[show abstract][hide abstract] ABSTRACT: Using dynamic, mass budget, and empirical models, we quantified sulphate-sulphur (SO4-S) leaching from soils in a large central European catchment (upper Vltava river, Czech Republic) over a 110-year period (1900-2010). SO4-S inputs to soils with synthetic fertilisers and atmospheric deposition increased in the 1950s-1980s, then rapidly decreased (~80%), and remained low since the middle 1990s. The proportion of drained agricultural land rapidly increased from 4 to 43% between the 1950s and 1990s; then the draining ability of the system slowly decreased due to its ageing. Sulphate concentrations in the Vltava exhibited similar trends as the external SO4-S inputs, suggesting that they could be explained by changes in atmospheric and fertiliser S inputs. The available data and modelling, however, showed that (i) internal SO4-S sources (mineralization of soil organic S in the drained agricultural land), (ii) a hysteresis in SO4-S leaching from forest soils (a net S retention at the high S inputs and then a net release at the lowered inputs), and (iii) hydrology must be taken into account. An empirical model was then employed, based on parameters representing hydrology (discharge), external SO4-S sources (inputs by synthetic fertilisers and atmospheric deposition), and internal SO4-S sources (mineralization related to soil drainage). The model explained 84% of the observed variability in annual SO4-S concentrations in the Vltava river during 1900-2010 and showed that forest soils were a net sink (105kgha(-1)) while agricultural land was a net source (55kgha(-1)) of SO4-S during 1960-2010. In the late 1980s, forest soils changed from a sink to a source of S, and the present release of SO4-S accumulated in forest soils thus delays recovery of surface waters from acidification, while S losses from agricultural soils increase the risk of future S deficiency in S-demanding crops.
Science of The Total Environment 10/2013; 470-471C:543-550. · 3.26 Impact Factor
[show abstract][hide abstract] ABSTRACT: In some of the eight glacial lakes in the Bohemian Forest we have observed first signs of zooplankton reco- very from acidity. The recovery has followed a drop in atmospheric sulphur and nitrogen deposition and consequent reversal in water chemistry of the lakes during the last decade. At present, stable populations of Ceriodaphnia quadrangula have returned to Lake Černé and Prášilské, and two circumneutral rotifers have recently occurred in the lakes with positive alkalinity: Laka, Großer Arbersee (Keratella testudo) and Kleiner Arbersee (K. valga). Moreover, in the mesotrophic, strongly acidified Lake Plešné, we documented increase in both phytoplankton and planktonic rotifers during the 1990s. A statistical comparison of seaso- nal data (1994, 1998, 2001 and 2003; Kruskal-Wallis test) showed a significant increase in pH and a signi- ficant drop in total reactive aluminium (Al T ). In parallel, a significant increase in chlorophyll a concentra- tion suggested the recovery of phytoplankton. In consequence, summer abundance of planktonic rotifers in Lake Plešné rose by more than two orders of magnitude during the 1990s.
Aktuality šumavského výzkumu II. Sborník z konference, 4.–7. 10. 2004, Srní, Česko. 07/2013;
[show abstract][hide abstract] ABSTRACT: Elevated and chronic nitrogen (N) deposition to N-limited terrestrial ecosystems can lead to ‘N saturation’, with resultant ecosystem damage and leaching of nitrate (NO3 −) to surface waters. Present-day N deposition, however, is often a poor predictor of NO3 − leaching, and the pathway of the ecosystem transition from N-limited to N-saturated remains incompletely understood. The dynamics of N cycling are intimately linked to the associated carbon (C) and sulphur (S) cycles. We hypothesize that N saturation is associated with shifts in the microbial community, manifest by a decrease in the fungi-to-bacteria ratio and a transition from N to C limitation. Three mechanisms could lead to lower amount of bioavailable dissolved organic C (DOC) for the microbial community and to C limitation of N-rich systems: (1) Increased abundance of N for plant uptake, causing lower C allocation to plant roots; (2) chemical suppression of DOC solubility by soil acidification; and (3) enhanced mineralisation of DOC due to increased abundance of electron acceptors in the form of SO42− SO 4 2 − and NO3 − in anoxic soil micro-sites. Here we consider each of these mechanisms, the extent to which their hypothesised impacts are consistent with observations from intensively-monitored sites, and the potential to improve biogeochemical models by incorporating mechanistic links to the C and S cycles.
[show abstract][hide abstract] ABSTRACT: We examined long-term data on water chemistry of Lake Rachelsee (Germany) following the changes in acidic depositions in central Europe since 1980s. Despite gradual chemical recovery of Rachelsee, its biological recovery was delayed. In 1999, lake recovery was abruptly reversed by a coincident forest die-back, which resulted in elevated terrestrial export of nitrate and ionic aluminum lasting ~5 years. This re-acidification episode provided unique opportunity to study plankton recovery in the rapidly recovering lake water after the abrupt decline in nitrate leaching from the catchment. There were sudden changes both in lake water chemistry and in plankton biomass structure, such as decreased bacterial filaments, increased phytoplankton biomass, and rotifer abundance. The shift from dominance of heterotrophic to autotrophic organisms suggested their substantial release from severe phosphorus stress. Such a rapid change in plankton structure in a lake recovering from acidity has, to the best of our knowledge, not been previously documented.
AMBIO A Journal of the Human Environment 06/2013; · 2.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: Biological response of aquatic macrophytes to changes in water chemistry
and temperature has been studied on a background of the long-term
research of Bohemian Forest lakes recovery from acid stress.
Isoëtes lacustris and I. echinospora are common aquatic macrophytes
adapted for living in soft-water lakes widely distributed in European
lake districts; however, in central Europe they are rare glacial
relicts. In Černé and Plešné lakes, two
populations survived a thirty-year period of severe acidification but
failed to reproduce. In our experimental and field studies on
Isoëtes reproduction we identified early ontogenetic stages to be
most vulnerable to changes in lake water pH, temperature, and aluminium
(Al) toxicity .We described specific symptoms on plantlets reflecting
various lake water acidity and Al-toxicity and defined critical limits
of the stressors for plant survival. Using a mathematical model we also
described temperature-related changes in species reproductive phenology
and revealed their narrow temperature tolerance. The knowledge of
critical environmental factors and their limits for species survival
allows us to infer changes in species reproduction in response to both
historical and ongoing changes in climate and lake water chemistry. Due
to species-specific ecological traits, we can now explain the recent
population recovery of I. echinospora contrasting with the poor
reproduction of I. lacustris that will be constrained by environmental
stressors for at least during the next 20 years.
[show abstract][hide abstract] ABSTRACT: This study describes the origin, bedrock geology, geomorphology, hydrological stability and physical and chemical characteristics of a representative set of 29 lakes in the ice-free parts of the Ulu Peninsula, James Ross Island, located close to the northern tip of the Antarctic Peninsula. Based on these features, six different types of lakes were defined: stable shallow lakes on higher-altitude levelled surfaces, shallow coastal lakes, stable lakes in old moraines, small unstable lakes in young moraines, deep cirque lakes and kettle lakes. We observed a significant relationship between lake type and water chemistry. Bedrock, lake age and morphometry together with altitude were the most important factors underlying the observed limnological variability. Our results further suggested possible nitrogen limitation in the lake ecosystems. However, physical factors such as low temperature and light were also likely to be limiting.
[show abstract][hide abstract] ABSTRACT: The 1998–2012 average composition of bulk precipitation was dominated by NH4+ (25 μmol.l–1) among cations and NO3 – (21 μmol.l–1) among anions in catchments of Plešné (PL) and Čertovo (CT) lakes in the Bohemian Forest. Concentrations of other ions averaged between 0.8 and 8.3 μmol.l–1. The average precipitation amount was 1372 mm, bulk deposition fluxes of major nutrients were 5.0, 4.7, and 3.5 kg.ha.yr–1 of NH4-N, NO3-N, and TON, respectively, and 22, 4.5, 2.6, 1.9, 0.5, 0.23 kg.ha.yr–1 of TOC, SO4-S, Ca2+, K+, Mg2+, and TP, respectively. Prior to bark beetle infestation in the PL catchment in 2004–2006, the average throughfall fluxes (TF) of Na+, H+, SO4 2–, NO3 –, Cl–, and TP, were on average 1.5–2.1 fold higher than their precipitation fluxes (PF). Higher TF:PF ratios (2.1–9.8) were observed for Mn, K+, Mg2+, Ca2+, and organic C, N, and P forms, while lower ratios (0.6–1.3) occurred for dissolved reactive P and NH4 +. After the forest infestation, throughfall deposition of ions and nutrients started to decrease in the PL catchment compared to the CT catchment. The greatest and most rapid changes occurred for K+, DOC, Mg2+, and Ca2+. Their fluxes rapidly decreased to values similar to precipitation fluxes within 6–8 years after the infestations. Slower changes occurred in throughfall fluxes of SO4 2–, NO3 –, and Cl–, and negligible changes so far occurred in the throughfall fluxes of NH4 +. The major reason for differing response of throughfall deposition of individual elements to forest dieback (and reduced surface area of canopies) was different contribution of canopy leaching (export from living and decaying canopy tissue) and microbial transformations to the elemental throughfall fluxes.
[show abstract][hide abstract] ABSTRACT: Correct identification of P forms together with their main Fe and Al binding partners in non-calcareous sediments is of crucial importance for evaluation of P cycling in water bodies. In this paper, we assess extraction methods frequently used for this purpose, i.e., a sequential five-step fractionation (water, bicarbonate buffered dithionite solution (BD), NaOH, HCl, nitric-perchloric acid), ascorbate extraction (pH ∼7.5), and oxalate extraction (pH ∼3), directly on a range of laboratory prepared Fe and Al minerals enriched with adsorbed P. Extraction selectivity and efficiency for particular P, Fe and Al forms were also verified by specific combinations of these extraction methods applied on freshwater sediment samples. In the sequential fractionation, BD was highly effective in dissolving both amorphous and crystalline Fe (hydr)oxides and the associated P, while neither FeS nor Al (hydr)oxides were dissolved. The following NaOH extraction effectively dissolved both amorphous and crystalline Al (hydr)oxides. The high solubilizing power of BD and NaOH to dissolve crystalline Fe and Al oxides that have only a small P-sorption ability prevents the use of resulting Fe/P and Al/P ratios as simple predictors of total P sorption capacity of sediments and soils. Ascorbate non-selectively extracted small proportions of FeS and amorphous Fe and Al (hydr)oxides, but significant amounts of adsorbed P, which hinders its use for the characterization of P forms in non-calcareous sediments. Similar nonselective characteristics were found for oxalate extractions. As oxalate extracts most of the adsorbed phosphate, it is not possible to use it unambiguously to determine specific Fe/P and Al/P ratios of active complexes. However, this method is convenient (and more selective than NaOH step in the sequential fractionation) for the determination of amorphous Al (hydr)oxides.
[show abstract][hide abstract] ABSTRACT: Nitrogen leaching persists in mountain forests of Europe even in the presence of decreasing N depositions. We have hypothesized
that this leaching is linked to soil N transformations occurring over the whole year, even at 0°C temperatures. The aims were
to estimate (1) the effect of temperature on N transformations and (2) N pools and fluxes. The study sites are situated in
the Bohemian Forest (Czech Republic). Litter, humus, and 0–10-cm mineral layers were sampled in early spring, and the effect
of temperature on net nitrification, net ammonification, and microbial N immobilization were measured in a short-term incubation
experiment without substrate addition. Nitrogen pools were calculated from the concentrations of N forms in the soil and soil
pool weights, while daily N fluxes were calculated from daily net rates of processes and soil pool weights. Relationships
between temperature and net nitrification, net ammonification, and microbial N immobilization did not follow the Arrhenius
type equation; all processes were active close to 0°C, indicating that microbial N transformations occur over the whole year.
Microbial N immobilization rate was generally greater than N mineralization rate. The microbial N pool was significantly larger
than mineral N pools. Organic layers containing tens of grams of available N per square meter contributed more than 70% to
the available N in the soil profile. Daily N fluxes were related to N pools. On average, N fluxes represented daily mineral
and microbial N pool changes of 1.14 and 1.95%, respectively. The effect of microbial composition on the C/N ratio of microbial
biomass and respiration is discussed.
Biology and Fertility of Soils 05/2012; 45(4):395-404. · 2.51 Impact Factor
[show abstract][hide abstract] ABSTRACT: Phosphate (PO4-P) sorption characteristics of soils and bedrock composition were determined in catchments of two mountain lakes, Plešné
Lake (PL) and Čertovo Lake (CT), situated in the Bohemian Forest (Czech Republic). The aim was to explain higher terrestrial
P export to mesotrophic PL compared to oligotrophic CT. Concentrations of Al and Fe oxides were the dominant parameters affecting
soil ability to adsorb PO4-P. Depending on concentrations of Al and Fe oxides, P sorption maxima varied from 9.7 to 70.5 mmol kg−1 and from 7.4 to 121 mmol kg−1 in organic and mineral soil horizons, respectively. The catchment weighted mean PO4-P sorption capacity was 3.4 mol m−2 and 11.9 mol m−2 in the PL and CT soils, respectively. The higher PO4-P sorption capacity in the CT catchment was predominantly associated with higher pools of soil and Fe oxides. The CT bedrock
(mica schist) released one order of magnitude less P than the PL bedrock (granite) within a pH range of catchment soils (pHCaCl2 of 2.5–4.5). The higher ability of PL bedrock to release P and the lower ability of PL soils to adsorb PO4-P thus contributed to the higher terrestrial P loading of this lake.
Water Air and Soil Pollution 04/2012; 173(1):243-259. · 1.75 Impact Factor
[show abstract][hide abstract] ABSTRACT: The sediment record from a 5.3-m core from Sargent Mountain Pond, Maine USA indicates strong co-evolutionary relationships
among climate, vegetation, soil development, runoff chemistry, lake processes, diatom community, and water and sediment chemistry.
Early post-glacial time (16,600–12,500 Cal Yr BP) was dominated by deposition of mineral-rich sediment, low in organic matter
and secondary hydroxides of Al and Fe; pollen indicate tundra conditions; diatom taxa indicate pH between 7.5 and 8, and total
P concentrations of about 25μg L−1, favoring higher productivity. Chemical weathering was rapid, with high alkalinity, pH, Ca, and P in runoff. As climate ameliorated,
about 12,500 Cal Yr BP, forest vegetation became established; soils would have developed vertical zonation, including organic
matter accumulation, and incipient podzolic horizons, with accumulating secondary hydroxides of Al and Fe that sequestered
P in the soils. Labile minerals (primarily apatite, Ca5(PO4)3(OH,F,Cl)) became depleted in the soil, further reducing the supply of P to the lake. Dissolved organic carbon (DOC) from
soil organic matter mobilized Al and Fe to the lake where Al(OH)3 (primarily) and Fe(OH)3 (minor) were precipitated. The sedimenting hydroxides adsorbed P from the water column, further reducing bioavailable P.
These long-term trends of moderating climate, and changing terrestrial biology, soils, and aquatic chemistry and phytoplankton
were interrupted by the 1,000-year long Younger Dryas cooling, which led to a temporary reversal of these processes, a period
that ended with the major onset of Holocene warming. The sequestration of P by soils would have strengthened because of long-term
soil acidification and pedogenesis. The lake was transformed from a more productive, high P, high pH, low DOC system into
an oligotrophic, relatively low P, acidic, humic lake over a period of 16,600years, a natural trend that continues. In contrast
to many human-affected lakes that become increasingly eutrophic, many lakes become more oligotrophic during their history.
The precursors for that are: (1) absence of human land-use in watersheds, (2) bedrock lithology and soil with a paucity of
soluble Ca-rich minerals, and (3) vegetation that promotes the accumulation of soil organic matter, podzolization, and increased
export of metal-DOC complexes, particularly Al.
KeywordsOligotrophication–Phosphorus–Sediment–Aluminum–Post-glacial weathering–Watershed evolution–Climate change
Journal of Paleolimnology 04/2012; 46(1):107-122. · 2.21 Impact Factor
[show abstract][hide abstract] ABSTRACT: The Bohemian Forest (Šumava, Böhmerwald) is situated in Central Europe and is among the most acidified lake districts in the
world. Deposition of S and N compounds in the area rapidly increased between 1950 and 1980, and reached a maximum in the 1980s.
During the 1990s, acid deposition decreased substantially, and current levels are comparable to the early 20th century for SO
, and to the mid 1960s for NO
. These changes in acid deposition have led to a partial recovery of the Bohemian Forest lakes. This paper provides an overview
of previous research, and details on the organization and aims of current research on the Bohemian Forest lakes. Available
historical data and regular monitoring (since 1984) provide a valuable background for long-term ecological research of the
catchment-lake ecosystems that currently focuses on (i) chemical reversal and biological recovery of the lakes, (ii) acidification
impacts on in-lake nutrient cycling, (iii) climatic effects on water chemistry, and (iv) catchment processes, including soil
biogeochemistry and acidification impacts on vegetation.
[show abstract][hide abstract] ABSTRACT: Fluxes of major ions and nutrients were measured in the watershed-lake ecosystem of a strongly acidified lake, Plešné jezero
(Plešné Lake), in the Czech Republic in hydrological years from 2001 through 2005. The lake is situated in a Norway spruce
forest and has a steep watershed between elevations of 1090 and 1378 m. The average water input and output from the ecosystem
was 1372 mm and 1157 mm (37 L km−2 s−1), respectively, and the water residence time averaged 306 days. Despite ecosystem recovery from acidification occurring since
the late 1980s, the Plešné watershed was an average net source of 25 mmol SO
m−2 yr−1. Nitrogen saturation of the watershed caused low retention of the deposited inorganic N (< 44% on average) before 2004. Then,
the watershed became a net source of 28–32 mmol m−2 yr−1 of inorganic N in the form of NO
due to climatic effects (a dry summer in 2003 and a cold winter in 2004) and forest dieback caused by a bark beetle attack
in 2004. Nitrogen transformations and SO
release were the dominant terrestrial sources of H+ (72 and 49 mmol m−2 yr−1, respectively) and the watershed was a net source of 24 mmol H+ m−2 yr−1. Ionic composition of surface inlets showed seasonal variations, with the most pronounced changes in NO
, ionic Al (Ali), and DOC concentrations, while the composition of subsurface inlets was more stable. The in-lake biogeochemical processes
reduced on average 59% of the incoming H+ (251 mmol H+ m−2 yr−1 on a lake-area basis). NO
assimilation and denitrification, photochemical and microbial decomposition of allochthonous organic acids, and SO
reduction in the sediments were the most important aquatic H+ consuming processes (358, 121, and 59 mmol H+ m−2 yr−1, respectively), while hydrolysis of Ali was the dominant in-lake H+ generating process (233 mmol H+ m−2 yr−1). Photochemical liberation from organic complexes was an additional in-lake source of Ali. The net in-lake retention or removal of total phosphorus, total nitrogen, and silica were on average 50%, 27%, and 23%,
respectively. The lake was a net source of NH
due to a cease in nitrification (pH < 5) and from NH
production by dissimilation exceeding its removal by assimilation.
[show abstract][hide abstract] ABSTRACT: We studied extracellular acid phosphatase activity (AcPA) of planktonic microorganisms, aluminium (Al) speciation, and phosphorus
(P) cycling in three atmospherically acidified (pH of 4.5–5.1) mountain forest lakes: Čertovo jezero (CT), Prášilské jezero
(PR), and Plešné jezero (PL) in the Bohemian Forest (Šumava, Böhmerwald). Microorganisms dominated pelagic food webs of the
lakes and crustacean zooplankton were important only in PR, with the lowest Al concentrations (193 µg L−1) due to 3–4 times lower terrestrial input. The lakes differed substantially in Al speciation, i.e., in the proportion of
ionic and particulate forms, with the highest proportion of ionic Al in the most acid CT (pH = 4.5). The P concentration in
the inlet of PL (mean: 22.9 µg L−1) was about five times higher than in CT and PR (3.9 and 5.1 µg L−1, respectively). Average total biomass of planktonic microorganisms in PL (593 µg C L−1) was, however, only ∼2-times higher than in CT and PR (235 and 272 µg C L−1, respectively). Enormous AcPA (means: 2.17–6.82 µmol L−1 h−1) and high planktonic C : P ratios suggested severe P limitation of the plankton in all lakes. Comparing 1998 and 2003 seasons,
we observed changes in water composition (pH and Al speciation) leading to a significant increase in phytoplankton biomass
in the lakes. The increase in the seston C : P ratio during the same time, however, indicates a progressive P deficiency of
the lakes. The terrestrial Al inputs, together with in-lake processes controlling the formation of particulate Al, reduced
P availability for planktonic microorganisms and were responsible for the differences in AcPA. At pH < 5, moreover, ionic
Al forms caused inhibition of extracellular phosphatases. We postulate that both particulate and ionic Al forms affect P availability
(i.e., inhibition of extracellular phosphatases and inactivation of P), specifically shape the plankton composition in the
lakes and affect plankton recovery from the acid stress.
[show abstract][hide abstract] ABSTRACT: Fluxes of major ions and nutrients were measured in the watershed-lake ecosystem of a strongly acidified lake, Čertovo jezero
(Čertovo Lake), in the 2001 through 2005 hydrological years. Water balance was estimated from precipitation and throughfall
amounts, and measured outflow from the lake. The average water input into and outflow from the watershed-lake ecosystem was
1461 mm and 1271 mm (40 L km−2 s−1), respectively, and the water residence time in the lake averaged 662 days. The ecosystem has been recovering from acidification
since the late 1980s. Still, however, Čertovo watershed was an average net source of 23 mmol m−2 yr−1 of SO
. Nitrogen saturation of the watershed caused low retention of the deposited inorganic N (23% on average). After a dry summer
in 2003 and a cold winter in 2004, the watershed became a net source of inorganic N (19 mmol m−2 yr−1). Nitrogen transformations and SO
release were the dominant terrestrial sources of H+ (81 and 47 mmol m−2 yr−1, respectively) and the watershed was a net source of 42 mmol H+ m−2 yr−1. Ionic composition of tributaries showed seasonal variations with the most pronounced changes in NO
, base cations, DOC, and ionic Al (Ali) concentrations. The in-lake biogeochemical processes reduced the incoming H+ by ∼50% (i.e., neutralized on average 222 mmol H+ m−2 yr−1, on a lake-area basis). Denitrification, SO
reduction, and photochemical and microbial decomposition of allochthonous organic matter were the most important in-lake
H+ consuming processes (215, 85, and 122 mmol H+ m−2 yr−1, respectively), while hydrolysis of Ali was the dominant H+ generating process (96 mmol H+ m−2 yr−1) in Čertovo Lake. Photochemical liberation from organic complexes was an additional in-lake source of Ali. The net in-lake retention or removal of nutrients (carbon, phosphorus, nitrogen, and silica) varied between 18% and 34%
of their inputs.
[show abstract][hide abstract] ABSTRACT: A limnological survey of eight small, atmospherically acidified, forested glacial lakes in the Bohemian Forest (Šumava, Böhmerwald)
was performed in September 2003. Water chemistry of the tributaries and surface layer of each lake was determined, as well
as species composition and biomass of the plankton along the water column, and littoral macrozoobenthos to assess the present
status of the lakes. The progress in chemical reversal and biological recovery from acid stress was evaluated by comparing
the current status of the lakes with results of a survey four years ago (1999) and former acidification data since the early
1990s. Both the current chemical lake status and the pelagic food web structure reflected the acidity of the tributaries and
their aluminium (Al) and phosphorus (P) concentrations. One mesotrophic (Plešné jezero) and three oligotrophic lakes (Černé
jezero, Čertovo jezero, and Rachelsee) are still chronically acidified, while four other oligotrophic lakes (Kleiner Arbersee,
Prášilské jezero, Grosser Arbersee, and Laka) have recovered their carbonate buffering system. Total plankton biomass was
very low and largely dominated by filamentous bacteria in the acidified oligotrophic lakes, while the mesotrophic lake had
a higher biomass and was dominated by phytoplankton, which apparently profited from the higher P input. In contrast, both
phytoplankton and crustacean zooplankton accounted for the majority of plankton biomass in the recovering lakes. This study
has shown further progress in the reversal of lake water chemistry as well as further evidence of biological recovery compared
to the 1999 survey. While no changes occurred in species composition of phytoplankton, a new ciliate species was found in
one lake. In several lakes, this survey documented a return of zooplankton (e.g., Cladocera: Ceriodaphnia quadrangula and Rotifera: three Keratella species) and macrozoobenthos species (e.g., Ephemeroptera and Plecoptera). The beginning of biological recovery has been
delayed for ∼20 years after chemical reversal of the lakes.
[show abstract][hide abstract] ABSTRACT: A sediment record of cladoceran remains was analysed in a 543 cm long core from Plešné jezero (Plešné Lake), the Bohemian
Forest, Czech Republic. The core covered the time period from the Oldest Dryas to the present. Littoral and benthic Cladocera
included 11 species of the family Chydoridae while three species (Bosmina longispina, Daphnia cf. pulicaria and D. cf. longispina) lived in the open water. Remains of Alona quadrangularis and Chydrous sphaericus occurred in the oldest sediment layers from the beginning of the Bølling chronozone. Bosmina longispina and Daphnia cf. pulicaria appeared about 400 years later. Inorganic sediment accumulated at a relatively high rate of ∼ 90 mg cm−2 yr−1 at that time, diluting cladoceran remains and organic matter. Remains of Cladocera accumulated at 0.1 to 0.01 of the Holocene
rate, making it difficult to observe effects of climate variation on the species structure of Cladocera in the Late-Glacial.
Production of remains increased after warming during the Younger Dryas-Preboreal transition at ∼11.6 kyr BP, and the proportion
of littoral species increased. The most important change in cladoceran fauna occurred at ∼10.5 kyr BP and culminated with
afforestation of the catchment around 10.3 kyr BP. The domaination of Bosmina longispina lasted for ∼250 years. The afforestation occurred concurrently with a decrease in lake water pH. Bosmina longispina and Daphnia cf. pulicaria disappeared, production of cladoceran remains decreased, but biodiversity increased. Planktonic Cladocera were represented
by Daphnia cf. longispina during most of the rest of the Holocene. The production of Cladocera never reached the Preboreal level. Since ∼ 5 cal. kyr
BP, the inferred pH continuously decreased. The final decline was likely caused by cooling during the Little Ice Age and by
sulphur emissions from ore smelting. The recent acidification of lake water and impoverishment of aquatic fauna was brought
about by emissions of sulphur and nitrogen compounds in the 20th century.
[show abstract][hide abstract] ABSTRACT: Concentrations of major nutrients (C, N, P) and acid soluble metals (Ca, Mg, K, Al, Fe, Mn, Pb, and Zn) were determined in
modern (0–1 cm) and pre-acidification (5–10 cm) sediment layers collected from 37 alpine and 3 forest lakes in the Tatra Mountains
(Slovakia, Poland) in 1996–1998. Sediment composition reflected catchment characteristics and productivity of lakes. In the
sediments of alpine lakes, C and N concentrations decreased and Mg increased with a decreasing proportion of vegetation and
soil in the catchment. Decreasing Ca:Mg ratios in sediments along the vegetation gradient was inverse to that in water, and
could be associated with different ratios of cations in water leachate from catchments and in solids which enter the lake
due to soil erosion. Phosphorus concentrations increased with the proportion of moraine areas, with till soils rich in P.
Concentrations of C, N, P, and Ca in sediments positively correlated to their concentrations in water. Sediment concentrations
of Al and Al:Ca ratios increased with decreasing sediment and water pH. A negative correlation between water pH and concentrations
of organic C in water and sediments indicated the important impact of organic acids on the acid status of the lakes exposed
to higher terrestrial export of organic matter. Compared to the pre-acidification period, the modern sediments had significantly
higher Fe, Mn, Zn, Pb, and K, but lower Mg concentrations. The Zn and Pb enrichment was more evident in oligotrophic alpine
lakes than in more productive forest lakes and was independent of lake water or sediment pH. Fe and Mn concentrations in the
modern sediments were higher than in ambient soils and bedrock, while those in pre-acidification sediments were similar to
contemporary soils and to the rock layer. The enrichment of the modern sediments with Fe and Mn thus probably resulted from
both their redox recycling and ecosystem acidification.
[show abstract][hide abstract] ABSTRACT: Data from two surveys of the Tatra Mountain lakes (Slovakia and Poland) performed in the autumns of 1984 (53 lakes) and 1993
or 1994 (92 lakes) were used to estimate spatial variability in water chemistry in this lake district during the period of
maximum European acid deposition. The ionic content of the lakes was generally low, with conductivity (at 20°C) ranging from
1.1 to 4.7 mS m−1 and 23% of the lakes had a depleted carbonate buffering system. Major factors governing differences in lake-water chemistry
were bedrock composition and amount of soil and vegetation in their catchment areas. Compared to lakes in the predominantly
granitic central part of the Tatra Mountains, lakes in the West Tatra Mountains had higher concentrations of base cations
and alkalinity due to the presence of metamorphic rocks in the bedrock. Concentrations of phosphorus, organic carbon, organic
nitrogen, and chlorophyll-a were highest in forest lakes and decreased with decreasing density of vegetation and soil cover in the catchment areas. Concentrations
of nitrate showed an opposite trend. Several exceptions to these general patterns in chemical and biological composition were
due to exceptional geology or hydrology of the lake catchments.
[show abstract][hide abstract] ABSTRACT: Ninety-one lakes distributed along the Tatra Mountains (most of lakes > 1 ha and 65% of lakes > 0.01 ha) were sampled and
analysed for ionic and nutrient composition in September 2004 (15 years after reduction in acid deposition). Eighty-one lakes
were in alpine zone and ten lakes in Norway spruce forest. The results were compared to similar lake surveys from 1994 (the
beginning of water recovery from acidification) and 1984 (maximum acidification). Atmospheric deposition of SO
and inorganic N decreased 57% and 35%, respectively, in this region from the late 1980s to 2000. Lake water concentrations
have decreased both by ∼50% on average (to 23 and 19 μmol L−1, respectively, in 2004) since 1984. While the decrease in SO
concentrations was stable throughout 1984–2004, most of the NO
decrease occurred from 1994 to 2004. The declines in SO
concentrations depended on catchment coverage with vegetation, being most rapid for SO
in forest lakes and for NO
in rocky lakes. Concentrations of the sum of base cations (dominated by Ca2+) significantly decreased between 1984 and 2004, with the highest change in rocky lakes. Most of this decline occurred between
1994 and 2004. Acid neutralising capacity (ANC) did not change in the 1984–1994 period, but increased on average by 29 μmol L−1 between 1994 and 2004, with the highest change in rocky lakes. Over the last decade, the proportion of lakes with ANC > 150
μmol L−1 increased from 15% to 21% and that of ANC < 20 μmol L−1 decreased from 37% to 20%. The highest decline in H+ and Al concentrations occurred in the most acid lakes. On a regional basis, no significant change was observed for total
phosphorus, total organic nitrogen, and dissolved organic carbon (DOC) in the 1994–2004 period. However, these parameters
increased in forest lakes, which exhibited an increasing trend in DOC concentrations, inversely related (P < 0.001) to their decreasing ionic strength (30% on average in 1994–2004).