Traditionally, biodiversity has often been estimated on the basis of abundance partly due to the need for complicated measurements of biomass. Here, we conducted robust measurements of the community composition and of the size structure of diatoms in the North Pacific to evaluate the importance of biomass on the biodiversity. We found that the two most useful evenness indices increased in most ...

cyanobacteria were collected and identified in five paddy fields with different soil textures of golestan province in iran. it was determined that nostoc ellipsosporum and nostoc muscorum were dominant in all sites among 20 species. to assess the ability of atmospheric nitrogen fixation by the species, their pure cultures were provided by growing on bg-11 solid culture medium. subsequently, eac...

an abrupt global warming event has been recorded in many parts of the world in sediments of latest maastrichtian age between 65.45-65.10 ma. this warm event was documented here at a section near ziyarat-kola in central alborz based on analysis of planktonic foraminifera. an unusual abundance of normally large-size species such as globotruncana arca, globigerinelloides subcarinatus, pseudoguembe...

The Indian mackerel (Rastrelliger kanagurta, Cuvier, 1817) is one of the commercial small pelagic fish in the Persian Gulf and Oman Sea. In the current research, feed preference index (FP), fullness index (FI), and stomach contents of Rastrelliger kanagurta were evaluated to assess the quantity and type of feed habits. A total of 573 specimens were collected randomly from Bandar - Abbas and Qes...

Nutrient enrichment in water and sediments due to excessive anthropogenic activities in recent years has caused excessive algal growth in the Caspian Sea. The current study was conducted to survey the abundance of phytoplankton, its dominant species and chlorophyll-a [Chl-a] concentration in algal bloom aspect in the Iranian coastal water of Caspian Sea during four seasons from 2013 to 2014. Th...

a survey was carried out to investigate the frequency of hard tick species (acari: ixodidae) on sheep in khorasan razvi province. a total of 812 ticks were collected from the sheep of different areas of khorsan razavi province five species were identified as follow: rhipicephalus turanicus (59.23%), hyalomma.marginatum turanicum (25.73%), hyalomma excavatum (14.8%), hyalomma anatolicum (8.3...

flora of jahanbin mountain area in chaharmahal and bakhtiari province, located between shahrekord and hafshejan cities, with 12’187 hectares and 2’150 to 3’300 m elevation above sea level, is investigated. vegetation of this area comprises of 273 species, 189 genera and 42 families. asteraceae (37 species, 13.5%), poaceae (31 species, 11.3%) and fabaceae (25 species, 9.1%) were the most importa...

In recent years, both the intraspecific and interspecific functional diversity (FD) of plant communities have been studied with new approaches to improve an understanding about the mechanisms underlying plant species coexistence. Yet, little is known about how global change drivers will impact intraspecific FD and trait overlap among species, and in particular how this may scale to impacts on c...