Hyperspectral imaging of sedimentary bacterial pigments: a 1700-year history of meromixis from varved Lake Jaczno, northeast Poland
- 454 Downloads
Hypoxia in freshwater systems is currently spreading globally and putting water quality, biodiversity and other ecosystem services at risk. Such adverse effects are of particular concern in permanently stratified meromictic lakes. Yet little is known about when and how meromixis and hypoxia became established (or vanished) prior to anthropogenic impacts, or how human activities such as deforestation, erosion and nutrient cycling affected the mixing regimes of lakes. We used calibrated hyperspectral imaging (HSI) data in the visible and near infrared range from a fresh, varved sediment core taken in Lake Jaczno, NE Poland, to map sedimentary pigments at very high resolution (sub-varve scale) over the past 1700 years. HSI-inferred bacteriopheophytin a (bphe a, produced by anoxygenic phototrophic bacteria) serves as a proxy for meromixis, whereas HSI-inferred green pigments (chlorophyll a and diagenetic products) can be used as estimators of aquatic productivity. Meromixis was established and vanished long before significant human disturbance in the catchment was observed in the late eleventh century AD. Under pre-anthropogenic conditions, however, meromixis was interrupted frequently, and the lake mixing regime flickered between dimixis and meromixis. During two periods with intense deforestation and soil erosion in the catchment, characterised by sedimentary facies rich in clay and charcoal (AD 1070–1255 and AD 1670–1710), the lake was mostly dimictic and better oxygenated than in periods with relative stability and a presumably closed forest around the lake, i.e. without human disturbances. After ca. AD 1960, meromixis became established quasi-permanently as a result of eutrophication. The persistent meromixis of the last ~60 years is unusual with respect to the record of the last 1700 years.
KeywordsBacteriopheophytin a Chlorophyll a Holocene Anthropocene 14C AMS gas ion source
This research was funded by the Swiss Contribution to the enlarged European Union CLIMPOL Project (PSRP-086/2010) and Swiss National Science Foundation Grant 200020-134945/1. Sönke Szidat performed the 14C gas ion source measurements at the LARA AMS Laboratory, University of Bern. CB performed all HSI analyses. CB, WT, Alicja Bonk, Małgorzata Kinder counted the varves. CB and MG designed the study and wrote the paper. All authors discussed and commented on the manuscript. We thank the following people for their help and contribution to this paper: Anna Poraj-Górska, Alicja Bonk, Małgorzata Kinder, Janusz Filipiak, Daniela Fischer, Tobias Schneider and Pascal Küpfer. We also thank both reviewers and the Editor for their thoughtful suggestions and careful editorial work.
- Amann B, Lobsiger S, Fischer D, Tylmann W, Bonk A, Filipiak J, Grosjean M (2014) Spring temperature variability and eutrophication history inferred from sedimentary pigments in the varved sediments of Lake Żabińskie, north-eastern Poland, AD 1907–2008. Global Planet Change 123:86–96CrossRefGoogle Scholar
- Balsam WL, Deaton BC (1991) Sediment dispersal in the Atlantic Ocean: evaluation by visible light spectra. Rev Aquat Sci 4:411–447Google Scholar
- Jenny J-P, Normandeau A, Francus P, Taranu ZE, Gregory-Eaves I, Lapointe F, Jautzy J, Ojala AE, Dorioz J-M, Schimmelmann A, Zolitschka, B (2016b) Urban point sources of nutrients were the leading cause for the historical spread of hypoxia across European lakes. Proc Nat Acad Sci 113(45):12655–12660CrossRefGoogle Scholar
- Krzywicki T (2002) The maximum ice sheet limit of the Vistulian Glaciation in northeastern Polandand neighbouring areas. Geol Q 46:165–188Google Scholar
- Lichtenthaler HK, Buschmann C (2001) Chlorophylls and carotenoids: measurement and characterization by UV–VIS spectroscopy. In: Wrolstad RE (ed) Current protocols in food analytical chemistry. Wiley, New York, pp F4.3.1–F4.3.8Google Scholar
- Mix AC, Rugh W, Pisias NG, Veirs S (1992) Color reflectance spectroscopy: a tool for rapid characterization of deep-sea sediments. In: Mayer L, Pisias N, Janecek T (eds) Proceedings ODP initial report on Integrated Ocean Drilling Program (IODP), College Station, pp 67–77Google Scholar
- R Development Core Team (2015) R: a language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Reimer PJ, Bard E, Bayliss A, Beck JW, Blackwell PG, Bronk Ramsey C, Buck CE, Cheng H, Edwards RL, Friedrich M, Grootes PM, Guilderson TP, Haflidason H, Hajdas I, Hatté C, Heaton TJ, Hoffmann DL, Hogg AG, Hughen KA, Kaiser KF, Kromer B, Manning SW, Niu M, Reimer RW, Richards DA, Scott EM, Southon JR, Staff RA, Turney CSM, van der Plicht J (2013) IntCal13 and Marine13 radiocarbon age calibration curves 0–50,000 years cal BP. Radiocarbon 55:1869–1887CrossRefGoogle Scholar
- Wacnik A, Tylmann W, Bonk A, Goslar T, Enters D, Meyer-Jacob C, Grosjean M (2016) Determining the responses of vegetation to natural processes and human impacts in north-eastern Poland during the last millennium: combined pollen, geochemical and historical data. Veg Hist Archaeobot 25:479–498CrossRefGoogle Scholar