نتایج جستجو برای: benthic health
تعداد نتایج: 990175 فیلتر نتایج به سال:
BACKGROUND Species distribution, abundance and diversity of mangrove benthic macroinvertebrate fauna and the relationships to environmental conditions are important parts of understanding the structure and function of mangrove ecosystems. In this study seasonal variation in the distribution of macrobenthos and related environmental parameters were explored at four mangrove stations along the Po...
The importance of the benthic filter feeding community as a natural control on eutrophication is considered. The important environmental factors favorable for such a control are relatively shallow water depths and a dense benthic filter feeding commmunity of small animals. The criteria are summarized in the equivalence of the water recycling time, t, for the benthic community and the time const...
AbstractThe Aitamir Formation is divided into two members the lower sandstone and the upper shale. 32 genera and 57 species of foraminifera have been recognized. According to identified foraminifera Rotalipora appenninica Interval Zone, Rotalipora globotruncanoides (Rotalipora brotzeni) interval zone and Whiteinella aumalensis-Dicarinella canaliculata assemblage zone are proposed and a l Albian...
Dams provide benefits for human societies, but now they are considered as one of the most important factors influencing habitat degradation and changing the hydrological water flow. In order to study the ecological effects of Zayandehroud Dam on the benthic communities and water quality of Zayandehroud river, six sampling stations were selected on the river substrate using biological indicators...
We examined the hypothesis that the d13C of benthic consumers is depleted in offshore, deeper waters where kelp and benthic microalgae are absent by conducting three analyses: (1) we analyzed d13C (and d15N) of consumers along a nearshore–offshore gradient in the field, (2) we analyzed d13C (and d15N) of consumers placed in cages at various depths and distances from shore, and (3) we reexamined...
Disturbance-mediated species loss has prompted research considering how ecosystem functions are changed when biota is impaired. However, there is still limited empirical evidence from natural environments evaluating the direct and indirect (i.e. via biota) effects of disturbance on ecosystem functioning. Oxygen deficiency is a widespread threat to coastal and estuarine communities. While the ne...
The high degree of physical factors in intertidal estuarine ecosystem increases material processing between benthic and pelagic compartments. In these ecosystems, microphytobenthos resuspension is a major phenomenon since its contribution to higher trophic levels can be highly significant. Understanding the sediment and associated microphytobenthos resuspension and its fate in the water column ...
Benthic iron fluxes from sites along the Oregon–California continental shelf determined using in situ benthic chambers, range from less than 10 lmol m 2 d 1 to values in excess of 300 lmol m 2 d . These fluxes are generally greater than previously published iron fluxes for continental shelves contiguous with the open ocean (as opposed to marginal seas, bays, or estuaries) with the highest fluxe...
A mechanistic understanding of the effects of nutrient enrichment in lotic systems has been advanced over the last two decades such that identification of management thresholds for the prevention of eutrophication is now possible. This study describes relationships among primary nutrients (phosphorus and nitrogen), benthic chlorophyll a concentrations, daily dissolved oxygen (DO) concentrations...
12 Benthic nitrogen (N2) fixation and sulfate reduction (SR) were investigated in the Peruvian 13 oxygen minimum zone (OMZ). Sediment samples, were retrieved by a multiple corer at six 14 stations (70 1025 m water depth) along a depth transect at 12°S, covering anoxic and 15 hypoxic bottom water conditions. Benthic N2 fixation was detected at all sites using the 16 acetylene reduction assay, wi...
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