Sources of primary production to Arctic bivalves identified using amino acid stable carbon isotope fingerprinting^*

* Originally presented at the 11th International Conference on the Applications of Stable Isotope Techniques to Ecological Studies (IsoEcol 2018), 30 July–3 August 2018, Universidad Andrés Bello, Viña del Mar, Chile.

ABSTRACT

Benthic invertebrates are a crucial trophic link in Arctic marine food webs. However, estimates of the contribution of different primary production sources sustaining these organisms are not well characterised. We measured the stable carbon isotope values (δ¹³C) of essential amino acids (EAAs) in muscle tissue from two common bivalve genera (Macoma spp. and Astarte spp.) collected in Hanna Shoal in the northeastern Chukchi Sea. Mixing models comparing the δ¹³C_EAA fingerprints of the bivalves to a suite of primary production endmembers revealed relatively high contributions of EAAs from phytoplankton and bacteria in both species. We also examined whether δ¹³C_EAA fingerprints could be produced from the EAAs preserved in bivalve shells, which could allow primary production sources to be estimated from ancient bivalve shells. The δ¹³C_EAA fingerprints from a suite of paired modern bivalve shells and muscle from Macoma calcarea from across the Chukchi Sea revealed a correspondence between the estimates of the dominant primary production source of EAAs derived from analyses of these two tissue types. Our findings indicate that δ¹³C_EAA fingerprinting of marine bivalves can be used to examine dominant organic matter sources in the Arctic marine benthos in recent years as well as in deeper time.

KEYWORDS:

• Benthos
• bivalves
• carbon-13
• Chukchi Sea
• compound-specific stable isotope analysis
• essential amino acid (EAA)
• Hanna Shoal
• isotope ecology
• mixing model

Acknowledgments

We thank Dr. Kenneth Dunton for supplying our project with benthic invertebrate samples from the Hanna Shoal. We thank Tim Howe and Norma Haubenstock for assistance in the laboratory. We thank Dr. Hajo Eiken, Ann-Christine Zinkann (both UAF) and Warren Horowitz (BOEM) for discussions that benefited this research effort.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Audrey G. Rowe http://orcid.org/0000-0002-5275-4504

Notes

* Originally presented at the 11th International Conference on the Applications of Stable Isotope Techniques to Ecological Studies (IsoEcol 2018), 30 July–3 August 2018, Universidad Andrés Bello, Viña del Mar, Chile.

Additional information

Funding

Funding was provided by the Coastal Marine Institute (CMI) and Bureau of Ocean Energy Management (BOEM) (Cooperative Agreement number M16AC00005).