scholarly journals Limnological evolution of Zelma Lake, a recently drained thermokarst lake in Old Crow Flats (Yukon, Canada)

2017 ◽  
Vol 3 (2) ◽  
pp. 220-236 ◽  
Author(s):  
Jana M.E. Tondu ◽  
Kevin W. Turner ◽  
Johan A. Wiklund ◽  
Brent B. Wolfe ◽  
Roland I. Hall ◽  
...  
Keyword(s):  
Light Availability ◽  
Drainage Water ◽  
Low Light ◽  
Site Specific ◽  
Thermokarst Lake ◽  
Warming Climate ◽  
Lake Drainage ◽  
Geochemical Variables ◽  
Old Crow Flats

Evidence from remote sensing studies suggests that the frequency of thermokarst lake drainage events is increasing in response to climate change, but the consequences of these changes on the limnology of remaining waterbodies remain unknown. Here, we utilize a multiparameter paleolimnological record and post-drainage water isotope and chemistry monitoring to characterize the limnological evolution of Zelma Lake in Old Crow Flats, Yukon. During the early part of the record (~1678 to 1900 CE), analysis of geochemical variables and algal pigments indicate relatively stable limnological conditions. Abruptly beginning at ~1900, Zelma Lake experienced a 40 year phase of reduced production, likely resulting from thermokarst shoreline expansion and associated increases in turbidity and low light availability. This was followed by ~70 years of increasing production, likely from the stabilization of shorelines combined with a warming climate. Zelma Lake catastrophically drained in June 2007. Post-drainage conditions were characterized by intense eutrophication marked by increases in nutrient and major ion concentrations and the unprecedented occurrence of okenone and diatoxanthin pigments. Comparison to the post-drainage paleolimnological record from another thermokarst lake in Old Crow Flats indicates that a sharp increase of production is likely a common outcome of thermokarst lake drainage, yet intensity differs owing to site-specific catchment characteristics.

scholarly journals Spatial analyses of thermokarst lakes and basins in Yedoma landscapes of the Lena Delta

2011 ◽  
Vol 5 (4) ◽  
pp. 849-867 ◽  
Author(s):  
A. Morgenstern ◽  
G. Grosse ◽  
F. Günther ◽  
I. Fedorova ◽  
L. Schirrmeister
Keyword(s):  
Spatial Analyses ◽  
Lena River ◽  
Thermokarst Lakes ◽  
Thermokarst Lake ◽  
Warming Climate ◽  
Future Potential ◽  
Lake Drainage ◽  
Carbon Balances ◽  
Lena River Delta ◽  
Ice Complex

Abstract. Distinctive periglacial landscapes have formed in late-Pleistocene ice-rich permafrost deposits (Ice Complex) of northern Yakutia, Siberia. Thermokarst lakes and thermokarst basins alternate with ice-rich Yedoma uplands. We investigate different thermokarst stages in Ice Complex deposits of the Lena River Delta using remote sensing and geoinformation techniques. The morphometry and spatial distribution of thermokarst lakes on Yedoma uplands, thermokarst lakes in basins, and thermokarst basins are analyzed, and possible dependence upon relief position and cryolithological context is considered. Of these thermokarst stages, developing thermokarst lakes on Yedoma uplands alter ice-rich permafrost the most, but occupy only 2.2% of the study area compared to 20.0% occupied by thermokarst basins. The future potential for developing large areas of thermokarst on Yedoma uplands is limited due to shrinking distances to degradational features and delta channels that foster lake drainage. Further thermokarst development in existing basins is restricted to underlying deposits that have already undergone thaw, compaction, and old carbon mobilization, and to deposits formed after initial lake drainage. Future thermokarst lake expansion is similarly limited in most of Siberia's Yedoma regions covering about 106 km2, which has to be considered for water, energy, and carbon balances under warming climate scenarios.

scholarly journals Correction: Limnological evolution of Zelma Lake, a recently drained thermokarst lake in Old Crow Flats (Yukon, Canada)

2021 ◽  
pp. 1-3
Author(s):  
Jana M.E. Tondu ◽  
Kevin W. Turner ◽  
Johan A. Wiklund ◽  
Brent B. Wolfe ◽  
Roland I. Hall ◽  
...  
Keyword(s):  
Thermokarst Lake ◽  
Old Crow Flats

Light-dependent seedling survival and growth of four tree species in Costa Rican second-growth rain forests

2005 ◽  
Vol 21 (4) ◽  
pp. 383-395 ◽  
Author(s):  
Silvia Iriarte Vivar Balderrama ◽  
Robin L. Chazdon
Keyword(s):  
Tree Species ◽  
Seedling Survival ◽  
Light Availability ◽  
Light Transmittance ◽  
Growth Responses ◽  
Low Light ◽  
Growth Increments ◽  
Light Gradient ◽  
Second Growth ◽  
Survival And Growth

The dependence of tree seedling survival and growth on light availability was evaluated over 15 mo in three second-growth, wet forest stands (15–18 y old) in north-eastern Costa Rica. Seedlings of four canopy tree species (Dipteryx panamensis, Hyeronima alchorneoides, Virola koschnyi and Vochysia guatemalensis) were planted into four canopy treatments in three replicated stands and in a pasture site, spanning a nearly complete gradient of light availability. Survival and growth of all species increased in response to increasing light availability, but species differed in survival in shaded microsites (6–20% light transmittance) and in growth increments per light increase. Hyeronima showed the highest mortality at low light levels and the highest relative height growth increase per light increase. In contrast, Virola showed high survival at low and moderate light, but showed the lowest leaf area and above-ground biomass per light increase among all species. Dipteryx and Vochysia maintained relatively high rates of survival and growth across the entire light gradient. Hyeronima and Virola showed trade-offs between growth and survival responses to light, unlike Dipteryx and Vochysia. Differences among species in seedling survival at low light may be determined by a variety of physiological and morphological traits that may or may not be mechanistically linked to growth responses.

Are resources allocated differently to symbiosis and reproduction in Geranium sylvaticum under different light conditions?

2004 ◽  
Vol 82 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Jarkko Korhonen ◽  
Minna-Maarit Kytöviita ◽  
Pirkko Siikamäki
Keyword(s):  
Resource Allocation ◽  
Forest Canopy ◽  
Light Availability ◽  
Growing Season ◽  
High Light ◽  
Mycorrhizal Colonization ◽  
Fungal Colonization ◽  
Low Light ◽  
Light Levels ◽  
Dark Septate Fungi

Light levels under the forest canopy are low and generally limit plant photosynthetic gains. We hypothesized that in low-light habitats, plant photosynthate acquisition is too low to allow the same magnitude of resource allocation to symbiosis and reproduction as in high-light habitats. We tested this hypothesis in a field study where Geranium sylvaticum L. plants were collected on three occasions during the growing season from shade and light habitats. In addition, we investigated the relationship between mycorrhizal colonization level and soil nutrient levels in shade and high-light habitats over a growing season. We found that light availability affects resource allocation in G. sylvaticum. Plants were intensively colonized with both arbuscular mycorrhizal and dark septate fungi, and the colonization intensities of these two different groups of fungi correlated positively with each other. In comparison with high-light meadows, mycorrhizal colonization levels were as high or higher in low-light forest habitats, but plants produced fewer flowers. This indicates that allocation to symbiosis was of higher priority than allocation to reproduction in low light. Seed size was not affected by light levels and did not correlate with fungal colonization levels. We found no relationship between fungal colonization levels and soil characteristics.Key words: arbuscular mycorrhiza, dark septate fungi, Geranium sylvaticum, reproduction, shade.

scholarly journals Comparative leaf growth strategies in response to low-water and low-light availability: variation in leaf physiology underlies variation in leaf mass per area in Populus tremuloides

2017 ◽  
Vol 37 (9) ◽  
pp. 1140-1150 ◽  
Author(s):  
Alec S. Baird ◽  
Leander D.L. Anderegg ◽  
Melissa E. Lacey ◽  
Janneke HilleRisLambers ◽  
Elizabeth Van Volkenburgh
Keyword(s):  
Populus Tremuloides ◽  
Leaf Growth ◽  
Light Availability ◽  
Leaf Mass Per Area ◽  
Growth Strategies ◽  
Low Light ◽  
Leaf Mass ◽  
Leaf Physiology

scholarly journals Light alters the impacts of nitrogen and foliar pathogens on the performance of early successional tree seedlings

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11587
Author(s):  
Alexander Brown ◽  
Robert W. Heckman
Keyword(s):  
Fungal Pathogens ◽  
Nitrogen Availability ◽  
Light Availability ◽  
High Light ◽  
Plant Performance ◽  
Forest Understory ◽  
Light Limitation ◽  
Tree Seedlings ◽  
Low Light ◽  
Foliar Damage

Light limitation is a major driver of succession and an important determinant of the performance of shade-intolerant tree seedlings. Shade intolerance may result from a resource allocation strategy characterized by rapid growth and high metabolic costs, which may make shade-intolerant species particularly sensitive to nutrient limitation and pathogen pressure. In this study, we evaluated the degree to which nitrogen availability and fungal pathogen pressure interact to influence plant performance across different light environments. To test this, we manipulated nitrogen availability (high, low) and access by foliar fungal pathogens (sprayed with fungicide, unsprayed) to seedlings of the shade-intolerant tree, Liquidambar styraciflua, growing at low and high light availability, from forest understory to adjacent old field. Foliar fungal damage varied with light and nitrogen availability; in low light, increasing nitrogen availability tripled foliar damage, suggesting that increased nutrient availability in low light makes plants more susceptible to disease. Despite higher foliar damage under low light, spraying fungicide to exclude pathogens promoted 14% greater plant height only under high light conditions. Thus, although nitrogen availability and pathogen pressure each influenced aspects of plant performance, these effects were context dependent and overwhelmed by light limitation. This suggests that failure of shade-intolerant species to invade closed-canopy forest can be explained by light limitation alone.

scholarly journals Low Light Availability Reduces the Subsurface Sediment Carbon Content in Halophila beccarii From the South China Sea

2021 ◽  
Vol 12 ◽  
Author(s):  
Chanaka Premarathne ◽  
Zhijian Jiang ◽  
Jialu He ◽  
Yang Fang ◽  
Qiming Chen ◽  
...  
Keyword(s):  
Carbon Content ◽  
Light Availability ◽  
Seagrass Beds ◽  
Biomass Carbon ◽  
Light Conditions ◽  
Above Ground Biomass ◽  
Low Light ◽  
Subsurface Sediment ◽  
Light Intensities ◽  
Sediment Carbon

Eutrophication, dredging, agricultural and urban runoffs, and epiphyte overgrowth could reduce light availability for seagrass. This may affect “blue carbon” stocks in seagrass beds. However, little research is available on the effect of light intensities on carbon sequestration capacity in seagrass beds, especially small-bodied seagrasses. The dominant seagrass Halophila beccarii, a vulnerable species on the IUCN Red List, was cultured in different light intensities to examine the response of vegetation and sediment carbon in seagrass beds. The results showed that low light significantly reduced leaf length and above-ground biomass, while carbon content in both above-ground and below-ground tissues were not affected. Low light reduced both the above-ground biomass carbon and the total biomass carbon. Interestingly, while under saturating light conditions, the subsurface and surface carbon content was similar, under low light conditions, subsurface sediment carbon was significantly lower than the surface content. The reduction of subsurface sediment carbon might be caused by less release flux of dissolved organic carbon from roots in low light. Taken together, these results indicate that reduced light intensities, to which these meadows are exposed to, will reduce carbon sequestration capacity in seagrass beds. Measures should be taken to eliminate the input of nutrients on seagrass meadows and dredging activities to maintain the “blue carbon” storage service by enhancing light penetration into seagrass.

scholarly journals Daily water-level variations of supraglacial lakes in the southern Inylchek Glacier, Central Asia

2020 ◽  
Author(s):  
Naoki Sakurai ◽  
Chiyuki Narama ◽  
Mirlan Daiyrov ◽  
Muhammed Esenamanov ◽  
Zarylbek Usekov ◽  
...  
Keyword(s):  
Water Level ◽  
Drainage Water ◽  
Water Levels ◽  
Supraglacial Lakes ◽  
Surface Models ◽  
Increase Rate ◽  
Aerial Vehicle ◽  
Water Level Variations ◽  
Daily Water ◽  
Lake Drainage

Abstract. To better understand the storage in and drainage through supraglacial lakes and englacial conduits, we investigated the daily water-level variations of supraglacial lakes on the southern Inylchek Glacier in Kyrgyzstan. To examine these variations, we used daily aerial digital images over three years (22 July–15 August 2017, 8–29 July 2018, and 12–19 July 2019) from an unmanned aerial vehicle (UAV) that were converted to digital surface models (DSMs) and ortho-images. Our main results are as follows. 1) When one lake drained, the water levels of other lakes might simultaneously increase, indicating that drainage water is shared with several lakes through a main englacial conduit. In one drainage event, a branch englacial conduit clearly connected to a main englacial conduit. 2) Sometimes, several lakes discharged simultaneously, indicating that several lakes had connected to a main englacial conduit that had opened. Such a case can cause larger-scale drainage than that from the opening of a branch englacial conduit. 3) Several lakes discharged twice in the same year, each time through a different conduit, indicating that the main englacial conduit can be abandoned and reused. 4) In some lakes, the water level gradually increased with nearly the same increase rate just before drainage. Such an increase may be an indicator of imminent lake drainage.

Functional shifts in leaves of woody invaders of deciduous forests between their home and away ranges

2019 ◽  
Vol 39 (9) ◽  
pp. 1551-1560 ◽  
Author(s):  
Kelsey A Martinez ◽  
Jason D Fridley ◽  
Riichi Oguchi ◽  
Masahiro Aiba ◽  
Kouki Hikosaka
Keyword(s):  
Rapid Evolution ◽  
Light Availability ◽  
Leaf Traits ◽  
Enemy Release ◽  
Carbon Gain ◽  
Native Range ◽  
Low Light ◽  
Trait Variation ◽  
Unit Leaf ◽  
Leaf Chlorophyll

Abstract Temperate forests are widely invaded by shade-tolerant shrubs and trees, including those of Eastern North America (ENA). However, it remains unknown whether these invaders are ‘preadapted’ for success in their new ranges due to unique aspects of their evolutionary history or whether selection due to enemy release or other postintroduction processes have driven rapid evolution in the invaded range. We sampled leaf traits of populations of woody understory invaders across light gradients in their native range in Japan and in their invaded ENA range to examine potential phenotypic shifts related to carbon gain and nitrogen use between ranges. We also measured leaf traits in three co-occurring ENA native shrub species. In their invaded range, invaders invested significantly less in leaf chlorophyll content (both per unit leaf mass and area) compared with native range populations of the same species, yet maintained similar rates of photosynthesis in low light. In addition, compared with ENA natives, ENA invaders displayed greater trait variation in response to increasing light availability (forest edges, gaps), giving them a potential advantage over ENA natives in a variety of light conditions. We conclude that, for this group of species, newly evolved phenotypes in the invaded range are more important than preadaptation for their success as shade-tolerant forest invaders.

Holocene pore‐ice δ 18 O and δ 2 H records from drained thermokarst lake basins in the Old Crow Flats, Yukon, Canada

2020 ◽  
Vol 31 (4) ◽  
pp. 497-508
Author(s):  
Sasiri Bandara ◽  
Duane Froese ◽  
Trevor J. Porter ◽  
Fabrice Calmels
Keyword(s):  
Thermokarst Lake ◽  
Old Crow Flats ◽  
Lake Basins
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