scholarly journals The role of internal feedbacks in shifting deep lake mixing regimes under a warming climate

2021 ◽  
Author(s):  
Jorrit P. Mesman ◽  
Julio A. A. Stelzer ◽  
Vasilis Dakos ◽  
Stéphane Goyette ◽  
Ian D. Jones ◽  
...  
Keyword(s):  
Deep Lake ◽  
Lake Mixing ◽  
Warming Climate

scholarly journals Links between plant species’ spatial and temporal responses to a warming climate

2014 ◽  
Vol 281 (1779) ◽  
pp. 20133017 ◽  
Author(s):  
Tatsuya Amano ◽  
Robert P. Freckleton ◽  
Simon A. Queenborough ◽  
Simon W. Doxford ◽  
Richard J. Smithers ◽  
...  
Keyword(s):  
Species Distribution Models ◽  
Range Shifts ◽  
Niche Conservatism ◽  
Historical Records ◽  
Perennial Species ◽  
Distribution Models ◽  
Climatic Niche ◽  
Warming Climate ◽  
Phenological Changes

To generate realistic projections of species’ responses to climate change, we need to understand the factors that limit their ability to respond. Although climatic niche conservatism, the maintenance of a species’s climatic niche over time, is a critical assumption in niche-based species distribution models, little is known about how universal it is and how it operates. In particular, few studies have tested the role of climatic niche conservatism via phenological changes in explaining the reported wide variance in the extent of range shifts among species. Using historical records of the phenology and spatial distribution of British plants under a warming climate, we revealed that: (i) perennial species, as well as those with weaker or lagged phenological responses to temperature, experienced a greater increase in temperature during flowering (i.e. failed to maintain climatic niche via phenological changes); (ii) species that failed to maintain climatic niche via phenological changes showed greater northward range shifts; and (iii) there was a complementary relationship between the levels of climatic niche conservatism via phenological changes and range shifts. These results indicate that even species with high climatic niche conservatism might not show range shifts as instead they track warming temperatures during flowering by advancing their phenology.

scholarly journals Oxycline oscillations induced by internal waves in deep Lake Iseo

2018 ◽  
Author(s):  
Giulia Valerio ◽  
Marco Pilotti ◽  
Maximilian Peter Lau ◽  
Michael Hupfer
Keyword(s):  
Internal Waves ◽  
Water Layer ◽  
Sediment Surface ◽  
Chemical Gradient ◽  
Deep Lakes ◽  
Deep Lake ◽  
Deep Waters ◽  
Basin Scale ◽  
First Time

Abstract. Lake Iseo is undergoing a dramatic de-oxygenation of the hypolimnion, representing an emblematic example among the deep lakes of the prealpine area that are, to a different extent, suffering from reduced deep water mixing. In the anoxic deep waters, the release and accumulation of reduced substances and phosphorus from the sediments is a major concern. Since the hydrodynamics of this lake was shown to be dominated by internal waves, in this study we investigate for the first time the role of these oscillatory motions on the vertical fluctuations of the oxycline, currently situated at a depth of around 95 m, where a permanent chemocline inhibits deep mixing by convection. Temperature and dissolved oxygen data measured at moored stations show large and periodic oscillations of the oxycline, with amplitude up to 20 m and periods ranging from 1 to 4 days. A deep dynamics characterized by larger amplitudes at lower frequencies is shown to be favoured by the excitation of second vertical modes in strongly thermally stratified periods and of first vertical modes in weakly thermally stratified periods, when the deep chemical gradient can support baroclinicity anyhow. These basin-scale internal waves cause in the water layer between 85 and 105 m depth a fluctuation of the oxygen concentration between 0 and 3 mg L−1 that, due to the bathymetry of the lake, changes the redox condition at the sediment surface. This forcing, involving about 3 % of the lake's sediment area, can have major implications for the biogeochemical processes at the sediment water interface and for the internal matter cycle.

Facing the future: the importance of substratum features for ecological engineering of artificial habitats in the rocky intertidal

2016 ◽  
Vol 67 (1) ◽  
pp. 131 ◽  
Author(s):  
Louise B. Firth ◽  
Freya J. White ◽  
Meredith Schofield ◽  
Mick E. Hanley ◽  
Michael T. Burrows ◽  
...  
Keyword(s):  
General Trend ◽  
Ecological Engineering ◽  
Grazing Pressure ◽  
Rocky Intertidal ◽  
Taxon Richness ◽  
Natural Habitats ◽  
Artificial Habitats ◽  
Warming Climate ◽  
North And South

Coastal defences are proliferating in response to climate change, leading to the creation of more vertical substrata. Efforts are being made to mitigate their impacts and create novel habitats to promote biodiversity. Little is known about the effect of aspect (i.e. north–south directionality) and inclination on intertidal biodiversity in artificial habitats. Artificial and natural habitats were compared to assess the role of aspect and substratum inclination in determining patterns of biodiversity at two tidal heights (high and mid). We also compared grazing activity between north- and south-facing surfaces in natural habitats to examine the potential for differential grazing pressure to affect community structure and functioning. Results were variable but some clear patterns emerged. Inclination had no effect on biodiversity or abundance. There was a general trend towards greater taxon richness and abundance on north-facing than south-facing substrata in natural and artificial habitats. On natural shores, the abundance and grazing activity of ‘southern’ limpets (i.e. Patella depressa) was greater on south-facing than north-facing substrata, with possible implications for further range-expansion. These results highlight the importance of incorporating shaded habitats in the construction of artificial habitats. These habitats may represent an important refuge from grazing pressure and thermal and desiccation stress in a warming climate.

scholarly journals Ecology and Distribution of Thaumarchaea in the Deep Hypolimnion of Lake Maggiore

Archaea ◽  
2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Manuela Coci ◽  
Nina Odermatt ◽  
Michaela M. Salcher ◽  
Jakob Pernthaler ◽  
Gianluca Corno
Keyword(s):  
Fish Analysis ◽  
Ecological Role ◽  
Deep Lake ◽  
Lake Maggiore ◽  
Ammonia Oxidizing Archaea ◽  
Catalyzed Reporter Deposition ◽  
Card Fish ◽  
Abundance And Distribution

Ammonia-oxidizing Archaea (AOA) play an important role in the oxidation of ammonia in terrestrial, marine, and geothermal habitats, as confirmed by a number of studies specifically focused on those environments. Much less is known about the ecological role of AOA in freshwaters. In order to reach a high resolution at the Thaumarchaea community level, the probe MGI-535 was specifically designed for this study and applied to fluorescencein situhybridization and catalyzed reporter deposition (CARD-FISH) analysis. We then applied it to a fine analysis of diversity and relative abundance of AOA in the deepest layers of the oligotrophic Lake Maggiore, confirming previous published results of AOA presence, but showing differences in abundance and distribution within the water column without significant seasonal trends with respect to Bacteria. Furthermore, phylogenetic analysis of AOA clone libraries from deep lake water and from a lake tributary, River Maggia, suggested the riverine origin of AOA of the deep hypolimnion of the lake.

scholarly journals Understanding Vietnamese consumers’ purchase intentionstoward green electronic productsin Hochiminh city –adapted tpb perspective

2015 ◽  
Vol 18 (4) ◽  
pp. 55-63
Author(s):  
Ngoc Bich Nguyen ◽  
Nam Van Nguyen ◽  
Bich Huy Hai Bui
Keyword(s):  
Environmental Protection ◽  
Environmental Sustainability ◽  
Environmental Issues ◽  
Purchase Intentions ◽  
Environmental Knowledge ◽  
High Rate ◽  
Role Of Government ◽  
Electronic Products ◽  
Warming Climate

Keeping the balance between high rate of economic growth and environmental sustainability is the most important task of many nations, especially developing nations including VietNam. According toGardner & Stern [1],many environmental issues such as global warming, climate change… due to pollution, loss of biodiversity are intrinsically related to human behavior. Besides the role of Government and business in environmental protection, individual purchase behaviour has a big effect on environmental protection, too. Hencethis research applies the theory of Planned Behavior to examine the factors that have impact on Vietnamese Consumers’ Purchase Intentions toward Green Electronic Products in Hochiminh City. Through directly interviewing 193 consumers in HCM city, the resultshowed that the most affected factor of Consumers’ Purchase Intentions toward Green Electronic Products is environmental knowledge(β =0,283),recognized consumer effectiveness(β =0,236), ecolabel (β =0,217), with adjusted R2is of 19,4%.

scholarly journals Broad-scale mercury bioaccumulation patterns in two freshwater sport fishes: testing the role of growth dilution in a warming climate

2018 ◽  
Author(s):  
Shyam M. Thomas ◽  
Stephanie J. Melles ◽  
Satyendra P. Bhavsar
Keyword(s):  
Northern Pike ◽  
Space Time ◽  
Spatiotemporal Variations ◽  
Latitudinal Zone ◽  
Space And Time ◽  
Spatiotemporal Trends ◽  
Warming Climate ◽  
Mercury Bioaccumulation ◽  
Broad Scale

AbstractSport fishes at the apex of aquatic food webs are indicators of mercury in the environment. However bioaccumulation of mercury in fish is a complex process that varies in space and time. Both large-scale climatic and environmental, as well as biological factors are drivers of these space-time variations. In this study, we avail a long-running monitoring program from Ontario, Canada to better understand spatiotemporal variations in fish mercury bioaccumulation. Focussing on two common large-bodied fishes (Walleye and Northern Pike), the data were first stratified by latitudinal zone (north, mid, and south) and eight temporal periods (between 1975 & 2015). A series of linear mixed-effects models (LMEMs) with latitudinal zone, time period, and their interactions as random effects were used to capture the spatial, temporal, and spatiotemporal variations in mercury bioaccumulation. The random slopes from the best-fitting LMEM were used to define bioaccumulation index and capture trends in space and time. Given the generally warming climate trend over the past 45 years, the role of growth dilution in modulating the bioaccumulation trends was also evaluated. The full model comprising of space, time and space-time interactions was the best-fit with interaction effects explaining most of the variation. Spatiotemporal trends showed overall similar patterns for both species. Growth dilution in conjunction with estimated rates of warming for different latitudinal zones failed to explain the spatiotemporal trends. Temporal trends showed contrasting bioaccumulation patterns-increasing in Northern Pike and decreasing in Walleye, suggesting temperature-driven growth dilution is more likely in latter. However, a space-for-time substitution revealed only a weak presence of growth dilution in Walleye, and it was not attributable to temperature differences. Overall, our study summarizes broad-scale variations in fish mercury and explores the role of growth dilution in shaping the observed patterns.

scholarly journals Oxycline oscillations induced by internal waves in deep Lake Iseo

2019 ◽  
Vol 23 (3) ◽  
pp. 1763-1777 ◽  
Author(s):  
Giulia Valerio ◽  
Marco Pilotti ◽  
Maximilian Peter Lau ◽  
Michael Hupfer
Keyword(s):  
Internal Waves ◽  
Water Layer ◽  
Sediment Surface ◽  
Chemical Gradient ◽  
Deep Lakes ◽  
Deep Lake ◽  
Deep Waters ◽  
Basin Scale ◽  
First Time

Abstract. Lake Iseo is undergoing a dramatic deoxygenation of the hypolimnion, representing an emblematic example among the deep lakes of the pre-alpine area that are, to a different extent, undergoing reduced deep-water mixing. In the anoxic deep waters, the release and accumulation of reduced substances and phosphorus from the sediments are a major concern. Because the hydrodynamics of this lake was shown to be dominated by internal waves, in this study we investigated, for the first time, the role of these oscillatory motions on the vertical fluctuations of the oxycline, currently situated at a depth of approximately 95 m, where a permanent chemocline inhibits deep mixing via convection. Temperature and dissolved oxygen data measured at moored stations show large and periodic oscillations of the oxycline, with an amplitude of up to 20 m and periods ranging from 1 to 4 days. Deep motions characterized by larger amplitudes at lower frequencies are favored by the excitation of second vertical modes in strongly thermally stratified periods and of first vertical modes in weakly thermally stratified periods, when the deep chemical gradient can support baroclinicity regardless. These basin-scale internal waves cause a fluctuation in the oxygen concentration between 0 and 3 mg L−1 in the water layer between 85 and 105 m in depth, changing the redox condition at the sediment surface. This forcing, involving approximately 3 % of the lake's sediment area, can have major implications for the biogeochemical processes at the sediment–water interface and for the internal matter cycle.

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