95Journal of Paleolimnology 28: 95–109, 2002.© 2002 Kluwer Academic Publishers. Printed in the Netherlands.

The paleolimnological analysis of sediments from highmountain lake NiÓÓÓÓÓné Terianske pleso in the High Tatras(Slovakia)

F. Šporka1, E. Štefková1, P. Bitušík2, A.R. Thompson3, A. Agustí-Panareda3, P.G. Appleby4, J.A. Grytnes5,C. Kamenik6, I. Krno7, A. Lami8, N. Rose9 & N.E. Shilland9

1Department of Hydrobiology, Institute of Zoology, Slovak Academy of Sciences, Dúbravská cesta 9,SK-842 06 Bratislava, Slovakia (E-mail: sporka@savba.sk; stefkova@savba.sk)2Department of Biology, Faculty of Ecology and Environmental Sciences, Technical University in Zvolen,Kolpašská 9B, SK-969 01 Banská Štiavnica, Slovakia (E-mail: bitusik@vsld.tuzvo.sk)3Department of Geology and Geophysics, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW,Scotland, UK4Department of Mathematical Sciences, University of Liverpool, P.O. Box 147, Liverpool L69 3BX, UK5Botanical Institute, University of Bergen, Allégaten 41, N-5007 Bergen, Norway6Institute of Limnology, Austrian Academy of Sciences, Gaisberg 116, 5310 Mondsee, Austria7Department of Hydrobiology, Faculty of Natural Sciences of Comenius University, Mlynská dolina B-2,SK-842 15 Bratislava, Slovakia (E-mail: krno@fns.uniba.sk)8CNR-Istituto, Italiano di Idrobiologia, Largo Tonolli, 50, 28922 Verbania-Pallanza, Italy9Environmental Change Research Centre, University College London, London WC1H 0AP, UK

Received 15 May 2000; accepted 9 January 2002

Key words: High Tatra Mountains, high mountain lake, lake sediments, diatoms, chrysophyte stomatocysts,chironomids, carbonaceous particles, plant pigments

Abstract

Sedimentological climate proxies and a 200-year long climate record, reconstructed using a data-set of European-wide meteorological data, have been compared at the high mountain lake NiÓné Terianske pleso in the High Tatras,Slovakia. Diatoms, chrysophyte stomatocysts, chironomids, plant pigments and spheroidal carbonaceous particles(SCPs) were analysed as well as sediment lithostratigraphic parameters. Using a radiometric approach the sedi-ment core was dated and a depth of 4.6 cm was found to correspond to 1852 AD. The sediment accumulation rate(0.0034 g·cm–2·yr–1) was one of the lowest identified in the European mountain lake project, MOLAR. Despite thisslow accumulation rate a remarkably coherent lithological and stratigraphic record has been recovered. The sedi-ments of this remote mountain site, largely free from the effects of direct human impact, have been found to dis-play a wealth of variability over the last 200 years.

The record of spheroidal carbonaceous particles, indicators of anthropogenic pollution deposition, begins around4.5–5.0 cm in depth (1833–1857). Temporal patterns are typical of European lake sites with the concentration peakingin the late 1970’s. The SCP/210Pb inventory ratio for the site is also in good agreement with the European latitudi-nal pattern. A strong influence of sample age on the chrysophyte assemblage composition in the upper-most 4–6 cmindicates that the main changes in the cysts have been related to long term environmental changes, probably pH.

Mountain Lake Research

MOLAR

This is the seventh of 11 papers published in this special issue on the palaeolimnology of remote mountain lakes in Europe resulting fromthe MOLAR project funded by the European Union. The guest editor was Richard W. Battarbee.

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Analysis of chironomid remains revealed a stable profundal community. Chironomids as a whole showed no cor-relations to temperature fluctuations in the last 200 years. Relatively abundant remains of Diamesa sp. head cap-sules and other taxa closely associated with stream conditions in the older layers contrast with the absence of Diamesasp. in the recent sediments. This change is considered to be evidence for the existence of a stronger, more stableinlet supplied from permanent granular snow fields in the lake basin. The most important changes in diatom as-semblages were observed at 3 cm. Many species of the genus Achnanthes spp. together with Navicula schmassmanniiand Orthoseira roeseana made up the greatest part of the diatom community above 3 cm, being absent or rare lowerin the record. A positive correlation between diatoms and mean summer temperature was found.

Introduction

European lakes situated above the natural timberlineboth in the arctic and alpine regions are considered tobe excellent indicators of environmental changes (e.g.,Fritz, 1996; Lotter et al., 1997; Barber et al., 1999).Despite their remoteness and the negligible direct hu-man impact in their catchments they are threatened byacid deposition, toxic air pollutants and by climaticchange. Lakes systems respond physically, chemicallyand biologically to changes in climate and these re-sponses are registered in a great variety of ways in lakesediment records (Battarbee, 2000).

Lake NiÓné Terianske pleso on the Slovakian side ofthe High Tatra Mountains was chosen as a study sitefor the multi-disciplinary and multi-national projectMOLAR (Mountain Lake Research) funded by the Eu-ropean Commission Framework Programme IV (En-vironment and Climate). One of main aims was tomeasure and model the temporal responses of remotemountain lake ecosystems to climate variability onseasonal inter-annual and decadal time-scales (Wathne& Rosseland, 2000). On account of the absence of long-term on-site meteorological data and lake ecosystemmonitoring, the present study used two distinct ap-proaches: (1) air temperature was reconstructed fromlong instrumental records of nearby lowland meteoro-logical stations (Agustí-Panareda & Thompson, thisissue); (2) multi-parameter sediment analyses were car-ried out. With the help of these data we analyse if thebiota of Lake NiÓné Terianske pleso have respondedto climatic trends.

Study site

Lake NiÓné Terianske pleso (49° 10′13′′N, 20° 00′54′′E)is located in the western part of the central High TatraMountains (Figure 1). It is situated in a short lateralvalley formed by local Quaternary glaciers at an alti-

tude 1941 m a.s.l. Its area is 4.8 ha; its water volumenearly 900 000 m3 while its maximum depth is 46 m(the second deepest lake in the High Tatras). The bed-rock surface consists of biotite-rich granite and tonalite.The catchment area (1.1 km2) is covered by alpine mead-ows, generally without dwarf pine, and bare rocks inroughly equal proportions. The catchment to lake sur-face area ratio is 22.9. Slopes fall steeply down to therocky lake shoreline. The lake has both an inflow andan outflow. Waterfalls flowing from the lake preventfish reaching the lake.

The lake can be classified as belonging to the alpine,non-acidified High Tatra lake group (Stuchlík et al.,1985; Krno, 1991). Climatically, this region belongs tothe Euroasian continental climatic zone (Smole± &OstroÓlík, 1991). At these altitudes of 1800 m a.s.l the

Figure 1. Location and bathymetric map of Lake NiÓn” Terianskepleso.

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mean daily temperatures in July reach +9 °C while theminimum mean temperatures fall in January to –10 °C.Characteristic for this mountain region are temperatureinversions. These occur on about 125 days per year. Themaximum precipitation is typically in the months ofJune to July and the minimum in January to April, asfor much of the eastern Alps. The mean total annualprecipitation is 1282 mm.

Methods

Coring and sampling

Four 7.4 mm (diameter) gravity Glew cores (Glew,1989) TERI96/5–TERI96/8 were taken from the deep-est area (35–46 m) and between 19.8 and 30.4 cm ofsediment was recovered (Table 1). From all cores thetop 6 cm were analysed in detail because they coverabout 200 hundred years (the time period of interest tothe MOLAR project) and because this represents thetime period for which air temperatures can be recon-structed accurately from the instrumental record.

Dating

Samples from core TERI96/7 were analysed for 210Pb,226Ra and 137Cs by direct gamma assay using OrtecHPGe GWL series well-type coaxial low background

intrinsic germanium detectors (Appleby et al., 1986).210Pb was determined via its gamma emissions at46.5 keV, and 226Ra by the 295 and 352 keW γ-raysemitted by its daughter isotope 214Pb following 3 weekstorage in sealed containers to allow radioactive equili-bration. 137Cs was measured by its emissions at 662 keV.The absolute efficiencies of the detectors were deter-mined using calibrated sources and sediment samplesof known activity. Corrections were made for the ef-fect of self-absorption of low energy γ-rays within thesample (Appleby et al., 1992).

Sediment and chemical analyses

The percentage dry weight (% DW) for each samplewas found by weighing 1–2 g of pre-homogenised wetsediment in a weighed crucible, drying the samplesovernight at 105 °C, then reweighing the crucible anddry sediment. Percentage loss-on-ignition (% LOI) wassubsequently measured by placing the crucibles anddry sediment in a muffle furnace at 550 °C for a fur-ther 3 h, cooling the samples in a desiccator and deter-mining the weight loss once again. Wet densities weremeasured for core TERI96/7 by filling a 2 cm3 weighedbrass vial with subsamples of homogenised sediment.The weights were then divided by two in order to con-vert the results to g/cm3. Carbon, nitrogen, and sulphurwere determined by a CNS analyser (NA 1500 Fisons)on weighed sub-samples of dry sediment (ca. 0.1 g)from core TERI96/6.

Table 1. Lake NiÓné Terianske pleso sediment core summary

Core code Coring date Extrusion interval No. samples Analyses made Responsible laboratory

TERI96/5 August 1996 0–30.4 cm @ 2 mm 152 DW, LOI UCLONchironomids TUFEES

TERI96/6 August 1996 0–28.4 cm @ 2 mm 142 DW, LOI UCLONC,S,N CNR-IIIpigments

TERI96/7 August 1996 0–30.0 cm @ 2 mm 150 DW, LOI UCLONdiatoms IZ SASChrysophytes ILIMNOLSCP UCLON210Pb dating ULIVmagnetics EML

TERI96/8 August 1996 0–19.8 cm @ 2 mm 99 back-up –stored wet (4 °C)

UCLON – University College London, Environmental Change Research Centre, UK; TUFEES – Technical University, Faculty of Ecologicaland Environmental Sciences Zvolen, SK; CNR – Istituto Italiano di Idrobiologia, Verbania-Pallanza, I; ULIV – University of Liverpool, En-vironmental Radiometric Centre, UK; IZ SAS – Institute of Zoology, Slovak Academy of Sciences, Bratislava, SK; ILIMNOL – Institute ofLimnology, Austrian Academy of Sciences, Mondsee, Austria.

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Spheroidal carbonaceous particles

The SCP analysis followed the method described byRose (1994) in which dried sediment is subjected tosequential chemical attack by mineral acids in order toremove unwanted fractions. A known fraction of sus-pension was evaporated onto a coverslip and mountedonto a microscope slide. The number of SCP on eachcoverslip was counted using a light microscope at ×400magnification and the sediment concentration calcu-lated in units of ‘number of particles per g dry mass ofsediment’ (g DM–1). The detection limit for the tech-nique is 100 g DM–1 and concentrations have an accu-racy of ± 45 g DM–1.

Diatoms

Diatom samples were prepared by using 30% hydrogenperoxide (H

2O

2) to treat 0.2 g of wet sediment. The clean

valves were mounted in Naphrax (Battarbee, 1986). Themicrosphere technique was used for absolute counting(Battarbee & Kneen, 1982). Diatoms were identifiedand counted under oil immersion at a magnification of1000× using a Leica (DML) microscope. Normally aminimum of 500 valves was counted per sample.

Chrysophyte stomatocysts

After splitting the samples for diatom and chrysophytestomatocyst analyses, relative stomatocyst abundanceswere counted using a SEM (Jeol JSM-35, minimum:200 cysts per sample). Stomatocyst identification andstatistical analyses followed methods described inKamenik et al. (2000).

Chironomids

The sediment subsamples were treated with 10% KOHfor 24 h and then sieved (100 µm mesh). The fractionretained on the sieve was manually sorted at 7–40×

magnifications in a counting tray. Chironomid headcapsules were mounted using Berlese fluid followingthe standard procedure of the MOLAR protocol. Theremains were identified with reference principally toWiederholm (1983) and Kowalyk (1985). To achievemore reliable taxonomic results larvae collected duringthe 1990’s were compared with those in the subfossilmaterial.

Pigments

Pigment analysis was performed on a weighed sub-sample of ca. 0.5 g wet sediment, and the pigmentswere extracted with 90% acetone overnight. The sus-pension was centrifuged at 4000 rpm for 10 min andthe supernatant was analysed with a spectrophotometerfor total pigments (chlorophyll and their derivatives,CD; crude carotenoids, TC) determination as in Lamiet al. (1994). An aliquot (300 µl) of the same acetoneextract was then injected into a HPLC system for theanalysis of single specific carotenoids as described inLami et al. (2000). Chlorophyll derivatives were ex-pressed as spectrophotometric units per gram organicmatter (U g OM–1) (Guilizzoni et al., 1983). The total andthe single carotenoids were expressed as mg g OM–1 andnmoles g LOI–1, respectively (Züllig, 1985; Lami et al.,2000).

Air temperature reconstruction and data analysis

The method used to reconstruct monthly air-tempera-ture series from 1781–1998 at lake Ni•né Terianskepleso is based on the stepwise multiple regression tech-nique (Agustí-Panareda & Thompson, this issue). Firsta parsimonious model is computed which relates theair-temperature record (1941–1989) at Lomnický Štít(elevation 2635 m), a mountain station close to lakeNiÓné Terianske pleso, with a set of twenty-one homog-enised European lowland records (1781–1998). Thisstatistical model allows the mean air-temperaturerecord at Lomnický Štít to be extended back in time foreach month to January 1781. The skill of this reconstruc-tion method varies with season and site. At LomnickýŠtít the skill is slightly lower than for other Europeansites, on account of Lomnický Štít being situated some-what to the southeast of most of the long Europeanlowland series. Nevertheless the mean square errorassociated with the reconstruction ranges only fromaround 1.1 °C in winter months (DJF) to around 0.7 °Cin summer months (JJA). In general the skill is high-est in spring and summer and lowest in winter.

Second a small temperature correction is made tothe extended record to account for the elevation differ-ence between Lomnický Štít and lake NiÓné Terianskepleso itself. The correction is based on monthly air-temperature lapse rates as estimated using radiosondedata from the European network of meteorological sta-tions. The lapse rates, at these high elevations above thethermal inversion layer, vary from –6.3 °C/km in June

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to –3.9 °C/km in December. Thus a monthly air-tem-perature reconstruction from 1781 to 1998 is obtainedat lake NiÓné Terianske pleso. This final reconstructionhas been validated using the short series of automaticweather station (AWS) data available (summer 1997)from lake NiÓné Terianske pleso. For these few months,for which a comparison between the modelled recon-struction and the weather observations is possible, wefind very acceptable results of a mean absolute bias of0.4 °C and an overall residual mean square monthlyerror of ± 1.9 °C.

Air temperature reconstruction

The main features revealed in the lake NiÓné Terianskepleso reconstruction are an annual air-temperature ofonly +0.1 °C with an early declining trend of –0.9 °Cper century in the nineteenth century (1781–1880), thenan increasing trend in the early twentieth century fol-lowed by a slight fall. This behaviour in air-temperatureis typical for much of Eastern Europe. These reconstruc-tions at lake NiÓné Terianske pleso are plotted in Fig-ure 2 with two examples of smoothing (LOESS spans0.5 and 0.05). During the cool period of the 1870’s thetwo particularly cold years were 1870 and 1875. Thelong-term annual temperature range at lake NiÓnéTerianske pleso, between winter and summer, is 16.5 °C.The range has decreased during the last 217 years be-ing unusually low (= oceanic climate) during the 1920/30’s and the 1970’s. A very noticeable seasonal trendis that the average summer temperatures at lake NiÓnéTerianske pleso declined from almost 10 °C in the 1790’sto 7.5 °C in the 1970’s before recovering slightly dur-ing the last few years. This long-term negative trend is

apparent in all five individual monthly records for Maythrough September. By contrast November air-tem-peratures rose during the last 217 years, while the re-maining six individual months displayed little if anylong term trend.

Linear regression analysis was used to find anypotential relationships between the biological and sed-imentological response variables and the instrumentallyreconstructed climatic variables (= predictor variables)(Battarbee et al., this issue). To harmonise the climaticpredictors and the response variables, the climatic vari-ables were smoothed along time with LOESS regres-sion (Cleveland et al., 1993). From this, an estimate ofthe climate was interpolated for the midpoint of eachsample used for the biological and sedimentologicalanalyses.

Results and discussion

Lithostratigraphy

Dry weight and LOI correlate extremely well betweenthe cores measured (see Figure 3).

TERI96/5 (Figure 3) exhibits two main peaks in wa-ter content and corresponding minima in % LOI at3.5 and 7.5 cm. At the uppermost peak % DW rises tomore than 45%. The lower peak is of a lesser magni-tude, reaching around 35%. The % LOI rises to over30% at the very surface, pinpointing it as the most or-ganic part of the core. The rest of the profile shows thecore to be relatively minerogenic, although % LOI gen-erally decreases from the bottom of the sequence pre-sented (10 cm) to the minimum at 3 cm.

TERI96/6 (Figure 3) shows exactly the same seriesof % DW and % LOI peaks as those of TERI96/5. Thetwo main % DW peaks are once again present. Thistime % DW attains 50% at 3 cm and 30% at 6.5 cm.High % LOI values are once more only seen at the topof the sequence corresponding to the % DW figures ofless than 3%. Once again % LOI gradually increasesfrom the bottom of the stratigraphy presented to theminimum at 3 cm.

TERI96/7 (Figure 3) also presents features commonto the other two cores namely two % DW peaks at 2 and6.5 cm, raised organic content in the top 2 cm of theprofile and below 8 cm. The wet density profile, un-measured for the other cores, closely matches that of% DW, picking out the same main features at 2 and6.5 cm. % DW ranges for this core are less extreme than

Figure 2. Mean annual air temperature at Lake NiÓn” Terianskepleso for the last two centuries and two examples of smoothing.

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Figure 3. Dry weight and loss-on ignition in % in core TERI96/5and TERI96/6 and dry weight, loss-on-ignition and wet density in% in core TERI96/7.

those for the other two with peaks up to 30% rather than45% as in TERI96/5 and TERI96/6. The more gentlefluctuations are echoed in the %LOI profile which doesnot have minima below 10% and remains much moreconstant than in the other two cores.

Chronology and sediment accumulation rates

Radiometric dates were calculated using either CRSand CIC 210Pb dating models (Appleby & Oldfield,1978a, 1978b) following an assessment as to whichmodel was most appropriate as described in Appleby& Oldfield (1983), Appleby et al. (1991), Appleby(1993) and Appleby (1998). Radiometric dating wascarried out on core TERI96/7. The results of the radio-metric analyses are summarised in Figure 4.

Lead – 210 activity

Equilibrium of total 210Pb activity of the supporting226Ra, corresponding to c. 150 years accumulation, wasreached at a depth of about 5 cm. As in an earlier core(TERI93/2), analysed from this site there were a numberof significant variations in 226Ra (supported 210Pb) ac-tivity with depth. Nevertheless the mean values in thetwo cores were very similar (54 Bq kg–1 in TERI96/7,51 Bq kg–1 in TERI93/2). The unsupported 210Pb ac-tivity versus depth profile includes a major deviationbetween 4.2 and 4.4 cm. A layer of slightly denser sedi-ment displays an initial small peak in dry bulk densitybetween 3 and 3.8 cm, a much larger peak at 1.4–2.6 cmsucceeds this.

Artificial fallout radionuclides

The 137Cs activity vs. depth profile was similar to thatof TERI93/2, with very high activities in the surficiallayers clearly dominated by fallout from the 1986Chernobyl accident. Significant levels of 241Am activ-ity were however detected between 0.2–1.0 cm, sug-gesting that these depths contain sediments recordingthe 1963 fallout maximum from the atmospheric test-ing of nuclear weapons (Appleby et al., 1991).

Core chronology

210Pb dates calculated using the CRS dating model sug-gest that the non-monotonic section of the 210Pb pro-file between 1.5–4 cm was associated with an episodeof rapid sediment accumulation peaking in the 1930’s.The 1993 core recorded a similar event between 2.5–4.5 cm depth that also included a layer of dense sedi-

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ment (between 3–4.5 cm). Although the period of mostrapid accumulation was in this case dated to the 1920’sit is reasonable to suppose both features have a com-mon origin.

For both cores the 210Pb profiles suggest that accu-mulation rates are normally low and relatively uniform.The mean accumulation rate in TERI96/7 (excludingthe above events) is estimated to be 0.0041 ± 0.0014 gcm–2 yr–1 (0.020–0.036 cm yr–1), compared to 0.0068 ±0.0017 g cm–2 yr–1 (0.041 cm yr–1) in TERI93/2. Some-what higher density layers at depths of 6, 16 and 18 cmsuggest that episodes of rapid accumulation do how-ever occur fairly regularly. Their origin could be inter-mittent input from the catchment or from the marginsof the lake.

The raw CRS model 210Pb dates place the 1963 levelin the core at a depth of 1.2 cm, a little below the depthindicated by the 241Am results. The discrepancy couldbe due to a modest increase in the 210Pb supply duringthe period of rapid accumulation. Using the CIC modelto calculate the mean accumulation rate in the surficialsediments, the transition at 1.4 cm depth is dated to1949. Hence we calculate a mean 210Pb flux of 77 Bqm–2 yr–1 during normal accumulation and 123 Bq m–2

yr–1 during the period of rapid accumulation. Figure 3gives 210Pb dates and accumulation rates as determinedusing a piecewise CRS model (Appleby, 2000) in whichthe 210Pb supply is assumed to be uniform only within

each section, < 1.4, 1.4–4.0 and > 4 cm. The episodeof rapid accumulation was most probably a relativelybrief event in the late 1920’s, and the elevated accu-mulation rates between 1890–1950 are most certainlyan artifact of the calculations, combined with somemixing with the adjacent layers.

Spheroidal carbonaceous particles

The results of the SCP analyses are presented in Fig-ure 5. The SCP profile for TERI96/7 clearly displaysall the characteristic features seen in lake sedimentcores throughout Europe (Rose et al., 1999). The recordbegins between 4.5 and 5.0 cm. It increases slowly be-fore a rapid increase in concentration takes place be-tween 2 and 0.75 cm. The concentration peaks and thendeclines to the sediment surface. The three SCP pro-file features typically used for sediment dating are allobservable in this core. These are the start of the parti-cle record, the start of the rapid increase in concen-tration and the SCP concentration peak. (Rose et al.,1995).

The 210Pb chronology for TERI96/7 provides thefollowing dates for these SCP features:

The start of the record 4.5–5.0 cm 1833–1857 ± 11The start of the rapid increase 1.7–1.9 cm 1935–1940 ± 2The SCP concentration peak 0.70 cm 1977 ± 2

Figure 4. Radiometric chronology of NiÓn” Terianske pleso core TERI96/7 showing CRS model 210Pb dates, the dated level determined fromthe 241Am stratigraphy, and the revised 210Pb dates calculated using the composite model. Also shown are sedimentation rates calculated usingthe composite model.

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The start of the SCP record is similar to that seen inmany areas across Europe and, as this is just about theearliest period for which SCPs are detected, suggestsa degree of contamination from the Industrial Revolu-tion. The start of the rapid increase in SCP concentra-tion is dated as 1935–1940 which is earlier than usuallyseen in the rest of Europe, where this is typically ob-served in the 1950’s. If the sediment depth/date for thisfeature is correct it is unlikely that the start of this rapidincrease represents a major development in electricitygeneration but may represent increased industrial out-put during the Second World War. The continued in-crease into the 1970’s might be a result of developmentin electricity generation as seen in other regions of Eu-rope. The SCP peak at 1977 ± 2 is in agreement withother areas of Europe. It is also in good agreement witha previous core taken from NiÓné Terianske pleso forAL:PE 2 (Rose et al., 1999) and so can be consideredas reasonably reliable.

Pigment records

The chemical and pigment analyses are presented inFigure 6. The variation in concentration for carbon,nitrogen and sulphur present similar profiles, with con-centrations of 1.1–13.0, 0.1–1.5 and 0.02–0.25% DWrespectively. They are rather constant along the core,but show marked reduction at ca. 3.5 cm. The upper-most layer with less organic content is evident in allthree cores considered (cf. Figure 3). Higher values are

found between 3 cm and the top of the core. The highcorrelation between carbon and loss-on-ignition (R =0.80, p < 0.01) indicates that organic carbon is the ma-jor carbon source.

The C/N ratio rises little. The value of ca. 10 pointsto a mainly autochthonous input. Lower values werefound in the top layer (0–3.5 cm) and between 23 and20 cm (Figure 6).

Labile chlorophylls and carotenoids (e.g., peridinin,fucoxanthin) are limited to the top part of the core. Thestrong increase of the index 430:410 nm (Lami et al.,2000) reveals that diagenetic processes in this lakemight be one the major factors controlling the preser-vation of pigments in the core. However, since most ofthe change observed in the top 3 cm are in agreementwith those observed also by other proxies less influ-enced by diagenesis such as diatoms and chironomids,the observed increase in pigment concentration couldbe interpreted as a real change in the lake trophic con-dition. The algal pigment assemblages (Figure 6) aredominated by carotenoids belonging to Cyanobacteria(oscillaxanthin, myxoxanthophyll, cantaxanthin andZeaxanthin) and to Cryptophytes (alloxanthin).

Diatom analysis and pH reconstruction

Diatom analysis of the entire core reveals many differ-ent assemblages. From the uppermost 6 cm (about 200years) of sediment in core TERI96/7 18 levels wereanalysed for diatoms. A total of 93 diatom taxa repre-senting 22 genera were recorded, consisting predomi-nantly of benthic and periphytic species. 17 speciesoccurred with an abundance greater than 5%. A sum-mary percentage diatom diagram illustrates the mostimportant changes in this part of the core (Figure 7).

In the upper 6 cm of the core several changes in dia-tom assemblages are noticeable. From 6 to 3 cm themost numerous diatoms were Navicula schmassmannii,Achnanthes minutissima and Fragilaria brevistriata.The most important changes regarding species compo-sition of diatom assemblages were registered from 3 cm(about 1900 AD) to the top. Some species, which werepreviously very rare or absent, started to increase inabundance. From 3 cm to the top Navicula schmass-mannii reached an abundance of nearly 40% beforedeclining to about 5%. A significant part of the wholeassemblage was made up of many species of the genusAchnanthes (e.g., Achnanthes marginulata, A. levanderi,A. subatomoides, and A. helvetica). In the uppermost1.5 cm nearly 17% was formed by the species Ortho-seira roeseana, previously a more minor constituent.

Figure 5. SCP concentration profiles in core TERI96/7.

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Changes in diatom assemblages in the top 3 cm wereprobably influenced by a change in the lake trophiccondition and by climatic changes.

Out of a total of 93 taxa present in the core material80 were present in the calibration data set used for thereconstruction of pH. The reconstructed pH is approxi-mately 6.8 at the base decreasing to 6.6 in the upperpart of the sediment core (Figure 7).

From statistical screening it is possible to derivesome general conclusions. During the ice-free seasontemperature relationships between diatom responsevariables and air temperature fluctuations were estab-lished. There were more variables significantly re-sponding to the summer temperature than to autumntemperatures. The first principal component (PCA1) ofthe diatom assemblage is found to be related to tem-perature patterns (Table 2), indicating that climatechange may have been an important control on the dia-

tom community during the last two hundred years.Turning to the assessment of individual taxa, an in-

crease of the more benthic species of the genus Ach-nanthes in the 20th century appears likely to have beenaffected by climate change. A relationship between themean October temperature and the diatoms Achnanthesmarginulata, A. subatomoides and A. helvetica (Fig-ures 8a–8c) shows that with increasing temperaturethe number of these diatoms also increases. Furtherpositive relationships between diatoms and summertemperature were found. These are summarised in Ta-ble 2 where on the basis of PCA relationships werefound with summer temperature (apparent r2 = 0.55).

Chrysophyte stomatocysts

Figure 9 illustrates the main changes in the stomatocystassemblage composition by means of PCA scores. A

Figure 6. Profile of nitrogen, carbon and sulphur, chlorophyll derivatives (ChlDerv), total carotenoid (TotCar) and selected specific carotenoidsidentified in core TERI96/6.

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linear response model was assumed, because of a gra-dient length of 1.0 standard deviations in DCA. All fourPCA axes were significant, explaining 65.6% of thevariance in the stomatocyst assemblage composition.Quantitative inference models were not applied, be-cause of a high number of stomatocyst types not in-cluded in the regional data set of Facher and Schmidt(1996) (26–71%, average 50.2%).

Linear regression analysis showed that changes inPCA axis 1 are significantly related to changes in pHas reconstructed from the diatom assemblages (R2 =0.58, p < 0.001). Partial RDA revealed that within thelast 150 years sample age (time) and June air tempera-ture, retrodicted from instrumental records, had signifi-cant effects on the stomatocyst assemblage composition.June air temperature explained 13.9%, with sample ageas covariable 7.9%, of the variance in the stomatocystassemblage composition. Sample age explained 18.1%,with June air temperature as covariable 12.2%, of thevariance in the stomatocyst assemblage composition.Both variables together explained 26.1%.

The significant influence of sample age on the chry-sophyte assemblage composition in the uppermost4.6 cm (last 150 years) indicates that the main changesin the cyst assemblages were related to long term en-vironmental changes, probably to changes in pH. Thesechanges, however, were not totally independent fromJune air temperature changes (R = 0.41, the interactionterm accounts for 6% of the variance which is one thirdof the variance explained by sample age). We assumethat June air temperature indirectly influenced thestomatocyst assemblage composition by changing theice break-up dates of NiÓné Terianske Pleso. Ice for-mation and ice break have both been shown to trig-ger encystment of chrysophytes (e.g., Agbeti & Smol,1995; Kamenik et al., 2000).

Chironomids

A total of 30 subsamples were analysed and 392 headcapsules found. The yield from each subsample variedfrom 1 to 25 head capsules. Eight chironomid taxa were

Figure 7. Summary diatom diagram (species occurring at > 5%) from core TERI96/7.

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Figure 8. Comparison between air temperature annual means, smoothed (LOESS span 0.05) temperatures and the sediment record for diatomspecies (Achnanthes subatomoides, A. marginulata, A. helvetica) and the chironomid (Micropsectra radialis).

Table 2. Fraction of variance explained for a wide range of sediment variables by mean air temperature. The most significant results (p-values= 0.02) are shown in bold

Core number Sediment variables Annual temperature Winter temperature Summer temperature Autumn temperature(LOESS span 0.5) (LOESS span 0.5) (LOESS span 0.5) (LOESS span 0.5)r2 p-value r2 p-value r2 p-value r2 p-value

TERI96/7 Depth 0.00 0.93 0.17 0.12 0.32 0.03 0.07 0.34DW 0.48 0.00 0.57 0.00 0.71 0.00 0.40 0.01LOI 0.21 0.08 0.86 0.00 0.73 0.00 0.24 0.06Chrysophytes PCA2 0.19 0.10 0.40 0.01 0.65 0.00 0.11 0.22Diatoms PCA1 0.19 0.10 0.33 0.03 0.55 0.00 0.02 0.60

TERI96/5 Depth 0.11 0.09 0.06 0.21 0.53 0.00 0.28 0.00DW 0.04 0.29 0.35 0.00 0.00 0.98 0.31 0.00LOI 0.07 0.17 0.34 0.00 0.01 0.65 0.24 0.01Chironomids PCA1 0.06 0.19 0.03 0.35 0.15 0.04 0.00 0.92

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identified. The subfossil record is dominated by Mic-ropsectra radialis followed by Procladius ‘tatrensis’,Heterotrissocladius marcidus, Micropsectra cf. junci,Diamesa spp., Eukieferiella sp., Zavrelimyia/Pentan-eurella and Bryophaenocladius (Figure 10).

There are no obvious changes in the taxonomic com-position of the profundal chironomid fauna, which con-sisted of M. radialis, H. marcidus and P. ‘tatrensis’.These four species occurred throughout the wholesubfossil record.

The analysis of the sediment core has provided im-portant information regarding the composition of pro-fundal chironomid communities in deep oligotrophicTatra lakes. The typical chironomid communities of theEuropean oligotrophic lakes (Brundin, 1956; Saether,1975) are represented only by M. radialis. Other mem-bers of the ‘Tanytarsus lugens’ community have notbeen found. On the other hand, Procladius ‘tatrensis’seems to be characteristic of Tatra lakes (Bitušík &Kubov.....ík, 1999).

Figure 9. PCA scores (axis 1) vs. depth, illustrating main changesin the chrysophyte stomatocyst assemblage composition.

Figure 10. Summary chironomid diagrams of core TERI96/5.

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No clear relationship between chironomid assem-blage and temperature change was found (Table 2).Only Micropsectra radialis has a significant negativerelationship with PCA1 (Table 3). However the re-sponse of M. radialis to climate is ambiguous. Therelative abundance of M. radialis head capsules followsthe trend of average air annual temperature to the be-ginning of the 20th century. But a negative relationshipwith temperature is expressed in the more recent pe-riod when amelioration through the 1930’s and 40’s iscoincident with a fall in abundance of M. radialis.Furthermore a temperature decline in the 1970’s ismarked by an increase in the species (Figure 8d).

M. radialis is a cold stenotherm inhabiting the pro-fundal region of oligotrophic lakes (Brundin, 1956).Decline of the species in the sediment record is oftenconsidered to be related to warming (e.g., Brooks,1997). The abundance of M. radialis in lake NiÓnéTerianske pleso mirrors the temperature fluctuationsduring the earlier part of the lake history. This suggeststhat periods with higher temperature supported moreabundant populations of M. radialis on account ofimproved food conditions. Catalan et al. (this issue)have similarly noted the effect of food availability on

cold stenotherm chironomids in the subfossil recordfrom lake Redó.

Conclusions

Sediment deposition at the remote mountain lake siteof NiÓné Terianske pleso has been continuous, since atleast 1852, and yields laterally consistent records asshown by the excellent between-core agreement ofloss-on-ignition and dry weight measurements.

The TERI96/7 SCP profile displays the typical fea-tures found in sediment cores throughout Europe. Theprofile is reasonably unambiguous with the start of therecord in the mid-19th century and the SCP concentra-tion peak dating to 1977 ± 2, similar to other Euro-pean areas. SCP data suggest that deposition at NiÓnéTerianske pleso is lower than at other Tatra sites (1993data). However, the SCP/210Pb ratio gives a reasonableagreement to the latitudinal pattern of SCP contamina-tion suggested for Europe.

Plant pigments, despite the possible strong interfer-ence of diagenetic processes, point to a marked increasein trophic level in the recent past of NiÓné Terianske

Table 3. Microfossils (diatoms and chironomids) with high scores (> 0.6) on any of the principal component analysis (PCA) of group vari-ability for the sediment record of lake NiÓné Terianske pleso (High Tatras) in the last two centuries. Since the variance is scaled to 1, the axiseigenvalues indicate the proportion of variance explained

PCA1 PCA2 PCA3 PCA4

Diatoms ( 95 taxa)Axes eigenvalue 0.347 0.152 0.130 0.057Achnanthes carissima 0.64 –0.02 –0.33 0.49Achnanthes laterostrata 0.63 –0.08 –0.23 0.51 Achnanthes marginulata 0.62 0.02 –0.43 0.66Achnanthes minutissima 0.30 –0.82 –0.36 0.24Achnanthes subatomoides 0.68 –0.11 –0.35 0.05Achnanthes helvetica 0.47 –0.42 –0.20 0.81Asterionella formosa 0.08 –0.65 0.58 –0.11Cymbella minuta 0.30 –0.89 –0.03 –0.11Denticula tenuis 0.27 –0.81 0.24 –0.15Fragilaria brevistriata –0.26 –0.88 0.00 0.19Fragilaria pseudoconstruens –0.50 –0.62 0.33 –0.16Navicula schmassmannii –0.52 –0.42 –0.71 –0.01Neidium bisulcatum 0.62 –0.45 0.08 –0.14Pinnularia microstauron 0.26 –0.77 0.04 –0.36Stauroneis anceps –0.13 –0.78 –0.17 0.21

Chironomids ( 9 taxa)Axes eigenvalue 0.398 0.229 0.130 0.116Micropsectra radialis –0.80 0.07 –0.14 –0.15Procladius “tatrensis” 0.59 –0.50 –0.67 –0.34Heterotrissocladius marcidus 0.54 0.78 0.24 0.14Micropsectra sp. 0.16 –0.75 1.00 –0.03

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pleso. Chironomids as a whole showed no correlationto temperature fluctuations in the last 200 years. OnlyMicropsectra radialis was found to be related to tem-perature trends and this may be due to changes in foodavailability as an indirect result of temperature change.The significant influence of sample age on the chry-sophyte assemblage composition in the uppermost4.6 cm (last 150 years) indicates that the main changesin the cyst assemblages were related to long term en-vironmental changes, probably to pH. In the upper partof the sediment core taxonomic changes in diatom as-semblages were found, mainly from 3 cm to the top.Species, which in the lower part of the core were veryrare or absent, started to prevail in the upper assem-blage zones. These were composed mainly of benthic/periphytic species e.g., Achnanthes spp., Fragilariaspp., Navicula schmassmannii. Changes in speciescomposition of diatoms may be related to the impactof acid deposition as evidenced by the increasing con-centrations of SCPs, also derived from fossil-fuel com-bustion sources. Similarly, the significant influence ofsample age on the chrysophyte assemblage composi-tion in the uppermost 4.6 cm (last 150 years) indicatesthat the main changes in the cyst assemblages wererelated to long term environmental change, probablypH. However, climate conditions, such as increases inthe autumn mean air temperature, were also found tocorrelate with diatom assemblage change.

Acknowledgements

We would like to thank all the people from the ECRCwho helped by sediment coring in the High Tatra Moun-tains, but especial thanks go to Simon Patrick and hiscolleague Chris Curtis, to Rick Battarbee and to theanonymous reviewers for their critical and constructivecomments on the manuscript. This study was fundedwithin the European Commission Programme IV: En-vironment and Climate (MOLAR Project; Contract No.ENV4 CT95 0007/IC20-CT96-0021).

References

Agbeti, M. D. & J. P. Smol, 1995. Chrysophyte population and en-cystment patterns in two Canadian lakes. J. Phycol. 31: 70–78.

Agustí-Panareda, A. & R. Thompson, 2002. Reconstructing air tem-perature at eleven remote alpine and arctic lakes in Europe from1781 to 1997 AD J. Paleolim. 28: 7–23.

Appleby, P. G., 1993. Forward to the 210Pb dating anniversary se-ries. J. Paleolim. 9: 155–160.

Appleby, P. G., 1998. Dating recent sediments by 210Pb: Problemsand solutions. Proc. 2nd NKS/EKO-1 Seminar, Helsinki, 2–4April 1997.

Appleby, P. G., 2000. Radiometric dating of sediment records inEuropean mountain lakes. J. Limnol. 59(suppl. 1): 1–14.

Appleby, P. G., P. J. Nolan, D. W. Gifford, M. J. Godfrey, F.Oldfield, N. J. Anderson & R. W. Battarbee, 1986. 210datingby low backgroud gamma counting. Hydrobiologia 141: 21–27.

Appleby, P. G. & F. Oldfield, 1978a. The calculation of 210Pb datesassuming a constant rate of supply of unsupported 210Pb to thesediment. Catena 5: 1–8.

Appleby, P. G. & F. Oldfield, 1978b. The assessment of 210Pb data fromsites with varying sediment accumulation rates. Hydrobiologia103: 29–35.

Appleby, P. G. & F. Oldfield, 1983. The assessment of 210Pb data fromsites with varying sediment accumulation rates. Hydrobiologia103: 29–35.

Appleby, P. G., N. Richardson & P. J. Nolan, 1991. 241Am dating oflake sediments. Hydrobiologia 214: 35–42.

Appleby, P. G., N. Richardson & P. J. Nolan, 1992. Self-absorp-tion corrections for well-type germanium detectors. Nucl. Inst.Meth. B 71: 228–233.

Barber K. E., R. W. Battarbee, S. J. Brooks, G. Eglington, E. Y.Haworth, F. Oldfield, A. C. Stevenson, R. Thompson, P. G.Appleby, W. E. N. Austin, N. G. Cameron, K. J. Ficken, P.Golding, D. D. Harkness, J. A. Holmes, R. Hutchinson, J. P.Lishman, D. Maddy, L. C. V. Pinder, N. L. Rose & R. E.Stoneman, 1999. Proxy records of climate change in the UKover the last two millennia: documented change and sedimen-tary records from lakes and bogs. J. Geol. Sci. Lond. 156: 369–380.

Battarbee, R. W., 1986. Diatom analysis. In: Berglund, B. E. (ed.).,Handbook of Holocene Palaeoecology and Palaeohydrology.John Wiley & Sons, Chichester, 527–570.

Battarbee, R. W., 2000. Paleolimnological approaches to climatechange, with special regard to the biological record. Quat. Sci.Rev. 19: 107–124.

Battarbee, R. W. & M. J. Kneen, 1982. The use of electronicallycounted microspheres in absolute diatom analysis. Limnol.Oceanogr. 27: 184–188.

Battarbee, R. W., J.-A. Grytnes, R. Thompson, P. G. Appleby, J.Catalan, A. Korhola, H. J. B. Birks, E. Heegaard & A. Lami,(2002). Comparing palaeolimnological and instrumental evi-dence of climate change for remote mountain lakes over the last200 years. J. Paleolim. 28: 161–179.

Bitušík, P. & V. Kubov.....ík, 1999. Sub-fossil chironomids (Diptera:Chironomidae) from the sediments of the Ni•né Terianske pleso(High Tatra Mts., Slovakia). Dipterologica bohemoslovaca 9:11–20.

Brooks, S. J., 1997: The response of Chironomidae (Insecta: Diptera)assemblages to late-glacial climatic change in Kråkenes lake,Western Norway. Quart. Proc. 5: 49–58.

Brundin, L., 1956: Die bodenfaunistischen Seetypen und ihreAnwendbarkeit auf die Südhalbkugel. Report Institute Fresh-water research, Drottningholm, 37: 186–235.

Catalan, J., S. Pla, M. Rieradevall, M. Felip, M. Ventura, T. Buchaca,L. Camarero, A. Brancelj, P. G. Appleby, A. Lami, J. A. Grytnes,A. Agustí-Panareda & R. Thompson, 2002. Lake Redó ecosys-tem response to an increasing warming in the Pyrenees duringthe twentieth century. J. Paleolim. 28: 129–145.

109

Cleveland, W. S., E. Grosse & W. M. Shyu, 1993. Local regressionmodels. In Chambers, J. M. & T. J. Hastie (eds), StatisticalModels in S. Chapman & Hall, London, 309–376.

Duff, K. A., B. A. Zeeb & J. P. Smol, 1995. Atlas of ChrysophyceanCysts. Kluwer Academic Publishers, Dordrecht.

Facher, E. & R. Schmidt, 1996. A silicious chrysophycean cyst-basedpH transfer function for Central European lakes. J. Paleolim.16: 275–321.

Fritz, S. C., 1996. Paleolimnological records of climatic change inNorth America. Limnol. Oceanogr. 41: 882–889.

Glew, J. R., 1989. A new trigger mechanism for sediments samplers.J. Paleolim. 2: 241–243.

Guilizzoni, P., G. Bonomi, G. Galanti & D. Ruggiu, 1983. Relation-ship between sedimentary pigments and primary production:evidence from core analyses of twelve Italian lakes. Hydro-biologia 103: 103–106.

Kamenik, C., R. Schmidt, K. Koinig, A. Agustí-Panareda, R.Thompson & R. Psenner, 2002. The Chrysophyte stomatocystcomposition in a high alpine lake (Gossenköllesee, Tyrol) inrelation to seasonality, temperature and land-use. Beih. NovaHedwigia (in press).

Kowalyk, H. E., 1985: The larval cephalic setae in the Tanypodinae(Diptera: Chironomidae) and their importance in generic de-terminations. Can. Entomol. 117: 67–106.

Krno, I., 1991. Macrozoobenthos of the Tatra lakes littoral (The HighTatras) and its effection by acidification. Biologia (Bratislava)46: 495–508.

Lami, A., F. Niessen, P. Guilizzoni, J. Masaferro & C. A. Belis,1994. Palaeolimnological studies of the eutrophication ofvolcanic Lake Albano (central Italy). J. Paleolim. 10: 181–197.

Lami, A., P. Guilizzoni, A. Marchetto, 2000. High resolution analy-sis of fossil pigments, carbon, nitrogen and sulphur in the sedi-ment of eight European alpine lakes: the MOLAR project. J.Limnol. 59(suppl. 1): 15–28.

Lotter, A. F., H. J. B. Birks, W. Hofmann & A. Marchetto, 1997.Modern diatom, cladocera, chironomid, and chrysophyte cystassemblages as quantitative indicators for the reconstructionof past environmental conditions in the Alps. I. Climate. J.Paleolim. 18: 395–420.

Rose, N. L., 1994. A note on further refinements to a procedure forthe extraction of carbonaceous fly-ash particles from sediments.J. Paleolim. 11: 201–204.

Rose, N. L., S. Harlock, P. G. Appleby & R. W. Battarbee, 1995. Thedating of recent lake sediments in the United Kingdom andIreland using spheroidal carbonaceous particle concentrationprofiles. Holocene 5: 328–335.

Rose, N. L., S. Harlock & P. G. Appleby, 1999. The spatial and tem-poral distributions of spheroidal carbonaceous fly-ash particles(SCP) in the sediment records of European mountain lakes.Water, Air Soil Pollut. 113: 1–32.

Sæther, O. A., 1975. Nearctic chironomids as indicators of lake ty-pology. Verh. Int. Ver. Limnol. 19: 3127–3133.

Smole±, F. & M. OstroÓlík, 1991. Biometeorological cooling at highMountain positions under various meteorological conditions.In Mountainous Meteorology, Climatology and Aerology of theLower Layers of Troposhere., Bratislava, SHMI, 159–165

Stuchlík, E., Z. Stuchlíková, J. Fott, L. RËÓicka & J. Vrba, 1985.Effects of acid precipitations on waters of the TANAP territory.Zborník TANAPu, 28: 173–211.

Wathne, B. M. & B. O. Rosseland (eds), 2000. MOLAR – Measur-ing and modelling the ynamics response of remote mountainlake ecosystems to environmental change: a program of Moun-tain Lake Research – MOLAR. Final Report 4/1999. Norwe-gian Institute for Water Research (NIVA), 201 pp.

Wiederholm. T. (ed.), 1983. Chironomidae of the Holarctic region. Keysand diagnoses. Part 1. Larvae. Ent. Scand. Suppl. 19: 1–457.

Züllig, H., 1985. Pigmente phototropher Bakterien in Seesedimentenund ihre Bedeuntung für die Seenforschung. Schweiz. Z. Hydrol.47: 87–126.

110