Kettle-hole Lake Research Articles

Diatom assemblages from short-lived jökulhlaup-formed kettle lakes in a proglacial outwash plain, south-east Iceland

ABSTRACTLittle is known about the ecological implications of high-magnitude, low frequency jökulhlaup events in proglacial systems. This study highlights how kettle lakes produced by jökulhlaups in proglacial areas create short-lived ecosystems and increase biodiversity. This research also demonstrates that as ice-margins retreat, creating new proglacial lakes and aquatic habitats, these sites may be increasingly important as sites of biogeochemical cycling and carbon fixing. Using diatoms from the base of former kettle hole lakes formed during the November 1996 jökulhlaup on Skeiðarársandur, south-east Iceland, we investigate the record of changing conditions of these lakes over their short (∼15 year) life span. Diatom assemblages were investigated in sediment sections up to 0.36m deep from the base of two kettle holes, and across a profile of surface sediments in one kettle hole. The diatom assemblages across all kettle holes are dominated by small benthic species (e.g. Achnanthes, Navicula, Nitzschia and Fragilaria spp.), with planktonic species (Cyclostephanos, Stephanodiscus spp.) present in only one kettle hole. The diatom assemblages are characterized by species with high nutrient and alkalinity optima. The variation in the diatom assemblages between different sedimentary units in the kettle holes’ basal stratigraphy reflect changes in the proportion of available habitat type (e.g. benthic, planktonic and littoral) resulting from changes in water levels, and changes in water chemistry relating to variations in sediment input (e.g. aeolian accumulation, slumping and re-working) and source of water (e.g. precipitation, ground water, snow melt). A conceptual model for typical kettle lake development in proglacial environments is also presented.

Autogenic and allogenic factors affecting development of a floating Sphagnum-dominated peat mat in a karst pond basin

Lateral expansion of floating vegetation mats over the surface of aquatic ecosystems (terrestrialization) is one of the ways of peatland development. This process was commonly studied in kettle-hole lakes, whereas karst ponds have received less attention. We used a suite of palaeoecological analyses at Karstovoe mire (Mordovia, Russia) to reconstruct the formation of a floating Sphagnum-dominated peat mat over the karst pond. The results show that the floating peat mat had covered the central part of the pond by ca. AD 1600. Remains of Scirpus sp. and Calamagrostis sp. in the basal layers indicate that these plants might form a framework on which Sphagnum mosses and sedges were established. The terrestrialization could be triggered by the ‘Medieval Warm Period’ (AD 950–1250) as droughts reduce water levels and allow the pioneering plants to colonize exposed bottom sediments on the margins of lakes. Later, the development of the mire was mainly driven by autogenic factors that could be explained by the relatively stable hydrological regime in freely floating or poorly attached vegetation mats. In the mid 19th century, the surface wetness of the mire started to decline that can be related to both increased human activity associated with fires and to a greater thickness of the mat so that autogenic and allogenic effects were difficult to disentangle. In less than a century after that, the fen transformed to a pioneer raised mire. Our results show complex and context-dependent effect of autogenic and allogenic factors on the development of floating peat mats.

Early Maglemosian culture in the Preboreal landscape: Archaeology and vegetation from the earliest Mesolithic site in Denmark at Lundby Mose, Sjælland

The transition from Late Palaeolithic to early Mesolithic cultures is strongly associated with the major environmental and climatic changes occurring with the shift from the Younger Dryas to the Holocene in northern Europe. In this paper, we present an interdisciplinary study combining archaeological and palaeoenvironmental research in an attempt to examine the relationship between environment and culture during this transition. Lundby Mose is a former kettle hole lake in southern Denmark where the earliest Danish human traces of the Holocene were excavated. Two types of bone deposits were found, 1) ritual offerings of worked, marrow-split elk bones and antler and 2) settlement waste with multiple species. These date to the early Holocene and are affiliated to the early Maglemose culture. The modelled 14C ages suggest that the bones were deposited in four phases. A pollen based palaeoenvironmental reconstruction suggests that the ritual offerings were deposited in an environment of limited, underdeveloped forest with unstable soils and areas of open grassland. The settlement waste deposit is associated with a more developed Preboreal forest type. This forest type was not fully established until c. 11,250 cal BP and if substantiated by further evidence, may be one of the reasons why there are no known early Maglemose/Preboreal settlement sites in southern Scandinavia.

Chironomid-based water depth reconstructions: an independent evaluation of site-specific and local inference models

Water depth is an important environmental variable that explains a significant portion of the variation in the chironomid fauna of shallow lakes. We developed site-specific and local chironomid water-depth inference models using 26 and 104 surface-sediment samples, respectively, from seven kettlehole lakes in the Plymouth Aquifer, southeast Massachusetts, USA. Our site-specific model spans a depth gradient of 5.6 m, has an \( {\text{r}}_{\text{jack}}^{2} \) of 0.90, root mean square error of prediction (RMSEP) of 0.5 m and maximum bias of 0.7 m. Our local model has a depth gradient of 11.7 m, an \( {\text{r}}_{\text{jack}}^{2} \) of 0.71, RMSEP of 1.6 m and maximum bias of 2.9 m. Principal coordinates of neighbourhood matrices (PCNM) analysis showed that there is no influence of spatial autocorrelation on the site-specific model, but PCNM variables explained a significant amount of variance (4.8%) in the local model. This variance, however, is unique from the variance explained by water depth. We applied the inference models to a Holocene chironomid record from Crooked Pond, a site for which multiple, independent palaeohydrological reconstructions are available. The chironomid-based reconstructions are remarkably similar and show stable water depths of ~5 m, interrupted by a 2-m decrease between 4,200 and 3,200 cal a BP. Sedimentological evidence of water level fluctuations at Crooked Pond, obtained using the so-called Digerfeldt approach, also shows a drop in water depths around that time. The period of reconstructed lower water levels coincides with the abrupt decline in moisture-dependent hemlock in this region, providing further evidence for this major palaeohydrological event. The site-specific model has the best performance statistics, but the high percent abundance of fossil taxa from the long core that are absent or rare in the training set makes the site-specific reconstruction unreliable for the period before 4,400 cal a BP. The fossil taxa are well represented in the local model, making it the preferred inference model. The strong similarity between the chironomid-based reconstructions and the independent palaeohydrological records highlights the potential for using chironomid-based inference models to determine past lake depths at sites where temperature was not an influencing factor.

Long-Term Fate of a Pulse Arsenic Input to a Eutrophic Lake

The long-term fate of a 30-year-old pulse arsenic input to a eutrophic lake was studied to determine if As has become effectively trapped in sediments or remains in active exchange with the water column. Legacy As was readily mobilized from sediments of Spy Pond (Arlington, MA), a eutrophic kettle-hole lake that was treated with 1000s kg As in the 1960s to manage excessive aquatic macrophyte growth. Arsenic was mobilized from hypolimnetic sediments during bottom-water anoxia in spring, summer, and fall, and As accumulated to maximum concentrations of 2100 nM. Mobilization of As from epilimnetic sediments was the largest source of As to the water column on a mass basis (145 mol), despite the fact that the epilimnion remains oxic year-round. Sediment cores revealed that surficial sediments contained As at 30-50 times background levels and suggested that there is contemporary As loading to hypolimnetic sediments (590 mol y(-1)). Mass balance estimates indicate that <5% of the contemporary As load comes from external inputs and that the remainder can be explained by mobilization and redistribution of legacy As, both through the water column and by vertical migration of dissolved As within sediments. These findings demonstrate that, decades after As inputs cease, As in contaminated sediments may remain labile and be mobilized to both anoxic and oxic water columns and accumulate to levels near the sediment surface and in the water column that may pose ongoing risks to ecological health.

Quantification of Holocene lake-level changes in Finnish Lapland using a cladocera – lake depth transfer model

During recent years, numerous studies dealing with Holocene lake level fluctuations have been conducted in Finnish Lapland. However, no quantification of lake level variations exists to date. Here, we applied a recently developed modern cladocera – lake depth transfer model to subfossil cladocerans analysed from three small and shallow (< 6 m) kettle-hole lakes in northwestern Finnish Lapland to provide estimates of the amplitudes of long-term lake-level changes in the region. The quantitative inferences were compared to pollen, charcoal and geochemical records from one of the study sites. The lake levels were inferred to be high during the early Holocene; they faced marked reduction up to 4–6 m in the mid-Holocene (≈7000–4000 cal yr BP), and rose again during the latter part of the Holocene. There is some indication of lowered lake levels around 1500 cal yr BP, but interpretation of such small-scale changes is hazardous due to large prediction errors in the initial cladoceran model. The overall pattern of the Holocene lake level variation generally followed the regional changes in climate humidity as reconstructed in previous studies by means of other sedimentary proxy indicators, such as pollen and oxygen isotopic compositions. We postulate that changes in winter precipitation may have had a greater influence on lake-levels than variations in summer precipitation or evaporation.

The Origin and Evolution of Lake Vähä-Pitkusta, SW Finland – A Multi-Proxy Study of a Meromictic Lake

Lake Vaha-Pitkusta is a 35-m deep meromictic kettle-hole lake in SW Finland. The topmost 15cm of the sediment stratigraphy consists of black gyttja, representing the last ca. 600years. A sediment core from the deepest point was examined with multi-proxy methods to determine the origin and evolution of the basin, the onset of the meromictic conditions and the primary factors that initiated the meromictic processes. The results indicate that Lake Vaha-Pitkusta became isolated from the Baltic basin during the Yoldia Sea stage. After initial unstable sedimentary conditions the development continued steadily until ca. 2500–2300 cal.BP when there is indication of lake level rise and/or increased surface runoff, probably resulting from a cooler and moister climate. The diatom and cladoceran results indicate only a slight rise in the trophic state following the increased erosion. Pollen evidence suggests weak anthropogenic activity in the catchment during the last 1000 years, and this had only little effect on the trophic state, which remained rather low. Thus, it is most unlikely that the trophic state was the primary reason for the origin of meromixis, although it may have contributed to it. We tentatively suggest that the primary reason was the peculiar morphometric dimensions of Lake Vaha-Pitkusta (small, deep, sheltered from winds) which made it very sensitive and that even a very slight increase in soluble electrolytes may push it over the edge into meromixation. It is possible that this did not occur during the cold/moist period around ca. 2300 cal.BP but during the Medieval Climate Anomaly. Studies on sediment geochemistry are needed to verify this assumption.

Upper Pleistocene stratigraphy at the Medininkai site, eastern Lithuania: a continuous record of the Eemian‐Weichselian sequence

Eemian—Weichselian sequences, located outside the maximum limit of the Late Weichselian ice sheet, provide excellent opportunities for the discovery of continuous sedimentary records encompassing the whole Last Interglacial/Glacial cycle. Such a sequence is recorded in a borehole (117P) through the succession in a small kettlehole lake located at Medininkai, eastern Lithuania. The succession consists of peat, gyttja and silt deposited on top of a Saalian till. Pollen and plant macrofossil analysis, lithological analysis, U/Th dating and mineral magnetic measurements on the sediments have allowed 19 lithostratigraphic units and 16 local pollen assemblage zones (LPAZ) to be identified. The palaeocarpological record reveals a clear transition from the Saalian Glacial to the Weichselian stadial and interstadial phases. The mineral magnetic parameters suggest a good correlation between the concentration of magnetic minerals and stadial and interstadial periods. The Merkine (Eemian) Interglacial and two Early Weichselian Interstadials, Jonionys 1 (Brörup) and Jonionys 2 (Odderade), separated by cryomers, are identified. Intervals interpreted as analogous to the Middle Weichselian Denekamp and Hengelo interstadials are also recognized on the basis of pollen assemblages. The results show alternating periglacial and interstadial palaeoenvironments in Lithuania during the Early and Middle Weichselian and are of importance for Late Pleistocene palaeoenvironmental reconstruction of the Baltic area as a whole.

Upper Pleistocene stratigraphy at the Medininkai site, eastern Lithuania: a continuous record of the Eemian-Weichselian sequence

Eemian-Weichselian sequences, located outside the maximum limit of the Late Weichselian ice sheet, provide excellent opportunities for the discovery of continuous sedimentary records encompassing the whole Last Interglacial/Glacial cycle. Such a sequence is recorded in a borehole (117P) through the succession in a small kettlehole lake located at Medininkai, eastern Lithuania. The succession consists of peat, gyttja and silt deposited on top of a Saalian till. Pollen and plant macrofossil analysis, lithological analysis, U/Th dating and mineral magnetic measurements on the sediments have allowed 19 lithostratigraphic units and 16 local pollen assemblage zones (LPAZ) to be identified. The palaeocarpological record reveals a clear transition from the Saalian Glacial to the Weichselian stadial and interstadial phases. The mineral magnetic parameters suggest a good correlation between the concentration of magnetic minerals and stadial and interstadial periods. The Merkine (Eemian) Interglacial and two Early Weichselian Interstadials, Jonionys 1 (Brorup) and Jonionys 2 (Odderade), separated by cryomers, are identified. Intervals interpreted as analogous to the Middle Weichselian Denekamp and Hengelo interstadials are also recognized on the basis of pollen assemblages. The results show alternating periglacial and interstadial palaeoenvironments in Lithuania during the Early and Middle Weichselian and are of importance for Late Pleistocene palaeoenvironmental reconstruction of the Baltic area as a whole. (Less)

Rapid hydrological changes during the Holocene revealed by stable isotope records of lacustrine carbonates from Lake Igelsjön, southern Sweden

A Holocene sediment sequence from Lake Igelsjön, south central Sweden, was studied by stable oxygen- and carbon-isotope analyses of different carbonate components. The deposit, which covers the time-span from ca 11,500 cal BP to the present, was laid down in a small, kettle-hole lake, the hydrological balance of which is presently dominated by groundwater flow. Isotopic records obtained on bulk carbonates originating mainly from summer-produced, calcitic algal encrustations exhibit several rapid shifts of more than 2‰, likely reflecting pronounced hydrological variations. Corresponding isotopic data obtained on calcitic gastropod opercula from parts of the profile show subdued responses to major climatic shifts, probably related to an extended calcification season. The isotopic records were complemented by studies of modern isotope hydrology, and our interpretations are based on a simplistic climate-hydrology model in which variations in groundwater generation within the lake catchment produce changes in groundwater level and related adjustments of lake level and surface/volume ratio of the basin during the ice-free season. Assumed periods of decreased lake volume in a relatively dry climate (low lake level) are characterised by enrichment in 18O and 13C resulting from increased evaporation/inflow ratio and atmospheric equilibration, respectively. In clear contrast to this situation, intervals of more humid climatic conditions give rise to increased lake volume (high lake level), possibly surface over flow, and relatively depleted isotopic ratios. Relatively humid conditions, which may correlate to a wide-spread cooling event recorded by various proxies across the North Atlantic region, are indicated by distinct isotopic shifts at ca 8300 and 8000 cal BP, bracketing a period of 18O-depletion. The period between ca 8000 and 4000 cal BP was characterised by relatively dry and stable climatic conditions, whereas the subsequent part of the Holocene experienced a more humid and variable climate following marked and coherent depletions in 18O and 13C at ca 4000 cal BP.

Devensian Lateglacial and early Holocene floral and faunal records from NE Northumberland

SUMMARY Radiocarbon-dated Late Devensian and early Holocene pollen, molluscan and ostracod assemblages, from the sediments of an infilled kettle-hole lake near Wooler in north-eastern Northumberland, are described and discussed in both a local and a wider context. During the Lateglacial interstadial, open birch woodland developed for a short time after herbaceous vegetation had first dominated the surrounding landscape. Scrub was present for the remainder of the interstadial. Mollusca and Ostracoda immigrated into the lake during the pre-woodland phase of the interstadial, then disappeared, perhaps due to a climatic deterioration. A depauperate fauna returned in the latter part of the interstadial, when a less hostile aquatic environment may have existed. In the succeeding Loch Lomond Stadial, a periglacial climate led to tundra-like vegetation and to the extirpation once again of the lacustrine fauna. In the early Holocene, Betula- then Corylus -dominated woodland was preceded by scrub and heath. Mollusca and Ostracoda recolonized the water body at the start of the Holocene, with the former quickly developing a diverse fauna. Two episodes of increased lake level with an intervening fall are suggested by the faunal assemblages. The second rise in water level was accompanied by vegetation changes in its environs, which may have been linked to a wetter and cooler climate than that which preceded it, and which occurred between 8000 and 7000 BP.

STEPHANODISCUS ALPINUSIN PLUßSEE, GERMANY. ECOLOGY, MORPHOLOGY AND TAXONOMY IN COMBINATION WITH INITIAL CELLS

Long-term observations (1972–1992) at mainly weekly intervals on the phytoplankton of the eutrophic, summer stratified kettle-hole lake Plussee, northern Germany have revealed Stephanodiscus alpinus Hustedt as an important component of the spring diatom bloom. It showed marked interannual differences in abundance, with the capacity to produce dense crops in the absence of other diatoms, contributing up to 5% of the annual phytoplankton biomass. S. alpinus has been present throughout postglacial time in Plussee (Hickel, unpubl.). A detailed investigation on the morphology of S. alpinus is made on material from plankton samples. The development of the morphological features of S. alpinus from hemispherical cell stage to the distinctive morphology of the vegetative cell is described. It is shown that S. alpinus has several constant features and is distinct and clearly delimited from other Stephanodiscus taxa.

Groundwater interaction with a kettle-hole lake: Relation of observations to digital simulations

Observations made on a small, fully penetrating, kettle hole lake are used to test predictions made using digital stimulation about the exchange of water between lakes and groundwater systems. On the upgradient side of Lower Nashotah Lake, groundwater inseepage decreases exponentially away from the shore. Water exchange on the downgradient side is controlled by the presence and strength of a groundwater mound, but that mound and its effects are ephemeral. When the mound increases in strength, it generates a local groundwater flow cell beneath it which contains water of chemical composition distinct from deeper, regional groundwater. The growing mound also causes local inseepage of groundwater to the lake in an expanding zone along the downgradient shore. All of these phenomena occur as they have been predicted in published studies where digital simulation of relatively simple groundwater-lake systems has been carried out. The field observations thus confirm the validity of the simulation studies and their usefulness as a tool for understanding water exchanges in unmonitored systems.

Direct Measurement of Groundwater Flow and Quality as a Lake Management Tool

ABSTRACT The flow of groundwater into and out of lakes can have a substantial impact on their hydrologic and nutrient budgets. The use of a simple device (a manometer) sensitive to differences in water pressure allows delineation of potential zones of contribution (inflow) and recharge (outflow). Application of simple seepage meters allows quantification of groundwater flows. Pore water extracted from lake sediments in zones of contribution can be chemically analyzed to allow quantification of nutrient loadings to the lake via the groundwater. In 1987, these devices were used to measure groundwater flow to 11 Massachusetts lakes. Groundwater inflow accounted for between 1 to 57 percent of the total lake inflows. Inflows were greatest in kettlehole lakes and least in stream impoundments. Seepage meter measurements were significantly affected by season and local shoreline topography. Distance from shoreline and sediment nature were also factors. A recommended approach for using these devices is considered. ...

Obervations on the occurrence of scales and bristles of mallomonas spp. (Chrysophyceae) in the micro-laminated sediments of a small lake in finnish North Karelia

Scales and bristles ofMallomonas crassisquama (Asmund) Fott andM. elongata Reverdin are reported from the laminated sediments of Laukunlampi, a small kettlehole lake in N. Karelia, Finland. The white summer laminae in the deeper sediment are composed almost entirely ofM. crassisquama scales and bristles. The taxonomy, ecology and distribution ofM. crassisquama andM. elongata are briefly discussed and factors influencing the preservation of scales and bristles in sediments are considered. It is suggested that analysis of sedimentary associations of scales, bristles and cysts could be used to improve cyst taxonomy inMallomonas.

Plant Succession at the Borders of a Kettle-Hole Lake

Plant Succession at the Borders of a Kettle-Hole Lake

On the Naiades of Long Island, New York

The following species are cited as occurring in this region: Elliptio complanatus Dillwyn (1). Described as being moderately abundant at Riverhead; Anodonta implicata Say (2, 3). Found in lake at Prospect Park, Brooklyn, and at Baisley's Lake, Jamaica South; Anodonta cataracta Say (3), from Kissena Park lake, Flushing. The writer notes the occurrence of this species at Lake Ronkonkema, a glacial kettle hole lake near the center of the island, where it seems fairly common. This species is widely distributed over the Atlantic slope. A number of specimens were transferred to St. John's lake, Cold Spring Harbor, in August, 1923, where their further progress may be noted. Ortmann remarks of the close relationship of cataracta and implicata, the latter differing from the former only by a thickening of the shell along its lower margin, a distinction hardly noticeable in young shells. Anodonta sp. are usually thinshelled under any condition of environment. Their ready adaptation to the lime-free waters of Long Island is thus easily understood. E. compltanatuts is a puzzling species due to the large number of variants representing it. While it is described as having a moderately thick shell, yet a form of it with shell so soft as to be easily indented with the finger, has been reported from a soft-water lake in New York (4). This would seem to indicate similar adaptability as the Anodontas. All are members of the depauperate Atlantic Coast Fauna, having been reported from New England by Johnson (5), and being found further south. The fair probability is their introduction on Long Island, one way or another through the agency of birds. A similarly curious distribution is reported for A. cataracta from the Tennessee drainage. This shell is not found in the Upper Tennessee draniage above Chattanooga except at a