RESEARCH LOCATION: Streams and rain collectors described and listed in the site's description and data files.

INVESTIGATORS:

PRINCIPAL INVESTIGATORS	E-MAIL ADDRESS:
William H. McDowell	wmcdowell@lternet.edu

OTHER RESEARCHERS	E-MAIL ADDRESS:
Frederick Scatena	fscatena@lternet.edu
Douglas Schaefer	DSchaef53@hotmail.com

CONTACT PERSONS	Phone Number (Include area code)	E-MAIL ADDRESS:
William H. McDowell	(603) 862-2249	wmcdowell@lternet.edu

SOURCE OF FUNDING (SPONSOR): NSF-LTER, USDA, and non-LTER NSF grants

DATA SET ABSTRACT: Rain, throughfall, and stream water are collected weekly at the Luquillo Mountain sites listed below. These data sets begin as early as 1983; LTER sampling began in 1988.

Rain and throughfall samples are the total catch for the week, and are exposed to field conditions for that time. No event sampling is conducted on a routine basis. Stream water samples are grab samples taken from the water/air interface at stream channel center on the sampling day (usually Tuesdays). Rain samples from WDEV are wet only from an automatically-closing collector that prevents any dry deposition (Aerochem Metrics NADP collector). RCEV and RCB are bulk or always-open collectors that receive dry deposition by sedimentation.

A continuous record of stream stage (height) is recorded by a datalogger at all ongoing stream sampling sites. Average daily streamflows are available from the USGS and at other locations (Hydrology and Meteorology) on this site.

All samples are measured for pH and conductivity, and then filtered (pre-combusted Whatman GF/F glass fiber filter) prior to further analysis. From 1983-1994 samples were cooled and returned to the San Juan chemistry laboratory for analysis. During those years, samples for NH₄ and NO₃ analyses were refrigerated continuously until analysis. Subsamples for NH₄ analysis were also preserved with 1 molar H₂SO₄. From 1994 on, samples for NH₄ and NO₃ were frozen until analysis, were not acidified, and all analyses were conducted at the University of New Hampshire.

Rain, Throughfall, and Stream water Sampling Sites
Descriptions of LTER LUQ rain, throughfall, and stream water weekly sample chemistry data from 1988 onwards. Chemical concentrations are recorded as mg/L or mg/L as appropriate. Values below detection limits are recorded as 1/2 the detection limit.

Site

Abbreviation

Description

Comments

Quebrada uno-Bisley	Q1		Bisley stream
Quebrada dos-Bisley	Q2		Bisley stream
Quebrada tres-Bisley	Q3		Bisley stream
Puente Roto Mameyes	MPR		Bisley stream	Previously PRM
Rio Mameyes Gage	MG		Bisley stream
Quebrada Toronja	QT = QT1		El Verde stream
Quebrada Sonadora	QS		El Verde stream
Rio EspirituSanto	RES4
Quebrada Guaba	QG		El Verde stream
Rio Icacos	RI		LEF South stream
Rio Sabana	RS
Quebrada Prieta	QP		El Verde stream
Quebrada Prieta A	QPA		El Verde stream
Quebrada Prieta B	QPB		El Verde stream
Rain Collector-Bisley	RCB		Bulk collector
Rain Collector-El Verde	RCEV		Bulk collector
Wet Dry-El Verde	WDEV		Wet only collector
Throughfall-Bisley	TFB=TCB		TF bulk 10-collector composite
Bisley Gap	BGAP		TF bulk 10-collector composite

DATA SET METHODS:
Analytical Techniques
pH - Electrometric with combination electrode
Conductivity - Conductivity bridge
Cl - up to 1989 by automated colorimetric analysis (thiocyanate); after 1989 by liquid chromatography with conductivity detection
NO₃-N - up to 1989 by automated colorimetric analysis (Cd-Cu reduction); after 1989 by liquid chromatography with UV or conductivity detection
SO₄-S - Liquid chromatography, conductivity detection
Na, K, Mg, and Ca - up to 1994 by atomic absorption spectroscopy; after 1994 by ion chromatography with conductivity detection
NH₄-N - automated colorimetric analysis (phenolhypochlorite)
PO₄-P - automated colorimetric analysis (molybdate blue)
DOC - up to 1998 by persulfate oxidation (McDowell et al. 1987); after 1998 by high temperature catalytic oxidation
DIC - by syringe stripping and infrared spectroscopy (Stainton 1973).
TDN - prior to 1998 by persulfate oxidation and automated colorimetric analysis; after 1998 by high temperature catalytic oxidation with chemiluminescent detection
TDP - by persulfate digestion followed by automated colorimetric analysis
SiO₂ - automated colorimetric analysis (molybdate blue)
DON - by difference (TDN - NO₃-N - NH₄-N)

Table 1. Data Abbreviations, Detection Limits, and Units of Measure

Datum	Abbreviation	Detection limit	Units
Discharge	Discharge		Cubic feet per second
Gage height	Gage_Ht		feet
pH	pH		pH units
Conductivity	Cond		micromho/cm
Chloride	Cl	0.1	mg/L
Nitrate	NO3-N	3-10	mg N/L
Sulfate	SO4-S	0.1	mg S/L
Sodium	Na	0.1	mg/L
Potassium	K	0.05	mg/L
Magnesium	Mg	0.1	mg/L
Calcium	Ca	0.1	mg/L
Ammonium	NH4-N	2-10	mg N/L
Soluble Reactive Phosphate	PO4-P	3	mg P/L
Dissolved Organic Carbon	DOC	0.1	mg/L
Dissolved Inorganic Carbon	DIC	0.2	mg/L
Total Dissolved Nitrogen	TDN	0.1	mg/L
Total Dissolved Phosphorus	TDP	3	mg/L
Silica	SiO2	0.1	mg/L as SiO2
Dissolved Organic Nitrogen	DON	0.1	mg/L

REFERENCES:
McDowell, W.H., J.J. Cole, and C.T. Driscoll. 1987. Simplified version of the ampoule-persulfate method for determination of dissolved organic carbon. Can. J. Fish. Aquat. Sci. 44:214-218.

Stainton, M.P. 1973. A syringe gas-stripping procedure for gas chromatographic determination of dissolved inorganic and organic carbon in fresh water and carbonates in sediments. J. Fish. Res. Bd. Can. 30:1441-1445.

CROSS-REFERENCES (other data sets related to this one):

SAMPLE LOCATION: ITES, Chemistry Laboratory

STORAGE SITES(of data files): ITES, Data Manager's File DM-001 , Drawer #2

INVESTIGATOR'S ASSIGNED KEYWORDS: Biogeochemical cycles, nutrient input/output relationships, ammonium, nitrate, sulfate, chloride, potassium, sodium, calcium, magnesium, phosphate, DOC, DON

LEF LTER OFFICIAL KEYWORDS (See table): BISLEY GAPS, EL VERDE, Q MAMEYES, Q PRIETA, Q TORONJA, Q ICACOS, RAIN, RIVER, BIOGEOCHEMICAL CYCLES, CATIONS AND ANIONS, NITROGEN, DISCHARGE, PEER REVIEWED JOURNAL

PUBLICATIONS:
McDowell, W.H., C. Gines-Sanchez, C.E. Asbury, and C.R. Ramos-Perez. 1990. Influence of sea salt aerosols and long-range transport on precipitation chemistry at El Verde, Puerto Rico. Atmospheric Environment 24A:2813-2821.

McDowell, W.H. and C.E. Asbury. 1994. Export of carbon, nitrogen, and major ions from three tropical montane watersheds. Limnology and Oceanography 39:111-125.

McDowell, W.H., A.E. Lugo, and A. James. 1995.  Export of nutrients and major ions from Caribbean watersheds.  J. North American Benthological Society 14:12-20.

McDowell, W.H.  1998.  Internal nutrient fluxes in a tropical rain forest.  Journal of Tropical Ecology 14:521-536.

Chestnut, T.J., D.J. Zarin, W.H. McDowell, and M. Keller.  1999.  A nitrogen budget for late-successional hillslope tabonuco forest, Puerto Rico.  Biogeochemistry 46:85-108.

Lewis, W.M. Jr., J.M. Melack, W.H. McDowell, M. McClain, and J.E. Richey.  1999.  Nitrogen yields from undisturbed watersheds in the Americas .  Biogeochemistry 46:149-162.

Schaefer, D.A., W.H. McDowell, F.N. Scatena, and C.E. Asbury. 2000. Effects of hurricane disturbance on stream water concentrations and fluxes in eight watersheds of the Luquillo Experimental Forest, Puerto Rico. J. Tropical Ecology 16:189-207.

Aitkenhead, J.A. and W.H. McDowell.  2000.  Soil C:N ratio as a predictor of annual riverine DOC flux at local and global scales.  Global Biogeochemical Cycles 14:127-138.

Heartsill-Scalley, T., F.N. Scatena, C. Estrada, W.H. McDowell, and A.E. Lugo.  2007.  Disturbance and long-term patterns of rainfall and throughfall nutrient fluxes in a subtropical forest in Puerto Rico.  J. Hydrology 333:472-485.

DISSEMINATION:

RESTRICTED ___ UNRESTRICTED _X__

REASONS TO RESTRICT DATA IN THIS DATA SET BEYOND ITS TWO YEAR POLICY PERIOD*:

*WILL HAVE TO BE APPROVED BY AT LEAST ONE LUQ LTER PRINCIPAL INVESTIGATORS: N. Brokaw, J. ZIMMERMAN, A. LUGO

FILING

_X_ "File" copy only:Data Management will only file an electronic copy of the data file and its documentation 
___ " Enter" data on-line:Data Management will be in charge of entering the data on computer files (Contact Eda C. Meléndez)

SITES DESCRIPTIONS:
The study site was the Luquillo Experimental Forest on the eastern end of Puerto Rico (18 15'N, 65 50'W). The Luquillo Experimental Forest is synonymous with the El Yunque National Forest and Caribbean National Forest and has been administered by the U.S. Forest Service for ~70 yrs. Elevation ranges from 200 to 1,000 m. The plant community is dominated by tabonuco (Dacryodes excelsa) forest type at elevations of 200-600m and the colorado (Cyrilla racemiflora) forest type at elevations of 600-750 m. On ridges and peaks above 750 m, vegetation consists of short-statured elfin forest. Palms (most commonly Prestoea montana) are found throughout the forest but are especially common along streams channels and in poorly drained areas. Human disturbance, consisting of small farms and selective tree harvesting (mostly at lower elevations), preceded Forest Service administration. Scattered plantation forests have been established since designation of the area as an experimental forest (Brown et al. 1983).

Precipitation ranges from 250 to >500 cm yr^-1 in the Luquillo Forest area and increases with elevation. Precipitation peaks in May and from August to November (McDowell and Estrada-Pinto 1988). Hurricanes and tropical depressions produce individual rainfall events that are highly unpredictable and very intense, and hurricanes are thought to play a major role in structuring plant community dynamics (Brown et al. 1983).

The following table summarizes the features of three of the  studied watersheds:

Table 2. Characteristics of three of the long-term study watersheds

		Icacos		Sonadora		Toronja
Elevation (m)		616-800		375-1,050		267-510
Aspect		S		NW		NW
Area (ha)		326		362		16.2
Bedrock		Quartz diorite		Andesite, mudstone		Andesite, mudstone
Soil		Utuado clay		Los Guineos clay		Los Guineos clay
Vegetation types
Tabonuco (%)		0		6		100
Colorado (%)		75		57		0
Palm (%)		24		25		0
		1		12		0
Channel slope (%)		1.4		24		20
Channel substrate		Sand, boulders		Boulders, cobbles		Clay cobbles

Geographical positional system (GPS) Coordinates for each location:

location	latitude	longitude

VARIABLES (ATTRIBUTES):

File Name or # above (all in which the variable appears)	all	all	all	all	all (except 0, 15 - 19)
AbbreviationAbbreviation(as it appears on the data file)	Code	Sample_ID	Sample_Date	Sample_Time	Qm^3
NAME OF VARIABLE	Sample Code	Watershed or Collector's location	Sampling date	Sampling time	Streamflow
DEFINITION OF VARIABLE	Numeric code of sample assigned at ITES. Data field is left blank when datum is missing.	Watershed or Collector's location where the sample is taken	Date of sampling (in mm/dd/yyyy). Pre-LUQ LTER period:03-Jun-83 to 17-Mar-87 (with gaps); LUQ LTER Period:25-Oct-88 to present. Data field is left blank when datum is missing.	Time of sampling in integer format. Data field is left blank when datum is missing.	Discharge as measured by a USGS streamflow station to the nearest 15 minutes to sampling time. Data field is left blank when datum is missing.
UNIT					cubicMetersPerSecond
PRECISION
RANGE OR LIST OF VALUES	1028,...	Quebrada uno-Bisley = Q1, Quebrada dos-Bisley = Q2, Quebrada tres-Bisley = Q3, Puente Roto Mameyes = MPR, Rio Mameyes Gage = MG, Quebrada Toronja = QT = QT1, Quebrada Sonadora = QS, Rio EspirituSanto = RES4, Quebrada Guaba = QG, Rio Icacos = RI, Rio Sabana = RS, Quebrada Prieta = QP, Quebrada Prieta A = QPA, Quebrada Prieta B = PB, Rain Collector-Bisley = RCB, Rain Collector-El Verde = RCEV, Wet Dry-El Verde = WDEV, Throughfall-Bisley = TFB=TCB, Bisley Gap = BGAP
DATA TYPE	integer	alphanumeric	datetime	integer	decimal
MISSING DATA CODES

VARIABLES (ATTRIBUTES):

File Name or # above (all in which the variable appears)	0	0	0	0	0
AbbreviationAbbreviation(as it appears on the data file)	Gage_Ht	Temp	pH	Cond	REMARKS
NAME OF VARIABLE	Gage height	Temperature	pH	Conductivity	REMARKS
DEFINITION OF VARIABLE	Gage Height at sampling time (in feet). Data field is left blank when datum is missing.	Temperature of sample at sampling time. Data field is left blank when datum is missing.	pH (Electrometric with combination electrode). Data field is left blank when datum is missing.	Conductivity (Conductivity bridge in micro-mho/cm ). Data field is left blank when datum is missing.	Comments about the conditions found in the field at the time of collection and/or the data entered. Data field is left blank when datum is missing.
UNIT	feet	celsius		Micro-mho per centimeters
PRECISION	0.1	0.01	.01	.01
RANGE OR LIST OF VALUES
DATA TYPE	decimal	decimal	decimal	decimal	alphanumeric
MISSING DATA CODES

VARIABLES (ATTRIBUTES):

File Name or # above (all in which the variable appears)	All (except 0)	All (except 0)	All (except 0)	All (except 0)	All (except 0)
AbbreviationAbbreviation(as it appears on the data file)	Cl	NO3	SO4-S	Na	K
NAME OF VARIABLE	Chloride	Nitrate Nitrogen	Sulfate	Sodium	Potassium
DEFINITION OF VARIABLE	Chloride (up to 1989 by automated colorimetric analysis (thiocyanate); after 1989 by liquid chromatography with conductivity detection) in mg/L. Data field is left blank when datum is missing.	Nitrate Nitrogen (up to 1989 by automated colorimetric analysis (Cd-Cu reduction); after 1989 by liquid chromatography with UV or conductivity detection) in ug N/L. Data field is left blank when datum is missing.	Sulfate Sulfur (Liquid chromatography, conductivity detection) in mg S/L. Data field is left blank when datum is missing.	Sodium (up to 1994 by atomic absorption spectroscopy; after 1994 by ion chromatography with conductivity detection) in mg/L. Data field is left blank when datum is missing.	Potassium (up to 1994 by atomic absorption spectroscopy; after 1994 by ion chromatography with conductivity detection) in mg/L. Data field is left blank when datum is missing.
UNIT	milligramsPerLiter	milligramsPerLiter	milligramsPerLiter	milligramsPerLiter	milligramsPerLiter
PRECISION	10%	5%	10%	10%	10%
RANGE OR LIST OF VALUES
DATA TYPE	decimal	decimal	decimal	decimal	decimal
MISSING DATA CODES

VARIABLES (ATTRIBUTES):

File Name or # above (all in which the variable appears)	All (except 0)	All (except 0)	All (except 0)	All (except 0)	All (except 0)
AbbreviationAbbreviation(as it appears on the data file)	Mg	Ca	NH4-N	PO4-P	DOC
NAME OF VARIABLE	Magnesium	Calcium	Ammonium Nitrogen	Phosphate P	Dissolved Organic Carbon
DEFINITION OF VARIABLE	Magnesium (up to 1994 by atomic absorption spectroscopy; after 1994 by ion chromatography with conductivity detection) in mg/L	Calcium (up to 1994 by atomic absorption spectroscopy; after 1994 by ion chromatography with conductivity detection) in mg/L	Ammonium Nitrogen (automated colorimetric analysis (phenolhypochlorite)] in ug N/L	Phosphate [automated colorimetric analysis (molybdate blue)] in ug P/L	Dissolved Organic Carbon (up to 1998 by persulfate oxidation (McDowell et al. 1987); after 1998 by high temperature catalytic oxidation) in mg C/L
UNIT	milligramsPerLiter	milligramsPerLiter	milligramsPerLiter	milligramsPerLiter	milligramsPerLiter
PRECISION	10%	10%	10%	10%	10%
RANGE OR LIST OF VALUES
DATA TYPE	decimal	decimal	decimal	decimal	decimal
MISSING DATA CODES

VARIABLES (ATTRIBUTES):

File Name or # above (all in which the variable appears)	All (except 0)	All (except 0)	All (except 0)	All (except 0)	All (except 0)	All (except 0, 15-19)
AbbreviationAbbreviation(as it appears on the data file)	DIC	TDN	TDP	SiO2	DON	TSS
NAME OF VARIABLE	Dissolved Inorganic Carbon	Total Dissolved Nitrogen	Total Dissolved Phosphorus	Silica	Dissolved Organic Nitrogen	Total Suspended Sediments
DEFINITION OF VARIABLE	Dissolved Inorganic Carbon [by syringe stripping and infrared spectroscopy (Stainton 1973).] in mg C/L	Total Dissolved Nitrogen (prior to 1998 by persulfate oxidation and automated colorimetric analysis; after 1998 by high temperature catalytic oxidation with chemiluminescent detection) in mg N/L	Total Dissolved Phosphorus (by persulfate digestion followed by automated colorimetric analysis) in ug P/L	Silica [automated colorimetric analysis (molybdate blue)] in mg SiO2/L	Dissolved Organic Nitrogen [by difference (TDN - NO3-N - NH4-N)] in mg N/L	Total Suspended Sediments in mg/L
UNIT	milligramsPerLiter	milligramsPerLiter	milligramsPerLiter	milligramsPerLiter	milligramsPerLiter	milligramsPerLiter
PRECISION	10%	10%	10%	10%	10%	10%
RANGE OR LIST OF VALUES
DATA TYPE	decimal	decimal	decimal	decimal	decimal	decimal
MISSING DATA CODES

COMPUTATIONAL METHODS:

Variable Name	Formula

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FOR DATA MANAGER USE ONLY

DATE OF LAST REVIEW: May 29, 2009
DATE OF LAST ENTRY : 2007
STAGE OF DATA SET MANAGEMENT (dates) :
RECEIVED ENTERED: April, 1997
FILED ON-LINE 4/29/97
REVIEWED BY RESEARCHER: 4/29/97
FILING MEDIA :
NAME OF DOCUMENTATION FILE : LTERDB20.FM*
NAME OF ON - LINE CATALOG : LTERDBAS
RECORD # : 20
DOCUMENT TYPE : magnetic media and hardcopies
PRIORITY TO BE ENTERED : fist