نتایج جستجو برای: diatom
تعداد نتایج: 5275 فیلتر نتایج به سال:
Diatoms are non-motile, unicellular phytoplankton that have the ability to form colonies in the form of chains. Depending upon the species of diatoms and the linking structures that hold the cells together, these chains can be quite stiff or very flexible. Recently, the bending rigidities of some species of diatom chains have been quantified. In an effort to understand the role of flexibility i...
We conducted a factorial shipboard continuous culture experiment to examine the interactive effects of altered iron, irradiance and CO2 on the summer phytoplankton community of the Ross Sea, Antarctica. After 18 days of continuous incubation, iron enrichment increased phytoplankton biomass, nutrient drawdown, diatom and Phaeocystis abundance, and some photosynthetic parameters. High irradiance ...
Diatoms, combined with a multiproxy study of lake sediments (organic matter, N, δ15N, δ13C, biogenic silica, grain size, Cladocera and chironomids, Alnus pollen) from Lone Spruce Pond, Alaska detail the late-glacial to Holocene history of the lake and its response to regional climate and landscape change over the last 14.5 cal ka BP. We show that the immigration of alder (Alnus viridis) in the ...
Sediment records from closed-basin lakes in the Northern Great Plains (NGP) of North America have contributed significantly to our understanding of regional paleoclimatology. A high-resolution (near decadal) fossil diatom record from Kettle Lake, ND, USA that spans the last 8500 cal. yr BP is interpreted in concert with percent abundance of aragonite in the sediment as an independent proxy of g...
Diagnosis of the Diatom Community upon Biofilm Development on Stainless Steels in Natural Freshwater
This paper reports the development of biofilms on stainless steels (SS) upon exposure in a natural freshwater ecosystem for about six months and focuses on the composition of diatom populations. By using environmental scanning electron microscopy (ESEM) technique, we provide a detailed description regarding diatom identification at species level as well as their main characteristics, including ...
Larval settlement of the polychaete Hydroides elegans Haswell, 1883 is mediated by marine biofilms; complex agglomerates of bacteria, diatoms, fungi and protozoa enmeshed in a matrix of extracellular polymers (EPS). In our previous investigations, benthic diatoms were demonstrated to be potent mediators of larval settlement in H. elegans. The putative diatom-derived settlement cues were heat-st...
The present-day study assesses diatom communities in river with relation to environmental conditions. Diatoms are susceptible to environmental conditions in river and their distribution is mainly governed by the physicochemical composition of the water. Diatoms and water samples were collected in 5 locations during summer season (May 2012). Analysed data were interpreted and the results are rep...
Diatoms are the major marine primary producers on the global scale and, recently, several methods have been developed to retrieve their abundance or dominance from satellite remote sensing data. In this work, we highlight the importance of the Southern Ocean (SO) in developing a global algorithm for diatom using an Abundance Based Approach (ABA). A large global in situ data set of phytoplankton...
A field experiment was employed in Florida Bay investigating the response of seagrass epiphyte communities to nitrogen (N) and phosphorus (P) additions. While most of the variability in epiphyte community structure was related to uncontrolled temporal and spatial environmental heterogeneity, P additions increased the relative abundance of the red algae-cyanobacterial complex and green algae, wi...
This paper presents a multiproxy high-resolution study of the past 2600 years for Seebergsee, a small Swiss lake with varved sediments at the present tree-line ecotone. The laminae were identi ed as varves by a numerical analysis of diatom counts in the thin-sections. The hypothesis of two diatom blooms per year was corroborated by the Pb and Cs chronology. A period of intensive pasturing duri...
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