A review of hydroecological results of the Northern River Basins Study, Canada. Part 2. Peace–Athabasca Delta

Prowse, Terry D.; Conly, F. Malcolm

doi:10.1002/rra.682

Cited by 40 publications

(39 citation statements)

References 7 publications

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“…However, comparison of PAD findings with the subarctic Mackenzie Delta also suggests that the PAD functions in a distinctive manner from other northern river deltas, possibly because of a milder local climate and consequently greater intrinsic primary production and lake evaporation (Flanagan et al ., 2003). In addition, flooding in the PAD occurs almost exclusively during the spring arising from ice jams (Prowse & Conly, 2002), whereas other delta systems may experience midsummer floods during periods of high flow (Lesack et al ., 1998). Finally, because the PAD may experience periods of multiple decades devoid of major floods (Wolfe et al ., 2006) that favour nutrient retention and cycling (Thormann et al ., 1998) and foodweb development (Baranyi et al ., 2002), shallow lakes in the PAD may be more ecologically similar to prairie wetlands (Timoney, 2002), known to have diverse ecosystem structure and temporally variable basin hydrology (Waiser, 2001; Pham et al ., 2008).…”

Section: Discussionmentioning

confidence: 99%

Interdecadal declines in flood frequency increase primary production in lakes of a northern river delta

McGowan

Leavitt

Hall

et al. 2011

Global Change Biology

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Human activities and climate change have greatly altered flooding regimes in many of the world's river deltas, but the impact of such changes remains poorly quantified on decadal to multidecadal timescales. This study identified the response of delta lake primary production (measured as the concentration of sedimentary pigments) to variations in flood frequency using spatial surveys and paleolimnological analyses of lakes in the Peace-Athabasca Delta (PAD), Canada. Surveys of 61 lakes spanning a range of hydrological conditions showed that those lakes that received flood waters less frequently were associated with elevated algal production (surface sedimentary pigments) and, in some lakes, increased growth of emergent macrophytes and epiphytic diatoms. Paleolimnological analyses of five lakes corroborated the contemporary spatial survey results by showing that production of pigments from most algal groups increased during recent periods of lower flood frequency in the 20th century as determined from increases in cellulose-inferred lake-water oxygen isotope composition and plant macrofossils, but remained stable in a 'reference' basin. In general, past periods of elevated algal production coincided with the increased abundance of submerged macrophytes or emergent vegetation that provide habitat for attached algae. These results suggest that interdecadal declines in river discharge arising from increased aridity, hydrologic regulation or consumptive water use will cause long-term increases in primary production and alter ecosystem processes (carbon sequestration, biological diversity) in aquatic delta ecosystems similar to the PAD where lakes become nutrient-rich in the absence of flooding.

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Section: Discussionmentioning

confidence: 99%

Interdecadal declines in flood frequency increase primary production in lakes of a northern river delta

McGowan

Leavitt

Hall

et al. 2011

Global Change Biology

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“…A second global change mechanism is the role of river‐ice breakup effects and ice‐jamming in controlling peak annual water levels in such deltas [ Marsh and Hey , 1989; Marsh and Lesack , 1996]. In the Mackenzie Delta, flood pulses [ Junk et al , 1989] driven by ice breakup control the degree to which river water moves off‐channel to replenish the waters of this extremely lake‐rich [ Emmerton et al , 2007] ecosystem, which presently exists because of such replenishment [ Marsh and Lesack , 1996; Prowse and Conly , 2002]. Lakes sustained on brief annual flood pulses are small, very abundant, and diverse, but cannot sustain fish because they are shallow and lack of water renewal over winter causes anoxia.…”

Section: Introductionmentioning

confidence: 99%

“…Lake‐richness varies among them, though the Lena is comparably lake‐rich to the Mackenzie. Our understanding of the linkage between river‐flooding hydrology and aquatic ecology in these systems is presently derived from work largely limited to the Mackenzie Delta (L. F. W. Lesack and P. Marsh, unpublished manuscript, 2007, hereinafter referred to as Lesack and Marsh, submitted manuscript, 2007) and Peace‐Athabasca Delta [ Prowse and Conly , 2002], with little comparable information available for the eurasian deltas [ ACIA , 2005]. We previously postulated that if the arctic region warms as expected, river ice jamming may become reduced [ Rouse et al , 1997] and would lead to reduced flood peaks in rivers, and the possibility that the higher elevation lakes in circumpolar deltas might dry up [ Marsh and Lesack , 1996].…”

Section: Introductionmentioning

confidence: 99%

Lengthening plus shortening of river‐to‐lake connection times in the Mackenzie River Delta respectively via two global change mechanisms along the arctic coast

Lesack

Marsh²

2007

Geophysical Research Letters

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[1] River deltas along the circumpolar arctic coast are lake-rich and poorly understood ecosystems, set in a region expected to change rapidly. Over the past 30+ years annual river-to-lake connection times in the Mackenzie Delta have lengthened (>30 days) in the lowest elevation lakes and may have shortened in the highest elevation lakes, respectively via sea level rise and declining effects of river-ice breakup. Lengthened connection times indicate summer low-water levels in the delta have increased by an amount (0.3 m) equivalent to three times local sea level rise (0.1 m) over the same period. Such an amplification effect of recent sea level rise has been completely unexpected and may be a result of enhanced storm surges in response to receding arctic sea ice or coastal backwater effects on the river flow. Shortened connection times are consistent with other work showing a decline in river-ice breakup effects, an important control on annual peak water levels. Citation: Lesack, L. F. W., and P. Marsh (2007), Lengthening plus shortening of river-to-lake connection times in the Mackenzie River Delta respectively via two global change mechanisms along the arctic coast, Geophys.

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“…The biological productivity and diversity of this extensive riparian landscape depends on periodic flooding and drying cycles. Details of the delta flora and fauna are summarized in Prowse and Conly (2002).…”

Section: Hydro-ecological Settingmentioning

confidence: 99%

“…Concern developed over the ecological health of this river system in the early 1970s following regulation of its main headwater river, the Peace River. Further concern following two decades of drying water conditions lasting into the 1990s prompted a series of major hydro-ecological assessments as part of the Northern River Basins Study (NRBS; Prowse and Conly, 2002;Prowse et al, 2002a) and the Peace-Athabasca Delta Technical Studies (PAD-TS, 1996). Although the PeaceAthabasca-Slave system was found to be influenced by the effects of flow regulation, the results indicated that climate variability over the past several decades has also been an environmental stressor on the region's hydrology (Prowse and Conly, 2001).…”

Section: Introductionmentioning

confidence: 99%

Climate Change, Flow Regulation and Land-Use Effects on the Hydrology of the Peace-Athabasca-Slave System; Findings from the Northern Rivers Ecosystem Initiative

Prowse

Beltaos

Gardner

et al. 2006

Environ Monit Assess

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Abstract. The Northern Rivers Ecosystem Initiative (NREI) was established in the late 1990s to address important science questions resulting from previous studies undertaken by the Northern Rivers Basin Study (NRBS). This manuscript summarizes the results from a number of reports on hydrologic research conducted on the Peace-Athabasca-Slave river and lake systems. Specific concerns expressed by the NRBS and subsequent NREI focused on how these systems were being affected by climate change, flow regulation and land-use changes. Issues addressed in this report include: the fate of aquatic perched basins within the Peace-Athabasca Delta under historical and future climate trends; the sources of major floods that replenish these basins and how the frequency, magnitude and source areas of such events have changed over time; the synoptic weather patterns and atmospheric teleconnections that are responsible for the generation of major snowmelt runoff that drive major floods; the potential effect that climate and land-use changes might have on basin runoff and delta lake levels; the specific hydro-climatic conditions required to produce major ice-jam floods on the Peace River and how these may be altered by climate change; remote-sensing methods to document delta flooding and vegetation change; and the dual effect of climate and flow regulation on the water levels of Great Slave Lake and how these may affect other nearshore processes, particularly wind seiches, that influence flooding of the Slave River Delta. A review of the major findings and recommendations for future research concludes the report.

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A review of hydroecological results of the Northern River Basins Study, Canada. Part 2. Peace–Athabasca Delta

Cited by 40 publications

References 7 publications

Interdecadal declines in flood frequency increase primary production in lakes of a northern river delta

Interdecadal declines in flood frequency increase primary production in lakes of a northern river delta

Lengthening plus shortening of river‐to‐lake connection times in the Mackenzie River Delta respectively via two global change mechanisms along the arctic coast

Climate Change, Flow Regulation and Land-Use Effects on the Hydrology of the Peace-Athabasca-Slave System; Findings from the Northern Rivers Ecosystem Initiative

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