نتایج جستجو برای: trophic structure

تعداد نتایج: 1579737  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده ادبیات و علوم انسانی 1388

abstract: the present thesis includes ; one preface and 11speeches , that each speech considered in different researches . the prefact part , studied grammer back ground , the first speech considered a brief description about grammatical credits . the second speech considered the different typs of sentences , from structure and meaning points of view . the third speech considered the verb es...

Journal: :international journal of environmental research 0
l.i. kiteresi kenya marine and fisheries research institute, p.o. box 81651, mombasa, kenya e.o. okuku kenya marine and fisheries research institute, p.o. box 81651, mombasa, kenya, 2 soil and water management division, faculty of bioscience engineering, katholike universiteit s.n. mwangi kenya marine and fisheries research institute, p.o. box 81651, mombasa, kenya, university of nairobi, p.o. box 30197, g.p.o, nairobi, kenya b. ohowa kenya marine and fisheries research institute, p.o. box 81651, mombasa, kenya v.o. wanjeri kenya marine and fisheries research institute, p.o. box 81651, mombasa, kenya s. okumu kenya marine and fisheries research institute, p.o. box 81651, mombasa, kenya m. mkono

phytoplankton communities play a significant role in the oceanic biological pump by forming the base of the trophic structure. increase in nutrients loading affects spatial and temporal distribution of phytoplankton. this study examined the phytoplankton community structure and ecological indices in relation to nutrients dynamics in both estuarine and oceanic areas of ramisi-vanga systems along...

Journal: :Nature communications 2012
Tyler D Tunney Kevin S McCann Nigel P Lester Brian J Shuter

Macroscopic ecosystem properties, such as major material pathways and community biomass structure, underlie the ecosystem services on which humans rely. While ecologists have long sought to identify the determinants of the trophic height of food webs (food chain length), it is somewhat surprising how little research effort is invested in understanding changes among other food web properties acr...

Journal: :Water 2022

Ecological information regarding trophic patterns and the inherent structure of freshwater aquatic communities is considered fundamental in ecological research. In this study, Greek fish fauna, belonging to Balkan biodiversity hotspot, were investigated, comparisons species feeding habits among ecoregions performed. The analyses based on widely used level index available composition datasets, a...

1999
Kenneth L. Heck

Attached epiphytes often make important contributions to total primary production in seagrass meadows. Additionally, they may increase the spatial complexity of seagrass habitats. Experiments conducted using artificial seagrass units (ASU) manipulated both epiphytic structure and epiphytic food resources. Previous work suggested that the increase in faunal density associated with epiphytes was ...

2010
Heidi L. Fuchs Peter J. S. Franks

The potential impacts of climate change on marine planktonic ecosystems remain difficult to predict. Climate forcing can alter nutrient availability and predator community composition, and here we show that these shifts may dramatically alter plankton trophic structure, size distributions and biomass. We modeled phytoplankton and zooplankton as a highly resolved size spectrum with size-dependen...

2016
Ailsa H C McLean Benjamin J Parker Jan Hrček Lee M Henry H Charles J Godfray

Recent research has shown that the bacterial endosymbionts of insects are abundant and diverse, and that they have numerous different effects on their hosts' biology. Here we explore how insect endosymbionts might affect the structure and dynamics of insect communities. Using the obligate and facultative symbionts of aphids as an example, we find that there are multiple ways that symbiont prese...

Journal: :Proceedings. Biological sciences 2005
Yves Cherel Keith A Hobson

Cephalopods play a key role in the marine environment but knowledge of their feeding habits is limited by lack of data. Here, we have developed a new tool to investigate their feeding ecology by combining the use of their predators as biological samplers together with measurements of the stable isotopic signature of their beaks. Cephalopod beaks are chitinous hard structures that resist digesti...

Journal: :Revista de biologia tropical 2013
Vineet Kumar Dubey Uttam Kumar Sarkar Ajay Pandey Wazir Singh Lakra

In India, freshwater aquatic resources are suffering from increasing human population, urbanization and shortage of all kind of natural resources like water. To mitigate this, all the major rivers have been planned for a river-interlinking through an interlinking canal system under a huge scheme; yet, the baseline information on ecological conditions of those tropical rivers and their fish comm...

2012
Valentina Lauria Martin J. Attrill John K. Pinnegar Andrew Brown Martin Edwards Stephen C. Votier

Climate change has had profound effects upon marine ecosystems, impacting across all trophic levels from plankton to apex predators. Determining the impacts of climate change on marine ecosystems requires understanding the direct effects on all trophic levels as well as indirect effects mediated by trophic coupling. The aim of this study was to investigate the effects of climate change on the p...

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