We quantified larval fingerprints during spawning at each of the potential source populations to develop a reference map that will allow us to assign settled mussels to natal sites based on the elemental fingerprints of their larval shell. To develop a reference map of elemental signatures, we reared larvae in situ at each major mussel population (see sample locations data). After populations spawned in the field (based on our monitoring of gonad indices in each population) adult mussels from multiple sites were collected, spawned in the laboratory and the eggs fertilized. Within 24-48 hours (before shell formation begins) larvae were placed into small chambers and moored in situ at 3-5m depth. Because spawning varied among the populations, we staggered our deployment of larvae to coincide with our estimates of spawning times. After four weeks, larval mussels were removed from in situ chambers, shells were rinsed in deionized water, dried and prepared for ICPMS. Settlers were collected from settlement plates deployed at each population.
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Elemental concentrations were determined from single spot ablation in larval shells (85% energy, 10 hz, 200 shots, 25 \u03bcm spot diameter) for both larvae and settlers. Elemental compositions were quantified by external calibration (USGS MACS-3) and internal standardization. We quantified elemental compositions from count per second (cps) measurements of 24Mg, 55Mn, 59Co, 88Sr, 138Ba, 139La, 208Pb and 46Ca using laser ablation inductively coupled mass spectrometry (213 Nd:YAG laser coupled with Elan DRC II ICPMS) at the University of Massachusetts, Boston (LA-ICPMS). Elemental abundances were calculated as analyte cps/ 43Ca cps. We performed a one-point calibration using gas blank and MACS-3, and ran MACS-1 as a check standard every ten samples. Analytical accuracy and precision based on repeated check standard analyses was 96 + 4.4% (mean + sd). Each sample was analyzed in triplicate and mean concentrations normalized to calcium are reported.
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Location:
\nGulf of Maine: Frenchmen Bay (44 28.239 N -68 15.927 W) to Machais Bay (44 39.350 N -67 21.320 W).
This dataset includes elemental fingerprints of larval, juvenile, and settler Mytilus collected in the Gulf of Maine between 2015 and 2017.\u00a0
Trace element concentrations relative to Ca (\u03bcmol element / mol Ca) were quantified using GeoPro(TM) software (Cetac Technologies). Concentrations were log transformed (log10 + 1), outliers were removed (identified as mean + 2*sd).
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BCO-DMO Data Manager Processing Notes:
\n* added a conventional header with dataset name, PI name, version date
\n* modified parameter names to conform with BCO-DMO naming conventions
\n* replaced character "\uff8d" with an apostrophe in site name "Bailey\uff8ds Island"
\n* Removed directionals from decimal degrees (negative longitudes are West; negative latitudes are South)
\n* Commas in location names changed to semicolons to support export as csv through the JGOFS system.
\n* Rounded lat/lons to 5 decimal places from 7.
\n* After communication with data submitter, Age value "Larval" changed to "Larvae" to be consistent with other values in the Age column. "Settlers" also changed to "Settler" to match other values of "Settler."
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Data version 2 replaces data version 1:
\n* Data from 2017 added.
\n* 2017 data submitted as an excel file exported to csv.
\n* Date format changed to ISO yyyy-mm-dd
\n* " N" and " W" removed from decimal degrees. (It is accurately negative for W, positive for N)
\n* Date and lat/lon ranges updated in metadata text and geospatio-temporal bounds