Gulf-Wide comparison of Thalassia testudinum demographics, morphology, flowering rates, and physiological responses to short-term shading (2010)

Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator:
Dauphin Island Sea Lab's Marines Ecosystem Lab
Publication_Date:
Unpublished material
Title:
Gulf-Wide comparison of Thalassia testudinum demographics, morphology, flowering rates, and physiological responses to short-term shading (2010)
Description:
Abstract:
This project will examine and compare phenotypic expressions and responses to light stress of genetically isolated Thalassia testudinum populations in three major regions of seagrass habitat in the Gulf of Mexico: Florida Keys, Florida panhandle, and Corpus Christi Bay, TX. I will examine population demographics such as average shoot age, average growth rate, and average flowering rate with comparisons among the three areas previously mentioned. I will also compare morphologies of T. testudinum from these genetically distinct populations and examine the relationship between phenotypic expression and local environmental conditions, such as temperature, salinity, and light availability. To determine any relationships between genetic response to changes in light quality and geographic location of a population, a short term shading experiment will be conducted in situ using light extinctions of 0, 45, and 90% of surface irradiance. This novel experiment is essential for understanding the tightly interwoven relationships between seagrass physiology and the surrounding abiotic environmental factors.
Purpose:
Gulf-Wide comparison of Thalassia testudinum demographics, morphology, and physiological responses to a short term shading experiment
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date:
20100322
Ending_Date:
20100722
Currentness_Reference:
ground condition
Status:
Progress:
In work
Maintenance_and_Update_Frequency:
As needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate:
-97.1
East_Bounding_Coordinate:
-80.8
North_Bounding_Coordinate:
30.3
South_Bounding_Coordinate:
24.8
Keywords:
Theme:
Theme_Keyword_Thesaurus:
None
Theme_Keyword:
Thalassia testudinum
Theme_Keyword:
turtle grass
Theme_Keyword:
seagrass
Theme_Keyword:
demographics
Theme_Keyword:
morphology
Theme_Keyword:
biomass
Theme_Keyword:
flowering rate
Theme_Keyword:
shading
Theme_Keyword:
adaptability
Theme_Keyword:
physiological response
Theme_Keyword:
structural plasticity
Theme_Keyword:
comparison
Theme:
Theme_Keyword_Thesaurus:
ISO Topic
Theme_Keyword:
biota
Theme_Keyword:
002
Theme_Keyword:
environment
Theme_Keyword:
007
Theme_Keyword:
oceans
Theme_Keyword:
014
Place:
Place_Keyword_Thesaurus:
None
Place_Keyword:
Gulf of Mexico
Place_Keyword:
GOM
Place_Keyword:
Florida Keys National Marine Sanctuary
Place_Keyword:
FKNMS
Place_Keyword:
Florida Bay
Place_Keyword:
Gulf Islands National Seashore
Place_Keyword:
Pensacola Bay
Place_Keyword:
Florida
Place_Keyword:
East Flats
Place_Keyword:
Corpus Christi Bay
Place_Keyword:
Texas
Place_Keyword:
Big Lagoon
Access_Constraints:
Permission to access these data must be given by Dr. Just Cebrian or Ashley McDonald.
Use_Constraints:
Acknowledgment of the DISL: Marine Ecosystems Lab and would be appreciated in products developed from these data, and such acknowledgment as is standard for citation and legal practices for data source is expected by users of these data. Users should be aware that comparison with other data sets for the same area from other time periods may be inaccurate due to inconsistencies resulting from changes in mapping conventions, data collection, and computer processes over time. The distributor shall not be liable for improper or incorrect use of these data, based on the description of appropriate/inappropriate uses described in the metadata document. These data are not legal documents and are not to be used as such.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person:
Just Cebrian or Ashley McDonald
Contact_Organization:
DISL: Marine Ecosystems Lab
Contact_Position:
Principal Investigator
Contact_Address:
Address_Type:
mailing and physical
Address:
101 Bienville Blvd.
City:
Dauphin Island
State_or_Province:
Al
Postal_Code:
36528
Country:
USA
Contact_Voice_Telephone:
251-861-2141 ext. 7564
Contact_Electronic_Mail_Address:
jcebrian@disl.org
Contact_Electronic_Mail_Address:
amcdonald@disl.org
Hours_of_Service:
8-5:00 CST
Contact_Instructions:
Please email either Dr. Just Cebrian or Ashley McDonald for further information.
Data_Set_Credit:
Dr. James Fourqurean Dr. Ken Dunton Bart Christiaen
Native_Data_Set_Environment:
Microsoft Excel
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Data_Quality_Information:
Logical_Consistency_Report:
Not applicable.
Completeness_Report:
No major lapses in data collection have occurred.
Lineage:
Process_Step:
Process_Description:
Initial environmental and biomass measurements will be taken at each site before shading structures are placed in the seagrass meadows. Environmental measurements will include: light attenuation of the water column using a LiCOR model Li-1400 datalogger with spherical bulbs, canopy and bottom depth, temperature, and salinity. Historical environmental data (such as light, temperature, and salinity) will be assembled from data gathering sites near the vicinity of my T. testudinum collection sites. These sites are: For Long Key, FL – Site 241 of the Seagrass Status and Trends Monitoring site at 24° 48.187’ N and 80° 48.614’ W in collaboration with James Fourqurean, Ph.D from the Florida International University. For East Flats, TX I will be using unpublished data from the collection site at 27° 49’ N and 97° 7’ W in collaboration with Ken Dunton, Ph.D from the University of Texas at Austin Marine Science Institute. For Big Lagoon, FL I will be using unpublished data from a long term study nearby the experimental site at 30° 18’ N and 87° 24’ W in collaboration with Bart Christiaen, Ph.D candidate at the Dauphin Island Ecosystems Lab. Initial biomass measurements will be made from some 300 shoots from each site replicate through random destructive sampling techniques. From these, I will determine seasonal vertical rhizome growth rates, horizontal rhizome growth rates, population demographics, and community age structure by measuring plastochrone intervals (PIs) of vertical rhizomes following the procedures set by Duarte et al. (1994). Using a micrometer to measure the distance between plastochrones (the PI), I will then plot the distance measurements against the number of the plastochrone to determine seasonal cycles (an example can be seen in Figure 2). From this plot I can visually determine the seasonal cycles of growth, translate these growth cycles into years, and from this determine the age of the shoot inspected. After measuring PIs for 30 of the oldest shoots from each population, I can estimate the number of leaves produced in one year for that population and use this information to estimate the age of the remaining sample shoots by counting plastochrones. Frozen samples will be brought back to the Dauphin Island Ecosystems lab for leaf morphology measurements. I will measure leaf width and length for some 300 shoots from each replicate site to determine the overall population averages. I will also use a micrometer to measure leaf thickness for 30 shoots from each site replicate to determine population average. Samples will also be shipped back frozen to the Dauphin Island Ecosystems Lab for chlorophyll and carbon: nitrogen analyses. Chlorophyll content and a/b ratios will be done by cutting 5 cm sections from the leaves (excluding 1 cm from both ends), and finely chopping the leaf sections and placing the pieces into a N,N-Dimethylformamide (DMF) solution, following the procedures set by Porra et al. (1989). This solution will then be allowed to soak for a period of two weeks until all pigments are extracted, and then an absorption spectrum will be measured at wavelengths of 663.8 & 646.8 nm. Chlorophyll a and b concentrations will then be determined using the following equations: Chl-a:12.00(A663.8) – 3.11(A646.8) Chl-b:20.78(A646.8) – 4.88(A663.8) Carbon: nitrogen ratios will be determined by first drying the aboveground and belowground portions of seagrass material for a period of 24 hours, then pulverizing the samples into a powder, followed by weighing out 1-2 mg of powder into sample tins. The analysis will be run by placing the samples into the Costech ECS analyzer at the Dauphin Island Sea Lab to determine the total nitrogen and carbon present in the samples by high temperature combustion of all inorganic and organic carbon and nitrogen to N2 and CO. The resulting gases are separated in a chromatographic column and measured using a thermal conductivity detector, following techniques set by Sharp (1974). Epiphyte coverage will be measured as the amount of biomass per area of 30 shoots from each replicate site. I will use a surgical razor to carefully scrape off all epiphytes covering the shoot and then the epiphytes will be placed into a drying oven to later be measured as dry weight. I will then measure the dry weight, length, and width of the leaves scraped to determine area of coverage. Average flowering frequency will also be measured by visually inspecting vertical rhizomes for previous flower scars, then using age reconstruction techniques to determine the year and season of flowering. I can then use the historical environmental data to examine the conditions up to 2 – 3 months prior to flowering to see if there are any correlations between physical conditions and floral initiation. Because T. testudinum is dioecious, I will also determine the sex of the flowers by visual examination of scars. From this information I can determine frequency of flowering of the two sexes. For the light limitation study, shading structures will be placed within the natural meadows, approximately 10cm above canopy height (Figure 3). There will be 10 shades per site constructed of PVC and vinyl coated fiberglass mesh insect screen with an 18 x 14 mesh size. Five screens will be set to extinguish 90% of surface irradiance (SI), 5 shades at 45% SI and 5 control structures with no shading for a total of 15 structures per site. Each major area will be broken up into two sampling sites each for replication, giving a total of 30 structures per major Gulf of Mexico region sampled. After the two week period, all samples will be collected, rinsed with fresh water, and immediately frozen. Morphology measurements including leaf length, width, and thickness will be done at the Dauphin Island Ecosystems Lab. These measurements will be averaged and compared between all treatments and controls using an ANOVA program. Ten shoots within the experimental shading area will be specifically chosen for the growth rate analysis. These shoots will be marked with fluorescent flagging tape and leaves of young mature shoots ( > 1 year old) and older will be hole punched directly above the oldest leaf’s sheath and growth rate determination will be done following the techniques set by Vermeer and Hunte (2008) two weeks after the onset of experimental shading. After initial setup for Long Key and East flats, all remaining environmental measurements including site maintenance (which includes cleaning screens of epiphytes), light measurements, and sample collecting will be conducted by collaborating institutions. I will also measure chlorophyll content and chlorophyll a/b ratios of the two treatments and controls for all sites and replicates. Chlorophyll will be analyzed using the same techniques as described above for the initial population comparison. Results will be averaged and compared between and among populations using an ANOVA. Soluble carbohydrate content analyses will be conducted for each shaded site replicate by affiliates at the Florida International University using frozen horizontal rhizome sections that total 10cm and were previously dried for two days at 50°C. These sections will be processed by grinding into a fine powder and soluble carbohydrates will be extracted by hot (80°C) ethanol and concentrations will be determined by the spectrophotometric resorcinol assay.
Process_Date:
Not complete
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person:
Just Cebrian or Ashley McDonald
Contact_Organization:
DISL: Marine Ecosystems Lab
Contact_Position:
Principal Investigator
Contact_Address:
Address_Type:
mailing and physical
Address:
101 Bienville Blvd.
City:
Dauphin Island
State_or_Province:
Al
Postal_Code:
36528
Country:
USA
Contact_Voice_Telephone:
251-861-2141 ext.7564
Contact_Electronic_Mail_Address:
jcebrian@disl.org
Contact_Electronic_Mail_Address:
amcdonald@disl.org
Hours_of_Service:
8-5:00 CST
Contact_Instructions:
Please email Dr. Just Cebrian or Ashley McDonald for further information.
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Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
Excel tables cataloging data in the following categories: morphometrics, age reconstruction, epiphyte and chlorophyll content.
Entity_and_Attribute_Detail_Citation:
Morphometric data contains the following attributes: horizontal rhizome number, shoot position, internodal distance (cm), vertical rhizome length (cm), vertical rhizome width (base), vertical rhizome width (mid), number of nodes, number of primords per shoot, primord length (cm), leaf position, sheath length (cm), blade length (cm), blade width (cm), herbivory (yes/no), flowering (yes/no).
Entity_and_Attribute_Detail_Citation:
Age reconstruction data contains the following attributes: internode number, internode distance, flower scars.
Entity_and_Attribute_Detail_Citation:
Epiphyte and chlorophyll content data contains the following attributes: shoot ID, shoot number, epiphyte biomass (gDW), shoot biomass (gDW), leaf thickness, shoot ID, chlorophyll a:b.
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Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person:
Just Cebrian or Ashley McDonald
Contact_Organization:
DISL: Marine Ecosystems Lab
Contact_Position:
Principal Investigator
Contact_Address:
Address_Type:
mailing and physical
Address:
101 Bienville Blvd.
City:
Dauphin Island
State_or_Province:
Al
Postal_Code:
36528
Country:
USA
Contact_Voice_Telephone:
251-861-2141 ext. 7564
Contact_Electronic_Mail_Address:
jcebrian@disl.org
Contact_Electronic_Mail_Address:
amcdonald@disl.org
Hours_of_Service:
8-5:00 CST
Contact_Instructions:
Please email either Dr. Just Cebrian or Ashley McDonald for further information.
Distribution_Liability:
The Dauphin Island Sea Lab's Marine Ecosystems Lab makes no warranty regarding these data, expressed or implied, nor does the fact of distribution constitute such a warranty. The DISL: Marine Ecosystems Lab cannot assume liability for any damages caused by any errors or omissions in these data, nor as a result of the failure of these data to function on a particular system.
Technical_Prerequisites:
Data sets were created using Microsoft Excel. A program capable of reading Excel files is necessary to view these data.
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Metadata_Reference_Information:
Metadata_Date:
201008
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:
Dauphin Island Sea Lab
Contact_Person:
Data Management Specialist
Contact_Position:
Data Management Specialist
Contact_Address:
Address_Type:
mailing and physical
Address:
101 Bienville Blvd.
City:
Dauphin Island
State_or_Province:
Al
Postal_Code:
36528
Country:
USA
Contact_Voice_Telephone:
251-861-2141
Contact_Electronic_Mail_Address:
metadata@disl.org
Hours_of_Service:
8-5:00 CST
Contact_Instructions:
Please email the metadata specialist for further information.
Metadata_Standard_Name:
FGDC Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version:
FGDC-STD-001-1998
Metadata_Access_Constraints:
none
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