Search results for "Fish"
showing 10 items of 3164 documents
Priming effect increases with depth in a boreal forest soil
2016
Abstract Climate warming increases labile carbon (C) inputs to soil through increased photosynthesis and C allocation belowground. This could counterintuitively lead to losses of soil C via priming effects (PE): the stimulation of soil organic matter (SOM) decomposition caused by labile C addition. Systematic quantification of PEs in different ecosystems is needed. We measured PEs of free-living soil microbes in different layers of a boreal forest soil, and found that the relative magnitude of the PE increased with soil depth. The relationship between relative PE and the added glucose amount also depended on the soil layer. Our results indicate that the decomposition of SOM in deeper soil l…
Mapping productivity and essential biophysical parameters of cultivated tropical grasslands from sentinel-2 imagery.
2020
Nitrogen (N) is the main nutrient element that maintains productivity in forages
Subtelomēru rajona hromatīna struktūras izmaiņu noteikšana ar qPCR
2015
Cilvēka subtelomēri ir izteikti polimorfiski un ir ar vislielāko gēnu blīvumu visā genomā. Subtelomēru sekvences pārmaiņas ir saistītas ar mentālo atpalicību, ļaundabīgām hematoloģiskajām slimībām, atkārtotiem spontānajiem abortiem un citām slimībām. Tādēļ subtelomēru reģiona pārmaiņu konstatēšana ir svarīga klīniskās izpētes sastāvdaļa. Subtelomēru pētniecībā galvenokārt tiek pielietotas divas metodes: FISH un SAT. Šajā darbā tika aprakstīta qPCR metode subtelomēru analīzei, kas, teorētiski ir lētāka, ātrāka un precīzāka alternatīva FISH un SAT metodēm. Darbā apraksta qPCR metodes pielietošanu, Y hromosomas p pleca subtelomēru reģiona pārmaiņu pētīšanai, 34 DNS paraugiem, kas iegūti no nea…
Straw uses trade-off only after soil organic carbon steady-state
2018
Soil organic matter (SOM) is the key for a healthy soil and a relevant property to achieve the sustainability on soil management. However, soils are still net exporters of organic matter. One example is the use of wheat straw residue for industrial and energy applications, which has gained attention in the last years. The offfarm use of this abundant and low cost resource should follow sustainability criteria to avoid soil degradation and SOM losses. Straw residue incorporation is recognized as a recommended management practice to control erosion and mitigate CO2 emissions by increasing SOM. The goal of this work was: i) to evaluate the steady-state carbon (C) level in relation to C input a…
Lake size and fish diversity determine resource use and trophic position of a top predator in high-latitude lakes
2015
Prey preference of top predators and energy flow across habitat boundaries are of fundamental importance for structure and function of aquatic and terrestrial ecosystems, as they may have strong effects on production, species diversity, and food-web stability. In lakes, littoral and pelagic food-web compartments are typically coupled and controlled by generalist fish top predators. However, the extent and determinants of such coupling remains a topical area of ecological research and is largely unknown in oligotrophic high-latitude lakes. We analyzed food-web structure and resource use by a generalist top predator, the Arctic charr Salvelinus alpinus (L.), in 17 oligotrophic subarctic lakes…
Selection of spawning substratum by European river lampreys (Lampetra fluviatilis) in experimental tanks
2014
The selection of spawning substratum by the river lamprey (Lampetra fluviatilis) was studied in two experimental tanks with different flow conditions. In both tanks, four gravel sizes mixed with 15% sand were available to the test animals. In the tank with the lower current speed, lampreys selected in favour of the finest (2–8 mm) gravel size available against gravel sizes 4–20 mm and 8–40 mm. Selection was also significantly different in the tank with higher current speed where selection against the medium-sized substratum (4–20 mm) was evident, but there were no differences between selection for gravel sizes 2–8 mm, 2–40 mm and 8–40 mm relative to availability. Substratum selection and ob…
Combined effect of low-molecular-weight organic acids and creosote on phosphatase activities in sandy soil
2018
This paper assesses the impact of creosote and low-molecular-weight organic acids (LMWOAs) on the activity of acid phosphomonoesterase, alkaline phosphomonoesterase, phosphotriesterase, and inorganic pyrophosphatase in soil. The experiment was carried out on loamy sand samples with organic carbon content of 8.71 g · kg -1 , with the following variable factors: dosages of creosote: 0, 0.5%, and 2.5%; type of LMWOAs: oxalic acid, tartaric acid, and citric acid in the amount of 50 mmol · kg -1 of soil; days of experiment: 1, 7, 14, 28, 56, 112. Obtained results showed that contamination with creosote caused decrease in the activity of soil phosphatases. The observed effect did not always incre…
Towards a framework for assessment and management of cumulative human impacts on marine food webs
2015
Effective ecosystem-based management requires understanding ecosystem responses to multiple human threats, rather than focusing on single threats. To understand ecosystem responses to anthropogenic threats holistically, it is necessary to know how threats affect different components within ecosystems and ultimately alter ecosystem functioning. We used a case study of a Mediterranean seagrass (Posidonia oceanica) food web and expert knowledge elicitation in an application of the initial steps of a framework for assessment of cumulative human impacts on food webs. We produced a conceptual seagrass food web model, determined the main trophic relationships, identified the main threats to the fo…
Discussion of “Three Simple Flumes for Flow Measurement in Open Channels” by Zohrab Samani
2018
In this paper the results on three simple flumes for flow measurements are discussed.
Effets du bruit marin sur le changement des poissons sparidés juvéniles entre les espèces et les stades de développement
2023
International audience; Marine noise is an emerging pollutant inducing a variety of negative impacts on many animal taxa, including fish. Fish population persistence and dynamics rely on the supply of early life stages, which are often very sensitive to disturbance. Impacts of marine noise pollution (MNP) on juvenile fish have rarely been investigated in temperate regions. This is particularly true for the Mediterranean Sea, which is considered as an MNP hotspot due to intensive maritime traffic. In this study, we investigate the relationship between MNP related to boat traffic and (i) assemblage structure and (ii) the density of juvenile fishes (post-settlers at different stages) belonging…