dissociation of this excited state, producing radicals, or by the formation of a diol radical after
reaction of an excited-state fatty acid with an
Because fatty acid–covered surfaces are ubiquitous, the photochemical production of gas-phase
unsaturated and functionalized compounds will
affect the local oxidative capacity of the atmosphere and will lead to secondary aerosol formation. This interfacial photochemistry may exert
a very large impact, especially if in general the
mere presence of a surface layer of a carboxylic
acid can trigger this interfacial photochemistry
at ocean surfaces, cloud droplets, and the surface of evanescent aerosol particles.
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This study was supported by the European Research Council (ERC)
under the European Union’s Seventh Framework Program
(FP/2007-2013)/ERC Grant Agreement 290852–AIRSEA. D.J.D.
acknowledges ongoing support from the Natural Sciences and
Engineering Research Council of Canada. The authors are grateful
to P. Mascunan and N. Cristin for the ICP-MS analysis and
N. Charbonnel and S. Perrier for the technical support provided by
IRCELYON. All the data presented here can be downloaded from
the supplementary materials.
Materials and Methods
Figs. S1 to S6
Tables S1 to S3
29 January 2016; accepted 23 June 2016
Eye lens radiocarbon reveals centuries
of longevity in the Greenland shark
Julius Nielsen,1,2,3,4 Rasmus B. Hedeholm,2 Jan Heinemeier,5 Peter G. Bushnell,6
Jørgen S. Christiansen,4 Jesper Olsen,5 Christopher Bronk Ramsey,7 Richard W. Brill,8,9
Malene Simon,10 Kirstine F. Steffensen,1 John F. Steffensen1
The Greenland shark (Somniosus microcephalus), an iconic species of the Arctic Seas,
grows slowly and reaches >500 centimeters (cm) in total length, suggesting a life
span well beyond those of other vertebrates. Radiocarbon dating of eye lens nuclei
from 28 female Greenland sharks (81 to 502 cm in total length) revealed a life
span of at least 272 years. Only the smallest sharks (220 cm or less) showed
signs of the radiocarbon bomb pulse, a time marker of the early 1960s. The age
ranges of prebomb sharks (reported as midpoint and extent of the 95.4%
probability range) revealed the age at sexual maturity to be at least 156 ± 22 years, and the
largest animal (502 cm) to be 392 ± 120 years old. Our results show that the Greenland
shark is the longest-lived vertebrate known, and they raise concerns about
The Greenland shark (Squaliformes, Som- niosus microcephalus) is widely distributed in the North Atlantic, with a vertical dis- tribution ranging from the surface to at least 1816-m depth (1, 2). Females outgrow
males, and adults typically measure 400 to 500 cm,
making this shark species the largest fish native to arctic waters. Because reported annual
growth is ≤1 cm (3), their longevity is likely to
be exceptional. In general, the biology of the
Greenland shark is poorly understood, and longevity and age at first reproduction are completely unknown. The species is categorized as
“Data Deficient” in the Norwegian Red List (4).
Conventional growth zone chronologies can-
not be used to age Greenland sharks because of
their lack of calcified tissues (5). To circumvent
this problem, we estimated the age from a chro-
nology obtained from eye lens nuclei by apply-
ing radiocarbon dating techniques. In vertebrates,
the eye lens nucleus is composed of metabol-
ically inert crystalline proteins, which in the cen-
ter (i.e., the embryonic nucleus) is formed during
prenatal development (6, 7). This tissue retains
proteins synthetized at approximately age 0: a
unique feature of the eye lens that has been
exploited for other difficult-to-age vertebrates
(6, 8, 9).
Our shark chronology was constructed from
measurements of isotopes in the eye lens nuclei from 28 female specimens (81 to 502 cm
total length, table S1) collected during scientific surveys in Greenland during 2010–2013
(fig. S1) (see supplementary materials). We used
radiocarbon (14C) levels [reported as percent of
modern carbon (pMC)] to estimate ages and
stable isotopes, 13C and 15N (table S1), to evaluate the carbon source (supplementary materials).
Depleted d13C and enriched d15N levels established that the embryonic nucleus radiocarbon
source was of dietary origin and represents a
high trophic level. In other words, isotope signatures are dictated by the diet of the shark’s
mother, not the sampled animals. We set the
terminal date for our analyses to 2012, because
samples were collected over a 3-year period.
The chronology presumes that size and age are
Since the mid-1950s, bomb–produced radiocarbon from atmospheric tests of thermonuclear
weapons has been assimilated in the marine
environment, creating a distinct “bomb pulse”
in carbon-based chronologies (10). The period of
rapid radiocarbon increase is a well-established
time stamp for age validation of marine animals
(11–14). Radiocarbon chronologies of dietary origin (reflecting the food web) and chronologies
reflecting dissolved inorganic radiocarbon of
surface mixed and deeper waters, have shown
that the timing of the bomb pulse onset (i.e., when
1Marine Biological Section, University of Copenhagen,
Strandpromenaden 5, 3000 Helsingør, Denmark. 2Greenland
Institute of Natural Resources, Post Office Box 570, Kivioq 2,
3900 Nuuk, Greenland. 3Den Blå Planet, National Aquarium
Denmark, Jacob Fortlingsvej 1, 2770 Kastrup, Denmark.
4Department of Arctic and Marine Biology, Ui T The Arctic
University of Norway, 9037 Tromsø, Norway. 5Aarhus AMS
Centre, Department of Physics and Astronomy, Aarhus
University, Ny Munkegade 120, 8000 Aarhus, Denmark.
6Department of Biological Sciences, Indiana University South
Bend, 1700 Mishawaka Avenue, South Bend, IN, USA.
7Oxford Radiocarbon Accelerator Unit, University of Oxford,
Dyson Perrins Building, South Parks Road, Oxford OX1 3QY,
UK. 8National Oceanic and Atmospheric Administration,
National Marine Fisheries Service, Northeast Fisheries
Science Center, James J. Howard Marine Sciences
Laboratory, 74 Magruder Road, Highlands, NJ 07732, USA.
9Virginia Institute of Marine Science, Post Office Box 1346,
Gloucester Point, VA 23062, USA. 10Greenland Climate
Research Centre, Greenland Institute of Natural Resources,
Post Office Box 570, Kivioq 2, 3900 Nuuk, Greenland.
*Corresponding author. Email: email@example.com