Tracking long-term acidification trends in Pockwock Lake (Halifax, Nova Scotia), the water supply for a major eastern Canadian city

Tropea, Amy E.; Ginn, Brian K.; Cumming, Brian F.; Smol, John P.

doi:10.1080/07438140709354016

Cited by 14 publications

(16 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Pockwock Lake, Halifax, Nova Scotia, a naturally humic lake that has been affected by local as well as regional sources of acidic deposition, a two-stage acidification process occurred. In the first stage , DI pH declined from 6.3 to 5.8, showing a similar trend in timing and diatom assemblage changes to other acidified, humic lakes in KNP (Tropea et al 2007) (Fig. 3).…”

Section: Fig 2 a Map Of The Study Lakes Examined In Recent Paleolimsupporting

confidence: 52%

“…1925) and were characterized by a shift in diatom sedimentary assemblage from dominance by Cyclotella to dominance by Frustulia and Eunotia spp. (Ginn et al (Gerber et al 2008;Ginn et al 2007cGinn et al , 2008bRajaratnam 2009;Thienpont et al 2008;Tropea et al 2007). Lakes that have undergone declines in DI pH > 0.2 pH units (see Table 1 for actual pH changes for acidified lakes) since pre-industrial times are represented by red boxes, and lakes that have not undergone DI pH declines> 0.2 pH units are represented by black circles.…”

Section: Acidification Of Surface Watersmentioning

confidence: 92%

See 1 more Smart Citation

Establishing past environmental conditions and tracking long-term environmental change in the Canadian Maritime provinces using lake sediments

et al. 2013

Self Cite

View full text Add to dashboard Cite

Freshwater lakes in the Canadian Maritime provinces have been detrimentally influenced by multiple, often synergistic, anthropogenically-sourced environmental stressors. These include surface-water acidification (and a subsequent decrease in calcium loading to lakes); increased nutrient inputs; watershed development; invasive species; and climate change. While detailed studies of these stressors are often hindered by a lack of predisturbance monitoring information; in many cases, these missing data can be determined using paleolimnological techniques, along with inferences on the full extent of environmental change (and natural variability), the timing of changes, and linkages to probable causes for change. As freshwater resources are important for fisheries, agriculture, municipal drinking water, and recreational activities, among others, understanding longterm ecological changes in response to anthropogenic stressors is critical. To assess the impacts of the major water-quality issues facing freshwater resources in this ecologically significant region, a large number of paleolimnological studies have recently been conducted in Nova Scotia and southern New Brunswick. These studies showed that several lakes in southwestern Nova Scotia, especially those in Kejimkujik National Park, have undergone surface-water acidification (mean decline of 0.5 pH units) in response to local-source SO 2 emissions and the long-range transport of airborne pollutants. There has been no measureable chemical or biological recovery since emission restrictions were enacted. Lakewater calcium (Ca) decline, a recently recognized environmental stressor that is inextricably linked to acidification, has negatively affected the keystone zooplankter Daphnia in at least two lakes in Nova Scotia (and likely more), with critical implications for aquatic food webs. A consistent pattern of increasing planktonic diatoms and scaled chrysophytes was observed in lakes across Nova Scotia and New Brunswick, suggesting that the strength and duration of lake thermal stratification has increased since pre-industrial times in response to warming temperatures (ϳ1.5°C since 1870). These include three lakes near Bridgewater, Nova Scotia, that are among the last known habitat for critically endangered Atlantic whitefish (Coregonus huntsmani). Overall, these studies suggest that aquatic ecosystems in the Maritime Provinces are being affected by multiple anthropogenic stressors and paleolimnology can be effective for inferring the ecological implications of these stressors. Résumé :Les lacs d'eau douce des provinces maritimes canadiennes ont été influencés de façon néfaste par de multiples agents stressants environnementaux souvent synergiques et de sources anthropogènes, incluant l'acidification de l'eau de surface (avec une diminution subséquente de la charge en calcium dans les lacs), les apports accrus en nutriment, le développement des bassins versants, les espèces envahissantes ainsi que le changement climatique. Alors que les études détaillées de ces agents ...

show abstract

Section: Fig 2 a Map Of The Study Lakes Examined In Recent Paleolimsupporting

confidence: 52%

Section: Acidification Of Surface Watersmentioning

confidence: 92%

Establishing past environmental conditions and tracking long-term environmental change in the Canadian Maritime provinces using lake sediments

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…In some lakes, changes in the diatom assemblage suggest that the lake underwent a degradation of DOC (humic, coloured water to clearwater) in response to acidification (e.g. Pockwock Lake in Halifax; Tropea et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

“…Sulphate deposition decreases towards the northeast of the province with the exception of an area east and downwind of local SO 4 2-sources at the city of Halifax (Clair et al, 2001). Previous studies by Ginn et al (2007a, b, c) and Tropea et al (2007) identified major environmental changes due to acidic inputs in lakes in Kejimkujik National Park and around Halifax, but little evidence of widespread lake acidification in other areas of the province. In these studies, before-and-after paleolimnological techniques (i.e.…”

Section: Introductionmentioning

confidence: 94%

Glasgow Lake: an early-warning sentinel of lake acidification in Cape Breton Highlands National Park (Nova Scotia, Canada)

et al. 2008

Self Cite

View full text Add to dashboard Cite

In contrast to other lakes studied in Cape Breton Highlands National Park (Nova Scotia, Canada), our paleolimnological results indicated that Glasgow Lake has been impacted by acidic deposition starting in the early 1900s. Based on analysis of diatom assemblages, the lake experienced a decrease in diatom-inferred lakewater pH from a pre-industrial pH of *5.8 to a current pH of 5.3 (2000-2002 measured mean pH = 5.0) as well as a decrease in diatom-inferred Gran-alkalinity. In this study, diatombased paleolimnological techniques were used in conjunction with a dynamic biogeochemical model (MAGIC) to assess both the timing and extent of the acidification trend, as well as determine a probable explanation as to why this lake, and none of the other 15 Cape Breton Highlands lakes studied for paleolimnology thus far, acidified under a peak nonmarine sulphate deposition load of 43.6 mmol c m -2 year -1 in the mid-1970s. Steady-state models estimate that Glasgow Lake had the lowest buffering capacity of six study lakes and estimated critical sulphate loading of\1 mmol c m -2 year -1 . MAGIC also estimated a loss of charge balance alkalinity from a pre-1850 value of 38 lmol c l -1 to a low of 12 lmol c l -1 . While no evidence of biological recovery has been recorded, MAGIC estimates an increase in charge balance alkalinity to 27 lmol c l -1 in 2002 in response to decreased SO 2 emissions. Of the five other lakes that were modelled, all showed trends towards more acidic states and subsequent increases in charge balance alkalinity; however, the empirical paleo-diatom approach applied to these lakes showed no evidence of acidification. Thus, Glasgow Lake has the lowest buffering capacity among the Cape Breton Highland study lakes and serves as a sentinel of potential acidification trends and recovery in this region.

show abstract

“…As a result, the protection and environmental remediation of drinking water sources have received considerable attention in research (Basu et al 2014), since drinking water quality is closely related to human health (Corlin et al 2016). In general, these research efforts include environmental policy and legislation planning (Syme and Nancarrow 2013;Xu et al 2016), water quality standard development (Goncharuk 2013), and health risk assessment (Chiang et al 2010;Houtman et al 2014;Sun et al 2015), water quality monitoring and modeling (Tropea et al 2007;Sokolova et al 2013;Chen et al 2015), and protection and remediation technology (Zhang et al 2011;Basu et al 2014). An important aspect of water quality modeling for drinking water source protection is identifying changes in water quality trends and specific change-point timing, which are important information for environmental protection performance evaluation and (Bodo 1989;Chowdhury and AlZahrani 2014).…”

Section: Introductionmentioning

confidence: 99%

Water quality trend and change-point analyses using integration of locally weighted polynomial regression and segmented regression

Huang

Wang

Xia

et al. 2017

Environ Sci Pollut Res

View full text Add to dashboard Cite

Trend and change-point analyses of water quality time series data have important implications for pollution control and environmental decision-making. This paper developed a new approach to assess trends and change-points of water quality parameters by integrating locally weighted polynomial regression (LWPR) and segmented regression (SegReg). Firstly, LWPR was used to pretreat the original water quality data into a smoothed time series to represent the long-term trend of water quality. Then, SegReg was used to identify the long-term trends and change-points of the smoothed time series. Finally, statistical tests were applied to determine the significance of the long-term trends and changepoints. The efficacy of this approach was validated using a 10-year record of total nitrogen (TN) and chemical oxygen demand (COD Mn ) from Shanxi Reservoir watershed in eastern China. Results showed that this approach was straightforward and reliable for assessment of long-term trends and change-points on irregular water quality datasets.The reliability was verified by statistical tests and practical considerations for Shanxi Reservoir watershed. The newly developed integrated LWPR-SegReg approach is not only limited to the assessment of trends and change-points of water quality parameters but also has a broad application to other fields with long-term time series records.

show abstract

Tracking long-term acidification trends in Pockwock Lake (Halifax, Nova Scotia), the water supply for a major eastern Canadian city

Cited by 14 publications

References 40 publications

Establishing past environmental conditions and tracking long-term environmental change in the Canadian Maritime provinces using lake sediments

Establishing past environmental conditions and tracking long-term environmental change in the Canadian Maritime provinces using lake sediments

Glasgow Lake: an early-warning sentinel of lake acidification in Cape Breton Highlands National Park (Nova Scotia, Canada)

Water quality trend and change-point analyses using integration of locally weighted polynomial regression and segmented regression

Contact Info

Product

Resources

About