Journal of Great Lakes Research最新文献

This study uses a one-dimensional steady-state hydraulic model and the Fluvial Egg Drift Simulator (FluEgg) to model the drift and dispersion of grass carp eggs and larvae in the Maumee River, Ohio, for 180 scenarios representing different combinations of 10 river flows, 6 water temperatures, and 3 spawning locations. The FluEgg simulations were used to quantify in-river suspended hatching rates (the percentage of eggs that hatch within the river and in suspension) and in-river larval retention rates (the percentage of larvae that reach the gas bladder inflation stage within the river after hatching in suspension), and identify which scenarios produce the highest likelihood of recruitment. The simulations indicate that at low flows, in-river suspended hatching and larval retention rates in the Maumee River are limited by the capacity of the flow to keep fertilized eggs in suspension, whereas at high flows, the limiting factor is the distance available for the eggs/larvae to drift in the river. A wide range of scenarios result in eggs hatching within the river, but all larvae drift into Maumee Bay prior to the gas bladder inflation stage when flows exceed the mean annual flow. The simulations were assessed in the context of the hydraulic conditions that trigger spawning and maximize egg fertilization and the nursery habitat requirements for larval grass carp. The results indicate that the Maumee River, although suitable for grass carp spawning, may not be an ideal setting for recruitment unless Maumee Bay provides adequate nursery habitat for larvae.

Grass carp (Ctenopharyngodon idella) are non-indigenous to North America having been translocated to the United States in the 1960s as a potential non-chemical solution for nuisance aquatic vegetation. Reproductively viable grass carp now exist in many watersheds in the United States. In the Great Lakes basin, grass carp were first discovered in the 1980s with direct confirmation of successful reproduction in 2015 via collection of fertilized grass carp eggs in the Sandusky River. Early life stage monitoring also confirmed reproduction in the Maumee River in 2017. During 2018–2021, no new spawning tributaries were discovered (18 total sampling events in five Great Lakes tributaries). In 2022, fourteen eggs with characteristics similar to grass carp were identified from the Huron River which is a tributary to Lake Erie’s Central Basin. Eggs were identified to species via DNA sequencing and were determined to be grass carp eggs. The confirmation of spawning in the Huron River represents a third spawning tributary in the Lake Erie basin and expands eastward the geographic extent of known grass carp spawning locations. Presently, the ability of the Huron River to support hatching and survival of larval grass carp is unknown. Discovery of the Huron River as a grass carp spawning tributary identifies the value of continued surveillance in Great Lakes tributaries for early life stages and conducting scientific inquiries evaluating the consistency of tributary use and survival of early life stages.

SIAL (Species in Ancient Lakes), an informal association dedicated to the study of the biodiversity, evolutionary and ecological history and conservation of ancient lakes worldwide, held its 9th International Conference at the Lake Tanganyika Beach Hotel, Tanzania in July 2022. This meeting showcased research on a wide range of SIAL related topics by about 100 attendees. Since its inception in the early 1990s, the field of SIAL studies has expanded rapidly, encompassing breakthrough technologies and data collection approaches, documenting species diversity patterns, incorporating a rapidly expanding understanding of deep time histories of these lakes through scientific drill cores, incorporating whole genome approaches to phylogenetic reconstructions, and experimental approaches to understanding such phenomena as assortative mating and sexual selection in models of ancient lake diversification. Increasingly, the SIAL community has also provided data on anthropogenic threats to these unique ecosystems from both local processes and climate change. The 10 papers assembled in this special volume provide a cross section of the presentations and concepts reviewed at the SIAL9 conference.

Control of invasive grass carp (Ctenopharyngodon idella) populations in the Western Lake Erie Basin merits adaptive management guided by the best available science. Presently (2024), capture of mature grass carp in rivers during spawning season is most efficient, so knowing when and where grass carp are spawning is essential information for natural resource agencies. Using bidirectional drift modeling and grass carp ichthyoplankton samples captured in the Maumee River during the 2017–2019 spawning seasons, this study identified 12 probable grass carp spawning areas in the lower 96.5-kilometers of the Maumee River. These spawning areas were located both above and below the Grand Rapids/Providence low-head dams. Three areas showed evidence of multiyear use, while nine had multi-event use. Spawning activity had no definitive diel variation and occurred at an average photoperiod of 15.15 h. The maturation metric ADD15, or annual degree days above 15 degrees Celsius, generally exceeded the 655 threshold for spawning; however, some spawning occurred when ADD15 ≤235, indicating spawners likely matured in a warmwater discharge. The probable spawning areas were generally characterized by mean velocities between 0.4 and 2.1 m per second (with locally higher velocities possible), areas of high turbulence produced by dam spillways or bedrock outcroppings, channel constrictions, confluences, islands, and bridges with piers in the water. Spawning suitability indices (SSI), based on velocity, varied considerably between spawning areas and SSI models. These results could be used to inform control efforts and predict potential grass carp spawning locations in other rivers under threat of invasion.

A high concentration of dissolved carbon in groundwater increases drinking water health risks and carbon transport. Understanding the comprehensive impact of hydrologic processes and geochemistry on dissolved carbon in shallow groundwater also is a fundamental prerequisite for estimating the carbon budget of lakes in the Tibetan Plateau. This study investigated the spatial–temporal characteristics of the hydrologic process, geochemistry and dissolved carbon in shallow groundwater by the stable isotope tracer method, Piper diagram and Boomerang envelope model. The driving factors of dissolved carbon in shallow groundwater were explored by correlation analysis and redundancy analysis. The results showed low dissolved inorganic carbon (DIC) concentrations and high dissolved organic carbon (DOC) concentrations during the thawing period and rainy season and high DIC concentrations and low DOC concentrations during the freezing period. The seepage velocity, soil carbon dioxide dissolution and gypsum dissolution were the main factors influencing DIC concentrations during the thawing period. The mineralization and decomposition of DOC and dissolution of carbonate rocks were the main factors influencing DIC concentrations during the freezing period. The concentrations of DOC were mainly controlled by the adsorption of Ca²⁺ and Mg²⁺, microbial activity and pollutants produced by human activities. Our results are useful for ecological sustainable development, human health, and research on the carbon transport in groundwater in the Tibetan Plateau.

Lake Ohrid is the oldest lake in Europe and has been designated as a UNESCO World Heritage Site for endemism of its biota. Its biodiversity is still not fully known and some taxa are particularly challenging to identify. DNA barcoding became a common method for the identification of such taxa and has become a crucial tool in biomonitoring and biodiversity studies. Accurate species identification through barcoding relies on curated reference libraries. Water mites are a species-rich group of ecologically important and widely distributed aquatic invertebrates for which little DNA barcoding data is available. Our study aims to develop the first reference library of COI barcodes for water mites from the ancient Lake Ohrid and surrounding springs, followed by analysis of their molecular diversity. Such libraries are well-developed for many waterbodies in Europe (e.g. Alpine Lakes), but are heavily underrepresented for the Mediterranean Region and completely absent for Lake Ohrid. We provide 327 COI barcodes clustered into 34 BINs (molecular equivalents of species) of which 6 are endemic. We identified 33 species, of which 20 are new for the Ohrid basin. We also identified several cases of intraspecific diversity suggesting morphologically cryptic species or previous misidentifications, suggesting that DNA barcoding is invaluable in the taxonomic identification of water mites. We discovered a relatively low turnover of species with neighbouring Lake Skadar, which may be a result of differences in their physical and geographical characteristics. Our study represents a major advance for the future taxonomic, phylogeographic studies and biomonitoring using water mites as model taxon.

Sampling was conducted in southeast Lake Michigan at a nearshore 17-m deep site off Muskegon, MI during 2007–2022 to evaluate how the zooplankton assemblage responds to differing environmental conditions, including temperature, tributary flow, and chlorophyll concentration. Three small-bodied groups composed over 65 % of overall zooplankton assemblage: diaptomid copepodites (24 %), Dreissena veligers (21 %), and Bosmina spp. (21 %). Dreissena veligers have become one of the predominant groups in the nearshore, whereas cyclopoid copepodites have become less prevalent compared to historical data from the 1970s and 1990s. Zooplankton composition exhibited strong seasonal patterns that reflected the life cycles of the main groups, with Bosmina, other cladocerans and veligers most important in summer when overall abundance was highest and adult or immature diaptomid copepods dominating the assemblage the rest of the year. Ordination analysis revealed differences among years in zooplankton assemblages, in particular, the three major groups, diaptomid copepodites, Bosmina, Dreissena veligers, were well separated. Both diaptomids and Diacyclops were associated with years with higher potential resource availability (i.e., tributary flow, TP, chlorophyll) and cooler temperatures. On the other hand, Bosmina were associated with years with warm spring air temperatures and low resource availability and veligers were associated with high Secchi depths. Years with strong contributions of both diaptomid and Diacyclops copepodites and adults were separated from years with strong contributions of Cercopagis pengoi, the predominant predatory cladoceran, whereas there was overlap between Bosmina and Cercopagis. Multiple invasive species and environmental factors have complex interactions that affect the current zooplankton assemblage in the nearshore.

Recent studies have identified the presence of microplastics and other anthropogenic microparticles in Arctic marine environments, but very little is known about anthropogenic microparticles in Arctic and sub-Arctic freshwater systems. Given the importance of freshwater systems to the health of northern communities, and their large input of water to the Arctic Ocean, circumpolar rivers and lakes should be considered within the context of anthropogenic microparticles in the region. Sample collections for this study were conducted in July and August of 2021 via a collaborative community-based approach. Thirty surface water samples were collected using a 300 µm Manta trawl from three sampling areas, the Yellowknife River (n = 10), Yellowknife Back Bay (n = 10), and Yellowknife Outer Bay (n = 10), to assess concentrations and transport of microplastics and other anthropogenic microparticles to Great Slave Lake, Northwest Territories. Each trawl was towed for 20-minutes, resulting in 16 to 233 m³ of water filtered per sample. Suspected anthropogenic microparticles were found in all samples, with concentrations ranging from 0.03–2.04 particles m⁻³, however, there were no significant differences in microparticle concentrations between sampling areas. A wide range of microparticle morphologies and colours were observed in the samples. A total of 1012 suspected anthropogenic microparticles were extracted from the surface water samples, of which fibres accounted for 87 % (n = 883), followed by fragments (11 %, n = 112), films (1 %, n = 7), and foams (1 %, n = 10). Our results indicate a widespread occurrence of microplastics and other anthropogenic microparticles in the surface waters surrounding Yellowknife, Northwest Territories.

Cisco (Coregonus artedi) have been extirpated from Lake Erie in North America since the 1960s, but they once supported one of the largest Laurentian Great Lakes fisheries. Numerous potential impediments to rehabilitation have been identified, including summer habitat refugia and predation. We used acoustic telemetry to investigate the thermal habitat use and survival of hatchery-reared adult cisco in Lake Erie. Fish were experimentally released (n = 50 per site) offshore at Dunkirk, New York, in the eastern basin and Huron, Ohio, in the central basin. Cisco in both basins found suitable summer oxythermal habitat in the metalimnion, suggesting that coldwater habitat availability is likely not an impediment for reestablishment. However, track end dates or predation dates were distributed across only four months with the last detection at 155 days. Predation sensors combined with temperature values during digestion indicated different potential predators: lake trout (Salvelinus namaycush) for the Dunkirk group and walleye (Sander vitreus) for the Huron group. Additionally, digestion temperatures of two tags indicated bird predation was also important, likely underestimated and suggested substantial use of the epilimnion by tagged fish. The results highlight the need for additional studies to address stocking optimization questions in support of future reintroduction experiments and related cisco conservation efforts.

Lake Kivu (Rwanda and Democratic Republic of Congo) is known to be unique among the African Great Lakes due to its peculiar history as a volcanic barrier lake and the frequent environmental pertubations caused by limnic eruptions. This lake is a major resource for riparian people but is also characterized by a depauperate fauna. For molluscs, available information is scarce and spatio-temporally restricted. We studied the freshwater molluscs of the lake and its tributaries and their biogeographical affinities, for the first time via genetic characterization. Our study revealed that the malacofauna of Lake Kivu, though admittedly poor compared to other African Great Lakes, is significantly more diverse than previously anticipated. The occurrence of living populations is restricted to a narrow fringe of littoral substrates, but some of the total of eight species occur much deeper than the immediate margins of the lake, i.e. down to a maximum of 15 m. The fauna displays ‘Nilotic’ biogeographic connections though widespread forms dominate. Differences in diversity occur in the North vs. South of Lake Kivu in species richness and abundance measures. This pattern can be attributed to recent volcanic eruptions and geochemical stressors in the north, but also to current and ongoing anthropogenic effects. A detailed study of schistosomiasis and fasciolosis with high spatial resolution along the local communities and their livestock is recommended since several potential intermediate host snails are present in Lake Kivu and its tributaries.