SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Noges Peeter) "

Sökning: WFRF:(Noges Peeter)

  • Resultat 1-10 av 15
  • [1]2Nästa
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  •  
2.
  •  
3.
  • Cremona, Fabien, et al. (författare)
  • Numerical Exploration of the Planktonic to Benthic Primary Production Ratios in Lakes of the Baltic Sea Catchment
  • 2016
  • Ingår i: Ecosystems (New York. Print). - 1432-9840 .- 1435-0629. ; 19:8, s. 1386-1400
  • Tidskriftsartikel (refereegranskat)abstract
    • Autotrophic structure refers to the partitioning of whole-ecosystem primary production between benthic and planktonic primary producers. Autotrophic structure remains poorly understood especially because of the paucity of estimates regarding benthic primary production. We used a conceptual model for numerically exploring the autotrophic structure of 13 hemiboreal lakes situated in the Baltic Sea catchment. We also used diel variations in primary production profiles to graphically evaluate levels of light and/or nutrient limitation in lakes. The input morphometric data, light extinction coefficients and dissolved carbon parameters were mostly obtained from in situ measurements. Results revealed that cross- and within-lake autotrophic structure varied greatly: one lake was clearly dominated by benthic production, and three lakes by phytoplankton production. In the rest, phytoplankton production was generally dominant but switch to benthic dominance was possible. The modelled primary production profiles varied according to lake water clarity and bathymetry. Our results clearly indicate that the relative contribution of benthic primary production to whole-lake primary production should be taken into account in studies about hemiboreal and boreal lakes.
  •  
4.
  • Hampton, Stephanie E., et al. (författare)
  • Ecology under lake ice
  • 2017
  • Ingår i: Ecology Letters. - 1461-023X .- 1461-0248. ; 20:1, s. 98-111
  • Forskningsöversikt (refereegranskat)abstract
    • Winter conditions are rapidly changing in temperate ecosystems, particularly for those that experience periods of snow and ice cover. Relatively little is known of winter ecology in these systems, due to a historical research focus on summer ‘growing seasons’. We executed the first global quantitative synthesis on under-ice lake ecology, including 36 abiotic and biotic variables from 42 research groups and 101 lakes, examining seasonal differences and connections as well as how seasonal differences vary with geophysical factors. Plankton were more abundant under ice than expected; mean winter values were 43.2% of summer values for chlorophyll a, 15.8% of summer phytoplankton biovolume and 25.3% of summer zooplankton density. Dissolved nitrogen concentrations were typically higher during winter, and these differences were exaggerated in smaller lakes. Lake size also influenced winter-summer patterns for dissolved organic carbon (DOC), with higher winter DOC in smaller lakes. At coarse levels of taxonomic aggregation, phytoplankton and zooplankton community composition showed few systematic differences between seasons, although literature suggests that seasonal differences are frequently lake-specific, species-specific, or occur at the level of functional group. Within the subset of lakes that had longer time series, winter influenced the subsequent summer for some nutrient variables and zooplankton biomass.
  •  
5.
  • Jenny, Jean Philippe, et al. (författare)
  • Scientists’ Warning to Humanity: Rapid degradation of the world's large lakes
  • 2020
  • Ingår i: Journal of Great Lakes Research. - : Elsevier BV. - 0380-1330. ; 46:4, s. 686-702
  • Forskningsöversikt (refereegranskat)abstract
    • © 2020 The Authors Large lakes of the world are habitats for diverse species, including endemic taxa, and are valuable resources that provide humanity with many ecosystem services. They are also sentinels of global and local change, and recent studies in limnology and paleolimnology have demonstrated disturbing evidence of their collective degradation in terms of depletion of resources (water and food), rapid warming and loss of ice, destruction of habitats and ecosystems, loss of species, and accelerating pollution. Large lakes are particularly exposed to anthropogenic and climatic stressors. The Second Warning to Humanity provides a framework to assess the dangers now threatening the world's large lake ecosystems and to evaluate pathways of sustainable development that are more respectful of their ongoing provision of services. Here we review current and emerging threats to the large lakes of the world, including iconic examples of lake management failures and successes, from which we identify priorities and approaches for future conservation efforts. The review underscores the extent of lake resource degradation, which is a result of cumulative perturbation through time by long-term human impacts combined with other emerging stressors. Decades of degradation of large lakes have resulted in major challenges for restoration and management and a legacy of ecological and economic costs for future generations. Large lakes will require more intense conservation efforts in a warmer, increasingly populated world to achieve sustainable, high-quality waters. This Warning to Humanity is also an opportunity to highlight the value of a long-term lake observatory network to monitor and report on environmental changes in large lake ecosystems.
  •  
6.
  •  
7.
  •  
8.
  • O’Reilly, Catherine M., et al. (författare)
  • Rapid and highly variable warming of lake surface waters around the globe
  • 2015
  • Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 42:24
  • Tidskriftsartikel (refereegranskat)abstract
    • In this first worldwide synthesis of in situ and satellite-derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean = 0.34°C decade−1) between 1985 and 2009. Our analyses show that surface water warming rates are dependent on combinations of climate and local characteristics, rather than just lake location, leading to the counterintuitive result that regional consistency in lake warming is the exception, rather than the rule. The most rapidly warming lakes are widely geographically distributed, and their warming is associated with interactions among different climatic factors—from seasonally ice-covered lakes in areas where temperature and solar radiation are increasing while cloud cover is diminishing (0.72°C decade−1) to ice-free lakes experiencing increases in air temperature and solar radiation (0.53°C decade−1). The pervasive and rapid warming observed here signals the urgent need to incorporate climate impacts into vulnerability assessments and adaptation efforts for lakes.
  •  
9.
  • Sharma, Sapna, et al. (författare)
  • A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009
  • 2015
  • Ingår i: Scientific Data. - : Macmillan Publishers Limited. - 2052-4463. ; 2
  • Tidskriftsartikel (refereegranskat)abstract
    • Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues.
  •  
10.
  • Gsell, Alena Sonia, et al. (författare)
  • Evaluating early-warning indicators of critical transitions in natural aquatic ecosystems
  • 2016
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424. ; 113:50, s. 8089-8095
  • Tidskriftsartikel (refereegranskat)abstract
    • Ecosystems can show sudden and persistent changes in state despite only incremental changes in drivers. Such critical transitions are difficult to predict, because the state of the system often shows little change before the transition. Early-warning indicators (EWIs) are hypothesized to signal the loss of system resilience and have been shown to precede critical transitions in theoretical models, paleo-climate time series, and in laboratory as well as whole lake experiments. The generalizability of EWIs for detecting critical transitions in empirical time series of natural aquatic ecosystems remains largely untested, however. Here we assessed four commonly used EWIs on long-term datasets of five freshwater ecosystems that have experienced sudden, persistent transitions and for which the relevant ecological mechanisms and drivers are well understood. These case studies were categorized by three mechanisms that can generate critical transitions between alternative states: competition, trophic cascade, and intraguild predation. Although EWIs could be detected in most of the case studies, agreement among the four indicators was low. In some cases, EWIs were detected considerably ahead of the transition. Nonetheless, our results show that at present, EWIs do not provide reliable and consistent signals of impending critical transitions despite using some of the best routinely monitored freshwater ecosystems. Our analysis strongly suggests that a priori knowledge of the underlying mechanisms driving ecosystem transitions is necessary to identify relevant state variables for successfully monitoring EWIs.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 15
  • [1]2Nästa

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy