Abstract
Historical climate change and human exploitation are thought to have played important roles in shaping population dynamics of sub-Antarctic marine predators, such as king penguins (Aptenodytes patagonicus) and Antarctic fur seals (Arctocephalus gazelle). For example, Antarctic fur seals on the sub-Antarctic South Georgia Island were nearly hunted to extinction by humans before the early 1900s. However, records of occupation history pre- and post-anthropogenic stress are often sporadic and challenging to interpret. In this study, we investigated paleoecological proxies in sediment cores from South Georgia Island to examine past marine predator population dynamics in the face of climate change and exploitation pressure. Sediment cores representing 1854 CE to present were collected from two sites on South Georgia Island in the South Atlantic and analyzed for geochemical (total carbon, total nitrogen, δ13C and δ15N values) and biological (e.g., seal hairs, penguin feathers) proxies. Proxies in both cores indicated the onset of the recovery of penguin and fur seal populations in the early to mid-1900s, following the cessation of hunting. Additionally, our results suggest marked increases in both penguin and seal populations beginning around 1950 CE. Between the 1950s and 2019, 97% of South Georgia Island’s glaciers retreated associated with recent climatic warming. This warming increased the availability of local breeding areas for king penguins, which likely explains the population rise during that time. This study deepens our understanding of the response of sub-Antarctic marine predator populations to past climate change and human exploitation, which may aid in predicting future ecosystem responses to environmental disturbance.
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Data availability
The data that support the findings of this study are openly available in the U.S. Antarctic Program Data Center at: https://doi.org/10.15784/601509
References
Adhikari PL, Maiti K, Overton EB, Rosenheim BE, Marx BD (2016) Distributions and accumulation rates of polycyclic aromatic hydrocarbons in the northern Gulf of Mexico sediments. Environ Pollut 212:413–423
Atkinson A, Hill SL, Pakhomov EA, Siegel V, Reiss CS, Loeb VJ, Sailley SF (2019) Krill (Euphausia superba) distribution contracts southward during rapid regional warming. Nat Clim Change 9(2):142–147
Barsanti M, Garcia-Tenorio R, Schirone A, Rozmaric M, Ruiz-Fernández AC, Sanchez-Cabeza JA et al (2020) Challenges and limitations of the 210Pb sediment dating method: results from an IAEA modelling interlaboratory comparison exercise. Quat Geochronol 59:101093
Basberg BL (2002) A ship ashore? Organisation and living conditions at South Georgia whaling stations, 1904–1960. Int J Marit Hist 14(1):93–113
Bonner WN (1968) The fur seal of South Georgia. The British Antarctic Survey, London
Carneiro LM, do Rosário Zucchi M, de Jesus TB, da Silva Júnior JB, Hadlich GM (2021) δ13C, δ15N and TOC/TN as indicators of the origin of organic matter in sediment samples from the estuary of a tropical river. Mar Pollut Bull 172:112857
Chen Y, Shen L, Huang T, Chu Z, Xie Z (2020) Transformation of sulfur species in lake sediments at Ardley Island and Fildes Peninsula, King George Island. Antarctic Peninsula Sci Total Environ 703:135591
Cook AJ, Poncet S, Cooper APR, Herbert DJ, Christie D (2010) Glacier retreat on South Georgia and implications for the spread of rats. Antarct Sci 22(3):255–263
Doidge DW, Croxall JP (1985) Diet and energy budget of the Antarctic fur seal, Arctocephalus gazella, at South Georgia. Antarctic nutrient cycles and food webs. Springer, Berlin, pp 543–550
Foley CM, Lynch HJ (2020) A method to estimate pre-exploitation population size. Conserv Biol 34(1):0256–0265
Foley CM, Hart T, Lynch HJ (2018) King Penguin populations increase on South Georgia but explanations remain elusive. Polar Biol 41(6):1111–1122
Foley CM, Fagan WF, Lynch HJ (2020) Correcting for within-season demographic turnover to estimate the island-wide population of King Penguins (Aptenodytes patagonicus) on South Georgia. Polar Biol 43(3):1–12
Forcada J, Trathan PN, Reid K, Murphy EJ (2005) The effects of global climate variability in pup production of Antarctic fur seals. Ecology 86(9):2408–2417
Gao X, Yang Y, Wang C (2012) Geochemistry of organic carbon and nitrogen in surface sediments of coastal Bohai Bay inferred from their ratios and stable isotopic signatures. Mar Pollut Bull 64(6):1148–1155
Gillespie R, Gillespie RG, Clague DA (2009) Encyclopedia of islands (No. 2). University of California Press, California
Gordon JE, Haynes VM, Hubbard A (2008) Recent glacier changes and climate trends on South Georgia. Global Planet Change 60(1–2):72–84
Hamley KM, Gill JL, Krasinski KE, Groff DV, Hall BL, Sandweiss DH, Lowell TV (2021) Evidence of prehistoric human activity in the Falkland Islands. Sci Adv 7(44):eabh3803
Headland RK and the Government of South Georgia Island (n.d.). “Whaling Stations” https://www.gov.gs/heritage-2/whaling-stations/. Accessed March 2021
Hobson KA, Piatt JF, Pitocchelli J (1994) Using stable isotopes to determine seabird trophic relationships. J Anim Ecol 63(4):786–798
Hodgson DA, Johnston NM (1997) Inferring seal populations from lake sediments. Nature 387(6628):30–31
Hodgson DA, Johnston NM, Caulkett AP, Jones VJ (1998) Palaeolimnology of Antarctic fur seal Arctocephalus gazella populations and implications for Antarctic management. Biol Conserv 83(2):145–154
Huang T, Sun LJ, Wang Y, Cheng Z, Yang Q, Sun S (2011) Relative changes in krill abundance inferred from Antarctic fur seal. PLoS ONE 6(11):e27331
Huang T, Sun L, Wang Y, Chu Z, Qin X, Yang L (2014) Transport of nutrients and contaminants from ocean to island by emperor penguins from Amanda Bay, East Antarctic. Sci Total Environ 468:578–583
Hunt GL, Heinemann D, Everson I (1992) Distributions and predator-prey interactions of macaroni penguins, Antarctic fur seals, and Antarctic krill near Bird Island, South Georgia. Mar Ecol Prog Ser 86:15–30
Jia J, Yang Y, Cai T, Gao J, Xia X, Li Y, Gao S (2018) On the sediment age estimated by 210Pb dating: probably misleading “prolonging” and multiple-factor-caused “loss”. Acta Oceanol Sin 37(6):30–39
Laws RM (1977) Seals and whales of the Southern Ocean. Phil Trans R Soc B 279:81–96
Le Bohec C, Durant JM, Gauthier-Clerc M, Stenseth NC, Park YH, Pradel R, Le Maho Y (2008) King penguin population threatened by Southern Ocean warming. PNAS 105(7):2493–2497
Liu X, Sun L, Xie Z, Yin X, Wang Y (2005) A 1300-year record of penguin populations at Ardley Island in the Antarctic, as deduced from the geochemical data in the ornithogenic lake sediments. Arct Antarct Alp Res 37(4):490–498
Liu X, Nie Y, Sun L, Emslie SD (2013) Eco-environmental implications of elemental and carbon isotope distributions in ornithogenic sediments from the Ross Sea region, Antarctica. Geochim Cosmochim Acta 117:99–114
Maiti K, Carroll J, Benitez-Nelson CR (2010) Sedimentation and particle dynamics in the seasonal ice zone of the Barents Sea. J Mar Syst 79(1–2):185–198
Meyers PA (1997) Organic geochemical proxies of paleoceanographic, paleolimnologic, and paleoclimatic processes. Org Geochem 27(5–6):213–250
NASA (2008) “South Georgia Island”, https://www.nasa.gov/. Accessed Sept 2019
Nie Y, Liu X, Sun L, Emslie SD (2012) Effect of penguin and seal excrement on mercury distribution in sediments from the Ross Sea region, East Antarctica. Sci Total Environ 433:132–140
Olsson O (1997) Diet of the king penguin Aptenodytes patagonicus during three summers at South Georgia. Ibis 139(3):504–512
Payne MR (1977) Growth of a fur seal population. Philos Trans Royal Soc London. B Biol Sci 279(963):67–79
Reid K, Arnould JP (1996) The diet of Antarctic fur sealsArctocephalus gazella during the breeding season at South Georgia. Polar Biol 16(2):105–114
Saito Y, Nishimura A, Matsumoto E (1989) Transgressive sand sheet covering the shelf and upper slope off Sendai. Northeast Jpn Mar Geol 89(3–4):245–258
Sanders S (2006) Important bird areas in the United Kingdom overseas territories. Royal Society for the Protection of Birds, Sandy
SCAR (2008) Scientific Committee for Antarctic Research, Expert Group on Seals Report. https://www.seals.scar.org/pdf/statusofstocs.pdf
Simpson GL (2018) Modelling palaeoecological time series using generalised additive models. Front Ecol Evol 6:149
Smith J (1960) Glacier problems in South Georgia. J Glaciol 3(28):705–714
Sun L, Xie Z, Zhao J (2000) A 3,000-year record of penguin populations. Nature 407(6806):858–858
Sun L, Liu X, Yin X, Zhu R, Xie Z, Wang Y (2004) A 1,500-year record of Antarctic seal populations in response to climate change. Polar Biol 27(8):495–501
Trathan PN, Reid K (2009) Exploitation of the marine ecosystem in the sub-Antarctic: historical impacts and current consequences. Pap Proc R Soc Tas 143(1):9–14
Trathan PN, Forcada J, Murphy EJ (2007) Environmental forcing and Southern Ocean marine predator populations: effects of climate change and variability. Philos Trans R Soc London, Ser B 362(1488):2351–2365
Trivelpiece WZ, Hinke JT, Miller AK, Reiss CS, Trivelpiece SG, Watters GM (2011) Variability in krill biomass links harvesting and climate warming to penguin population changes in Antarctica. PNAS 108(18):7625–7628
Wang P, D’Imperio L, Biersma EM, Ranniku R, Xu W, Tian Q et al (2020) Combined effects of glacial retreat and penguin activity on soil greenhouse gas fluxes on South Georgia, sub-Antarctica. Sci Total Environ 718:135255
Weddell J (1825) A voyage towards the South Pole, per-formed in the years 1822–24. London, Longman, Hurst, Rees, Orme, Brown, and Green, London UK
Wood SN (2011) Fast stable restricted maximum likelihood and marginal likelihood estimation of semiparametric generalized linear models. J R Stat Soc B 73(1):3–36
Xie Z, Sun L (2008) A 1,800-year record of arsenic concentration in the penguin dropping sediment. Antarctic Environ Geol 55(5):1055–1059
Acknowledgements
This research was funded by the National Science Foundation (Grant Nos. 1443585 and 1826712) to M. Polito and K. McMahon. The 210Pb dating was carried out by LSU Shell endowment fund to K. Maiti. Thank you to the Government of South Georgia & the South Sandwich Islands, J. Lee, T. Hart, Quark Expeditions, and the staff and crew of the Ocean Endeavour for permitting and logistical assistance on South Georgia Island. Thank you to H. Bennadji and P.O. Clower for assistance with elemental analysis, stable isotope analysis, and radiometric dating. Thank you to C. Foley and H. Lynch for insights into king penguin population counts and for their thoughtful review of this manuscript. Thank you also to A. Herrmann for helpful feedback on an earlier version of this manuscript.
Funding
This research was funded by the Office of Polar Programs (OPP) National Science Foundation Grant Nos. 1443585 and 1826712. M. J. Polito and K. W. McMahon.
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MJP, KWM, and AKK conceived and designed research. MJP and KWM collected samples. AKK and KM conducted experiments. MJP and KM contributed analytical tools. AKK and MAD analyzed data. AKK and MJP wrote the initial draft of the manuscript. All authors revised and approved the manuscript.
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Kristan, A.K., Maiti, K., McMahon, K.W. et al. Biological and geochemical proxies in sediment cores reveal shifts in marine predator population dynamics relative to historic anthropogenic exploitation and recent climate change at South Georgia Island sub-Antarctic. Polar Biol 45, 1379–1389 (2022). https://doi.org/10.1007/s00300-022-03067-8
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DOI: https://doi.org/10.1007/s00300-022-03067-8
Keywords
- Antarctic fur seal
- Climate change
- Glacial retreat
- King penguin
- Paleoecology
- Stable isotopes