Early-20th Century Environmental Changes Inferred Using Subfossil Diatoms from a Small Pond on Melville Island, N.W.T., Canadian High Arctic

Keatley, Bronwyn E.; Douglas, Marianne S. V.; Smol, John P.

doi:10.1007/s10750-005-1737-5

Cited by 24 publications

(15 citation statements)

References 49 publications

(70 reference statements)

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“…In addition, reversed trends occurred in sedimentary TOC, TN and OM (Fig. The general biostratigraphical shifts in Einstaken are consistent with many other high arctic palaeolimnological studies from Canada showing, for example, distinct top core changes in diatom assemblages (Douglas et al 1994;Smol et al 2005) and increases in Nostoc (Keatley et al 2006) that have been attributed to recent climate warming in the Arctic. The general biostratigraphical shifts in Einstaken are consistent with many other high arctic palaeolimnological studies from Canada showing, for example, distinct top core changes in diatom assemblages (Douglas et al 1994;Smol et al 2005) and increases in Nostoc (Keatley et al 2006) that have been attributed to recent climate warming in the Arctic.…”

Section: Late Holocenesupporting

confidence: 84%

“…a BP, which is probably indicative of the highly transparent water column and intensive UV radiation. The presence of Nostoc in high-latitude lake sediments has previously been attributed to warmer climate conditions (Keatley et al 2006;Rouillard et al 2012). Likewise, previous investigations from western Spitsbergen in Svalbard (Birks 1991;Svendsen & Mangerud 1997) and the arctic Atlantic sector (Humlum 2005) have suggested that air temperatures reached their Holocene maximum during the mid-Holocene between c. 9000−5000 cal.…”

Section: Mid-holocenementioning

confidence: 86%

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Ultraviolet radiation exposure of a high arctic lake in Svalbard during the Holocene

Nevalainen

Rantala

Luoto

et al. 2014

Boreas

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Long‐term fluctuations in lake‐water optical properties were examined using a Holocene sediment sequence and multi‐proxy palaeolimnological approach in Lake Einstaken, Nordaustlandet, Svalbard. UV‐absorbance of sedimentary cladoceran remains provided information on underwater UV exposure and changes in lake‐catchment coupling processes were inferred from sediment geochemistry. In addition, aquatic community succession was used as an indicator for lake‐water bio‐optical properties and a Holocene record of sun activity (sunspots) was utilized to evaluate long‐term solar forcing. The results indicated that the UV‐absorbance of cladoceran remains was highest (i.e. maximum UV‐induced pigmentation) for a short period during the early Holocene and for several millennia during the mid‐Holocene. Sun activity was high during these time intervals, probably impacting the UV intensities, but it is probable that the amount of UV‐attenuating compounds (e.g. dissolved organic carbon (DOC)) also significantly affected the underwater UV environment and were low during high UV exposure. Benthic autotrophic communities also responded to the millennial changes in lake‐water optical properties. UV‐resistant Nostoc cyanobacterial colonies were established during the mid‐Holocene, indicative of high underwater UV intensities, and Fontinalis mosses thrived during the early Holocene, indicating a highly transparent water column. The results further suggested that underwater UV exposure decreased during the late Holocene, which is probably attributable to increased DOC and decreased solar forcing. Owing to the location of Lake Einstaken and its catchment in the periglacial barren landscape of the polar desert, the fluctuations of bio‐optical lake‐water properties were apparently forced by postglacial environmental processes and Holocene climate development. These factors controlled sea shoreline proximity, water discharge, ice‐cover duration and littoral‐benthic primary production and further affected the underwater UV environment. Although the role of solar forcing cannot be underestimated, the current record emphasizes the role of climate‐mediated lake‐catchment interactions in impacting bio‐optical properties and UV exposure of high arctic aquatic systems.

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Section: Late Holocenesupporting

confidence: 84%

Section: Mid-holocenementioning

confidence: 86%

Ultraviolet radiation exposure of a high arctic lake in Svalbard during the Holocene

Nevalainen

Rantala

Luoto

et al. 2014

Boreas

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“…; Antoniades et al., ; Keatley et al. ) and Cyclotella species dominant in deeper lakes with the development of planktonic habitat (Sovari et al. ; Rühland et al.…”

Section: Discussionmentioning

confidence: 99%

“…Other studies have suggested that, during the LIA, extensive ice cover resulted in only a narrow moat of shallow open water forming during the summer which allowed Fragilaria species to dominate (e.g., Smol et al 2005;Smol and Douglas 2007). Decreasing ice cover post-LIA resulted in changes to diatom community composition with moss epiphytic taxa dominant in new littoral habitat (Douglas et al 1994;Antoniades et al, 2005;Keatley et al 2006) and Cyclotella species dominant in deeper lakes with the development of planktonic habitat (Sovari et al 2002;R€ uhland et al 2003;R€ uhland and Smol 2005). We also find that small epipsammic Fragilaria species are outcompeted by taxa commonly found in benthic mats at the end of the 19th century, likely due to decreased ice cover and creation of new available habitat.…”

Section: Limnological Regime Shift Caused By Climate Warmingmentioning

confidence: 99%

Limnological regime shifts caused by climate warming and Lesser Snow Goose population expansion in the western Hudson Bay Lowlands (Manitoba, Canada)

MacDonald

Farquharson

Merritt

et al. 2015

Ecology and Evolution

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Shallow lakes are dominant features in subarctic and Arctic landscapes and are responsive to multiple stressors, which can lead to rapid changes in limnological regimes with consequences for aquatic resources. We address this theme in the coastal tundra region of Wapusk National Park, western Hudson Bay Lowlands (Canada), where climate has warmed during the past century and the Lesser Snow Goose (LSG; Chen caerulescens caerulescens) population has grown rapidly during the past ∽40 years. Integration of limnological and paleolimnological analyses documents profound responses of productivity, nutrient cycling, and aquatic habitat to warming at three ponds (“WAP 12”, “WAP 20”, and “WAP 21″), and to LSG disturbance at the two ponds located in an active nesting area (WAP 20, WAP 21). Based on multiparameter analysis of 210Pb-dated sediment records from all three ponds, a regime shift occurred between 1875 and 1900 CE marked by a transition from low productivity, turbid, and nutrient-poor conditions of the Little Ice Age to conditions of higher productivity, lower nitrogen availability, and the development of benthic biofilm habitat as a result of climate warming. Beginning in the mid-1970s, sediment records from WAP 20 and WAP 21 reveal a second regime shift characterized by accelerated productivity and increased nitrogen availability. Coupled with 3 years of limnological data, results suggest that increased productivity at WAP 20 and WAP 21 led to atmospheric CO2 invasion to meet algal photosynthetic demand. This limnological regime shift is attributed to an increase in the supply of catchment-derived nutrients from the arrival of LSG and their subsequent disturbance to the landscape. Collectively, findings discriminate the consequences of warming and LSG disturbance on tundra ponds from which we identify a suite of sensitive limnological and paleolimnological measures that can be utilized to inform aquatic ecosystem monitoring.

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“…As one might expect in a warming climate (Table 1), diatom assemblages in shallow ponds at Cape Herschel and in other high Arctic areas (eg Antoniades et al . 2005; Keatley et al . 2006) shifted toward those characteristic of extended open‐water periods, with more habitat differentiation and complexity in the littoral zone.…”

Section: Tracking the Development Of Planktonic Communities In Deepermentioning

confidence: 99%

From controversy to consensus: making the case for recent climate change in the Arctic using lake sediments

Smol

Douglas

2007

Frontiers in Ecology and the Environment

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233

125

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w ww ww w. .f fr ro on nt ti ie er rs si in ne ec co ol lo og gy y. .o or rg g © © The Ecological Society of America E cologists and environmental scientists are constantly faced with the challenge of working at the most appropriate temporal and spatial scales to reach defendable conclusions. Few recent questions have elicited more discussion and debate than those concerning the nature, magnitude, and effects of global climate change. Although there is no longer any serious scientific debate about the influence of greenhouse-gas emissions on climate, many questions remain concerning the relative importance of natural versus anthropogenic causes of climate change, as well as the spatial and temporal scales of climate-related effects on ecosystems. Each of these questions has a temporal component, yet long-term monitoring data, which will help us to find the answers, are often scarce or non-existent. Fortunately, a variety of natural archives preserve proxy data of past environmental and ecological changes, some examples of which are highlighted in this issue of Frontiers. Here, we focus on paleolimnology -the multidisciplinary science that uses the physical, chemical, and biological information preserved in lake and river sediments to reconstruct past environmental conditions (Cohen 2003; Smol in press). We also summarize the development of ideas (and associated challenges) following an earlier paper (Douglas et al. 1994), which proposed that a worrisome record of recent climate warming is preserved in Arctic sediments.The lack of long-term instrumental data in polar regions is especially disconcerting, because Arctic ecosystems, due in part to a variety of positive-feedback mechanisms, are warming at a faster rate than are other parts of the planet (ACIA 2004). In fact, based on the brief temporal windows of available instrumental meteorological data, average temperatures in the Arctic have risen at twice the rate of the rest of the world over the past few decades (ACIA 2004). Not surprisingly, polar regions are therefore often referred to as the "miners' canary" of the planet. Using a variety We live in a constantly changing environment, yet tracking ecological change is often very difficult. Long-term monitoring data are frequently lacking and are especially sparse from Arctic ecosystems, where logistical difficulties limit most monitoring programs. Fortunately, lake and pond sediments contain important archives of past limnological communities that can be used to reconstruct environmental change. Here, we summarize some of the paleolimnological studies that have documented recent climate warming in Arctic lakes and ponds. Several hypotheses have been evaluated to determine if warming, resulting in changes in ice cover and related variables (eg increased habitat availability), was the factor most strongly influencing recent diatom and other biotic changes. Striking and often unprecedented community changes were evident in post-1850 sediments, and could be linked to ecological shifts consistent with warming. Be...

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Early-20th Century Environmental Changes Inferred Using Subfossil Diatoms from a Small Pond on Melville Island, N.W.T., Canadian High Arctic

Cited by 24 publications

References 49 publications

Ultraviolet radiation exposure of a high arctic lake in Svalbard during the Holocene

Ultraviolet radiation exposure of a high arctic lake in Svalbard during the Holocene

Limnological regime shifts caused by climate warming and Lesser Snow Goose population expansion in the western Hudson Bay Lowlands (Manitoba, Canada)

From controversy to consensus: making the case for recent climate change in the Arctic using lake sediments

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