Kalamazoo River Research Articles

Genetic analysis of two species of Mnomen in the Kalamazoo Watershed reveal panmixia in Z. Aquatica, structure among Z. Palustris, and hybridization in areas of sympatry.

Mnomen or wild rice of the genus Zizania is an important part of Native American culture, especially in Michigan for the Ojibwe nation. An oil spill in 2010 along the Kalamazoo River and the subsequent clean-up lead to renewed interest in management of Mnomen within the Kalamazoo watershed. The affected water bodies were surveyed for Zizania species to map existing populations, determine the existing genetic diversity and species present, and to identify potential hybridization. Using Traditional Ecological Knowledge of rice beds and opportunistic sampling of encountered plants, 28 rice beds were sampled. Two species of Zizania were identified Z. palustris and Z. aquatica. Genetic diversity was measured using 11 microsatellite loci and was moderately high for both species (Z. aquatica HE = 0.669, H0 = 0.672, n=26 and Z. palustris HE = 0.697, H0 = 0.636, n=57). No evidence of population bottle-necking was found. Z. palustris was found to have k=3 populations on the landscape, while Z. aquatica was found to be a single panmictic population. Several individual hybrids were confirmed using genotyping and they were all found in areas where the two species co-occurred. Additionally, Z. aquatica was found to have expanded into areas historically with only Z. palustris downstream of the oil spill, potentially due to dredging and sediment relocation as part of the clean-up effort.

Freshwater turtle populations as bioindicators following an oil spill: Delayed demographic changes reveal long-term impacts

Chronic, long-term impacts of oil spill disasters on wildlife often exceed short-term, highly visible mass mortalities and widespread oiling of individuals. Species with long lifespans, late maturation, and low recruitment rates are particularly vulnerable to long-term population-level impacts but can be useful as indicator species for ecosystem recovery. In 2010, one of the largest freshwater oil spills in the U.S. occurred in the Kalamazoo River, MI, when 3.2 million L of spilled oil impacted 56 km of river and associated wildlife. During cleanup and restoration efforts in 2010–2011, thousands of northern map turtles (Graptemys geographica) were captured, cleaned, and released. During 2019–2020 northern map turtles were captured to evaluate changes in the population size, demography, and size classes nine to ten years later.Population demography shifts occurred in the first few years after the spill in a species that otherwise exhibits minimal demographic fluctuation under “normal” conditions. In comparing demographic parameters at the time of the oil spill to values ∼ 10 years post-spill, a nearly 30% reduction in population size was detected, distribution of body size shifted to smaller males and females, and there was a shift in the population sex ratio between 2011 and 2019. There were also signals of failed recruitment in cohorts that would have hatched during the years immediately before and after the oil spill. These data suggest that beyond the direct mortality caused by the spill, declines in the estimated population size and shifts in the size distribution of northern map turtles are likely indicative of negative demographic impacts incurred following the 2010 oil spill and resulting cleanup.

An integrated watershed-scale framework to model nitrogen transport and transformations

Excess nitrogen in water bodies is associated with a number of environmental problems, including hypoxia and eutrophication. Originating from anthropogenic activities such as fertilizer application, and influenced by watershed characteristics such as the structure of the drainage network, stream discharge, temperature, and soil moisture, factors influencing nitrogen transport and transformation are many and interconnected. This paper describes the development and application of a process-oriented nitrogen model based on the modeling framework of PAWS (Process-based Adaptive Watershed Simulator) that can describe coupled hydrologic, thermal and nutrient processes. The integrated model was tested for an agricultural watershed with complex land use, namely the Kalamazoo River watershed in Michigan, USA. Nitrogen transport and transformations on the landscape were modeled by representing multiple sources and processes (fertilizer/manure application, point sources, atmospheric deposition, nitrogen retention and removal in wetlands and other lowland storage, etc.) across multiple hydrologic domains (streams, groundwater, soil water). The coupled model provides a tool to examine nitrogen budgets and to quantify the impacts of human activities and agricultural practices on the riverine export of nitrogen species. Model results indicate that the river network removed approximately 5.96 % of the total anthropogenic nitrogen input to the watershed, and that the riverine export of nitrogen accounted for 29.22 % of the total anthropogenic inputs during 2004–2009 while the groundwater contribution of nitrogen to the rivers during the same period was found to be 18.53 % highlighting the important role of groundwater within the watershed.

Assessing translocation success and long‐distance homing in riverine turtles 10 years after a freshwater oil spill

AbstractWildlife translocation is often used as a mitigation strategy for construction projects and other disturbances to habitat. In 2010, one of the largest freshwater oil spills in the United States occurred in the Kalamazoo River in Michigan, when over 3.2 million L of diluted bitumen crude oil impacted nearly 56 km of riverine habitat. During 2010 and 2011 cleanup efforts, 686 northern map turtles (Graptemys geographica) were captured from oil‐impacted stretches of the river, cleaned, rehabilitated, and translocated 2.5–84.3 km from their original capture location. The goal of this translocation effort was to release turtles within the same watershed, but away from ongoing cleanup operations, so individuals could potentially return to their original home range after it had been cleaned of oil and restored. In this study, we evaluated the success of translocation as an emergency mitigation strategy for freshwater turtles by quantifying recapture probability and homing by northern map turtles translocated varying distances from their home ranges. During subsequent years of survey up to 10 years post‐spill, 230 of the translocated turtles were recaptured, of which 104 exhibited homing by returning to their original home ranges. Turtles translocated to sites nearest their original capture location had a higher probability of recapture and homing than those translocated further away. Females had a higher probability of returning to original home ranges than males when translocated greater distances. In addition, four females and one male are known to have traveled >50 km between capture and release locations, which to our knowledge is the greatest travel distance recorded for any freshwater turtle species in the United States. Our results demonstrate that riverine turtles have considerable homing ability when displaced long distances, which has important implications for design and success of translocation projects.

No Evidence of Long-Term Effects on Physiological Stress or Innate Immune Functioning in Northern Map Turtles a Decade After a Freshwater Oil Spill

Environmental perturbations such as chemical spills often have immediate and obvious effects on the health of ecosystems and individual organisms. However, the long-term effects of such perturbations are less evident and often less well-understood. In July 2010, a ruptured pipeline spilled diluted bitumen into the Kalamazoo River in Michigan, USA, ultimately oiling 56 km of the river channel. During spill cleanup operations, the most common vertebrate species rescued from the oiled river channel was the Northern Map Turtle (Graptemys geographica), of which over 2000 individuals were captured, cleaned of oil, and released. We returned to areas along the 2010 spill gradient to determine whether turtles from locations that had experienced different magnitudes of oiling in 2010 differed in baseline stress levels or immune functioning in 2020, which was 10 yr after the oil spill. In 2020, we collected blood samples from 100 individual Northern Map Turtles along the 2010 spill gradient and subsequently quantified the heterophil:lymphocyte ratio, bactericidal capacity, and natural antibody agglutination. We found no correlation between turtles' 2020 capture locations relative to the origin of the 2010 oil spill and either mean stress level (heterophil:lymphocyte ratio) or immune functioning (bactericidal capacity and natural antibody agglutination ability). Thus, we found no evidence that Northern Map Turtles sampled along a gradient of oil exposure resulting from the 2010 Kalamazoo River oil spill experienced long-term effects on physiological stress levels or immune functioning. Importantly, our sampling did not include any individuals that may have died during 2010–2020 from poor health after the oil spill and therefore is biased toward healthy turtles remaining in the population. Interestingly, we found that a subset of turtles known to have been oiled in 2010 actually had higher natural antibody titers than turtles sampled from a control site that presumably had never been exposed to oil. We cannot exclude the possibility of other long-term effects of the oil spill on the Map Turtle population, such as decreased reproductive output. We recommend that long-term monitoring of populations and ecosystems be included in spill mitigation plans to track the recovery of populations and ecosystems over time and to document any effects that may become evident only years after the spill event.

Community engagement and the importance of partnerships within the Great Lakes Areas of Concern program: A mixed-methods case study

The Great Lakes Areas of Concern (AOC) program was created through amendments to the Great Lakes Water Quality Agreement (GLWQA) in 1987 to restore contaminated sites using an ecosystem-based approach. This program represents one of the first instances of ecosystem-based management (EBM) in the Great Lakes region with a specific focus on the inclusion of the public and local stakeholders in the process. Despite official language incorporating EBM in the AOC program, implementation of these practices has not been consistent across AOCs given differences in local arrangements of Public Advisory Councils (PACs), approaches to community engagement, and environmental problems. To better understand community engagement in these complex AOCs, this research investigated community, PAC, and state agency perspectives in three AOCs in Michigan: the Kalamazoo River, Saginaw River and Bay, and Rouge River AOCs. We gathered data through interviews, focus groups, and participatory observations with community members, PAC members, and state officials in each AOC. Findings indicate that communities in these areas have minimal connection to the AOC program and PACs. Community members tended to have greater connection to local organizations that provide a variety of opportunities for community members to engage with their environment in ways they value. To better connect the public to the AOC program, PACs may benefit from intentional partnerships with community organizations to increase community engagement. To consistently bolster community engagement in AOCs, we further recommend that state agencies provide additional resources to improve connection to local communities.

Associations between corbiculid and unionid densities and distributions throughout a Laurentian Great Lakes catchment, Michigan, U.S.A.

Abstract Some corbiculids (bivalve clams in the genus Corbicula) are invasive, having spread nearly worldwide and are thought to impact native unionid mussels. To determine the density and distributional associations of invasive corbiculids co‐occurring with native unionids, corbiculid clam and unionid mussel surveys were conducted at 122 sites in the Kalamazoo River catchment, Michigan, U.S.A. Unionid densities ranged from 0 to 97 (x̅ = 7.45 ± 15.38 SD) live unionids found per person hour while corbiculid densities varied from 0 to 0.24 (0.012 ± 0.037) g/cm3. Corbiculid distributions were clumped (Moran's I test: Index = 0.281, Z = 2.228, p = 0.026) and highest along the main branch of the river. Unionid distributions, both individual species and at family level, were found to be randomly distributed throughout the catchment (Moran's I test: Index = 0.343 to −0.022, Z = 1.913 to −0.118, p value = 0.056 to 0.970). Overall, unionid species richness, as well as the distribution of 13 unionid species, were negatively associated with corbiculid density. Although corbiculids can inhabit the same river reaches with unionids, unionid species richness and densities may be negatively influenced by the presence of corbiculids. Although many species of unionids were negatively associated with corbiculid density, our research showed that they can co‐exist in the same river reaches. Overall, unionids were positively correlated with corbiculids throughout the catchment, probably because the two groups have similar habitat requirements. It is therefore important to consider unionids and corbiculids concurrently in conservation planning and the management of invasive corbiculids.

Survival outcomes of rehabilitated riverine turtles following a freshwater diluted bitumen oil spill

Rehabilitation is often used to mitigate adverse effects of oil spills on wildlife. With an increase in production of alternatives to conventional crude oil such as diluted bitumen (dilbit), emergency spill responders and wildlife rehabilitators need information regarding the health and survival of free-ranging vertebrates exposed to dilbit under natural conditions. In 2010, one of the largest freshwater oil spills in the United States occurred in the Kalamazoo River in Michigan, when over 3.2 million liters of spilled dilbit impacted 56 km of riverine habitat. During 2010 and 2011 cleanup efforts, thousands of northern map turtles (Graptemys geographica) were captured from oiled stretches of the river, cleaned, rehabilitated, and released. We conducted extensive mark-recapture surveys in 2010, 2011, and 2018–2021, and used this dataset to evaluate the monthly survival probability of turtles 1–14 months post-spill and 8–11 years post-spill based on whether turtles were temporarily rehabilitated and released, overwintered in captivity and then released, or were released without rehabilitation. We found that rehabilitated or overwintered turtles had a higher probability of survival 1–14 months post-spill than non-rehabilitated turtles; however, 8–11 years post-spill the among-group differences in monthly survival probability had become negligible. Additionally, following the oil spill in 2010, nearly 6% of northern map turtles were recovered dead, died during rehabilitation, or suffered injuries that precluded release back into the wild. Our results demonstrate that exposure to dilbit in free ranging turtles causes direct mortality, while effort spent on the capture and rehabilitation of oiled freshwater turtles is important as it increases monthly survival 1–14 months post-spill.

FluOil: A Novel Tool for Modeling the Transport of Oil-Particle Aggregates in Inland Waterways

Spilled oil in inland waterways can aggregate with mineral and organic particles to form oil-particle aggregates (OPAs). OPAs can be transported in suspension or deposited to the bed. Modeling the fate and transport of OPAs can provide useful information for making mitigation decisions. A novel open-source tool, FluOil, is developed to predict where OPAs may deposit and when they arrive in affected river/lake reaches by implementing the random walk particle tracking algorithm to represent the advection, diffusion, deposition, and resuspension of OPAs. The usability of FluOil is demonstrated with the 2010 Kalamazoo River oil spill case study. An unsteady hydrodynamic model simulates the river hydraulics and provides hydraulic data for use in FluOil. Settling velocity and critical shear stress for resuspension are the most important OPA properties concerning the transport and deposition of OPAs. Settling velocity determines the vertical distribution of OPAs and, thus, the travel speed, whereas critical shear stress determines where and when OPAs are deposited and resuspended.

Population growth of microcrustaceans in water from habitats with differing salinities.

Inland salt marshes are a rare habitat in North America. Little is known about the invertebrates in these habitats and their ability to cope with the brackish conditions of the marsh. We studied the population growth of ostracods found in an inland salt marsh (Maple River salt marsh) and of copepods found in the wetland habitat immediately adjacent to the freshwater Kalamazoo River. By studying these species in water from both habitats, we aimed to find out if they performed differently in the two habitats. We also tested Daphnia pulex in water from the two habitats due to the history of Daphnia spp. as model organisms. We found that copepods performed better in water taken from the Maple River salt marsh, and the ostracods and D. pulex performed equally well in either water. This was unexpected, since ostracods are found in the salt marsh and copepods in the freshwater area. As a second experiment, we tested the invertebrates in pairwise interactions. In water from the Kalamazoo River, ostracods outperformed the other two species, but there was no difference between D. pulex and copepods. No species outperformed the other in salt marsh water. Our results show no local adaptation to salinity, suggesting that ostracods and copepods may be limited in their respective distributions by dispersal limitation or habitat suitability.

Quantification of resilience metrics as affected by conservation agriculture at a watershed scale

It is suggested that conventional tillage operations exacerbate global environmental changes and affect the sustainability of our food production systems. Therefore, no-till has been introduced as one of the conservation agriculture practices to counteract these challenges. No-till has been adopted by a substantial number of farmers in major cropping regions; however, its resilience from large scale implementation has been overlooked. The majority of the studies have reported only a few aspects of the no-till practice (e.g., yield, soil properties, etc.), often with contradicting observations. To fill this gap, we present an approach that integrates long-term field experimental data and modeling to quantify resilience at a watershed scale. The study was conducted in the Kalamazoo River watershed located in Michigan, USA. Recharge, groundwater table, soil moisture, yield, and net return were used as resilience metrics. The DSSAT sequence crop model was developed for a corn-soybean-wheat rotation and calibrated using the yield and soil moisture data from a long-term (1993–2019) experiment for the conventional and the no-till treatment conducted within the study area. Soil moisture, recharge and yield were simulated, and the recharge was fed into a calibrated groundwater model to analyze changes in groundwater heads. The results illustrate clear evidence of higher recharge and net return under the no-till treatment, which were statistically significant for all crops at the watershed scale. Moreover, the no-till treatment consistently retained greater soil moisture than the conventional treatment, thereby helping to mitigate the impacts of droughts. The rise in groundwater table as affected by the adoption of no-till practices in this watershed has ranged between 0.1 and 0.5 m, depending on the underlying groundwater system, and has the potential to beneficially affect the aquifers and groundwater-dependent ecosystems. Therefore, the conservation agriculture could improve the overall resilience of the row crop system.

Bacterioplankton respond with similar transcriptional activity to allochthonous dissolved organic matter in coastal and offshore Lake Michigan

AbstractLake Michigan is one of the largest lakes in the world and the second largest of the North American Great Lakes by volume. Over the last two decades, the lake has witnessed significant ecological changes due to proliferation of invasive quagga mussels into its deeper offshore regions. The impact of these changes on the labile dissolved organic matter pool available for bacterial consumption and the relative importance of terrestrially derived DOM (t‐DOM) for bacterial metabolism across Lake Michigan in the post‐mussel period is poorly understood. Here, we investigated Lake Michigan bacterial community structure and activity in offshore and coastal regions near the mouth of Kalamazoo River, one of the largest tributaries to southern Lake Michigan. In addition, we evaluated short‐term bacterioplankton response to a pulse of t‐DOM (leaf litter leachate) in shipboard mesocosms set up using nearshore and offshore lake‐water. The bacterial community composition and activity for the natural and t‐DOM enriched samples were characterized using combined metagenomics and metatranscriptomics. We observed four‐fold more transcripts for Cyanobacteria in the offshore bacterial community compared to nearshore, highlighting the importance of Cyanobacterial primary production in supporting microbial food web of the oligotrophic offshore. However, despite this and certain differences in DOM related transporter gene transcripts between the two regions, the nearshore and offshore bacterial communities showed a similar response to t‐DOM, primarily in the form of increased transcriptional activity for aromatic compound metabolism. The use of metagenome assembled genomes identified populations within the Bacteroidetes phylum that play an important role in t‐DOM response.

Waterpower and Allegan, Michigan

Waterpower and Allegan, Michigan Patrick R. Hudson On an out-of-the-way back street in the city of Allegan stands a remnant of Allegan's, and indeed Michigan's, industrial heritage. Enter Allegan from the southeast on M-89, turn on Second Street using the "Old Iron Bridge" to cross the Kalamazoo River, and follow Second Street to its end at Water Street. There, instead of turning left toward the business district, turn right and follow the signs to the mill district. Crossing the bridge, look to the right to find the Allegan dam. The bridge runs over what is left of the old millrace. Look to the left across the mill pond to find a small concrete block building on the spot where Allegan's industrial and civic origins began. The Origins of the City In 1837, Michigan became a state. The development of these forested peninsulas from territory to statehood was delayed for over a decade by Ohio's claims on the port of Toledo, originally within the territorial boundary of Michigan. For the new state legislature, its greatest challenge was overcoming the early characterizations—by General Duncan McArthur and Edward Tiffin, Surveyor General of the United States, among others—of Michigan as a mosquito-infested swamp.1 The publication of John Farmer's gazetteer Farmer's Guide to Michigan in 1830 was the first of a number of documents refuting previous detrimental characterizations of the state. It became one of the catalysts for the migration of New Englanders and upstate New Yorkers to the Michigan territory.2 This migration, characterized as "Michigan Fever," was a movement of communities rather than the "rugged individuals" of common myth. These groups generally included skilled tradesmen, such as millwrights, masons, carpenters, bakers, butchers, and seamstresses, as well as farmers and lumbermen. In many cases, a surveyor would be sent [End Page 105] out to find the type of land the community desired, then a company would be formed to purchase the land and organize development. This type of company founded the village of Allegan. A group of businessmen, known as the Boston Company, hired a surveyor to lay out an industrial town and seat of government for the new county of Allegan. The economic life of this community would be centered around a millrace providing waterpower for industries. The company was initially successful. Within two years, Allegan was incorporated as a village. The village's near central location allowed Allegan to claim the county seat. Waterpower was the cheapest, most abundant source of energy available until after the Civil War, when coal-powered steam engines began to replace waterpower.3 The siting of settlements at locations suitable for a dam and watermill was typical of settlement patterns during the 1830s. The nineteenth century was a time when the general impression in both Europe and Anglo-America was that the individual could use science and industry to overcome nature. The religious fervor of the Second Great Awakening fed the common belief that mankind held a God-given right to remake the natural world for its use and prosperity.4 As important as waterpower, technology, and the physical setting were for any location, transportation connections for Allegan became a limitation for future development. The ancient aboriginal trail to the north and south in western Michigan ran ten miles east of the settlement, and the Kalamazoo River, running through the village site, did not have enough depth year-round to support river transport for heavy cargo to or from Lake Michigan.5 Michigan's territorial government (from 1827-1835) and state legislature (from 1835-1844) experimented with various means of funding roads. None of the territorial roads reached Allegan County. The 1835 state constitution provided for transportation improvements, but the Panic of 1837 put an end to state funding. This was followed in 1844 by the Plank Road experiment, which amounted to licensing private toll roads but proved to be a failure due to the very short lifespan of such roads. Michigan's 1850 constitution turned the question of road funding over to local townships and allowed for conscript labor to construct and maintain such roads. This method failed to provide for any...

Particle Size Distribution of Kalamazoo River Sediments by FieldSed

The FieldSed is an inexpensive portable device for performing an image-based soil particle size analysis. The process, which includes the image analysis, is referred to as SedImaging (short for sediment imaging). The FieldSed was used for an investigation of Kalamazoo River sediments to generate over 100 particle size distributions (PSDs). Core samples taken from the river were tested in a nearby field lab. When necessary, samples were processed prior to testing in the FieldSed to remove particles greater than 2.0 mm and those finer than 0.075 mm. Doing so was necessary to ensure the efficiency of the current SedImaging method. A small number of specimens was selected for quality control testing to determine the reproducibility of SedImaging results. This testing also involved sieve analyses in ascertaining the agreement between SedImaging and sieving results. The control test results presented in this paper demonstrate that the FieldSed is a promising device that can rapidly, accurately, and repeatedly determine particle size distributions in field labs for geotechnical and geoenvironmental applications.

Application of the SOSim v2 Model to Spills of Sunken Oil in Rivers

Sunken oil transport processes in rivers differ from those in oceans, and currently available models may not be generally applicable to sunken oil in river settings. The open-source Subsurface Oil Simulator (SOSim) model has been expanded to handle spills of sunken oil in navigable rivers, utilizing Bayesian inference to integrate field concentration data with bathymetric data to predict the location and movement of sunken oil. A novel prior likelihood function incorporates bathymetric input, with sampling grid and default parameters adapted appropriately for rivers. SOSim v2 was demonstrated versus field observations taken following the M/T (Motor Tanker) Athos I oil spill. The model was also modified to operate in 1-D, to assess the longitudinal distribution of sunken oil in a non-navigable river using available poling data collected following the Enbridge Kalamazoo River oil spill in 2010. Results of both case studies were consistent with observed data and local bathymetry in 2-D and 1-D, and the model is suggested as a complement to deterministic models for oil spill emergency response in rivers.

Spatiotemporal variations of albedo in managed agricultural landscapes: inferences to global warming impacts (GWI)

Albedo can be used to quantify ecosystem and landscape contributions to local and global climate. Such contributions are conventionally expressed as radiative forcing (RF) and global warming impact (GWI). We contextualize our results within landscape carbon production and storage to highlight the importance of changes in albedo for landscape GWI from multiple causes, including net ecosystem production (NEP) and greenhouse gas (GHG) emissions. To examine the spatiotemporal changes in albedo (Δα) in contrasting managed landscapes through calculations of albedo-induced RF (RFΔα) and GWI (GWIΔα) under different climatic conditions. We selected five contrasting landscapes within the Kalamazoo River watershed in southern Michigan USA as proof of concept. The daily MCD43A3 MODIS (V006) product was used to analyze the inter- and intra-annual variations of growing season albedo. In addition, the variations of RFΔα and GWIΔα were computed based on landscape composition and climate. The RFΔα (− 5.6 W m−2) and GWIΔα (− 1.3 CO2eq ha−1 year−1) were high in forest-dominated landscapes, indicating cooling effects and CO2eq mitigation impacts similar to crops. The CO2eq mitigation of cropland-dominated landscapes was on average 52% stronger than forest-dominated landscapes. In the landscape with the highest proportion of forest, under dry and wet conditions CO2eq mitigation was reduced by up to 24% and ~ 30%, respectively; in one cropland-dominated landscape wet conditions reduced CO2eq mitigation by 23%. Findings demonstrate that quantifying spatiotemporal changes in albedo in managed landscapes and under different climatic conditions is essential to understand how landscape modification affects RFΔα and GWIΔα and thereby contributes to ecosystem-level GWI.

Forensic identification and quantification of oil sands-based bitumen released into a complex sediment environment

On or about July 25, 2010, approximately 843,000 gal of condensate diluted bitumen (dilbit, a heavy oil) was released into the Kalamazoo River near Marshall, Michigan. As the discharged Line 6B oil migrated downstream the lighter diluent volatilized, formed visible oil droplets/flakes in the water column, became denser than water and/or became aggregated with sediment and migrated to the underlying bottom sediments. Accurate identification and determination of the amount of Line 6B oil present in the sediment was a primary requirement for remediation and allocation of liability. Based on a multi-tiered application of advanced hydrocarbon fingerprinting methodology, key chemical characteristics of the spilled oil were identified that allow for distinguishing heavy oil-related contamination from the complex river sediment background hydrocarbon contamination. It was determined that among the characteristics evaluated, concentration ratios of selected tri-aromatic steranes and triterpanes were most efficient parameters for identification and quantification of the spilled oil in the environment. This quantification approach was successfully applied and validated with field sample results and is consistent with the well-established environmental stability of these petroleum biomarkers and modern hydrocarbon fingerprinting methodology.

Linear downscaling from MODIS to landsat: connecting landscape composition with ecosystem functions

The open and free access to Landsat and MODIS products have greatly promoted scientific investigations on spatiotemporal change in land mosaics and ecosystem functions at landscape to regional scales. Unfortunately, there is a major mismatch in spatial resolution between MODIS products at coarser resolution (≥ 250 m) and landscape structure based on classified Landsat scenes at finer resolution (30 m). Based on practical needs for downscaling popular MODIS products at 500 m resolution to match classified land cover at Landsat 30 m resolution, we proposed an innovative modelling approach so that landscape structure and ecosystem functions can be directly studied for their interconnections. As a proof-of-concept of our downscaling approach, we selected the watershed of the Kalamazoo River in southwestern Michigan, USA as the testbed. MODIS products for three fundamental variables of ecosystem function are downscaled to ensure the approach can be extrapolated to multiple functional measurements. They are blue-sky albedo (0–1), evapotranspiration (ET, mm), and gross primary production (GPP, Mg C ha−1 year−1). An object-oriented classification of Landsat images in 2011 was processed to generate a land cover map for landscape structure. The downscaling model was tested for the five Level IV ecoregions within the watershed. We achieved satisfactory downscaling models for albedo, ET, and GPP for all five ecoregions. The adjusted R2 was > 0.995 for albedo, 0.915–0.997 for ET, and 0.902–0.962 for GPP. The estimated albedo, ET, and GPP values appear different in the region. The estimated albedo was the lowest for water (0.076–0.107) and the highest for cropland (0.166–0.172). Estimated ET was the highest for the built-up cover type (525.6–687.1 mm) and the lowest for forest (209.7–459.7 mm). The estimated GPP was the highest for the build-up cover type (8.65–9.85 Mg C ha−1 year−1) and the lowest for forest. Estimated values for albedo, ET, and GPP appear reasonable for their ranges in the Kalamazoo River region and are consistent with values reported in the literature. Despite these promising results, the downscaling approach relies on strong assumptions and can carry substantial uncertainty. It is only valid at a spatial scale where similar climate, soil, and landforms exist (i.e., values in isolated patches of the same cover type are similar). Plausibly, the uncertainties associated with each estimation, as well as the model residuals, can be explored for other pattern-process relationships within the landscape.

Modeling the effects of vegetation on stream temperature dynamics in a large, mixed land cover watershed in the Great Lakes region

Stream temperature controls biological processes and affects the species composition of aquatic communities. Riparian vegetation plays an important role in influencing stream temperatures due to vegetation shading and by changing the riparian microclimate (wind speed, relative humidity, etc). This paper explores the effects of spatial heterogeneity in riparian vegetation on stream temperature using a process-based hydrologic model in a 5200 km2 mixed land-use watershed (Kalamazoo River, Michigan, USA). By explicitly incorporating interactions of thermal and water fluxes at the air-land surface and surface-subsurface interfaces, the model enables comprehensive representation of stream thermal dynamics. The riparian land-use effects on stream temperature are represented by coupling with a vegetation phenology module. The riparian land-use information is rescaled using different nested resolutions within a model grid cell to represent the land-use effects on stream temperature to show that a resolution of 90 m × 90 m best represents the land-use effects while simulating stream temperatures using 1 km × 1 km model grid cells. The simulation covers a 7-year period from 2003 to 2009, during which period the results are compared with multiple observations. Stream thermal budgets and responses of stream temperature to vegetation change scenarios including potential deforestation effects are reported.

Quantifying the space – time variability of water balance components in an agricultural basin using a process-based hydrologic model and the Budyko framework

Process-based distributed hydrologic models (PBHMs), which link watershed characteristics with process representations, are useful tools to evaluate distributed and ensemble hydrologic responses of a basin to climate inputs. However, complexities associated with parameter interactions and their spatial heterogeneity may introduce high uncertainty in the parameterization of a PBHM. The Budyko curve framework offers an effective approach for evaluating the variability in the water balance components from a PBHM and can be used to explore the link between model performance with parameter heterogeneities and the Budyko curve characteristics. In this work a PBHM was calibrated using a multi-site calibration strategy, which was built upon a step-wise calibration algorithm combined with multiple calibration targets including river discharges, evapotranspiration and ground water heads, to reduce compensation errors caused by component interactions. This strategy was used for the Kalamazoo River watershed in Michigan, USA, with obvious physiographic and land surface heterogeneities. The Budyko framework characterized the water balance variability at the sub-watershed scale; two empirical methods were used to evaluate the calibrated PBHM parameters using Budyko-estimated values and to assess the physical relevance of the parameters. The relative infiltration capacity is found to play an important role in affecting the spatial variability of the annual water balance of this watershed. This work brings out the importance of optimizing calibration strategies by linking catchment heterogeneities with processes reasoning in order to understand the underlying hydrologic controls.