Moss Lake Research Articles

Evaluating pharmaceuticals and other organic contaminants in the Lac du Flambeau Chain of Lakes using risk-based screening techniques.

In an investigation of pharmaceutical contamination in the Lac du Flambeau Chain of Lakes (hereafter referred to as "the Chain"), few contaminants were detected; only eight pharmaceuticals and one pesticide were identified among the 110 pharmaceuticals and other organic contaminants monitored in surface water samples. This study, conducted in cooperation with the Lac du Flambeau Tribe's Water Resource Program, investigated these organic contaminants and potential biological effects in channels connecting lakes throughout the Chain, including the Moss Lake Outlet site, adjacent to the wastewater treatment plant lagoon. Of the 6 sites monitored and 24 samples analyzed, sample concentrations and contaminant detection frequencies were greatest at the Moss Lake Outlet site; however, the concentrations and detection frequencies of this study were comparable to other pharmaceutical investigations in basins with similar characteristics. Because established water-quality benchmarks do not exist for the pharmaceuticals detected in this study, alternative screening-level water-quality benchmarks, developed using two U.S. Environmental Protection Agency toxicological resources (ToxCast database and ECOTOX knowledgebase), were used to estimate potential biological effects associated with the observed contaminant concentrations. Two contaminants (caffeine and thiabendazole) exceeded the prioritization threshold according to ToxCast alternative benchmarks, and four contaminants (acetaminophen, atrazine, caffeine, and carbamazepine) exceeded the prioritization threshold according to ECOTOX alternative benchmarks. Atrazine, an herbicide, was the most frequently detected contaminant (79% of samples), and it exhibited the strongest potential for biological effects due to its high estimated potency. Insufficient toxicological information within ToxCast and ECOTOX for gabapentin and methocarbamol (which had the two greatest concentrations in this study) precluded alternative benchmark development. This data gap presents unknown potential environmental impacts. Future research examining the biological effects elicited by these two contaminants as well as the others detected in this study would further elucidate the ecological relevance of the water chemistry results generated though this investigation.

Diatom-inferred centennial-millennial postglacial climate change in the Pacific Northwest of North America

A diatom record from Moss Lake, Washington, USA spans the last 14,500 cal year and revealed Holocene climate change in the Pacific Northwest (PNW), including evidence for periodicities related to ocean-atmosphere teleconnections and/or variations in solar output. Three main climate phases were identified: (i) Late Pleistocene to early Greenlandian (until 10,800 cal year BP, spanning GI-1, GS-1), with a cold climate and low diatom abundance; (ii) early Greenlandian to Northgrippian (10,800–7500 cal year BP), shifting to a warmer climate; and (iii) late Northgrippian and Meghalayan from 7500 cal year BP onwards, with a cooler, moist climate. These climate shifts are in good agreement with the pollen record from the same core and other regional studies. Fluctuations in Discostella pseudostelligera and Aulacoseira taxa suggest climate cycles of different frequency and amplitude throughout the record. Spectral and wavelet analyses revealed periodicities of approximately 1400 and 400–500 years. We interpret the ~ 1400-year and ~ 400–500-year cycles to reflect alternating periods of enhanced (and reduced) convective mixing in the water column, associated with increased (and decreased) storms, resulting from ocean–atmosphere teleconnections in the wider Pacific region. The ~ 1400-year periodicity is evident throughout the Late Pleistocene and late Northgrippian/Meghalayan, reflecting high-amplitude millennial shifts from periods of stable thermal stratification of the water column (weak wind intensity) to periods of convective mixing (high wind intensity). The millennial cycle diminishes during the Greenlandian, in association with the boreal summer insolation maximum, consistent with suppression of ENSO-like dynamics by enhanced trade winds. Ocean–atmosphere teleconnection suppression is recorded throughout the PNW, but there is a time discrepancy with other records, some that reveal suppression during the Greenlandian and others during the Northgrippian, suggesting endogenic processes may also modulate the Moss Lake diatom record. The large amplitude of millennial variability indicated by the lake data suggests that regional climate in the PNW was characterised over the longer term by shifting influences of ocean–atmosphere dynamics and that an improved understanding of the external forcing is necessary for understanding past and future climate conditions in western North America.

CYP1A expression in freshwater fish of western New York as an indicator of pollution levels.

Various species of freshwater fish regulate the expression of certain proteins in response to environmental contamination. Previous research has shown that CYP1A expression increases in response to contaminant levels and can result in increased tumor formation. Fish in contaminated environments would thus benefit by downregulating the expression of CYP1A to reduce tumor prevalence as an adaptive strategy. Alternatively, monitoring of the CYP1A protein in fish can serve as a bioindicator of the pollution level of an environment. This study evaluated CYP1A expression in twelve different species of freshwater fish from seven bodies of water throughout western NY including Cuba Lake, Genesee River, Hanging Bog, Love Canal, Moss Lake, Rushford Lake, and Tifft Nature Preserve. Western blot analysis was used to measure CYP1A expression as a marker of site pollution and potential fish population adaptation. It was hypothesized that low CYP1A expression at a site with known contamination would suggest signs of adaptation to pollution levels present. Furthermore, if at least one sample from a species showed CYP1A expression, then the CYP1A antibody (Caymen Chemical, USA; 173132) had compatibility with that species, eliminating falsely suspected adaptation. The results from this study suggest possible adaptation of fish may be occurring in the polluted Tifft Nature Preserve and Genesee River. In contrast, CYP1A expression in fish from Cuba Lake, Hanging Bog, Love Canal, Moss Lake, and Rushford Lake appear to represent known pollution levels and adaptation is not likely occurring. Results from this study are preliminary and next steps include collection and analysis of sediment to provide a stronger correlation between pollution at sites and CYP1A expression.

Diatom-inferred aquatic impacts of the mid-Holocene eruption of Mount Mazama, Oregon, USA

AbstractHigh-resolution diatom stratigraphies from mid-Holocene sediments taken from fringe and central locations in Moss Lake, a small lake in the foothills of the Cascade Range, Washington, have been analyzed to investigate the impacts (and duration) of tephra deposition on the aquatic ecosystem. Up to 50 mm of tephra was deposited from the climactic eruption of Mount Mazama 7958–7795 cal yr BP, with coincident changes in the aquatic ecosystem. The diatom response from both cores indicates a change in habitat type following blanket tephra deposition, with a decline in tychoplanktonic Fragilaria brevistriata and Staurosira venter and epiphytic diatom taxa indicating a reduction in aquatic macrophyte abundance. Additionally, the central core shows an increase in tychoplanktonic Aulacoseira taxa, interpreted as a response to increased silica availability following tephra deposition. Partial redundancy analysis, however, provides only limited evidence of direct effects from the tephra deposition, and only from the central core, but significant effects from underlying environmental changes associated with climatic and lake development processes. The analyses highlight the importance of duplicate analyses (fringe and central cores) and vigorous statistical analyses for the robust evaluation of aquatic ecosystem change.

Baseline Ecological Risk Assessment of the Calcasieu Estuary, Louisiana: Part 1. Overview and Problem Formulation

A remedial investigation/feasibility study (RI/FS) of the Calcasieu Estuary cooperative site was initiated in 1998. This site, which is located in the southwestern portion of Louisiana in the vicinity of Lake Charles, includes the portion of the estuary from the saltwater barrier on the Calcasieu River to Moss Lake. As part of the RI/FS, a baseline ecological risk assessment (BERA) was conducted to assess the risks to aquatic organisms and aquatic-dependent wildlife exposed to environmental contaminants. The purpose of the BERA was to determine if adverse effects on ecological receptors are occurring in the estuary; to evaluate the nature, severity, and areal extent of any such effects; and to identify the substances that are causing or substantially contributing to effects on ecological receptors. This article describes the environmental setting and site history, identifies the chemicals of potential concern, presents the exposure scenarios and conceptual model for the site, and summarizes the assessment and measurement endpoints that were used in the investigation. Two additional articles in this series describe the results of an evaluation of effects-based sediment-quality guidelines as well as an assessment of risks to benthic invertebrates associated with exposure to contaminated sediment.

Concentration, Molecular Weight Distribution and Neutral Sugar Composition of DOC in Maritime Antarctic Lakes of Differing Trophic Status

The molecular weight distributions and hydrolysable neutral sugar composition of dissolved organic carbon (DOC) was investigated in four maritime Antarctic lakes on Signy Island of different trophic status; Heywood Lake (eutrophic), Light Lake (oligo-mesotrophic), Sombre Lake and Moss Lake (both oligotrophic). Tangential flow ultra-filtration (TFU) was used to separate DOC into high molecular weight (HMW; >1000 Da) and low molecular weight (LMW; 1000 Da total organic carbon and had extremely high concentrations of total hydrolysable neutral sugars (11 μM) corresponding to 43% of total DOC. However, no clear pattern was apparent with regard to lake trophic status and potential sources of DOC, and the measured variations in individual aldose concentration, composition and their various molecular weight fractions.

The structure and stability of the bacterioplankton community in Antarctic freshwater lakes, subject to extremely rapid environmental change

In this study, variation in the bacterioplankton community structure of three Antarctic lakes of different nutrient status, was determined in relation to physical and chemical gradients at depth and at time intervals, across the seasonal transition from winter ice-cover to the summer ice-free period. The three lakes studied were: Moss Lake (low nutrient, with typical nutrient concentrations of 80 μg l −1 nitrate and 10 μg l −1 dissolved reactive phosphate), Sombre Lake (low nutrient, but becoming progressively enriched, with typical nutrient concentrations of 185 μg l −1 nitrate and 7 μg l −1 dissolved reactive phosphate) and Heywood Lake (enriched, with typical nutrient concentrations of 1180 μg l −1 nitrate and 124 μg l −1 dissolved reactive phosphate). Bacterioplankton community structure was determined using a combination of PCR amplification of 16S rRNA gene fragments and denaturing gradient gel electrophoresis (DGGE). Results indicated marked changes in this bacterioplankton community structure, which were particularly associated with the transition period. However, significant changes also occurred during the period of holomixis. Comparison of the results from lakes of different nutrient status suggest that increased levels of nutrient input, and in the timing and duration of ice cover will lead to marked changes in the structure and stability of the bacterioplankton community at existing levels of environmental change.

Bacterioplankton community structure in a maritime antarctic oligotrophic lake during a period of holomixis, as determined by denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH).

The bacterioplankton community structure in Moss Lake, a maritime Antarctic oligotrophic lake, was determined with vertical depth in the water column, during the ice-free period on Signy Island in the South Orkney Islands. Bacterioplankton community structure was determined using a combination of direct counting of 4',6-diamidino-2-phenylindole (DAPI) stained cells, PCR amplification of 16S rRNA gene fragments, denaturing gradient gel electrophoresis (DGGE) and in situ hybridization with group-specific, fluorescently labeled oligonucleotide probes. Using PCR amplification of 16S rRNA gene fragments and DGGE, the bacterioplankton community composition was shown to be constant with vertical depth in the water column. Specific bacterioplankton species identified through cloning and sequencing the DGGE products obtained were Flavobacterium xinjiangensis (a Flavobacterium), Leptothrix discophora (a beta-Proteobacterium), and a number of uncultured groups: two beta-Proteobacteria, an unclassified Proteobacterium, three sequences from Actinobacteria, and a Cyanobacterium. Fluorescence in situ hybridization (FISH), however, demonstrated that there were minor but significant fluctuations in different groups of bacteria with vertical depth in the water column. It showed that the beta-Proteobacteria accounted for between 26.4 and 71.5%, the alpha-Proteobacteria 2.3-10.6%, the gamma-Proteobacteria 0-29.6%, and the Cytophaga-Flavobacterium group 1.8-23.5% of cells hybridizing to a universal probe. This study reports the first description of the community structure of an oligotrophic Antarctic freshwater lake as determined by PCR-dependent and PCR-independent molecular techniques. It also suggests that the bacterioplankton community of Moss Lake contains classes of bacteria known to be important in freshwater systems elsewhere in the world.

Ganienkeh: Haudenosaunee Labor-Culture and Conflict Resolution

Controversy has surrounded the Mohawk community of Ganienkeh in upstate New York since its inception and, to this day, passionate opinions accompany any consideration of Ganienkeh. 1 For the last dozen years, many have argued that Ganienkeh is merely a legal shelter for profiteering endeavors (such as Indian gaming or trafficking tobacco and alcohol) and the warrior society often associated with them. Others suggest that such endeavors do not fully represent the Ganienkeh community, and that, to whatever extent they are part of recent life at Ganienkeh, they are necessary adjustments to changing economic, political, and legal conditions and not signs of wholesale corruption. Far from academic, this disagreement has been at the root of violent tensions within Haudenosaunee government and society. 2 Unfortunately the intensity and complexity of recent developments and debates obscures a different story of Ganienkeh. Ganienkeh's founding was a rare case of Indigenous people reclaiming land from the United States. What motivated the Ganienkeh Mohawks to move so boldly, what sustained them during the years of conflict resulting from their action, and what can be learned from the Ganienkeh conflict and its resolution? Contemporary perceptions and understandings of Ganienkeh are too charged to provide sufficient context to answer questions about Ganienkeh's origins or its broader significance to Haudenosaunee-American interaction and other conflicts arising from that interaction. Therefore, without denying their significance, this article will set aside more recent controversies associated with Ganienkeh and ground an analysis of the conflict in sources generated during the conflict itself. When the Ganienkeh conflict is viewed outside the controversies of today, Haudenosaunee labor-culture stands out as a motivating and sustaining force within the Ganienkeh community as it sought to re-establish its claim on Haudenosaunee land and a Haudenosaunee way of life. Two aspects of the Ganienkeh conflict are the focus of this paper: the public discourse pertaining to the dispute and the negotiation process between the [End Page 1] state of New York and the Ganienkeh Mohawks which sought to end it. 3 I will begin by presenting historical and scholarly background on the Ganienkeh conflict. Then I will primarily attempt to show that differences between Haudenosaunee and American labor-cultures strongly contributed to the cause and continuation of the dispute while also providing a common focal point for public and official communication between otherwise disparate parties. In the process I hope this discussion of the Ganienkeh conflict connotes the possibility that labor concerns should figure prominently in discourse about other conflicts and Indigenous life in general. The Beginning of the Ganienkeh Conflict May is a precious "between time" in the Adirondack mountains of New York State when the snow is finally melting, the whine of recreational snowmobiles is fading, and stampedes of summer residents and tourists have not yet doubled or tripled a town's population. The small communities of Moose Lake and Eagle Bay probably spent 13 May 1974, like most days in May, subtly shifting the conversation from complaints about snow to complaints about mud and generally enjoying the "month between." The dawn of 14 May, however, found early arrivals for the summer season of 1974. Under cover of darkness a well-armed group of Mohawks had traveled down from reservations along the Canadian-U.S. border and occupied some six hundred acres of nearby state land, which encompassed a closed girl's camp and a body of water called Moss Lake. As a standoff developed between local residents, the New York State Police, and the Mohawks, the obscure mountain communities near Moss Lake quickly became national news. It was soon clear that, unlike tourists, the Mohawks were not leaving after the fall foliage passed. Over a year later, on 6 July 1975, The New York Times ran an article by Richard Severo describing the ongoing conflict. 4 Severo recounted that in 1797 Joseph Brandt, a Mohawk of disputed status, signed away nine million acres of Mohawk land to New York State for fifteen...

Rock-magnetic Study of Gold Mineralization Near a Weakly Deformed Archean Syenite, Thunder Bay, Canada

Gold mineralisation occurs near granitoid plutons in the Shebandowan granite-greenstone belt of the Superior Province in the Canadian Shield. Conventional structural and petrographic observations show that the Moss Lake Syenite pluton escaped penetrative, deformation. Nevertheless, anisotropy of magnetic susceptibility (AMS) reveals a well-developed, consistent, cryptic magnetic fabric, largely due to multidomain magnetite. The magnetic foliation is subparallel to the earlier schistosity and reveals the dissipating, stress field that was insufficient to produce conventional tectonic fabrics in the syenite. Palaeomagnetic studies reveal that the characteristic remanence carried by magnetite scatters around the known palaeofield for this region. The feeble strain that imposed the (AMS) magnetic fabric barely affected the palaeomagnetic signal. Gold mineralisation occurs where shear zones intersect the eastern margin of the pluton. Late haematisation concentrates in the auriferous sheared zones. Unlike the palaeomagnetic signature of magnetite, haematite-remanences disperse in a plane parallel to the schistosity due to tectonic effects rather than magnetic refraction. We infer that the shear-zones' haematite-remanences developed after the post tectonic, cryptic magnetic fabric was imposed on the pluton. Since gold is found in the haematised shear zones, we infer that gold mineralisation may postdate the feeble, regional deformation of the syenite and is therefore clearly postmagmatic.

The construction of a diatom‐based chlorophyll a transfer function and its application at three lakes on Signy Island (maritime Antarctic) subject to differing degrees of nutrient enrichment

SUMMARY1. Canonical correspondence analysis of a diatom and water chemistry dataset from fifty‐nine maritime Antarctic lakes situated on Signy and Livingston Islands showed that nutrients and functions of nutrients (NH4+, chlorophyll a) accounted for a significant fraction of the variance in the diatom data.2. Weighted averaging regression was used to construct a diatom‐based transfer function for inferring chlorophyll a concentrations from sediment core diatom assemblages.3. The transfer function was applied to 210Pb‐dated sediment cores from three lakes (Moss, Sombre and Heywood) receiving different levels of nutrient input from fur seal populations, i.e. low, medium and high, respectively.4. Moss Lake showed relatively stable reconstructed chlorophyll a values, and no evidence of recent eutrophication, agreeing with measured chlorophyll a concentrations at the site.5. Changes in diatom assemblages and results of chlorophyll a reconstructions at Sombre Lake suggested that nutrient enrichment had occurred, which could be clearly linked to fluctuations in the measured water chemistry over the last 10–14 years.6. Despite recorded increases in recent nutrient inputs there was no apparent diatom response at Heywood Lake.

Magmatic sulphide/volatile interaction as a mechanism for producing chalcophile element enriched, Archean Au-quartz, epithermal AuAg and Au skarn hydrothermal ore fluids

A combination of available geological, geophysical and geochemical evidence indicates that significant parts, or components, of Archean Au-quartz vein, epithermal AuAg and Au skarn ore fluids were magmatically derived, and that Au, Ag and associated, enriched elements were also magmatically derived (e.g., Giggenbach, 1986; Henley and Hoffmann, 1987; Sillitoe, 1989; Sillitoe and Bonham, 1990; Spooner, 1991 a,b). There is a significant core of commonality in element occurrence in Archean Au-quartz vein, Archean Hemlo-type, epithermal AuAg and Au skarn systems which suggests a shared genetic process. For instance, 44% ( n=12) of 27 elements occur in more than seven of ten ore deposit subdivisions: Au, Ag, Fe, Cu, Pb, Zn, Hg, Mo, Sb, As, Te and S (nine metals; two metalloids: one non-metal). Addition of B and W gives 52% ( n=14) in more than five subdivisions. The frequency of occurrence of enriched chalcophile/siderophile elements is high at 85%; 23 out of 27. The converse is also high at 74% (23 of 31): all significant chalcophile/siderophile elements occur enriched in Archean Au-quartz vein, Archean Hemlo-type, epithermal AuAg and Au skarn deposits. However, if magma volatile saturation occurred after gravitational loss of magmatic sulphide melt/suspended solids, then Au, Ag and associated chalcophile elements would have been effectively removed from the magma because of known high sulphide-melt/silicate-magma partition coefficients of ∼ 10 2–10 4 (e.g., Au at ∼ 3×10 4; Se at ∼ 10 3). Hence, it is proposed that Archean Au-quartz vein, Archean Hemlo-type, epithermal AuAg and Au skarn ore fluids derive their characteristic element enrichments by high-temperature fluid/vapour dissolution of magmatic sulphide-liquid droplets/solids ( T<∼ 1010–1050°C) enriched in Au and associated elements (e.g., 1–13 ppm Au in MORB sulphide globules; Mathez and Peach, 1989) in mafic/intermediate igneous compositions before sulphide loss. The key components of the mineralization enrichment process are sulphide melt/silicate magma partition, during which ore-grade Au concentrations can be produced from non-anomalous background Au abundances of ∼ 1 ppb (enrichment factor=∼ 10 4), high aqueous-phase sulphide solubilities at high temperatures (e.g., Hemley et al., 1986; to 600°C), and selective Au precipitation. Support for this hypothesis is provided by: (a) the element association in Au skarns which shows 81% and 75% overlaps with associations in epithermal AuAg and Archean Au-quartz vein systems, respectively; (b) being able to explain enrichments of a variety of low-abundance elements simply because they are chalcophile (e.g., Se, Tl; Sb, Hg, Bi, As, Te; Ni, Co, Cd, Pd, Pt; Mo, W as scheelite); and (c) being able to explain a tendency for certain large AuAg systems to occur associated with volatile-rich (e.g., subduction zone magmas, 3–7 wt% H 2O; sodic alkaline magmas, ∼ 0.5–1 wt% H 2O; c.f., ∼ 0.1 wt% H 2O in MORB), more mafic/intermediate magma compositions (e.g., Au skarns, Meinert, 1989; Hollinger-McIntyre, ∼ 995 tonnes Au; Ashanti, ∼ 710 tonnes Au; Cripple Creek, ∼ 590 tonnes Au; Ladolam, ∼ 570 tonnes Au; Porgera, ∼ 410 tonnes Au; Kerr Addison-Chesterville, ∼ 335 tonnes Au; Emperor, Fiji, ∼ 120 tonnes Au). On the basis of well-defined igneous intrusive associations, the typical presence of H 2OCO 2 low-salinity ore fluids, and particularly the presence of carbonate ( δ 13C=−4.5±0.6‰) and a chalcophile element association (AuAgSFeCuPbZnMoWAsSbBiTe) which is very similar to those of Archean Au-quartz vein, epithermal AuAg and Au skarn ore systems, a magmatic origin for Cordilleran Au-quartz vein ore systems may be assessed (e.g., Sierra Nevada Au province, California; ∼ 3,150 tonnes Au; Clarke, 1970). This proposal can explain why Archean Au-quartz and, particularly, epithermal AuAg systems occur associated with several different magma series such as calc-alkaline, shoshonitic, sodic alkaline with and without TiNbTa subduction depletions, and components of the Archean tonalite-trondhjemite-granodiorite (TTG) association. These series share a common property of being relatively volatile-rich, thus causing magmatic volatile saturation in more mafic compositions before loss of magmatic sulphide. This process is essentially unavoidable, and should have repeated in space and time. Implications for mineral exploration include a justification for large-tonnage, low-grade Au targets in, or related to, mafic/intermediate intrusions in Archean terrains (e.g., Moss Lake, N.W. Ontario; diorite hosted, >65 mtonnes at ∼ 1 g/tonne Au; >65 tonnes Au) and a justification for evaluating mafic, sodic and potassic alkaline complexes.

Response to Hauptman's Review of Sovereignty and Symbol

After reading Hauptman's (1990) review of my book, Sovereignty and Symbol: Indian-White Conflict at Ganienkeh, I feel compelled to address the numerous errors and misrepresentations the review contains. They begin with the false statement, after reference to events at the Moss Lake site of Ganienkeh from 1974 through 1977, that Gail H. Landsman ... was a witness to these events. This is a curious statement, because I certainly make no such claim. My book states that my fieldwork began in December 1979, after the occupation of Moss Lake was over and the community of Ganienkeh (and the dispute over it) had moved to the town of Altona. I was no more a witness to the Ganienkeh takeover or the shootings of Stephen Drake and Aprile Madigan than any other interested person reading newspaper reports at the time. As the first chapter of my book is quite explicit about both the methods I employed and the somewhat unusual circumstances of doing fieldwork in a dispute setting, it is particularly surprising that Hauptman makes such a mistake. However, this inaccuracy pales by comparison to the fact that his review addresses only a small portion of my book. Except for the brief acknowledgment that I provide some information about the non-Indian

Trace element concentrations in fish from three Adirondack lakes with different pH values

Concentrations of 29 elements were detected in the axial muscle, and 44 elements were detected in the gut contents of white suckers (Catostomus commersoni) and yellow perch (Perca favescens) from three lakes located in the New York State Adirondack Preserve. The study lakes were acidic Darts Lake, variable pH Lake Rondaxe, and circumneutral Moss Lake. For the majority of the elements, there were no clear differences in the muscle concentrations among fish inhabiting the three types of lakes.

Fish species distribution in relation to water quality gradients in the North Branch of the Moose River Basin

The distribution of fish species in the North Branch of the Moose River (Lake Rondaxe to headwaters of Big Moose Lake) was determined by intensive netting and electrofishing surveys of lakes and streams in the watershed during 1982–83. A chronology of changes in fish species occurrence in the drainage system was reconstructed from earlier published surveys conducted in 1882 and 1931 and unpublished survey data obtained by the NYSDEC during the period 1948–1975. Native species present in 1882 were also collected in 1931. Smallmouth bass (Micropterus dolomieu) were introduced in the early 1900's and were present in collections made in 1931. Major changes in the fish community have taken place since 1931. The smallmouth bass and many of the native species found in the earlier surveys were either absent or restricted in occurrence to downstream sites (eg. L. Rondaxe and Moss L. sub-drainage) in 1982. Non-native species introduced after 1931 (yellow perch,Perca flavescens; central mudminnow,Umbra limi; banded killifish,Fundulus diaphanus) are currently widely distributed throughout the drainage system. In particular, the yellow perch is now a dominant species in the larger lakes of the basin. Comparisons of survival rates for caged fish transferred from high to low pH sites in the Big Moose drainage system demonstrated relatively greater acid tolerane of non-native species (yellow perch, mudminnow, killifish) than native cyprinids. Watershed acidity gradients (pH and aluminum concentrations) and relative physiological acid tolerance are major determinants of currently observed fish species distribution patterns in the North Branch of the Moose River. Differences in age and size structure of fish populations inhabiting acidic and non-acidic lakes of the drainage system were apparent, but difficult to interpret without additional information onpopulation size and potential density dependent parameters such as age specific growth and survival rates. Differential hatching success was observed for yellow perch eggs reciprocally transferred between acid (Big Moose) and neutral (Moss L.) lakes. Eggs transferred from Moss L. to Big Moose L. exhibited poor hatching success as a result of alterations in egg membrane structure that inhibited normal egg expansion and the hatching process. This effect was not evident in eggs from the same parents reared in Moss Lake nor in eggs from the Big Moose parents reared in both lakes. These experimental observations suggested possible genetic adaptation to acid stress by the yellow perch population inhabiting Big Moose Lake.

Seasonal microbial activity in Antarctic freshwater lake sediments

Seasonal fluctuations in population numbers and activity were monitored in bottom sediments of oligotrophic Moss Lake, mesotrophic Heywood Lake and eutrophic Amos Lake on Signy Island, South Orkney Islands, during 1976–78. Heywood and Amos Lakes became anoxic under winter ice cover (8–10 months) and significant populations of facultatively anaerobic heterotrophs and sulphate-reducing bacteria developed. In contrast, Moss Lake surface sediments never became anoxic and anaerobic bacteria were virtually absent. Direct microscopic counts and viable plate counts fluctuated relatively little in Moss Lake throughout the study period, whereas distinct seasonality was observed in the more enriched lake systems. Similarly, measurements of oxygen consumption and dark 14CO2 uptake by mud cores indicated no obvious seasonal fluctuations in Moss Lake data, in contrast to the marked seasonal pattern observed in data from the other lakes. In these latter systems, oxygen uptake rates were highest in summer (c. 400 mg O2 m-2 d-1) and virtually undetectable in winter. Comparison of oxygen uptake with oxygen concentration and temperature revealed differences, between lakes, in uptake response to oxygen concentration, whereas uptake response to temperature did not differ significantly between lakes. Chemosynthetic production in the Signy Island lake sediments was in the range 1.6–35.3 μg C m-2 (mud surface) d-1 with highest values recorded in Amos Lake under winter ice cover and anoxic conditions. The findings from this and earlier studies of the three lakes have been assembled to indicate the relative importance of green plants and bacteria to the carbon cycle in these permanently cold systems.

The Production Ecology of Benthic Plants in Some Antarctic Lakes: I. In Situ Production Studies

(1) The vegetation of three oligotrophic lakes on Signy Island (Antarctica) is dominated by benthic algal felts and aquatic mosses, and the phytoplankton is sparse. Five seasonal factors affect underwater irradiance-daylength, the sun's elevation, iceand snow-cover and water clarity. Calculated irradiance at the bottom of the lake varies from c. 1 at midwinter to 2600 kJ m-2 day-1 in early summer. (2) Primary production of three representative benthic communities was measured in situ at monthly intervals over 11 months. Photosynthesis and respiration were estimated from changes in oxygen concentration in light and dark bottles using a semi-micro-Winkler method. There was measurable production for 9 months of the year, but the plants were below compensation point during early winter (June to early August). Compensation and light-saturation points were both at unusually low irradiance. (3) Maximum production rate (measured as oxygen evolution rate per unit ash-free dry weight, ,ug mg'1 day-1) was: Tolypothrix-Plectonema community (Sombre Lake) 10.8; Phormidium-dominated algal felt (Changing Lake) 4.2; aquatic mosses Calliergon and Drepanocladus (Moss Lake) 7.7. Calculated as equivalent carbon production, these rates are 4, 1.5 and 3 jug mg1 day1. Annual production as carbon per unit area of lake for the three communities was 9, 3-3 and 4 g m-2. (4) Comparison is made with similar lakes in the Arctic and Antarctic. The polar environment accentuates the differences between lakes dominated by either phytoplankton or by benthic vegetation.

Morphology and adaptation of aquatic mosses in an Antarctic lake

Two species of moss growing in Moss Lake on Signy Island, South Orkney Islands, had unusual morphologies with large leaves and long internodes. Both Calliergon sarmentosum and Drepanocladus cf. aduncus differed from their terrestrial counterparts and from each other in the character of their leaves. The two genera differed in the ability of the terrestrial forms to develop a large-leaved growth form. Calliergon, which was represented by the same species in both environments, changed to the aquatic morphology when separated shoots were grown either submerged or under damp conditions. Ught intensity was not an important factor influencing change in morphology. In contrast, terrestrial Drepanocladus uncinatus, the closest taxonomic counterpart of D. cf. aduncus on Signy Island, did not show any adaptation under similar conditions. The aquatic forms also showed a corresponding degree of plasticity in their natural habitat. Calliergon varied from robust shoots to microphyllous or even leafless stems whereas Drepanocladus cf. aduncus only grew in the robust form. These differences were related to the success of the two species at different depths and it is suggested that the very low compensation points of the two mosses (reported in a separate study) resulted from the morphology of the plants.

The biology of an Antarctic aquatic moss community

SUMMARY. Two species of aquatic moss (Calliergon sarmentosum and Drepanocladus sp.) occur in deep water in Moss Lake, Signy Island (60° 43′S, 45° 38′W). Their elongate stems support a structurally complex community of epiphytic algae and associated invertebrates which has a greater diversity than the surrounding benthic algal communities.Qualitative differences in the distribution and abundance of the epiphytic algae are described. Two groups of algae present on both mosses are distinguished–‘habitual’ and ‘casual’ epiphytes. On Calliergun, algae are most abundant in the leaf axil. The succession of epiphytes down the stem and the progressive deterioration of the moss plant are used to characterize six stem zones.The invertebrates are benthic and most move actively among the moss. Six species of rotifers are more or less permanently attached and show a preference for the middle stem zones where epiphyte cover is highest. Four species favour the leaf axil, the other two colonize the bare underside of the leaf.A settlement experiment has shown the importance of wind‐induced mixing in summer for the transport of some epiphytic species from shallow parts of the lake. The settlement of sessile rotifers is effected by their larvae.Photosynthesis declines from the stem apex to the dead old stem. Much of the primary production of the community is algal. The respiration maximum occurs where the highest concentration of epiphytic algae and invertebrates is found.Interrelationships between the invertebrates and the epiphytic algae are suggested and a comparison is made between these data and other studies.

Studies in the Post-glacial history of British vegetation XIV. Late-glacial deposits at Moss Lake, Liverpool

Investigations of deposits at a built-over site near the centre of Liverpool disclose a basal stratigraphic sequence characteristic of the west-European Late-glacial period. Detailed pollen analyses confirm that the deposits extended from the Late-glacial (Zone I) to the Post-glacial thermal maximum (Zone VII a ). The lake was overgrown in Zone VI by floating sphagna , and in Zone VII a typical raised bog developed. Macroscopic remains of lake and fen plants were recovered in great abundance and together with frequent non-tree pollen these permitted a detailed reconstruction of the vegetational history of both the lake and the surrounding upland. Several species of notably disjunct or restricted present-day range have been recorded here, Cotoneaster cf. integerrima Medic., Elatine hexandra (Lapierre) D.C., Lycopodium annotinum L., Pilularia globulifera L., and Linum anglicum Mill., whilst tentative identification of species such as Agropyron junceiforme, A. &amp; D. Löve, Gentiana campestris (L.), Lotus uliginosus Schkuhr, and Vicia sepium L. cast new light on the natural status of other British plants. Numerous further records confirm and extend our knowledge of the history of the British flora, especially in the Late-glacial and early Post-glacial periods.