Search results for "lake"

Littoral energy pathways in highly humic boreal lakes

2017

Littoral zones in lakes are among the most productive habitats in the world, but have been seriously understudied, as most limnological studies have concerned only pelagic habitats. The likely importance of littoral zones in clear lakes is widely acknowledged, but in contrast their role in dystrophic humic lakes has generally been assumed to be minor. In this thesis, littoral importance in whole-lake metabolism was studied in small and highly humic lakes in Southern Finland, where Lake Mekkojärvi was the principal study lake. Primary production (PP) measurements revealed that littoral periphyton, growing on surrounding aquatic vegetation, can dominate the whole-lake PP, and the highly autot…

Applicability and consequences of the integration of alternative models for CO2 transfer velocity into a process-based lake model

2019

Freshwater lakes are important in carbon cycling, especially in the boreal zone where many lakes are supersaturated with the greenhouse gas carbon dioxide (CO2) and emit it to the atmosphere, thus ventilating carbon originally fixed by the terrestrial system. The exchange of CO2 between water and the atmosphere is commonly estimated using simple wind-based parameterizations or models of gas transfer velocity (k). More complex surface renewal models, however, have been shown to yield more correct estimates of k in comparison with direct CO2 flux measurements. We incorporated four gas exchange models with different complexity into a vertical process-based physico-biochemical lake model, MyLak…

The influence of lipid content and taxonomic affiliation on methane and carbon dioxide production from phytoplankton biomass in lake sediment

2021

The greenhouse gases methane (CH4) and carbon dioxide (CO2) are end products of microbial anaerobic degradation of organic matter (OM) in lake sediments. Although previous research has shown that phytoplankton lipid content influences sediment methanogenesis, current understanding on how OM quality affects methanogenesis is still limited. Such information is needed to more accurately assess how lake greenhouse gas emissions may change in response to anthropogenic activities. We cultured 11 phytoplankton species from five classes and studied how taxonomic identity, C : N ratio, lipid content, and fatty acid composition of phytoplankton biomass affects the CH4 and net CO2 production in anaero…

Runon merkityksen pirstaloitu sijainti : analysoidut William Blaken runot "The Sick Rose" ja "London": hyvän ja pahan, aineen ja hengen, subjektin ja…

1999

L'habitat néolithique récent de Geispolsheim "Forlen" (Bas-Rhin) : contribution à la périodisation de la culture de Munzingen et à l'étude de ses rel…

2011

The recent Neolithic site of Forlen in Geispolsheim, attributed to the recent Munzingen, has yielded a series of enclosures containing ceramic forms unprecedented in the context of Munzingen B. We have detected the influence of late productions by the Pfyn culture and propose the identification of a new stage in the recent Munzingen, which we have unoriginally named Munzingen C, and is typified by the appearance of ceramic forms with rounded profiles. This episode may date from around 3650-3550 BC, a late dating that has been confirmed by two carbon 14 tests. The discovery allows a strong claim to be made that ancient trading networks that linked the Rhine Valley with the Swiss Plateau and …

Dangerous relationships : biases in freshwater bioassessment based on observed to expected ratios

2018

Copyright by the Ecological Society of America The ecological assessment of freshwaters is currently primarily based on biological communities and the reference condition approach (RCA). In the RCA, the communities in streams and lakes disturbed by humans are compared with communities in reference conditions with no or minimal anthropogenic influence. The currently favored rationale is using selected community metrics for which the expected values (E) for each site are typically estimated from environmental variables using a predictive model based on the reference data. The proportional differences between the observed values (O) and E are then derived, and the decision rules for status ass…

Effects of mechanical mixing on lake water quality, with special emphasis on under-ice phytoplankton

2015

Under-ice temperature and oxygen conditions in boreal lakes

2013

Sustainability of interlocked fishing district -management concept for commercial fishing in Finnish lake fishery

2012

Heidi Blake: Tappolista. Kremlin salamurhaohjelma

2021

Kirja-arvostelu teoksesta Blake, Heidi (2020): Tappolista. Kremlin salamurhaohjelma ja Vladimir Putinin sota länttä vastaan. (From Russia with Blood 2019) Suom. Aura Nurmi. Atena. nonPeerReviewed