Small Meromictic Lake Research Articles

Predator recognition learning by northern redbelly dace Chrosomus eos from a small kettle lake with a dynamic predator community

Predation, and the risk of predation, shape the ecology, behavior, and evolution of many species. Small fishes navigate a perilous landscape of risk in the shallow waters of the littoral zone. Moreover, in small lakes, the predator community can be dynamic due to stochastic colonization and extirpation events. These conditions select for the ability by small fish to acquire recognition of novel predators through associative learning. Chemical cues associated with predation events, such as damage-released chemical cues from conspecifics, and the odor of predators, inform prey of the presence of risk, and facilitate acquired recognition of novel predator odor. Deming Lake, MN, is a small meromictic lake with intermittent connections to neighboring lakes in the watershed. Annual sampling of the littoral fish community between the years 2000 and 2023 reveals a history of colonization and extirpation by relatively large-bodied species such as yellow perch Perca flavescens and pumpkinseed sunfish Lepomis gibbosus. Ice cover data, combined with limnological depth profiles of dissolved oxygen, confirm that dissolved oxygen is limiting during the winter and consistent with the hypothesis that extirpation of large-bodied species in Deming Lake is likely due to winter anoxia. These data set the stage for an experimental demonstration of acquired recognition of the odor of allopatric rock bass Ambloplites rupestris by bass-naïve northern redbelly dace Chrosomus eos from Deming Lake. Rock bass have been absent from Deming Lake since at least the year 2000. Predator-recognition learning allows redbelly dace, and many other small-bodied fishes that face variable predator species over ontogenetic, spatial, and temporal scales, a mechanism to adapt quickly to indicators of predation risk.

Morphometric Characters and Feeding Habits in the Early Ontogenesis of Kildin Cod Gadus morhua kildinensis (Gadidae) from Lake Mogilnoe (Kildin Island, Barents Sea)

Kildin cod Gadus morhua kildinensis is a subspecies of Atlantic cod with extremely small population size, listed in the Red Data Book of the Russian Federation, which inhabits the waters of a small meromictic lake on the Kildin Island (Barents Sea). Comparative studies of morphobiological characteristics and feeding habits of Kildin cod in the juvenile period were conducted for the first time. Comparison of sample sets of adult Kildin cod and fingerlings on the basis of multivariate analysis of variance demonstrates a high degree of differences in the complex of morphometric characters. The diet of the analyzed sample set of Kildin cod fingerlings consisted of ostracodes (Ostracoda), larvae of polychaetas (Polychaeta), cladocerans (Cladocera), and gammarids (Gammaridae). The special features of changes in the diet of Kildin cod in the early ontogenesis are discussed.

From the lagoon to the meromictic lake: a case study of lake-bottom sediments of Lake Kislo-Sladkoe (the Karelian Coast of White Sea, Russia)

The distribution of diatoms in the core of bottom sediments of the small meromictic Lake Kislo-Sladkoe on the Karelian Coast of White Sea was studied. The changes in diatom associations in the column show the isolation of the lagoon from the sea and its transformation into a meromictic lake. First alteration of dominant species marks the decrease of hydrodynamic activity as a result of the formation of spit and transformation of the lagoon into semi-closed bay. Second shift in species composition reflects the onset of the strong stratification and occurrence of a bottom anoxic layer.

Sharp water column stratification with an extremely dense microbial population in a small meromictic lake, Trekhtzvetnoe.

Located on the shore of Kandalaksha Bay (the White Sea, Russia) and previously separated from it, Trekhtzvetnoe Lake (average depth 3.5 m) is one of the shallowest meromictic lakes known. Despite its shallowness, it features completely developed water column stratification with high-density microbial chemocline community (bacterial plate) and high rates of major biogeochemical processes. A sharp halocline stabilizes the stratification. Chlorobium phaeovibrioides dominated the bacterial plate, which reached a density of 2 × 108 cell ml-1 and almost completely intercepts H2 S diffusion from the anoxic monimolimnion. The resulting anoxygenic photosynthesis rate reached 240 μmol C l-1 day-1 , exceeding the oxygenic photosynthesis rate in the mixolimnion. The rates of other processes are also high, reaching 4.5 μmol CH4 l-1 day-1 for methane oxidation and 35 μmol S l-1 day-1 for sulfate reduction. Metagenomic analysis demonstrated that the Chl. phaeovibrioides population in the bacterial plate layer had nearly clonal homogeneity, although some fraction of these cells harbour a plasmid. The Chlorobium population was associated with bacteriophages that share homology with CRISPR spacers in the host. These features make the ecosystem of the Trekhtzvetnoe Lake a valuable model for studying regulation and evolution processes in natural high-density microbial systems.

Relationships between physico-chemical and microbiological parameters in the monimolimnion of a forest meromictic lake

The small meromictic Lake Zapadłe in North-Eastern Poland was the subject of our research in the vegetation period between April and November. Our study were to aim a better recognition of meromixis phenomenon and find connections between hydrochemical and microbiological parameters. Here, the monimolimnion layer was below 10 m depth with the chemocline between 13-14 m. Highly significant Spearman’s ranks correlations of P<0.05 were found between conductivity and biochemical oxygen demand (0.91), ammonium nitrogen (0.96), phosphate (0.91), iron (0.77) and manganese (0.82). Favourable conditions for bacterioplankton growth and function here included; the absence of water circulation, the presence of anaerobic conditions and hydrogen sulphide, a constant water temperature and highly significant correlations between total bacterial counts (TBC), bacterial biomass (BB) and biochemical oxygen demand (BOD), conductivity, total organic carbon (TOC) and dissolved organic carbon (DOC). The pool of bacteria-forming biomass increased significantly in the lower part of the monimolimnion. A highly significant correlation (P<0.05) existed between bacterial biomass (BB) and their anaerobic metabolic products: ammonium (r=0.75), hydrogen sulphide (r=0.45) and phosphate (r=0.68) anaerobic metabolic products. This correlation indicated the significant proportion of anaerobic sulfate-reducing bacteria. The impact of physico-chemical parameters on bacterioplankton biomass during the June-November growth season was clearly illustrated in the correspondence canonical analysis (CCA). This recorded its greatest mass at 15 to 17 metres above the lake bed. Although no clear seasonal variations were noted in bacterioplankton composition described by Denaturing Gradient Gel Electrophoresis (DGGE). The monimolimnion lake layer contained 46 Operational Taxonomic Units (OTUs). Subsequent comparison of the upper and lower minimolimnion layers showed 37 of these OTUs were common, while 5 were unique in the upper monimolimnion strata and 4 in the lower layers.

Characterization of Thrombolitic Bioherm Cyanobacterial Assemblages in a Meromictic Marl Lake (Fayetteville Green Lake, New York)

The Fayetteville Green Lake is a small (0.258 km2) meromictic marl lake that is host to a thrombolitic bioherm inhabited by coccoid and filamentous cyanobacteria. To date there has been only limited study of bioherm cyanobacterial community ecology, and none focusing on their molecular diversity. Samples of the bioherm were collected along vertical and spatial transects on a portion of the thrombolite in early fall 2010. Cyanobacterial assemblage spatial variability and operational taxonomic unit composition was analyzed by automated rRNA intergenic spacer analysis (ARISA). A total of 123 cyanobacterial ARISA operational taxonomic units were observed across all fingerprints. Cyanobacterial assemblages were variable across depth and spatial gradients, and may be structured by gradients in light availability and habitat stability. Cyanobacterial community fingerprints were more taxonomic unit rich, diverse, and had greater fingerprint similarity in deeper samples than those at the surface. Several operational taxonomic units were common to all samples taken, while the majority of assemblage components were heterogeneous between transects and depths. Hence, our results suggest that cyanobacterial communities on the thrombolite in Green Lake represent a mixture of taxa that are selected for by prevailing physicochemical conditions, while other taxa are selected for on spatial scales of meters and may represent more specialized cyanobacteria on the thrombolite. Moreover, our data suggest that the depth-dependent structure of bioherm cyanobacterial assemblages may be a consequence of habitat conditions, which may include light intensity and quality, temperature variation and habitat stability.

Double‐diffusive deep water circulation in an iron‐meromictic lake

From a small meromictic lake, we present observations of a circulation pattern that has not been documented in the limnological literature before. While surface cooling drives a vertical circulation of the upper water layer (mixolimnion), the deeper water layer (monimolimnion) is not included because of its higher salt concentration. However, double diffusion (higher diffusivity of heat than of dissolved substances) facilitates the faster escape of heat from the monimolimnion compared to dissolved substances during cold periods. As a consequence, interfacial cooling drives a vertical circulation within the monimolimnion without breaking the stratification toward the mixolimnion. In the presented case, the geochemical setting does not permit dissolved substances to accumulate in the mixolimnion. As a consequence, the system approaches the case of two immiscible layers in thermal contact. Below the interface, a convection layer is formed that exceeds the staircase layer thickness of double diffusion when conservative salts are involved. Finally, the entire lake circulates as two separate convection layers. This has a decisive impact on the formation of gradients and the redistribution of dissolved substances in lakes.

Climate changes during the last glacial termination inferred from diatom-based temperatures and pollen in a sediment core from Längsee (Austria)

A sediment core section from Langsee, a small meromictic lake in the southern Alpine lowland (Carinthia, Austria) close to the Wurmian ice margin, was investigated by means of diatoms and pollen. The main aims of the study were to reconstruct water temperature as a signal of climate change during the last glacial termination, compare the aquatic and terrestrial response to the changing climate, and place our findings into a climatic frame on the northern hemispheric scale. A calibration data set (ALPS06) of 116 lakes was constructed using data from newly studied lakes and from two previously published data sets and we established a transfer function for predicting summer epilimnetic water temperatures (SEWT). A locally weighted weighted average regression and calibration model (R jack 2 = 0.89; RSMEP = 1.82°C) was applied to the fossil diatom assemblages in order to reconstruct SEWT. Three major sections were distinguished in the time window of approximately 19–13 cal ka BP, which fitted well with the oxygen isotope curve and the isotope-event stratigraphy from the Greenland ice-core GRIP. The first section was a warming period (SEWT range from 11.6 to 18.0°C; average 15.8°C = ca. 6°C below present) called the Langsee oscillation, which probably correlates with the warmer sub-section (GS-2b) of the Greenland Stadial 2. The subsequent section represents a climate cooling, called the Langsee cold period (SEWT range between 10.6 and 15.9°C; average 12.9°C), which probably corresponds with the sub-section GS-2a of the Greenland Stadial 2, the Heinrich 1 cold event of the North Atlantic, and partially the Gschnitz Stadial in the Alps. The Langsee cold period shows a tri-partition: Two colder phases are separated by a warmer inter-phase. The passive ordination of the core sample scores along maximum water depth indicated that the Langsee cold period was drier than the Langsee oscillation. Strong short-term fluctuations during the Langsee oscillation and the Langsee cold period indicate climate instability. The third section represented climate warming during the Langsee late glacial interstadial (=Greenland Interstadial 1, GI-1) with an average SEWT of 17.5°C. From the minor climatic fluctuations during this interstadial, mainly indicated by pollen, the fluctuation most likely related to the Gerzensee oscillation showed a SEWT decline. During the early immigration and expansion period of shrubs and trees, aquatic and terrestrial records showed distinct discrepancies that might have arose because of time lags in response and differences in sensitivity.

Distribution of chloropigments in suspended particulate matter and benthic microbial mat of a meromictic lake, Lake Kaiike, Japan.

We investigated the distribution of chloropigments in a small meromictic lake, Lake Kaiike, south-west Japan. In the water-column, concentrations of Chl a related to cyanobacteria, BChl a related to purple sulphur bacteria, and three types of BChl e homologues (BChls e1, e2 and e3) related to brown-coloured green sulphur bacteria, were maximal at the redox boundary. Below the redox boundary, absolute concentrations of Chl a and BChl a gradually decreased with depth, whereas BChls e remained rather constant. Suspended particulate matter (SPM) at the deeper region of the anoxic water-column was enriched in highly alkylated BChl e homologues compared with SPM at the redox boundary. The shift in the relative content of highly alkylated BChl e homologues beneath the boundary was associated with community related adaptation of brown-coloured green sulphur bacteria to changes in light quality/quantity, resulting from the optical absorption and reflectance of SPMs in the overlying water-column. Benthic microbial mats were characterized by high abundances of BChls e, in which highly alkylated homologues were substantially abundant. This suggests that the BChls e in the microbial mat may be derived from the low-light adapted brown-coloured green sulphur bacteria forming the bacterial mat.

A new Lateglacial chronostratigraphic tephra marker for the south-eastern Alps: The Neapolitan Yellow Tuff (NYT) in Längsee (Austria) in the context of a regional biostratigraphy and palaeoclimate

Längsee is a small meromictic lake in Carinthia, SE Alps, with partially varved Lateglacial sediments. The Längsee tephra correlates to the Neapolitan Yellow Tuff (NYT), an eruption from the Campanian Volcanic Province, Italy. This tephra provides a Lateglacial chronostratigraphic time marker from central Italy across the Adriatic Sea to the southeastern Alps. The Längsee tephra is discussed in the context of pollen, geochemical, and microstratigraphical data from a profundal sediment core from Längsee. The age of 14,120 cal yr BP for the NYT has been accepted from the Monticchio chronology. The timescale for the Lateglacial in the Längsee record is based on laminae counts and has been linked to calendar year ages using the NYT tephrachronological marker. Consequently, the mass expansion of Betula has been dated at 14,270 cal yr BP. The expansion of P. sylvestris started concurrent with the NYT, and about 180 yr later, at 13,940 cal yr BP, P. sylvestris forests were established. The Younger Dryas biozone at Längsee is characterized only by a slight increase in non-arboreal pollen and dominated by pine with visible variations only in pine pollen types. Differentiation of pine pollen types allowed the recognition of three minor fluctuations during the Lateglacial interstadial. Two of these oscillations tentatively have been correlated with the Aegelsee and Gerzensee oscillations in Switzerland as well as with vegetation changes in NW Germany.

Palynological evidence for Holocene palaeoenvironments from the lower Gordon River valley, in the World Heritage Area of southwest Tasmania

A Holocene palaeoenvironmental history from the World Heritage Area of southwest Tasmania is reconstructed using an 8000-year palynological record from Lake Fidler, a small meromictic lake adjacent to the lower reaches of the Gordon River. The sequence indicates that cool temperate rainforest has remained dominant in the region for at least the last 8000 years, confirming the wilderness value of this important conservation area. There is little evidence for fire in the region throughout this period and no discernible evidence for anthropogenic impact until approximately 1815 when small-scale convict logging activities commenced along the Gordon River. The record demonstrates the long-term presence of stands of one of the world's oldest living trees, Huon pine (Lagarostrobos franklinii), with significant increases in this species in the mid-to late Holocene. This expansion is evident in several Tasmanian records and is associated with declines in other important Tasmanian plant species. It is proposed that it represents a regional phenomenon possibly related to climate change. Examination of the climate signal from other Australian Holocene pollen records provides some support for this interpretation.

Association of cobalt and manganese in aquatic systems: Chemical and microscopic evidence

The distributions of cobalt and manganese in the water column of Paul Lake, a small meromictic lake located in the upper Michigan peninsula, follow remarkably Similar patterns. At the oxycline, these elements show pronounced concentration gradients. In May 1994, Co and Mn increase from detection limits to 6 nM and 3 μM, respectively. The association between Co and Mn can be attributed to the sorption of cobalt to manganese hydrous oxides, and the redox-driven interconversion between dissolved Mn and particulate Mn-oxides species, which is often mediated by micro-organisms. In this paper, we have used a multi-method approach to the study of Co:Mn association in an aquatic system. First, using equilibrium calculations, we discuss the chemical speciation of dissolved Co and Mn in the water column. Second, we present a Transmission Electron Microscopic (TEM) characterization of individual Mn-rich micro-particles. These particles were primarily observed at the oxic/anoxic transition. Micrographs confirm the biological origin of the hydrous manganese oxides. Analytical Electron Microscopy clearly establishes that Co and Fe are scavenged by micro-organisms bearing a Mn-oxide crust. Co:Mn ratios were determined on individual particles by Energy Dispersive Spectrometry (EDS). The comparison of the average Co:Mn ratio in particles to the one in solution shows that Co is enriched in the Mn-oxides overgrowths. High resolution TEM-EDS analyses of environmental particles proves to be a powerful tool to unveil chemical associations that are difficult to deduce from changes in the water chemistry.

Vertical distributions of Sb(III) and Sb(V) in Pavin Lake, France

Vertical profiles of dissolved total inorganic antimony (ΣSb), Sb(V) and Sb(III) have been determined in Pavin Lake, a small meromictic lake in France. A slight depletion of Sb(V) in the surface water is observed. The concentration is about 0.1 nM at the surface and it is about 0.35 nM at depths in the oxic water column of the mixolimnion. In contrast, an enrichment of Sb(III) at the surface is observed. The concentration is about 0.1 nM at the surface and it is undetectable at depths. Both Sb(V), thermodynamically stable species, and Sb(III), thermodynamically unstable species, are equally important species at the surface. At the depths, on the other hand, Sb(V) is the only detectable species in accordance with the thermodynamic prediction. A possible perturbation induced by biological activity is suggested. In the anoxic waters of the monimolimnion, only ΣSb has been determined. The concentration is low, less than 0.06 nM. Precipitation of antimony sulfide is suggested.

The influence of road salts on the salinity and the meromictic stability of Lake Svinsjøen, southeastern Norway

Primarily as a result of road salting, the water masses ofLake Svinsjoen, a small meromictic lake in southeasternNorway, have been subject to great changes in salinity duringthe period 1947–1995. The greatest change in saltconcentration has occurred in the upper part of themonimolimnion (depth 10–15 m) where mean conductivityincreased 104.2 per cent, from 143 to 292 μS cm−1. Inthe upper mixolimnion (depth 0-5 m), mean conductivity rosefrom 130 to 238 μS cm−1 during the same period. Theions responsible for the salinity changes were Na+ andCl− from de-icing salts, and Ca2+ and Cl− fromsalts used to keep down dust from roads. Further sources ofCa2+ are the road asphalt and increased weathering andleaching of the lime-rich rocks caused by acid precipitation,the main source of the additional inputs of SO\(_{\text{4}}^{{\text{2 - }}} \) tothe lake. The salinity changes caused major changes inmeromictic stability, S\(S\prime _c \). In the period1947-1966, S\(S\prime _c \) increased by 24 g cm cm−2,and the maximum level of meromictic stability, 125 gcm−2, was found in 1966. As a result of higher rate ofsalt accumulation in the upper part of the monimolimnion andin the mixolimnion, S\(S\prime _c \) decreased by 30 g cmcm−2 during the period 1966-1991, and a simultaneousrise in the chemocline took place. In the period 1991-1995 anadditional decrease of 26 g cm cm−2 occurred. Continuedectogenic inputs of salts through processes typical of thetime period investigated will in future further weaken thelake's meromictic stability, and may cause the demise ofmeromixis in Lake Svinsjoen, a development which may haveimportant implications for primary productivity of thelake.

A phytoplankton compartment model for a small meromictic lake with special reference to species-specific niches and long-term changes

As a first step towards a larger ecosystem model mainly the photosynthesis-light-temperature responses of phytoplankton were evaluated. The iterative procedure to optimize the prognostic value of the modelling equations is based on multiple regression analysis and residual statistics. Within the evaluations vertical, seasonal and long-term variability of phytoplankton were considered in order to identify the specific situation in the lake.

Fossil chrysophycean cyst flora in a small meromictic lake in southern Ontario, and its paleoecological interpretation

Fossil chrysophycean cysts were identified and counted from the laminated sediment core from Crawford Lake. Thirty-two morphotypes have been described, most of them for the first time. The detailed description of the cysts is presented, including scanning electron photomicrographs. The abundance of certain morphotypes appears to be related to lake paleoproductivity. On this basis, fossil cyst flora have been divided into three characteristic groups: eutrophic–, mesotrophic–, and oligotrophic–meromictic forms. Our data demonstrate that chrysophycean cyst distribution can reflect lake conditions and, therefore, are potentially useful in paleoecological studies.

Vertical distributions of zooplankton and population dynamics of Daphnia in a meromictic lake

Vertical distributions of zooplankton were studied in relation to profiles of temperature, oxygen and chlorophyll a in Roi Lake, a small meromictic lake in central Alberta. Zooplankton were distributed fairly evenly through the oxygenated part of the water column in early summer, but a gradual descent of several species became evident in June. The vertical distribution of chlorophyll was dominated by a huge peak at the 8- to 9-m-deep chemocline. the location of a plate of photosynthetic sulfur bacteria. Ambient concentration of chlorophyll was a poor predictor of the numbers of zooplankton and the fecundity of Daphnia pulicaria at different depths, and per capita birth rates of Daphnia were usually highest in the surface waters. The reproductively disadvantageous restriction of daphnids to deep water by late summer and their catastrophic decline in the face of high ambient concentrations of chlorophyll suggest that factors other than temperature and food supply are important in influencing the dynamics and distribution of zooplankton in this lake.

Seasonal succession and microlamina formation in a meromictic lake displaying varved sediments

ABSTRACTIn a small meromictic lake near Toronto, Canada, a mass mortality of photosynthetic bacteria followed the ventilation of the chemocline during fall (autumn) and resulted in 3–8 g m‐2 day‐1 of organic matter being deposited as a dark layer in sediment traps which were suspended in the permanently anaerobic zone. This mass mortality of photosynthetic bacteria occurred in late autumn following the annual thermal destratification of the lake's mixolimnion. Wind mixing during this period of homeothermy resulted in the introduction of low levels of dissolved oxygen into the lake's chemocline. The ensuing mass mortality of photosynthetic bacteria resulted in the release of elemental sulphur as the sulphur‐rich bacteria decomposed and sank to the bottom of the lake. The ferrous ions in the water below a depth of 15 m in Crawford Lake reacted with this sulphur to form black ferrous sulphides and pyrite which formed a dark microlamina on the lake floor. Each dark microlamina was overlain by a light coloured (calcite‐rich) layer which was deposited each spring and summer during the 3 yr period of this study.The mechanism of microlamina formation elucidated here has been based on the examination of bi‐weekly sediment trap information. This approach has permitted an explanation of the mechanisms by which specific events such as calcite precipitation and phytoplankton seasonal succession are transcribed into the sediment record.

Productivity of algal picoplankton in a small meromictic lake

Productivity of algal picoplankton in a small meromictic lake

Cultural disturbances and trophic history of a small meromictic lake from central Canada

Cultural disturbances and trophic history of a small meromictic lake from central Canada