Plum Island Ecosystems LTER Database

Acceptance and utilization of LTER data requires that:

(1) The Principal Investigator be sent a notice stating reasons for acquiring any data and a description of the publication intentions.
(2) The Principal Investigator of the data set be sent a copy of the report or manuscript prior to submission and be adequately cited in any resultant publications.
(3) A copy of any resultant publications should be sent to:

Principal Investigator
Ecosystems Center
Marine Biological Laboratory
7 MBL St.
Woods Hole, MA 02543

Dataset URLs:METADATA: HTML, Rich Text, XML(EML compliant)
DATA: Comma Delimited, Excel file with Metadata and data
Dataset ID:HTL-EST-Clam-growth.01
Dataset Title:Age and annual growth of clams (Mya arenaria) during 2010 to 2011 in the Plum Island Sound estuary, Newbury, Rowley and Ipswich, MA.
Investigator 1: 
First Name:Chuck
Last Name:Hopkinson
Address line 1:University of Georgia
Address line 2:229 Marine Sciences
Address line 3:
City:Athens
State:GA
Zip Code:30602
Country:USA
Associate Investigators:Kyung-Ah Koo, Emily Davenport
Keywords:LTER, PIE, Plum Island Ecosystems, population dynamics, softshell clam growth
Abstract:Age and annual growth of soft shell clams (Mya arenaria) were estimated using internal growth lines . The accuracy of these estimates was assessed by comparing them to a d18O analysis of shell carbonate at six sites in the Plum Island Sound estuary
Contact: Plum Island Ecosystems LTER Information Manager
The Ecosystems Center
Marine Biological Lab
7 MBL St
Woods Hole, MA 02543
Phone (508) 289 7485
Email: pie_im@mbl.edu
Online URL: http://pie-lter.ecosystems.mbl.edu
DATA FILE INFORMATION:
Data File URL http://ecosystems.mbl.edu/PIE/data/HTL/data/HTL-EST-Clam-growth.csv
Data File Name HTL-EST-Clam-growth
Beginning Date 5/1/2010
End Date 4/1/2011
Number of Data Records 290
Other Files to Reference HTL-EST-Clam-densitysediment, HTL-EST-Clam-chlorophyll, HTL-EST-Clam-isotopes, HTL-EST-Clam-lengthweight
Availability Status Type 1
Quality Control Information
Maintenance Description Data complete for 2011
Log of Changes: Version 01: September 29, 2015, data and metadata created to comply with importation to Drupal and LTER PASTA. Used MarcrosExportEML_HTML (working)pie_excel2007_Jan2015.xlsm 1/15/15 4:26 PM for QA/QC to EML 2.1.0
 
RESEARCH LOCATION: HTL-PR-RR-Clams HTL-SO-GF-Clams HTL-SO-TL-Clams HTL-SO-IB-Clams HTL-RO-Clubmouth-Clams HTL-RO-Sweeneymouth-Clams  
Geographic Description Site of clam surveys near railroad bridge on Parker River, Newbury, MA Site of clam surveys, alias "Grandkids Flat", southeast of Cape Merrill in Plum Island Sound, Newbury, MA Site of clam surveys, Third Creek, south of Roger Island River, Plum Island Sound, Ipswich, MA. Site of clam surveys, Ipswich Bluff flats, east of Ipswich Bay Yacht Club, Plum Island, Ipswich, MA. Site of clam surveys, mouth of Clubhead Creek, off Rowley River, Rowley, MA Site of clam surveys, mouth of Sweeney Creek, off Rowley River, Ipswich, MA  
Location Bounding Box              
West Bounding Coordinate              
East Bounding Coordinate              
North Bounding Coordinate              
South Bounding Coordinate              
OR if single point location              
Latitude 42.760367 42.7483 42.7518 42.70875 42.732018 42.727844  
Longitude -70.86325 -70.810983 -70.81635 -70.7859 -70.83836 -70.84776  
Elevation              
               
               
 
TAXONOMIC COVERAGE:
Taxonomic Protocols
Organisms studied Mya arenaria
 
Methods:Six sampling sites were selected along the flanks of the lower 14 km of the estuary where clams were found.
Approximately 20 clam shells =10 cm with obvious external growth lines and patterns were selected at each site in total for internal growth line analyses , and two shells from each site were selected for the oxygen stable isotope analyses (del18O).

One valve of each clam shell was used for delineation of internal growth lines and the other valve was then used to transcribe internal lines onto the shell surface in order to estimate size for each year of growth. For internal growth line analysis, the valves were first embedded in epoxy resin (to prevent shell fracture during sectioning . The valves were sectioned from the umbo to the ventral margin using a rock saw .The cross-sectional surface was ground with 240, 320 and 600 abrasive papers and polished using a Buehler Grinder-Polisher . We periodically observed the cross-section under a microscope during the grinding-polishing process and continued the process until the internal growth lines became apparent. Annual growth lines were identified, marked and counted under the microscope .The internal growth lines were transcribed onto the shell surface of the matching valve and then shell length was measured for each year of age . Shell length was measured as the maximum distance across the shell surface, typically perpendicular to the cross-sectional cut The measurements were made to the nearest 0.01mm using digital vernier calipers.

For oxygen stable isotope analysis, we collected sequential shell-carbonate samples from two shells from each site (total twelve shells). Two to five samples were collected between presumed growth lines and on the growth lines by grinding a strip approximately 1 cm long by 1 mm of shell width with 0.5 to 1 mm intervals between samples from the ventral margin to umbo . The samples were ground with a dremel. When grinding the shell, the entire shell from inner surface outwards was collected, as opposed to only layers corresponding to specific times when new shell material was laid down. Therefore each sample from shell edge to chondricle included growth from all prior years in addition to new group, blending seasonal data. Prior to analysis, we cleaned the shell surface and the inner shell layer several times to remove organic matter. The samples were muffled in a muffle furnace for 1 h at 380° C to further remove organic contaminants. Collected grindings were powdered in a mortar and pestle, and stored in sample vials for submission to an isotope analysis laboratory (Colorado Plateau Stable Isotope Laboratory at Northern Arizona University.)

Data Table

Variable Name Variable Description Units Measurement Scale Code Information Number Type DateTime Format Missing Value Code Missing Value Code Explanation
Date_range Date range that clams were sampled in   nominal       NA NA = not available
Station_ID Name of sampling station   nominal       NA NA = not available
Clam_ID Name of individual clam sampled   nominal       NA NA = not available
Latitude Latitude of sampling station (decimal degrees) degree ratio   real   NA NA = not available
Longitude Longitude of sampling station (decimal degrees) degree ratio   real   NA NA = not available
Size_Year1 Size of first year internal growth ring millimeter ratio   real   NA NA = not available
Size_Year2 Size of second year internal growth ring millimeter ratio   real   NA NA = not available
Size_Year3 Size of third year internal growth ring millimeter ratio   real   NA NA = not available
Size_Year4 Size of fourth year internal growth ring millimeter ratio   real   NA NA = not available
Size_Year5 Size of fifth year internal growth ring millimeter ratio   real   NA NA = not available
Size_Year6 Size of sixth year internal growth ring millimeter ratio   real   NA NA = not available
Size_Year7 Size of seventh year internal growth ring millimeter ratio   real   NA NA = not available
Size_Year8 Size of eighth year internal growth ring millimeter ratio   real   NA NA = not available
d18O measure of the ratio of stable isotopes 18O:16O in clam shell growth rings partPerThousand ratio   real   NA NA = not available
d13C measure of the ratio of stable isotopes 13C:12C in clam shell growth rings partPerThousand ratio   real   NA NA = not available
Ventral_margin_distance Distance from the ventral margin millimeter ratio   real   NA NA = not available
Annual_growth Annual growth ring evident   nominal       NA NA = not available
Season Type of ring- indicating winter dormancy or growing season   nominal       NA NA = not available