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Florida Bay and Biscayne Bay pollen data

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Frequently-anticipated questions:

What does this data set describe?

Title: Florida Bay and Biscayne Bay pollen data
Abstract:
This project developed, refined, and utilized a variety of proxies to provide estimates of seasonal, interannual, and decadal salinity history of Florida Bay and Biscayne Bay based on strategically placed sediment cores that aided in the validation and sensitivity testing of hydrologic models and decision making in water management. The datasets contain the pollen information at various depths in the cores.
  1. How should this data set be cited?

    Willard, Debra, 2006, Florida Bay and Biscayne Bay pollen data.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -80.62
    East_Bounding_Coordinate: -80
    North_Bounding_Coordinate: 25.26
    South_Bounding_Coordinate: 25

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 26-Feb-1994
    Ending_Date: 01-Nov-1996
    Currentness_Reference: ground condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: spreadsheet

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      Indirect_Spatial_Reference: Florida Bay and Biscayne Bay
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (5)

    2. What coordinate system is used to represent geographic features?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.01. Longitudes are given to the nearest 0.01. Latitude and longitude values are specified in Degrees and decimal minutes.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    The pollen data are listed by species and depth in the core. See the individual datasets for the species found at each site. Pollen sums are based on abundance of all identifiable taxa.
    Entity_and_Attribute_Detail_Citation: USGS personnel

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    Debra Willard
    U.S. Geological Survey
    Project Chief
    926A National Center
    Reston, VA 20192
    USA

    703 648-5320 (voice)
    703 648-6953 (FAX)
    dwillard@usgs.gov

Why was the data set created?

Terrestrial ecosystems of south Florida have undergone numerous human disturbances, ranging from alteration of hydroperiod, fire history, and drainage patterns from the introduction of the canal system to expansion of agricultural activity to the introduction of exotic species, Over historical time, dramatic changes in the ecosystem have been documented and these changes have been attributed to various human activities. However, the natural variability of the ecosystem was unknown and needed to be determined to assess the true impact of human activity on the modern ecosystem. The project was designed to document historical changes in the terrestrial ecosystem quantitatively, to date any changes and determine whether they resulted form documented human activities, and to establish the baseline level of variability on the south Florida ecosystem to estimate whether the observed changes are greater than would occur naturally.

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    Date: 1997 (process 1 of 3)
    Coring Procedure Long cores (>1 m in length), were taken in >30 cm of water through the "moon pool" of a motorized 25 ft pontoon barge either grounded on the bank or anchored with 4 anchors. The location was established by GPS. A portable 12 ft high tripod was placed over the moon pool to hold the coring piston and for extraction of the core. Cores were taken with 10.8 cm-diameter, clear, FDA food grade polycarbonate tubing. A PVC piston with two O-ring seals was used. The piston was pushed into the bottom of the core tube to a position several cm above the bottom of the tube. A 10 m length of .25 cm diameter braided polypropylene line, attached to a ring threaded into the top of the piston, was pulled through the core tube. The core tube was then carefully lowered through the moon pool and any air trapped in the space between piston and the bottom of the core tube was removed and filled with water. When the tube was several cm above the bottom the free end of line attached to the piston was affixed to the head of the tripod. Thus when the core tube penetrates the sediment the piston remains in a fixed position a few cm above the sediment surface producing a vacuum that retards compaction. When the apparatus was set in positions the core tube was quickly thrust about 30 cm into the sediment by hand. Next, an aluminum clamp with handles was fixed to the core tube and two people then forced the core barrel in until it reached the underlying Pleistocene limestone. Next the clamp with handles was removed and a clamp with lifting rings was attached near the air/water interface. A cable through a pulley at the top of the tripod and attached to a hand winch mounted on one leg of the tripod was attached to the lifting ring on the clamp. The cable winch was necessary for extraction due to the weight of the core and strong suction created by the mud. Before extraction, the polypropylene line was removed from the tripod and fixed to the extraction clamp. This was to ensure that the piston remained in a fixed position during extraction and to retard loss of sediment from the bottom of the barrel. A benefit of the clear core tubing was that any leakage around the piston's O-ring seal could be readily observed during the extraction process. A person in the water wearing a face mask observed the core tube to be certain no sediment was lost at the sediment/water interface, to record any elevation difference between the sediment surface inside and outside the core at full penetration, and to quickly place a plastic pipe cap on the bottom of the core as it emerged from the sediment. The core was winched above the surface of the moon pool and lowered to rest vertically on deck. The pipe cap was taped tightly to the tube to prevent leakage. Excess tubing was cut off just below the piston using a large pipe cutter so the piston could be carefully removed without disturbing the sediment surface. In some cases the water above the sediment was carefully siphoned off with a tube to prevent sloshing of water during transport to the laboratory which would disturb the sediment surface. In other cases the piston was left in the core tube during transport. All cores were transported vertically. Each evening cores were transported vertically to a local hospital where X-ray photographs were prepared.

    The cores were selected for analysis based on the x-rays. Those cores selected for further analysis were selected on the basis of laminations or other features which indicated the lack of disturbance. The core was placed in an extruding device vertically. The core was then extruded up into a template and sliced. This slice (hockey puck) was placed on a preweighed titanium plate and the wet weight determined. The ring was then removed and the slice was trimmed to remove the outer portion of the core. This was done to prevent any contamination that may have occurred at the side of the core barrel during the coring operation. This sample was then bagged and weighed. This weight was found to be important in the determination of water content and thus the dry weigh as water was lost during the period of initial sampling and the laboratory analysis. These sample were then stored in a refrigerator and then transhipped to the home based laboratory. For those core selected for trace metal analysis, the slices were sampled from the center of the "hockey puck" with titanium tools and place in an acid washed plastic bottle and frozen.

    Approximately 50 short cores were planned to be collected for analysis of flora, faunal, and charcoal abundances. The cores were dated using 210Pb and 14C. Additionally, pollen, plant macrofossils, and invertebrate faunas were analyzed from surface samples. These samples were collected from sites throughout the region to maximize representation of modern plant communities. The resulting data provided the basis for comparison with down-core assemblages to determine how much change in vegetational distribution has occurred.

    Date: 1997 (process 2 of 3)
    Age models for the last century of deposition are based on lead-210 (210Pb) and, where applicable, first occurrences of pollen of the exotic plant Casuarina, which was introduced to south Florida in the late 19th century (Langeland 1990). Lead-210 activity was measured by alpha spectroscopy using the method outlined in Flynn (1968) in which 210Pb and its progeny, polonium-210 (210Po), are assumed to be in secular equilibrium. Supported 210Pb activity was determined by continuing measurements until activity became constant with depth. Excess 210Pb activity was calculated by subtracting the supported 210Pb activity from the total 210Pb activity. Accumulation rates were calculated by fitting an exponential decay curve to the measured data using least-squares optimization and making the assumptions of a constant initial excess lead-210 concentration (the constant initial concentration [CIC] model).

    Date: 2000 (process 3 of 3)
    Approximately 0.5 - 1.0 g of dry sediment was used for palynological analysis. Pollen and spores were isolated from these samples using standard palynological techniques (Traverse 1988). After drying and weighing samples, Lycopodium marker tablets with known concentrations of Lycopodium spores were added to approx. 0.5 g of sediment for calculation of absolute pollen concentrations (Stockmarr 1971). The samples were first acetolyzed (9 parts acetic anhydride : 1 part sulfuric acid) in a hot-water bath (100 deg. C) for 10 min, then neutralized and treated with 10% KOH in a hot-water bath for 15 min. Neutralized samples were sieved with 10-micron and 200-micron sieves, and the 10 - 200 lm fraction was stained with Bismarck Brown, mixed with warm glycerin jelly, and mounted on microscope slides. Raw data for pollen samples are reposited in the North American Pollen Database (NAPD) at the World Data Center for Paleoclimatology in Boulder, Colorado, USA, and at the US Geological Survey South Florida Information Access (SOFIA) site.

    Pollen and spore identification (minimally 300 grains per sample) was based on reference collections of the U.S. Geological Survey (Reston, Virginia). Pollen sums were based on abundance of all identifiable taxa. The interpretations of past plant communities are based on the quantitative method of modern analogues (Overpeck et al. 1985). The squared chord distance (SCD) between down-core pollen assemblages and a suite of 197 surface samples collected throughout southern Florida in the early 1960s and 1995 to define the similarity between each fossil and modern pollen assemblage. Internal comparison among surface samples from 10 vegetation types indicates that samples with SCD values approx. 0.15 may be considered close analogues (Willard et al. 2001). If analogues were present for a fossil assemblage, the source vegetation for the fossil assemblage was identified as one of the 12 types represented in the modern database. Cores were divided into pollen zones based on a combination of visual inspection, objective zonation using CONISS (Grimm 1992), and modern analogues.

    Person who carried out this activity:

    Debra A Willard
    U.S. Geological Survey
    926A National Center
    Reston, VA 20192

    703 648 5320 (voice)
    703 648 6953 (FAX)
    dwillard@usgs.gov

  3. What similar or related data should the user be aware of?

    Willard, Debra A. Weimer, Lisa M., 1997, Palynological Census Data from Surface Samples in South Florida: USGS Open-File Report 97-0867, U.S. Geological Survey, Reston, VA.

    Online Links:

    Willard, Debra A. Bernhardt, Christopher E.; , 2004, Atlas of Pollen and Spores of the Florida Everglades: Palynology 28, American Association of Stratigraphic Palynologists, Arlington, TX.

    Online Links:

    Other_Citation_Details:
    Posted with permission from Palynology and the American Association of Stratigraphic Palynologists
    Willard, Debra A. Weimer, Lisa M.; Riegel, W., 2001, Pollen assemblages as paleoenvironmrntal proxies in the Florida Everglades: Review of Palaeobotany and Palynology v. 113 n. 4, Elsevier Science B.V., Amsterdam, Netherlands.

    Stuvier, M. Reimer, P. J.; Bard, E.; Beck, , 1998, INTCAL98 radiocarbon age calibration, 24,000-0 cal BP: Radiocarbon v. 40, n. 3, University of Arizona, Tucson, AZ.

    Online Links:

    Grimm, E. C., 1992, CONISS: a Fortran 77 program for stratigraphically constrained cluster analysis by the mothod of incremental sum of squares: Computers & Geosciences v. 13, issue 1, Elsevier Science, Ltd., Amsterdam, Netherlands.

    Online Links:

    Other_Citation_Details:
    The abstract may be viewed online at the Science Direct website. The full article is available for purchase from the Science Direct website.
    Traverse, A., 1988, Paleopalynology: Unwin Hyman, Boston, MA.

    Stockmarr, J., 1971, Tablets with spores used in absolute pollen analysis: Pollen et Spores v. 13, Museum national d'histoire naturelle, Paris, France.

    Overpeck, J. T. Webb, III, T.; Prentice, I., 1985, Quantative interpretation of fossil pollen spectra: Dissimilarity coefficients and the method of modern analogs: Quaternary Research v 23, issue 1, Elsevier Science, Ltd., Amsterdam, Netherlands.

    Online Links:

    Other_Citation_Details:
    The abstract may be viewed online at the Science Direct website. The full article is available for purchase from the Science Direct website.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    not available

  5. How consistent are the relationships among the observations, including topology?

    not available

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: none
Use_Constraints: none

  1. Who distributes the data set? (Distributor 1 of 1)

    Heather S.Henkel
    U.S. Geological Survey
    600 Fourth St. South
    St. Petersburg, FL 33701
    USA

    727 803-8747 ext 3028 (voice)
    727 803-2030 (FAX)
    hhenkel@usgs.gov

  2. What's the catalog number I need to order this data set?

    FL and Biscayne Bays Pollen Data

  3. What legal disclaimers am I supposed to read?

    The data have no implied or explicit guarantees

  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 16-Jan-2008
Metadata author:
Heather Henkel
U.S. Geological Survey
600 Fourth Street South
St. Petersburg, FL 33701
USA

727 803-8747 ext 3028 (voice)
727 803-2030 (FAX)
sofia-metadata@usgs.gov

Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <http://sofia.usgs.gov/metadata/sflwww/fb_bb_pollen_data.faq.html>

U.S. Department of the Interior, U.S. Geological Survey
Comments and suggestions? Contact: Heather Henkel - Webmaster
Generated by mp version 2.8.18 on Wed Jan 16 16:41:40 2008