نتایج جستجو برای: aquatic ecosystems
تعداد نتایج: 72145 فیلتر نتایج به سال:
Climate change is having profound impacts on a range of ecological processes in aquatic ecosystems (Amundrud & Srivastava, 2019; Antiqueira et al., 2018; Walther 2002), as global temperatures rise and the frequency extreme weather events increases (Frölicher IPCC, 2014). This includes which connect terrestrial (Larsen 2016) through donor-controlled fluxes energy matter form organisms (Recalde o...
Received on 27 July 2000 Accepted on 27 September 2000 Abstract The freshwater aquatic biodiversity is depleting alarmingly due to the introduction of exotic species and other anthropogenic activities. The indiscriminate transfer of exotic fishes has brought about a wide array of problems including extirpation of indigenous species. The exotics compete with the indigenous species for food, habi...
A large variety of aquatic animals was found to emit the potent greenhouse gas nitrous oxide when nitrate was present in the environment. The emission was ascribed to denitrification by ingested bacteria in the anoxic animal gut, and the exceptionally high N(2)O-to-N(2) production ratio suggested delayed induction of the last step of denitrification. Filter- and deposit-feeding animal species s...
The true bugs (Insecta: Heteroptera) are one of the most important insects which included several pest and beneficial species (predators and parasitoids) and therefore have important role in agroecosystems. The fauna of aquatic and semi-aquatic Heteroptera was studied in paddy fields and around aquatic ecosystems in some regions of Iran through 2004-2009. Totally 58 species from 14 families inc...
Understanding river food webs requires distinguishing energy derived from primary production in the river itself (autochthonous) from that produced externally (allochthonous), yet there are no universally applicable and reliable techniques for doing so. We compared the natural abundance stable isotope ratios of hydrogen (deltaD) of allochthonous and autochthonous energy sources in four differen...
Ecologists have greatly advanced our understanding of the processes that regulate trophic structure and dynamics in ecosystems. However, the causes of systematic variation among ecosystems remain controversial and poorly elucidated. Contrasts between aquatic and terrestrial ecosystems in particular have inspired much speculation, but only recent empirical quantification. Here, we review evidenc...
BACKGROUND We present herein our results regarding the accumulation of four heavy metals (copper, cadmium, lead, and zinc) in four aquatic species plants (Ceratophyllum demersum, Potamogeton pectinatus, Potamogeton lucens, Potamogeton perfoliatus) collected from the Danube River, South-Western part of Romania and their possible use as indicators of aquatic ecosystems pollution with heavy metals...
To maximise the long-term use of limited ecosystem services in South Africa, managers continually require approaches to optimise the establishment of balances between the use and protection of ecosystems to ensure sustainability. Surface freshwater aquatic ecosystems are dynamic and difficult to manage effectively. Sound management protocols that can identify and rank threats to these ecosystem...
‘Grazing ecosystem’ is typically used to describe terrestrial ecosystems with high densities of mammalian herbivores such as the Serengeti in East Africa or the Greater Yellowstone Ecosystem in North America. These abundant, large herbivores determine plant community dynamics and ecosystem processes. The general concepts that define grazing ecosystems also aptly describe many aquatic ecosystems...
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