Life Sciences Commons^™

Under Ice Photosynthetic Primary Production And Dark Carbon Fixation In A Temperate Freshwater System, Vanessa Cubillos Tellez

Dissertations, Master's Theses and Master's Reports

Ice-covered lakes are vulnerable to environmental change, especially those in the Northern Hemisphere where ice cover is rapidly declining due to global warming. These changes can alter metabolic processes and disrupt carbon cycling driven by primary producers who form the base of the food chain and are key to sustaining ecosystem function. Photosynthetic primary production and dark carbon fixation under the ice in the Keweenaw Waterway, a temperate freshwater system that is ice-covered for ~3 months out of the year, were studied using a carbon isotopic labeling (14C-bicarbonate) technique. Water samples were collected weekly during ice cover and monthly during …

Restoring Human And More-Than-Human Relations In Toxic Riskscapes: “In Perpetuity” Within Lake Superior’S Keweenaw Bay Indian Community, Sand Point, Valoree Gagnon, Evelyn H. Ravindran

Michigan Tech Publications

Lake Superior’s Keweenaw Bay is the ancestral and contemporary homeland of the Anishinaabe Ojibwa and their relatives. It is also a toxic riskscape: Its waters, shorelines, and fish beings are polluted by an unknown tonnage of legacy mining waste rock called “stamp sands,” which contain unsafe levels of toxic compounds. This paper describes Ojibwa stewardship principles and reciprocal obligations, illustrating First Treaty With Gichi-Manitou practices of restoring relations within a toxic riskscape. Defined here, riskscapes are places and spaces where pollution/toxicity relations are continually reconfigured in literal, symbolic, and systemic ways. We share a story from Keweenaw Bay’s Sand Point …

Anthropogenic Influences On The Decline, Restoration, And Eco-Evolutionary Dynamics Of Lake Superior’S Coaster Brook Trout, Austin Johnson

Dissertations, Master's Theses and Master's Reports

The coaster brook trout is a life history variant of the brook trout (Salvelinus fontinalis) that is characterized by either lake residency or migration between stream and lake habitats. Coaster brook trout were once widespread throughout Lake Superior and its tributaries, but populations declined sharply in the late 19^th and early 20^th centuries. Historically, brook trout were a popular target of recreational and subsistence fishing in the Lake Superior basin, and it has been hypothesized that angling pressure combined with multiple forms of industrial development are what drove the coaster brook trout’s decline. In the mid …

The Decline Of Lake Superior's Woodland Caribou: A Historical Gis Analysis, Jordan W. Kelley

Dissertations, Master's Theses and Master's Reports

Lake Superior’s woodland caribou have been declining since the early 1800s. This thesis asks: why? We hypothesize that as settlers expanded into the region, industrial development in woodland caribou habitat reduced woodland caribou persistence. Using an Historical Geospatial Information System (HGIS) analysis, we find that historical mining and railroad infrastructure are associated with woodland caribou extirpation, while wetlands and protected areas are associated with caribou persistence. We also conducted a stakeholder synthesis of the region to help understand diverse perspectives within and between advocacy coalitions that take different positions on the most effective caribou restoration policies. Beliefs on recovery options …

Copper-Rich “Halo” Off Lake Superior's Keweenaw Peninsula And How Mass Mill Tailings Dispersed Onto Tribal Lands, W. Charles Kerfoot, Noel Urban, Jaebong Jeong, Carol Maclennan, Sophia Ford

Michigan Tech Publications

Over a century ago, shoreline copper mills sluiced more than 64 million metric tonnes of tailings into Lake Superior, creating a “halo” around the Keweenaw Peninsula with a buried copper peak. Here we examine how tailings from one of the smaller mills (Mass Mill, 1902–1919) spread as a dual pulse across southern Keweenaw Bay and onto tribal L'Anse Indian Reservation lands. The fine (“slime clay”) fraction dispersed early and widely, whereas the coarse fraction (stamp sands) moved more slowly southward as a black sand beach deposit, leaving scattered residual patches. Beach stamp sands followed the path of sand eroding from …

Coastal Ecosystem Investigations With Lidar (Light Detection And Ranging) And Bottom Reflectance: Lake Superior Reef Threatened By Migrating Tailings, Charlie Kerfoot, Martin M. Hobmeier, Sarah Green, Foad Yousef, Colin Brooks, Robert Shuchman, Michael Sayers, Et Al.

Michigan Tech Publications

Where light penetration is excellent, the combination of LiDAR (Light Detection And Ranging) and passive bottom reflectance (multispectral, hyperspectral) greatly aids environmental studies. Over a century ago, two stamp mills (Mohawk and Wolverine) released 22.7 million metric tons of copper-rich tailings into Grand Traverse Bay (Lake Superior). The tailings are crushed basalt, with low albedo and spectral signatures different from natural bedrock (Jacobsville Sandstone) and bedrock-derived quartz sands. Multiple Lidar (CHARTS and CZMIL) over-flights between 2008–2016—complemented by ground-truth (Ponar sediment sampling, ROV photography) and passive bottom reflectance studies (3-band NAIP; 13-band Sentinal-2 orbital satellite; 48 and 288-band CASI)—clarified shoreline and …

Climate Anomalies And Primary Production In Lake Superior, Marcel L. Dijkstra

Dissertations, Master's Theses and Master's Reports - Open

This dissertation supports the modeling of primary production in Lake Superior by offering site specific kinetics and algorithms developed from lab experiments performed on the natural phytoplankton assemblage of Lake Superior. Functions, developed for temperature, light and nutrient conditions and the maximum specific rate of primary production, were incorporated in a 1D specific primary production model and confirmed to published in-situ measured rates of primary production.

An extensive data set (supporting model calibration and confirmation), with a fine spatiotemporal resolution, was developed from field measurements taken bi-weekly during the sampling seasons of 2011, 2012 and 2014; considered to be meteorologically …

Factors Affecting Diporeia Growth Rates In Lake Superior, Miles J. Corcoran

Dissertations, Master's Theses and Master's Reports - Open

An ability to predict population dynamics of the amphipod Diporeia is important in understanding how energy pathways in the Lake Superior food web might be altered by disturbances to the ecosystem. Estimating growth rates for this prominent prey item for fish requires information on the physiological effects of changes to its environment. These effects have been investigated for Diporeia in other Great Lakes, but little is known about Lake Superior populations. The primary objective of this study is to obtain quantitative data for rates of Diporeia respiration and consumption that can be incorporated into a bioenergetics model for Lake Superior. …