Lower Great Lakes Research Articles

Assessment of crAssphage as a human fecal source tracking marker in the lower Great Lakes

CrAssphage or crAss-like phage ranks as the most abundant phage in the human gut and is present in human feces-contaminated environments. Due to its high human specificity and sensitivity, crAssphage is a potentially robust source tracking indicator that can distinguish human fecal contamination from agricultural or wildlife sources. Its suitability in the Great Lakes area, one of the world's most important water systems, has not been well tested. In this study, we tested a qPCR-based quantification method using two crAssphage marker genes (ORF18-mod and CPQ_064) at Toronto recreational beaches along with their adjacent river mouths. Our results showed a 71.4 % (CPQ_064) and 100 % (ORF18-mod) human sensitivity for CPQ_064 and ORF18-mod, and a 100 % human specificity for both marker genes. CrAssphage was present in 57.7 % or 71.2 % of environmental water samples, with concentrations ranging from 1.45 to 5.14 log10 gene copies per 100 mL water. Though concentrations of the two marker genes were strongly correlated, ORF18-mod features a higher human sensitivity and higher positive detection rates in environmental samples. Quantifiable crAssphage was mostly present in samples collected in June and July 2021 associated with higher rainfall. In addition, rivers had more frequent crAssphage presence and higher concentrations than their associated beaches, indicating more frequent and greater human fecal contamination in the rivers. However, crAssphage was more correlated with E. coli and Enterococcus at the beaches than in the rivers, suggesting human fecal sources may be more predominant in driving the increases in E. coli and Enterococcus at the beaches when impacted by river plumes.

Fen development along the southern shore of Lake Ontario

Fen development along a drowned-river-mouth tributary to Braddock Bay, Lake Ontario was studied to address its formation. Nested piezometers were installed to assess groundwater contributions and obtain water chemistry samples. Soil and geology information came from existing sources. We converted paleo lake levels from published reports to IGLD1985 and calendar years BP for use in analyzing vegetation changes over time using a combination of peat-core plant macrofossils and modern surveys. Piezometer data showed upward discharge, water at 3-m depth had pH 6.9, specific conductivity of 508 µS/cm, and alkalinity 206 mg/L as CaCO3. Hydraulic head and mineralized water chemistry decreased at shallower depths. Vegetative development began 1790 cal yr BP with sedges and brown moss when land surface was 0.135 m above lake level. Lake levels increased, and by 1590 cal yr BP, water was 0.17 m deep and sedges were joined by shoreline emergent species. Water depth then increased to 0.525 m but began decreasing as lake levels fell. Peatland species appeared around 810 cal yr BP when water depth was reduced to 0.225 m. About 585 cal yr BP, additional peatland species appeared when land surface was 0.075 m above lake level. Sphagnum became prominent 80 cal yr BP (0.81 m above lake level), representing 67 % mean cover in modern vegetation. Isolation of the surface from calcareous groundwater resulted in transition from rich fen to poor fen. These wetlands are rare in the lower Great Lakes and deserve protection of their characteristic hydrology, water chemistry, and vegetation structure.

The Nelson stone tool cache, North-Central Ohio, U.S.A.: Assessing its cultural affiliation

The Nelson stone tool cache was discovered in 2008 in Mount Vernon, Ohio. The cache does not include any diagnostic materials, and independent age control is unavailable. Although aspects of its 164 bifaces are suggestive of a Clovis affiliation – including the occasional occurrence of unmistakable flute scars – nearly all are in the early- to mid-stages of production, there are no definitive finished Clovis fluted points that would make it possible to assign the cache to that time period. To ascertain its cultural affiliation, we undertook a detailed qualitative and quantitative comparison of the Nelson cache bifaces with ones known to be both Clovis and post-Clovis in age. We also conducted geochemical sourcing, ochre analyses, and microwear analysis to understand the context of the cache, regardless of its age and cultural affinity. By some key measures it is consistent with Clovis caches in this region and elsewhere, but the case remains unproven. Nonetheless, if the Nelson cache is from the Clovis period, it is significant that most of its bifaces appear to be made on large flakes, in keeping with Clovis technology in the Lower Great Lakes, and an economically conservative, risk-mitigating strategy that conforms to predictions of human foragers colonizing the area in late Pleistocene times.

David W. Schindler—Icon and Iconoclast

David W. Schindler—Icon and Iconoclast

Boundaries and hybridization in a secondary contact zone between freshwater mussel species (Family:Unionidae).

Correct species identification and delineation are crucial for effective conservation and management. However, species delineation can be problematic in the presence of morphological ambiguities due to phenotypic plasticity, convergence, and/or interspecific hybridization. Here, we investigated the degree of hybridization between two closely related freshwater mussel species [Bivalvia: Unionidae; Lampsilis siliquoidea (Barnes) and L. radiata (Gmelin)] that present intermediate forms in areas of sympatry. Unionids have a distinct form of mitochondrial DNA (mtDNA) inheritance, termed doubly uniparental inheritance (DUI) where female mtDNA (F-type) is transmitted to all progeny but male mtDNA (M-type) is mostly inherited by the males resulting in mostly homoplasmic females and heteroplasmic males. An individual was identified as hybrid when F-type and M-type mtDNA of the two different species were found in the same individual. Twelve out of 116 sequenced males were identified as hybrids indicating that these species hybridize where their geographic range overlaps in the lower Great Lakes and St. Lawrence basins. Microsatellite analyses further support the occurrence of hybridization but at a larger spatial scale than indicated by the mitochondrial analyses. We also found that strong within-species population genetic structure affects the detection of purebred individuals overestimating the number of hybrids. Given the large geographic scale and proportion of hybrids found in this study, natural hybridization and introgression need to be considered when implementing local biodiversity inventories, identifying waterbodies as source of organisms for relocation and restoration projects and when setting appropriate conservation policies.

Early Maize in Northeastern North America: A Comment on Emerson and Colleagues

Emerson and colleagues (2020) provide new isotopic evidence on directly dated human bone from the Greater Cahokia region. They conclude that maize was not adopted in the region prior to AD 900. Placing this result within the larger context of maize histories in northeastern North America, they suggest that evidence from the lower Great Lakes and St. Lawrence River valley for earlier maize is “enigmatic” and “perplexing.” Here, we review that evidence, accumulated over the course of several decades, and question why Emerson and colleagues felt the need to offer opinions on that evidence without providing any new contradictory empirical evidence for the region.

Onset of the Paleoanthropocene in the Lower Great Lakes Region of North America: An Archaeological and Paleoecological Synthesis

Beyond its centrality to debates on the definition of a global chronostratigraphic geologic unit, the Anthropocene concept has served as a useful theoretical construct with which to assess regional-scale anthropogenic impacts on prehistoric ecological systems through the recognition of earlier “Paleoanthropocene” events predating the onset of modern, industrial, global-scale effects. To this end, we present data derived from the archaeological and paleoecological records of the lower Great Lakes region of northeastern North America to evaluate the nature, magnitude, and timing of Native American land use impacts over the course of the Holocene. We identified three phases of emerging and progressively intensifying anthropogenic influence coinciding with initial human paleopopulation increase (5400–2500 BP), regional introduction of maize (Zea mays; 2500–1100 BP), and the regional adoption of maize-based agriculture (1100–300 BP). Each phase was accompanied by notable shifts in one or more proxy indicators of amplified fire regimes (increased soil charcoal deposition, higher lake sediment charcoal influx, greater percentages of fire-tolerant pollen taxa), decreased forest canopy density (increased herbaceous pollen taxa, enriched speleothem δ13C values), paleopopulation growth (increased archaeological 14C date frequencies), and dietary innovations (increased cultigen 14C date frequencies, enriched pottery residue δ13C values). Although prominent climate excursions also greatly influenced forest species composition, forest structure, and disturbance regimes, demographic and cultural factors impinging on Native American subsistence regimes and settlement patterns became increasingly important modulators of ecological processes over the course of the Holocene.

Learning from Each Other: a Communities of Practice Approach to Decorative Traditions of Northern Iroquoian Communities in the Late Woodland

In this paper, we employ a communities of practice approach to investigate precontact childhood social learning and pottery production in the Lower Great Lakes. Until recently, there has been an implicit assumption that childhood learning involved primarily parent-child interactions. Building on current research that has begun to improve understanding of Indigenous socialization strategies, we apply a multi-scalar decorative analysis to investigate traditions of learning among potting communities in Southern Ontario and upstate New York, from ca. 900–1650 CE. Through a series of statistical analyses, we demonstrate a remarkable continuity in motif practices by child potters that is not evident among skilled potters, who were more impacted by social, demographic, and economic changes in their communities. The multi-generational tradition spanning at least 750 years leads us to suggest that child potters learned primarily in child groups through peer-to-peer learning. Although peer-to-peer learning has been observed ethnographically, this practice has often been overlooked in archaeology and warrants further inquiry.

Evolutionary trajectory of fish Piscine novirhabdovirus (=Viral Hemorrhagic Septicemia Virus) across its Laurentian Great Lakes history: Spatial and temporal diversification.

Piscine novirhabdovirus = Viral Hemorrhagic Septicemia Virus (VHSV) first appeared in the Laurentian Great Lakes with large outbreaks from 2005 to 2006, as a new and novel RNA rhabdovirus subgenogroup (IVb) that killed >30 fish species. Interlude periods punctuated smaller more localized outbreaks in 2007, 2010, and 2017, although some fishes tested positive in the intervals. There have not been reports of outbreaks or positives from 2018, 2019, or 2020. Here, we employ a combined population genetics and phylogenetic approach to evaluate spatial and temporal evolutionary trajectory on its G‐gene sequence variation, in comparison with whole‐genome sequences (11,083 bp) from a subset of 44 individual isolates (including 40 newly sequenced ones). Our results show that IVb (N = 184 individual fish isolates) diversified into 36 G‐gene haplotypes from 2003 to 2017, stemming from two originals (“a” and “b”). G‐gene haplotypes “a” and “b” differed by just one synonymous single‐nucleotide polymorphism (SNP) substitution, remained the most abundant until 2011, then disappeared. Group “a” descendants (14 haplotypes) remained most prevalent in the Upper and Central Great Lakes, with eight (51%) having nonsynonymous substitutions. Group “b” descendants primarily have occurred in the Lower Great Lakes, including 22 haplotypes, of which 15 (68%) contained nonsynonymous changes. Evolutionary patterns of the whole‐genome sequences (which had 34 haplotypes among 44 isolates) appear congruent with those from the G‐gene. Virus populations significantly diverged among the Upper, Central, and Lower Great Lakes, diversifying over time. Spatial divergence was apparent in the overall patterns of nucleotide substitutions, while amino acid changes increased temporally. VHSV‐IVb thus significantly differentiated across its less than two decades in the Great Lakes, accompanied by declining outbreaks and virulence. Continuing diversification likely allowed the virus to persist at low levels in resident fish populations, and may facilitate its potential for further and future spread to new habitats and nonacclimated hosts.

Long-term changes in the autumn migration phenology of dabbling ducks in southern Ontario and implications for waterfowl management

Delays in waterfowl autumn migration have been widely reported by hunters and ornithologists throughout North America. The implications of such delays are vast, with potential effects on the efficacy of population management, reduced social and economic opportunities, and reduced resource availability by overuse and over-grazing in key staging areas. In this study, we tested for changes in autumn migration timing for six abundant species of dabbling ducks in southern Ontario, Canada. We applied generalized linear mixed models to test for effects of year and climate indices El Nino Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) on the Julian date of peak abundance as observed during aerial surveys conducted throughout the lower Great Lakes. Our analyses revealed delays of 11–18 days between 1968 and 2011 for four of six focal species: mallard, American black duck, American wigeon and gadwall. La Nina and El Nino events had no effect on migration timing for American black duck, American green-winged teal or American wigeon, while an increase in the annual NAO index resulted in a delayed migration for American wigeon. There was an NAO:ENSO interaction for mallard and gadwall migration; an increase in NAO advanced peak migration dates during La Nina events. However, an increase in NAO delayed migration for gadwall during the neutral phase of the ENSO and delayed migration for both species during El Nino events. Blue-winged teal and American green-winged teal showed no change in migration timing. Given that climate forecasts indicate continued positive-value phases, the autumn migrations for mallard, American black duck, gadwall and American wigeon may become increasingly delayed. Wildlife managers should use all available data, including from standardized aerial surveys, citizen science and climate models to inform and direct adaptive population management, hunting regulations, wildlife emergency response and habitat conservation.

Trends in herring gull egg quality over four decades reflect ecosystem state

Egg quality (size, energy density) is important in determining early survival of birds. Here, we examine temporal (1981–2019) trends in herring gull (Larus argentatus) egg volume and energy density at breeding colonies on all five Laurentian Great Lakes. Temporal declines in egg volume were observed at 4/6 colonies on the upper Great Lakes (Lakes Superior, Michigan, Huron). On the lower Great Lakes (Lakes Erie, Ontario, and connecting channels) egg volume declined at 3/8 colonies and increased at one site. Egg energy density (kJ/g of egg contents) declined at 4/6 upper Great Lakes colonies and at 2/8 lower Great Lakes colonies. All of the upper Great Lakes colonies showed declines in either egg volume or energy density, or both, and these declines were related to dietary markers in eggs (fatty acids, stable nitrogen and carbon isotopes). On the lower Great Lakes and connecting channels, declines in egg volume or energy density were related to dietary endpoints in 3/5 instances. An information-theoretic approach indicated that trends in egg volume were best explained at the colony level while egg energy density trends were best explained by lake of origin. Diet-related declines in herring gull egg quality are likely a reflection of broad-scale ecosystem changes limiting aquatic food availability for gulls, particularly on the upper Great Lakes. These changes may be contributing to population declines in herring gulls and other surface-feeding aquatic birds. This study highlights the value of long-term monitoring of wildlife for identifying ecosystem change.

Extended U.S. Tornado Outbreak During Late May 2019: A Forecast of Opportunity

AbstractThe second half of May 2019 was an unusually active period for tornadic thunderstorms across the U.S. Great Plains, Midwest, and lower Great Lakes. While this period typically coincides with the peak climatological frequency of tornadoes, preliminary reports of tornadoes were over triple the expected 30‐year average. Multiple‐day outbreaks of tornadoes are not unprecedented in the United States; however, this event was perhaps the first to be forecast at subseasonal lead times (3–4 weeks) by the Extended Range Tornado Activity Forecast team. This forecast of opportunity was driven, in part, by anomalous convective forcing in portions of the tropical Indian and Pacific Oceans, causing subsequent changes in Northern Hemisphere atmospheric angular momentum. This manuscript analyzes the evolution of hemispheric‐scale circulation features leading up to the event, examines teleconnection processes known to influence U.S. tornadoes, and provides insights into the forecast process at subseasonal lead times.

Relationships between the distribution and abundance of the invasive faucet snail (Bithynia tentaculata) and environmental factors in Laurentian Great Lakes coastal wetlands

The faucet snail (Bithynia tentaculata) was introduced to the Great Lakes region in the late 1800s. Faucet snails alter native community dynamics and are an intermediate host for multiple trematode parasites that can be lethal to waterfowl when the snails are consumed. Although faucet snails have been established in the Great Lakes for over a century, their populations appear to have remained small for most of this period and their known distribution was limited to the lower Great Lakes, though basin-wide surveys were lacking until recently, so snails may have gone undetected. We compiled data from a five-year coastal wetland monitoring program spanning all of the Great Lakes, providing a basin-wide inventory of faucet snail populations and confirming the snail’s presence in every Great Lake. Further, we identified potential drivers of faucet snail occurrence and abundance (individuals per sampling replicate) across the basin and within individual lakes to identify factors that could lead to elevated risk of range expansion. Across the basin and within individual lakes, faucet snail occurrence was related to human recreational transport (proximity to a boat launch) and eutrophication (anthropogenic land-use, elevated nutrient concentrations). In addition, at sites where faucet snails occurred, they were most abundant at wetlands with surrounding forest cover, suggesting that the species can thrive in a range of environmental conditions. Our results suggest that limiting passive transport of faucet snails is vital to minimizing their spread to remote wetlands where the snails may thrive once established.

Morphometric differentiation and gene flow in emerald shiners (Notropis atherinoides) from the lower Great Lakes and the Niagara River

Abstract Differences in habitat (e.g., water velocity, prey, and predator regimes) are a driving force causing adaptive divergence among fish populations. This study used geometric shape analysis to assess morphological differences among emerald shiner (Notropis atherinoides) populations inhabiting the Niagara River, Lake Erie, and Lake Ontario. It was expected that emerald shiners inhabiting the two lakes would have more robust bodies and smaller heads, while river emerald shiners were expected to display more fusiform bodies with larger heads. The results of this study indicate that emerald shiners from Lake Erie and the Niagara River had a more robust form on average than individuals from Lake Ontario. Specifically, emerald shiners collected from Lake Ontario displayed more streamlined bodies and larger heads than emerald shiners collected from Lake Erie and the Niagara River. In addition, this divergence in body shape has apparently occurred despite the lack of distinct genetic differentiation as measured with microsatellite variation. Our results suggest that differences in water velocity alone may not be responsible for phenotypic variation in body shape among these emerald shiner populations, and other factors such as differences in prey or predator regimes are likely involved.

Locating Settler Colonialism in Early American History

Locating Settler Colonialism in Early American History Jeffrey Ostler (bio) Is settler colonialism simply a trendy buzzword, or will it become an enduring and useful concept in North American history in general and early American history in particular? Recent criticisms (some seen in print, some heard in conference sessions and hallways) object to theorizations and applications of settler colonialism that appear reductionist and teleological, arguably leave little room for contingency, and risk reversing advances in the field that highlight Native agency and resist declensionist narratives of Native disappearance. Other critical commentary seems to imply that settler colonialism may be a useful framework (at least for some times and places) if modified and more carefully applied, while still other commentary suggests that the concept is more or less useless, if not dangerous, and should be encouraged to expire.1 Whether or not criticisms of settler colonialism will lead to the concept's elimination is anyone's guess. In my view, however, the concept is useful not simply as a theoretical construct but because it identifies an actual historical phenomenon. For that reason, it should be interrogated and refined, but it should also be retained. In other words, in the same way that scholars who object to particular theories of capitalism seldom deny capitalism's reality, problems in theorizing settler colonialism do not mean that it does not exist. If settler colonialism is a name for an actual historical phenomenon, where and when can it be found in early American history? [End Page 443] One place is in the founding of the United States, a process beginning with the Treaty of Paris in 1763 and ending around twenty-five years later with the Constitution's ratification. Although some accounts of the coming of the American Revolution continue to focus exclusively on matters of taxation and urban protest, a growing body of scholarship, partly inspired by a general recognition that American Indians are central to early American history, has emphasized the role of the 1763 Royal Proclamation, which restricted western settlement and created uncertainties for speculators in Indian lands.2 Although this scholarship has not necessarily invoked the concept of settler colonialism, it leads to the conclusion that a central purpose of the founding of the United States was to secure the freedom to convert Indian lands into private property, a process that meant, to use settler colonialism's terminology, the elimination of Indigenous people. This purpose was revealed during the Revolutionary War through U.S. military operations against Native nations that aimed not simply to defeat Indians allied with the British but to destroy Natives' resistance to colonial settlement in general and thus gain control over their lands.3 The importance of obtaining Native lands was also evident in the making of the Constitution, which established mechanisms for funding a national army to subjugate the multinational confederacy (including Shawnees, Delawares, Wyandots, Ottawas, Potawatomis, Miamis, Chickamauga Cherokees, and others) formed to defend its Ohio Valley territories in the late 1780s and early 1790s.4 Combined with the Northwest Ordinance (1787), which allowed new states to be admitted "on an equal footing" while at the same time sanctioning genocidal war against Native nations that resisted U.S. demands for their lands, the Constitution's federalism provided a framework for containing tensions between frontier/localism on the one hand and metropolitan/national authority on the other. In doing so, the nation's founding document created the cohesion necessary to pursue elimination.5 [End Page 444] To identify the elimination of Native people as central to the United States' founding does not mean that they were actually eliminated. Although the United States claimed a good portion of eastern North America, its ambitions often exceeded its capacity, especially in its early years. But the United States was nothing if not relentless, and even after military failures, most notably the Native confederacy's defeat of Arthur St. Clair's army in 1791, the federal, state, and territorial governments continued to mobilize fresh bodies for war and thereby wear down Native resistance. Using treaties as a mechanism for dispossession, the United States chipped away at Native lands in the Southeast, the Ohio Valley, and the lower Great Lakes...

Pesticides related to land use in watersheds of the Great Lakes basin

In this study, we evaluated the distribution and concentrations of a range of neonicotinoid insecticides (NNIs) and other insecticides, fungicides, biocides and selected herbicides in watersheds that drain into the lower Great Lakes in Ontario, Canada. Polar Organic Chemical Integrative Samplers (POCIS) were deployed in 18 watersheds during late May to late June of 2016. Grab samples were also collected in 7 of these watersheds. There was generally good agreement between the time-weighted average concentrations of pesticides estimated from the POCIS and the concentrations detected in grab samples. The NNIs, thiamethoxam, clothianidin and imidacloprid, were present in several watersheds at concentrations that exceeded the Canadian Water Quality Guideline for imidacloprid of 0.23 μg/L. The new generation insecticides, flonicamid and flupyradifurone were also detected in some watersheds, which is the first report of these pesticides in the peer-reviewed literature. Atrazine, 2,4-D, dicamba, carbendazim, thiophanate methyl and several azole-based fungicides were also widely detected. Discriminant Function Analysis (DFA) indicated that a high proportion (i.e. >80%) of the watersheds could be discriminated from each other on the basis of the pattern of pesticides detected in surface waters, and the proportion of field crops in the watershed.

Migratory routes and wintering locations of declining inland North American Common Terns

ABSTRACT Common Terns (Sterna hirundo) breeding at inland lakes in North America have experienced significant population declines since the 1960s. Although management actions aimed at mitigating effects of habitat loss and predation have been largely effective, numbers continue to decline, which suggests that the population may be limited during the nonbreeding season. Between 2013 and 2015, we used light-level geolocators to track Common Terns nesting at 5 inland colonies—from Lake Winnipeg in Manitoba, Canada, to the eastern Great Lakes region of the United States and Canada—to identify migratory routes and stopover and wintering sites and to determine the strength of migratory connectivity among colonies. Within 46 recovered tracks, we found evidence of a longitudinal gradient in use of migration routes and stopover sites among colonies and identified major staging areas in the lower Great Lakes and at inland and coastal locations along the Atlantic coast, Florida, and the Gulf of Mexico. Low migratory...

Neonicotinoid pesticides in drinking water in agricultural regions of southern Ontario, Canada

Because of the persistence and solubility of neonicotinoid insecticides (NNIs), there is concern that these compounds may contaminate sources of drinking water. The objective of this project was to evaluate the distribution of NNIs in raw and treated drinking water from selected municipalities that draw their water from the lower Great Lakes in areas of southern Ontario, Canada where there is high intensity agriculture. Sites were monitored using Polar Organic Chemical Integrative Samplers (POCIS) and by collecting grab samples at six drinking water treatment plants. Thiamethoxam, clothianidin and imidacloprid were detected in both POCIS and grab samples of raw water. The frequency of detection of NNIs was much lower in treated drinking water, but some compounds were still detected at estimated concentrations in the low ng L−1 range. Thiamethoxam was detected in one grab sample of raw drinking water at a mean concentration of 0.28 μg L−1, which is above the guidelines for drinking water recommended in some jurisdictions, including the European Union directive on pesticide levels <0.1 μg L−1 in water intended for human consumption. Further work is required to determine whether contamination of sources of drinking water with this class of insecticides is a global problem in agricultural regions.

Prevalence of antibiotic resistance genes in bacterial communities associated with Cladophora glomerata mats along the nearshore of Lake Ontario.

The alga Cladophora glomerata can erupt in nuisance blooms throughout the lower Great Lakes. Since bacterial abundance increases with the emergence and decay of Cladophora, we investigated the prevalence of antibiotic resistance (ABR) in Cladophora-associated bacterial communities up-gradient and down-gradient from a large sewage treatment plant (STP) on Lake Ontario. Although STPs are well-known sources of ABR, we also expected detectable ABR from up-gradient wetland communities, since they receive surface run-off from urban and agricultural sources. Statistically significant differences in aquatic bacterial abundance and ABR were found between down-gradient beach samples and up-gradient coastal wetland samples (ANOVA, Holm-Sidak test, p < 0.05). Decaying and free-floating Cladophora sampled near the STP had the highest bacterial densities overall, including on ampicillin- and vancomycin-treated plates. However, quantitative polymerase chain reaction analysis of the ABR genes ampC, tetA, tetB, and vanA from environmental communities showed a different pattern. Some of the highest ABR gene levels occurred at the 2 coastal wetland sites (vanA). Overall, bacterial ABR profiles from environmental samples were distinguishable between living and decaying Cladophora, inferring that Cladophora may control bacterial ABR depending on its life-cycle stage. Our results also show how spatially and temporally dynamic ABR is in nearshore aquatic bacteria, which warrants further research.

A Case Study of Anomalous Snowfall with an Alberta Clipper

An Alberta clipper moved over western New York state on 11-12 January 2004, producing snowfall amounts of up to 27 cm in portions of the region during a roughly 12-h period. In addition, lightning and thunder were reported. Such systems, known primarily for their fast motion and relatively dry nature, are not generally associated with significant snowfalls. A postmortem analysis of this event, following an ingredients-based methodology, revealed that as the weak low approached the lower Great Lakes, it came under the influence of coupled 300-hPa jets that produced enhanced divergence and significant upward vertical motion over western New York, resulting in the enhanced convective snowfall over the region for a limited time. Instability and possible enhancement via the Great Lakes are also investigated, which show that while there was at least modest instability over the region during the time of heavy snowfall, lake enhancement was unlikely.