average annual rainfall and throughfall fluxes of K, Ca, Mg, Cl, Na, and SO4–S were similar but somewhat larger than those reported for most tropical forests. Rainfall inputs of nitrogen

Research Location: 
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