Nutrient (TN, DIN, TP, TDP, SRP) data from snowpack samples in the Athabasca Oil Sands Region, Alberta, Canada

Nutrient (TN, DIN, TP, TDP, SRP) data from snowpack samples in the Athabasca Oil Sands Region, Alberta, Canad

VRS-chlorophyll-a data from 23 sediment cores from study lakes in the Athabasca Oil Sands Region, Alberta, Canada

VRS-chlorophyll-a data from 23 sediment cores from study lakes in the Athabasca Oil Sands Region, Alberta, Canad

Anthropogenic activity in the Halifax region, Nova Scotia, Canada, as recorded by bulk geochemistry of lake sediments

<p>Dunnington DW, Spooner IS, Krkošek WH, Gagnon GA, Cornett RJ, Kurek J, White CE, Misiuk B, Tymstra D. 2018. Anthropogenic activity in the Halifax region, Nova Scotia, Canada, as recorded by bulk geochemistry of lake sediments. Lake Reserv Manage. 34:334–348.</p> <p>Separating the timing and effects of multiple watershed disturbances is critical to a comprehensive understanding of lakes, which is required to effectively manage lacustrine systems that may be experiencing adverse water quality changes. Advances in X-ray fluorescence (XRF) technology has led to the availability of high-resolution, high-quality bulk geochemical data for aquatic sediments, which in combination with carbon, nitrogen, δ¹³C, and δ¹⁵N have the potential to identify watershed-scale disturbance in lake sediment cores. We integrated documented anthropogenic disturbances and changes in bulk geochemical parameters at 8 lakes within the Halifax Regional Municipality (HRM), Nova Scotia, Canada, 6 of which serve as drinking water sources. These data reflect more than 2 centuries of anthropogenic disturbance in the HRM that included deforestation, urbanization and related development, and water-level change. Deforestation activity was documented at Lake Major and Pockwock Lake by large increases in Ti, Zr, K, and Rb (50–300%), and moderate increases in C/N (>10%). Urbanization was resolved at Lake Fletcher, Lake Lemont, and First Lake by increases in Ti, Zr, K, and Rb (10–300%), decreases in C/N (>10%), and increases in δ¹⁵N (>2.0‰). These data broadly agree with previous paleolimnological bioproxy data, in some cases identifying disturbances that were not previously identified. Collectively these data suggest that bulk geochemical parameters and lake sediment archives are a useful method for lake managers to identify causal mechanisms for possible water quality changes resulting from watershed-scale disturbance.</p

Recent Warming, Rather than Industrial Emissions of Bioavailable Nutrients, Is the Dominant Driver of Lake Primary Production Shifts across the Athabasca Oil Sands Region

<div><p>Freshwaters in the Athabasca Oil Sands Region (AOSR) are vulnerable to the atmospheric emissions and land disturbances caused by the local oil sands industry; however, they are also affected by climate change. Recent observations of increases in aquatic primary production near the main development area have prompted questions about the principal drivers of these limnological changes. Is the enhanced primary production due to deposition of nutrients (nitrogen and phosphorus) from local industry or from recent climatic changes? Here, we use downcore, spectrally-inferred chlorophyll-<i>a</i> (VRS-chl<i>a</i>) profiles (including diagenetic products) from 23 limnologically-diverse lakes with undisturbed catchments to characterize the pattern of primary production increases in the AOSR. Our aim is to better understand the relative roles of the local oil sands industry versus climate change in driving aquatic primary production trends. Nutrient deposition maps, generated using geostatistical interpolations of spring-time snowpack measurements from a grid pattern across the AOSR, demonstrate patterns of elevated total phosphorus, total nitrogen, and bioavailable nitrogen deposition around the main area of industrial activity. However, this pattern is not observed for bioavailable phosphorus. Our paleolimnological findings demonstrate consistently greater VRS-chl<i>a</i> concentrations compared to pre-oil sands development levels, regardless of morphological and limnological characteristics, landscape position, bioavailable nutrient deposition, and dibenzothiophene (DBT)-inferred industrial impacts. Furthermore, breakpoint analyses on VRS-chl<i>a</i> concentrations across a gradient of DBT-inferred industrial impact show limited evidence of a contemporaneous change among lakes. Despite the contribution of bioavailable nitrogen to the landscape from industrial activities, we find no consistency in the spatial pattern and timing of VRS-chl<i>a</i> shifts with an industrial fertilizing signal. Instead, significant positive correlations were observed between VRS-chl<i>a</i> and annual and seasonal temperatures. Our findings suggest warmer air temperatures and likely decreased ice covers are important drivers of enhanced aquatic primary production across the AOSR.</p></div

Alternative field curve modelling approach : regional models

In this thesis, we focus on thorough yield curve modelling. We build on extended classical Nelson-Siegel model, which we further develop to accommodate unobserved regional common factors and principal components. We centre our discussion on central European currencies' yield curves: CZK, HUF, PLN and SKK. We propose two novel models to capture regional dynamics; one based purely on state space formulation and the other relying also on principal components of the regional yield curves. Moreover, we supplement the models with two application examples in risk management and structural break detection. The main contribution of this thesis is a creation of a complete framework that enables us to analyse yield curves, to design risk scenarios and to detect structural breaks of various types

Deposition map of total dissolved phosphorus in 2014 snowpack.

<p>Interpolated loads of total dissolved phosphorus (TDP) (mg/m²) to the Athabasca Oil Sands Region in March 2014. Sedimentary VRS-chl<i>a</i> enrichment factors and DBT enrichment factors from each study lake are overlain.</p

Correlations between 5-year averaged VRS-chl<i>a</i> Z scores and 5-year averaged temperature data.

<p>Results from Pearson correlations between VRS-chl<i>a</i> Z scores (averaged over 5-year intervals) from highly and minimally DBT-enriched sites and all sites combined and annual and seasonal AOSR temperature (averaged over the same 5-year intervals).</p

Map of study area.

<p>Locations of 23 study lakes and two local communities (Fort McMurray and Fort McKay), and the footprint of industrial oil sands development. Lakes were cored in March 2011, 2012, 2013, or 2014. Many of the lakes have multiple names (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0153987#pone.0153987.s001" target="_blank">S1 Table</a>).</p

Deposition map of soluble reactive phosphorus in 2014 snowpack.

<p>Interpolated loads of soluble reactive phosphorus (SRP) (mg/m²) to the Athabasca Oil Sands Region in March 2014. Sedimentary VRS-chl<i>a</i> enrichment factors and DBT enrichment factors from each study lake are overlain.</p

Enrichment factors from minimally and highly DBT-enriched sites.

<p>VRS-chl<i>a</i> enrichment factors, corresponding DBT enrichment factors, and average post-2000 DBT concentrations, organized by DBT enrichment factor. Asterisks (*) denote sites for which breakpoint analysis was not considered appropriate and was thus not applied. RAMP 227 is excluded because the DBT record does not extend to pre-oil sands industry.</p