Ann Bucklin

Professor Emeritus of Marine Sciences

My research focus is the molecular ecology and evolution of zooplankton.  I have used diverse molecular approaches to study the population genetics / genomics, phylogeography, biodiversity, and evolution of marine holozooplankton, especially copepods and euphausiids. See

Reference databases for DNA sequences:  A long-term goal is completion of taxonomically-complete and geographically-extensive databases including DNA sequences for specimens of marine zooplankton identified by taxonomic experts. The Census of Marine Zooplankton (CMarZ; was an international collaboration during 2004-2010 with a primary goal of determining DNA barcode sequences, including mitochondrial cytochrome oxidase I (COI), for specimens of marine zooplankton identified by taxonomic experts. My efforts toward the goal of global reference databases for zooplankton for multiple gene regions has continued through my leadership of an international SCOR Working Group, MetaZooGene (WG157,

Metabarcoding Zooplankton Biodiversity: We are analyzing zooplankton samples by metabarcoding, which entails High-Throughput Sequencing of selected marker genes (COI and hypervariable regions of 18S rRNA) for DNA extracted from zooplankton samples. The overarching goal of these efforts is to ensure that metabarcoding will be increasingly viewed as a reliable, accurate, rapid and cost-effective methodology for analysis of species diversity of pelagic ecosystems and applications for ecosystem assessment and detection of impacts of climate change.

Food Web Dynamics in the Deep Ocean: Another important focus is biodiversity and food web dynamics of the deep ocean. We are collaborating with scientists and engineers from Woods Hole Oceanographic Institution on a project called the Ocean Twilight Zone (OTZ, see Research cruises have collected from mesopelagic depth zones (1,000 – 4,000 m) and yielded samples reflecting biodiversity across the pelagic assemblage. Ongoing analysis of these samples is providing new clues about many unknown and never-before-seen inhabitants of these dark regions, far below the surface. We are focusing on food web dynamics and are using DNA metabarcoding analysis of gut contents of mesopelagic fishes and salps.  We will test for prey selection and diet preferences by comparing the diversity of gut contents of different species with the surrounding waters.

For more information about my research interests with a summary over the longer term, see

Research Projects

Molecular (metabarcoding) detection of invasive marine zooplankton species in the Gulf of Maine. Co-P.I.s Ann Bucklin & Paola Batta-Lona (UConn Marine Sciences). Marine Biological Laboratory, Plum Island Ecosystems LTER (P.I. Anne Giblin, MBL)

The Ocean Twilight Zone. Woods Hole Oceanographic Institution (Audacious Project): Lead PI H. Sosik (WHOI)

MetaZooGene: Toward a new global view of marine zooplankton biodiversity based on DNA metabarcoding and reference DNA sequence databases (SCOR Working Group 157). Scientific Committee for Ocean Research. See and

Recent Research Group Members and Visitors

– Paola Batta-Lona (Postdoctoral Fellow, 2018 – 2021) Now Research Assistant Professor, UConn Marine Sciences, Email

– Melissa Wojcicki (M.S. Student, 2018 – 2021) Email

– Marta Carreton (Visiting Ph.D. Student, 2019) Institute of Marine Sciences (ICM-CSIC), Barcelona, Spain; Email

– Hayley DeHart (Research Technician, 2015 – 2018) Now at Johns Hopkins University; Email

– Heidi D. Yeh (M.S. Student, 2016-2018). Now at Rutgers University; Email

– Jennifer Questel (Postdoctoral Fellow, 2016-2017). Now at University of Alaska Fairbanks; Email

– Birgitte Nilsson (Visiting Graduate Student, 2016-2017, Roskilde University, Denmark) Email

Courses taught @ UConn

Techniques in Marine Molecular Biology (MARN 3015/5015)  Molecular approaches include analysis of DNA and RNA variation using diverse technologies and platforms; genomics and transcriptomics; differential gene expression; population genetics and phylogenetics. Laboratory training in molecular protocols and procedures, with access to state-of-the-art molecular and bioinformatics facilities at UConn. Applications include analysis of marine biodiversity from microbes to mammals, adaptation and evolution of marine organisms, and topics selected by students. (UConn – Avery Point, Fall 2022)

Seminar in Marine Biodiversity and Conservation (MARN 3812/ 5812) Co-taught with Dr. Tracy Romano. Presentations from guest experts and class discussions allow critical examination of state-of-the-art research, policy and regulatory frameworks of marine conservation biology and associated environmental, cultural, and socio-economic implications. (UConn & Mystic Aquarium; Spring 2021)

Marine Biology (MARN 3014) This course seeks to provide understanding of and appreciation for the diversity of marine life and the fundamental characteristics of marine environments. An important focus of the course is marine conservation biology, with guest lectures by Mystic Aquarium experts. (UConn – Avery Point; Spring 2022).  See

Oceanography Alumni

– Melissa Wojcicki – M.S. 2021

– Heidi D. Yeh – M.S. 2018

– Kayla Erikson – M.S. 2015

– Paola Batta Lona – Ph.D. 2014

– Ebru Unal – Ph.D. 2011

– Brian Ortman – Ph.D. 2008

Honors Received

Fulbright Senior Fellowship, Institute of Marine Research, Bergen, Norway (1993-1994)

Fellow of the American Association for the Advancement of Science (Elected 1995)

Member, Connecticut Academy of Science and Engineering (Elected 2006)

International Council for Exploration of the Sea (ICES) Service Award (2017)

International Council for Exploration of the Sea (ICES) Outstanding Achievement Award (2019)

University of Connecticut Faculty Excellence in Research and Creativity-Sciences Award (2020)

Publications (2010-2023)

For full reference list, see ORCID; GoogleScholar ResearchGate


O’Brien, T.D., L. Blanco-Bercial, P.G. Batta-Lona, J.M. Questel, A. Bucklin* (In press) DNA barcode reference databases: MetaZooGene Atlas and Database. Protocols for DNA Barcoding, Methods in Molecular Biology (Springer Nature)

Bucklin, A., J.M. Questel, P.G. Batta-Lona, M. Reid, P.H. Wiebe, R.G. Campbell and C.J. Ashjian (2023) Population genetic diversity and structure of the euphausiids Thysanoessa inermis and T. raschii in the Arctic Ocean: Inferences from COI barcodes. Marine Biodiversity 53:70.

Bernhard, J.M., L. Fisher, Q. Murphy, L. Sen, H. Yeh, A. Louyakis, F. Gomaa, M. Reilly, P. Batta-Lona, A. Bucklin, V. Le Roux, and P.T. Visscher (2023) Transition from stromatolite to thrombolite fabric: Role for reticulopodial protists in lake microbialites of a Proterozoic ecosystem analog? Frontiers in Microbiology 14:1210781.

Castellano, K.R., P.G. Batta-Lona, A. Bucklin, and R.J. O’Neill (2023) Salpa genome and developmental transcriptome analyses reveal molecular flexibility enabling reproductive success in a rapidly changing environment. Scientific Reports 13: 21056.


Bucklin, A., Batta-Lona, P.G., Questel, J.M., Wiebe, P.H., Richardson, D.E., Copley, N.J. and O’Brien, T.D. (2022) COI metabarcoding of zooplankton species diversity for time-series monitoring of the NW Atlantic continental shelf. Front. Mar. Sci. 9:867893.


Bucklin, A., K.T.C.A. Peijnenburg, K.N. Kosobokova, T.D. O’Brien, L. Blanco-Bercial, A. Cornils, T. Falkenhaug, R.R. Hopcroft, A. Hosia, S. Laakmann, C. Li, L. Martell, J.M. Questel, D. Wall-Palmer, M. Wang, P.H. Wiebe, A. Weydmann-Zwolicka (2021) Toward a global reference database of COI barcodes for marine zooplankton. Marine Biology 168 (78).

Bucklin, A., J.M. Questel, L. Blanco-Bercial, S.B. Smolenack, A. Frenzel, and P.H. Wiebe (2021) Population connectivity of the euphausiid, Stylocheiron elongatum, in the Gulf Stream (NW Atlantic Ocean) in relation to COI barcode diversity of Stylocheiron species. ICES Journal of Marine Science.

Bucklin, A., K.T.C.A. Peijnenburg, K.N. Kosobokova, and R. Machida (2021) New insights into biodiversity, biogeography, ecology, and evolution of marine zooplankton based on molecular approaches. ICES Journal of Marine Science,

Questel, J.M., R.R. Hopcroft, H.M. DeHart, K. Kosobokova, C. Smoot, and A. Bucklin (2021) Metabarcoding analysis of zooplankton biodiversity of the Pacific-Arctic Chukchi Borderlands region.  Marine Biodiversity 51 (4).

Thorrold, S.R.; A. Adams; A. Bucklin; K. Buesseler; G. Fischer; A. Govindarajan; P. Hoagland; D. Jin; A. Lavery; J. Llopez; L. Madin; M. Omand; P.G. Renaud; H.M. Sosik; P. Wiebe; D.R. Yoerger; W. Zhang (2021) Twilight Zone Observation Network: A Distributed Observation Network for Sustained, Real-Time Interrogation of the Ocean’s Twilight Zone, Marine Technology Society Journal, 55: 92-93.


Crouch, K.E., L. Blanco-Bercial, D.E. Richardson, N.J. Copley, P.H. Wiebe, and A. Bucklin (2020) Species-specific patterns of distribution and abundance of the cryptic copepods Pseudocalanus moultoni and P. newmani on Georges Bank (NW Atlantic Ocean) 1995-2012. Cont. Shelf Research 208: 104242.

DeHart, H.M., L. Blanco-Bercial, M. Passacantando, J.M. Questel, and A. Bucklin (2020) Pathways of pelagic connectivity: Eukrohnia hamata (Chaetognatha) in Arctic Ocean. Frontiers in Marine Science.

Yeh, H.D., J.M. Questel, K. Maas, and A. Bucklin (2020) Metabarcoding analysis of prey and microbiota composition of the copepod Calanus finmarchicus in the North Atlantic Ocean. Deep-Sea Research II.


Bucklin, A., Yeh, H.D., Questel, J.M., Richardson, D.E., Reese, B., Copley, N.J., and Wiebe, P.H. (2019) Time-series metabarcoding analysis of zooplankton diversity of the NW Atlantic continental shelf. ICES Journal of Marine Science 76: 1162–1176.  doi:10.1093/icesjms/fsz021.


Bucklin, A., K. DiVito, I. Smolina, M. Choquet, J.M. Questel, G. Hoarau and R.J. O’Neill (2018) Population Genomics of Marine Zooplankton. In: Population Genomics: Marine Organisms, O.P. Rajora and M. Oleksiak (Eds.), Springer Publ.  Manuscript as submitted available at:

Bucklin, A. (2018) Scientists are using DNA to study ocean life and reveal the hidden diversity of zooplankton. The Conversation. Published online June 7, 2018;

Nilsson, B., P.M. Jepsen, A. Bucklin and B.W. Hansen (2018) Environmental stress responses of marine copepods: Evidence of experimental handling artifacts for Acartia tonsa (Dana). Frontiers Mar. Science:


Batta-Lona, P.G., A. Maas, R. O’Neill, P.H. Wiebe, and A. Bucklin. 2017. Transcriptomic profiles of spring and summer populations of the Southern Ocean salp, Salpa thompsoni, in the Western Antarctic Peninsula region. Polar Biol. 40: 1261-€“1276. doi:10.1007/s00300-016-2051-6

Choquet, M., M. Hatlebakk, A.K.S. Dhanasiri, K. Kosobokova, I. Smolina, J.E. Soreide, C. Svensen, W. Melle, S. Kwasniewski, K. Eiane, M. Daase,V. Tverberg, S. Skreslet, A. Bucklin and G. Hoarau. 2017. Genetics redraws pelagic biogeography of Calanus. Biol.  Lett. 13: 20170588.

Snelgrove, P., E. Vanden Berghe, P. Miloslavich, N. Bailly, A. Brandt, A. Bucklin, and 23 others. 2017. Global patterns in marine biodiversity (Chapter 34). In The First Global Integrated Marine Assessment: World Ocean Assessment I.  Cambridge University Press. Pp. 501-524.

Wiebe, P.H., M.C. Benfield, and A. Bucklin. 2017. Sampling, preservation, and counting of samples: ii) Zooplankton, Chapter 10: In: Marine Plankton: A Practical Guide to Ecology, Methodology, and Taxonomy. Claudia Castellani and Martin Edwards [Eds.] Oxford University Press. doi:10.1093/oso/9780199233267.001.0001


Bucklin, A., P.K. Lindeque, N. Rodriguez-Ezpeleta, A. Albaina, and M. Lehtiniemi. 2016. Metabarcoding of marine zooplankton: Progress, prospects and pitfalls.  J. Plankton Res. Horizons 38: 393-400.  doi:10.1093/plankt/fbw023

Blanco-Bercial, L. and A. Bucklin. 2016. New view of population genetics of zooplankton: RAD-seq analysis reveals population structure of the North Atlantic planktonic copepod Centropages typicus. Molec. Ecol. 25: 1566-1580  doi: 10.1111/mec.13581

Jue, N., P.G. Batta-Lona, S. Trusiak, C. Obergfell, A. Bucklin, M. O’Neill, and R.J. O’Neill. 2016. Rapid evolutionary rates and unique genomic signatures discovered in the first reference genome for the Southern Ocean salp, Salpa thompsoni (Urochordata, Thaliacea). Genome Biol. Evol. 8: 3171-3186 doi: 10.1093/gbe/evw215

Nigro, L.M., M.V. Angel, K. Blachowiak-Samolyk, R.R. Hopcroft, and A. Bucklin. 2016. Identification, discrimination, and discovery of species of marine planktonic ostracods using DNA barcodes. PLoS-One 11(1): e0146327.  doi:10.1371/journal.pone.0146327

Questel, J.M., L. Blanco-Bercial, R.R. Hopcroft, and A. Bucklin. 2016. Phylogeography and connectivity of four sibling species of Pseudocalanus (Copepoda: Calanoida) in the North Pacific and Arctic Ocean. J. Plankton Res. doi:10.1093/plankt/fbw025

Wiebe, P.H., A. Bucklin, S. Kaartvedt, A. Rostad, and L. Blanco-Bercial. 2016. Vertical distribution and migration of euphausiid species in the Red Sea. J. Plankton Res.  doi:10.1093/plankt/fbw038


Bucklin, A., D.J. McGillicuddy, P.H. Wiebe and C.S. Davis. 2015. Habitat usage by the cryptic copepods Pseudocalanus moultoni and P. newmani on Georges Bank (Northwest Atlantic). Cont. Shelf Res. 111: 83-94. doi:10.1016/j.csr.2015.11.001

Nair, V.R., F.X. Kidangan, R.G. Prabhu, A. Bucklin and S. Nair. 2015. DNA barcode of Chaetognatha from Indian Waters. Indian J. Geo-Marine Sci. 44: 1366-1376.

Vinas, M.D., L. Blanco-Bercial, A. Bucklin, H. Verheye, J. Guilherme, F. Bersano, and S. Ceballos. 2015. Phylogeography of the copepod Calanoides carinatus s.l. (Kroyer) reveals cryptic species and delimits C. carinatus s.s. distribution in SW Atlantic Ocean. J. Exp. Mar. Biol. Ecol. 468: 97-104. doi:10.1016/j.jembe.2015.03.012


Aarbakke, O.N., A. Bucklin, C. Halsband, and F. Norrbin. 2014. Comparative phylogeography and demographic history of five sibling species of Pseudocalanus (Copepoda: Calanoida) in the North Atlantic Ocean. J. Exp. Mar. Biol. Ecol. 461: 479-488. doi:10.1016/j.jembe.2014.10.006

Blanco-Bercial, L., A. Cornils, N.J. Copley, and A. Bucklin. 2014. DNA barcoding of marine copepods: assessment of analytical approaches to species identification. PLOS-Currents Tree of Life [2014 June 23]. doi: 10.1371/currents.tol.cdf8b74881f87e3b01d56b43791626d2


Christie, A.E., V. Roncalli, P. Batta-Lona, M.D. McCoole, B.L. King, A. Bucklin, D.K. Hartline, and P.H. Lenz. 2013. In silico characterization of the insect diapause-associated protein couch potato (CPO) in Calanus finmarchicus (Crustacea: Copepoda). Comp. Biochem. Physiol. Part D 8: 45-€“57. doi:10.1016/j.cbd.2012.11.002

Unal, E., A. Bucklin, P.H. Lenz, and D.W. Towle. 2013. Gene expression of the marine copepod Calanus finmarchicus: Responses to small-scale environmental variation in the Gulf of Maine (NW Atlantic Ocean). J. exp. Mar. Biol. Ecol. 446:76-85. doi:10.1016/j.jembe.2013.04.020


Cepeda, G.D., L. Blanco-Bercial, A. Bucklin, C.M. Beron, M.D. Vinas. 2012. Molecular taxonomic analysis of three species of Oithona (Copepoda, Cyclopoida) from the Argentine sector of the South Atlantic Ocean: comparative analysis using 28S rDNA. PLoS-One 7 (4): e35861. doi:10.1371/journal.pone.0035861

Kozol, R., L. Blanco-Bercial, and A. Bucklin. 2012. Lack of genetic divergence between Calanus agulhensis and C. sinicus (Copepoda; Calanoida). PLoS-One 7(10): e45710. doi:10.1371/journal.pone.0045710

Lenz, P.H., E. Unal, R.P. Hassett, C.M. Smith, A. Bucklin, A.E. Christie, and D.W. Towle. 2012. Functional genomics resources for the North Atlantic copepod, Calanus finmarchicus: EST database and physiological microarray. Comp. Biochem. Physiol. Part D, 7: 110–123. doi:10.1016/j.cbd.2011.12.001


Aarbakke, O.N.S., A. Bucklin, C. Halsband-Lenk, and M.F. Norrbin. 2011. Discovery of Pseudocalanus moultoni Frost 1989 in Northeast Atlantic waters based on mitochondrial COI sequence variation. J. Plankton Res.  33: 1487-1495. doi: 10.1093/plankt/fbr057

Batta-Lona, P.G., A. Bucklin, T. Patarnello, N.J. Copley, and P.H. Wiebe, 2011. Population genetic variation of the southern ocean krill, Euphausia superba, in the western Antarctic Peninsula region using Single Nucleotide Polymorphisms (SNPs).   Deep-Sea Res. II 58:1652-1661 doi:10.1016/j.dsr2.2010.11.017

Blanco-Bercial, L. F. Ãlvarez-Marques, and A. Bucklin. 2011. Comparative phylogeography and connectivity of sibling species of the marine copepod Clausocalanus (Calanoida). J. Exp. Mar. Biol. Ecol. 404: 108-115 doi:10.1016/j.jembe.2011.05.011

Blanco-Bercial, L., J. Bradford-Grieve, and A.Bucklin. 2011. Molecular phylogeny of Calanoida (Copepoda). Mol. Phylogen. Evol. 59: 103-€“113 [ ]

Bortolotto, E., A. Bucklin, M. Mazzavilaa, L. Zane, and T. Patarnello. 2011. Gone with the currents: lack of genetic differentiation at the circum-continental scale in the Antarctic krill Euphausia superba. BMC Genetics 12: 32  doi:10.1186/1471-2156-12-32

Bucklin, A., D. Steinke, and L. Blanco-Bercial, 2011. DNA barcoding of marine metazoa. Annual Review of Marine Science 2011, Vol. 3: 471-508 doi:10.1146/annurev-marine-120308-080950

Govindarajan, A.F., A. Bucklin, and L.P. Madin. 2011. A molecular phylogeny of the Thaliacea. J. Plankton Res. 33:843-853 doi:10.1093/plankt/fbq157


Bucklin, A., R.R. Hopcroft, K.N. Kosobokova, L.M. Nigro, B.D. Ortman, R.M. Jennings, and C.J. Sweetman. 2010. DNA barcoding of Arctic Ocean holozooplankton for species identification and recognition. Deep-Sea Res. II 57:40-48. doi:10.1016/j.dsr2.2009.08.005

Bucklin, A., S. Nishida, S. Schnack-Schiel, P.H. Wiebe, D. Lindsay, R.J. Machida, and N.J. Copley. 2010. Chapter 13. A Census of Zooplankton of the Global Ocean, In: Marine Life: Diversity, Distribution, and Abundance. A. McIntyre [Ed.], Wiley-Blackwell, Oxford. Pp. 247-265

Bucklin, A., B.D. Ortman, R.M. Jennings, L. Nigro, C.J. Sweetman, N.J. Copley, and P.H. Wiebe. 2010. A €œRosetta Stone€ for zooplankton: DNA barcode analysis of holozooplankton diversity of the Sargasso Sea (NW Atlantic Ocean). Deep-Sea Res. II 57:2234-2247. doi:10.1016/j.dsr2.2010.09.025

Grabbert, S., J. Renz, H.-J. Hirche, and A. Bucklin. 2010. Species-specific PCR (SS-PCR) discrimination of species of the calanoid copepod Pseudocalanus, P. acuspes and P. elongatus, in the Baltic and North Seas. Hydrobiologia 652:289-297. doi:10.1007/s10750-010-0360-2

Jennings, R.M., A. Bucklin, H. Ossenbrugger, and R.R. Hopcroft. 2010. Analysis of genetic diversity of planktonic gastropods from several ocean regions using DNA barcodes. Deep-Sea Research II 57:2199-2210. doi:10.1016/j.dsr2.2010.09.022

Jennings, R.M., A. Bucklin, and A.C. Pierrot-Bults. 2010. Barcoding of arrow worms (Phylum Chaetognatha) from three oceans: genetic diversity and evolution within an enigmatic phylum. PLoS-ONE. doi:10.1371/journal.pone.0009949

Ortman, B. D., A. Bucklin, F. Pages, and M. Youngbluth. 2010. DNA barcoding of the Medusozoa. Deep-Sea Res. II 57:2148-2156. doi:10.1016/j.dsr2.2010.09.017

Sutton, T.T., P.H. Wiebe, L.P. Madin and A. Bucklin. 2010. Diversity and community structure of pelagic fishes to 5000 m depth in the Sargasso Sea. Deep-Sea Res. II 57:2220-2233. doi:10.1016/j.dsr2.2010.09.024

Unal, E. and A. Bucklin. 2010. Basin-scale population genetic structure of the planktonic copepod Calanus finmarchicus in the North Atlantic Ocean. Prog. Oceanogr. 87:175-186. doi:10.1016/j.pocean.2010.09.017

Wiebe, P.H., A. Bucklin, L.P. Madin, M.V. Angel, T. Sutton, F. Pages, R.R. Hopcroft, and D. Lindsay. 2010. Deep-sea holozooplankton species diversity in the Sargasso Sea, Northwestern Atlantic Ocean. Deep-Sea Res. II 57:2157-2166. doi:10.1016/j.dsr2.2010.09.018


Contact Information