Data (part) from Penk 2005 MSc thesis

Data (part) from:
Penk MR (2005) Investigation into the food sources of the cockle (Cerastoderma edule) in Dublin Bay: multiple stable isotopes approach. MSc thesis. Centre for the Environment, University of Dublin, Trinity College, Ireland
Sample preparation:
Cerastoderma edule (Linnaeus, 1758) were frozen directly upon collection. They were thawed and processed within two months of collection. Adductor muscle tissues were extracted, rinsed with Milli Q water and acidified in 10% HCl to remove any shell remains. They were than rinsed twice with Milli Q water and dried for 24 hrs at 60°C. Dried samples were crushed using mortar and pestle, placed in plastic 10 ml tubes and retained for analysis.

Sediment samples were dried at 60°C rinsed with Milli Q water and sieved through a 63 μm sieve using a soft paintbrush. Particles obtained after sieving (<63 μm) were placed in the oven at 60°C to evaporate all water. Dry particles were placed in glass beakers. Samples were then acidified by adding 10% HCl (at approximately five times sample volume) to remove carbonates. Beakers were than placed on a warm place to evaporate all acid. Dry sediment samples were than rinsed by adding Milli Q water to the beakers (five times the sample volume) and the beakers placed on a warm plate until dry. Rinsing was repeated three times to remove acid residues by evaporation. Dry samples were then crushed using a mortar and pestle, placed in plastic tubes and retained for analysis.
Sample processing:
Samples were weighed into microanalytical capsules on a Sartorius MC5 microanalytical balance. Samples were than analyzed on 18 August 2005 for stable isotopes of C and N ratios using a Thermo Delta Plus continuous flow isotope ratio mass spectrometer (CF-IRMS) coupled to a CE Instruments 1112 Flash elemental analyser (EA) by a Conflo III interface. Results were obtained in relation to international standards (atmospheric nitrogen and carbon from PeeDee Belemnite) and presented as standard delta connotations Additionally, %N, %C as well as C:N ratio values have been obtained. The precision of the elemental analyser has been established on L-Alanine standard samples (for Δ13C: 0.82‰, for Δ15: 0.21‰).