02/05/2019


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Data use policy 

As a condition for use of this data set, users agree:
(1) To notify the lead investigator (Luitgard Schwendenmann, l.schwendenmann@auckland.ac.nz) if the dataset is to be used in any publication;
(2) To provide formal recognition that, at our discretion, may include co-authorship or acknowledgements on publications;
(3) To recognise that we may be using these data for scientific analyses, papers or publications that are currently planned or in preparation, and that such activities have precedence over any that that you might wish to prepare.


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Citation: 

Francois Jost and Luitgard Schwendenmann (2019): Data: Water stable isotope signature of soil and xylem samples under different land use systems, Panama.

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Short description:

This data set contains soil and xylem water delta18O and delta2H values of soil and xylem samples collected in different land use systems in Panama. The samples were collected and analysed by Francois Jost for his Masterthesis entitled "Using Stable Isotopes (D, 18O) to Estimate Plant Water Uptake in Different Vegetation Types, Panama", University of Goettingen, 2009 under the supervision of Dr. Luitgard Schwendenmann.

The data set includes two files:
Santa Fe_metadata.txt
Santa Fe soil and xylem water 2H_18Ovalues.csv


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Acknowledgement:

This research project was partly funded through grant COL07-44 from SENACYT (Secretaría Nacional de Ciencia, Tecnología e Innovación, Panama). The research was conducted under a scientific permit (No. SC/P-2-07) issued by ANAM in Panama (Autoridad Nacional del Ambiente, Panama).

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Site description and methods used:


Site description
The research area is located in the Santa Fe district, Veraguas province, Central Panama. Three communities within the district (Alto de Piedra, Bermejo and Muelas) were selected for the study. This area is located in the Bulaba River sub-basin, which is part of the Santa Maria River watershed. A description of the study area and study sites can be found in Macinnis-Ng et al. 2012 (doi.10.1007/s10533-012-9709-0) and Macinnis-Ng et al. 2014 (doi.10.1002/hyp.9754).


Experimental setup 
Soil and plant tissue samples were collected from three secondary forests (rastrojo), three mixed crop sites (agriculture, cultivos), and three pastures (grass) in March/April (dry season) 2008. 

Sample collection
Depending on the species, xylem samples were obtained by taking stem cores (using an increment corer, 5 mm in diameter), suberized branches or basal culms. The bark was removed from the stem and branch samples, as evaporative gas exchange in the bark tissue can result in isotopically enriched water (Dawson and Ehleringer, 1993). Soil samples were obtained within a 10 to 50 cm radius (depending on the size of the plant) from the plant at the following depth intervals: 0–10, 10–30, 30–50 and 50–70 cm. We pooled two to three soil cores for a given depth interval.
Plant tissue and soil samples were placed in 40-ml borosilicate glass bottles, closed with a Teflon-coated lid, wrapped in Parafilm and kept frozen until analyses.

Water extraction and isotopic analyses 
Water was extracted from plant and soil samples by cryogenic vacuum extraction (Ehleringer and Dawson, 1992). Plant tissue and soil samples were extracted (90 min to 120 min based on the results of extraction time curves). All extracted water samples were analysed for both deuterium (d2H) and oxygen (d18O). The isotopic composition was measured by injecting water into a high temperature conversion/elemental analyzer (TC/EA) coupled via a Con-Flo III interface to a Delta V Plus isotope ratio mass spectrometer (Thermo-Electron Cooperation, Bremen, Germany) as described in Gehre et al. (2004). All samples were analysed four times. The value of the first injection was discarded, and the remaining values were averaged. The d2H and d18O values are expressed in delta per mil (‰) relative to the Vienna Standard Mean Ocean Water standard. Measurement precision was 2‰ for d2H and 0·04‰ for d18O. Water samples were analysed at the Center for Stable Isotope Research and Analysis (KOSI), University of Göttingen, Germany.