نتایج جستجو برای: plankton

تعداد نتایج: 4818  

2017
William J Chivers Anthony W Walne Graeme C Hays

The response of marine plankton to climate change is of critical importance to the oceanic food web and fish stocks. We use a 60-year ocean basin-wide data set comprising >148,000 samples to reveal huge differences in range changes associated with climate change across 35 plankton taxa. While the range of dinoflagellates and copepods tended to closely track the velocity of climate change (the r...

Journal: :Journal of theoretical biology 2010
C J Rhodes A P Martin

It is increasingly recognised that viruses are a significant active component of oceanic plankton ecosystems. They play an important role in biogeochemical cycles as well as being implicated in observed patterns of species abundance and diversity. The influence of viral infection in plankton ecosystems is not fully understood. Here we use a number of well-founded mathematical models to investig...

Journal: :Brazilian journal of biology = Revista brasleira de biologia 2002
F A Lansac-Tôha L F M Velho J Higuti E M Takahashi

Cyclopid copepods from samples of fauna associated with aquatic macrophytes and plancton obtained in lotic and lentic environments were obtained from the upper Paraná River floodplain (in the states of Paraná and Mato Grosso do Sul, Brazil). Macrophytes were collected in homogeneous stands and washed. Plankton samples, taken from the water column surface and bottom, were obtained using a motor ...

2016
Stephen J. Beckett Joshua S. Weitz

The dilution method is the principal tool used to infer in situ microzooplankton grazing rates. However, grazing is the only mortality process considered by the theoretical model underlying the interpretation of dilution method experiments. We show an alternative interpretation arises when there is concurrent niche competition within the plankton community. We find that grazing rates may be ove...

Journal: :Proceedings. Biological sciences 2000
A Bracco A Provenzale I Scheuring

Coexistence of competitive species is severely limited by the availability of resources and the characteristics of the environment. In particular, the so-called 'competitive exclusion principle' states that, at equilibrium, the number of coexisting species cannot be larger than the number of resources for which they compete. However, many in situ observations have revealed prolonged coexistence...

Journal: :Journal of environmental biology 2006
Sibel Yigit Ahmet Altindag

The concentration of heavy metals (Cr, Cd, Hg and Pb,) was determined by atomic absorption spectrophotometry in sediment, water, plankton and fish samples from Lake Egirdir in South-Western Turkey. Lake Egirdir is an important bird nesting and visiting areas, and it is also used as irrigation and drinking water source. The heavy metal concentrations were in the order Cd > Pb > Cr > Hg in water,...

Journal: :Annual review of marine science 2014
Michael J Behrenfeld Emmanuel S Boss

Nutrient and light conditions control phytoplankton division rates in the surface ocean and, it is commonly believed, dictate when and where high concentrations, or blooms, of plankton occur. Yet after a century of investigation, rates of phytoplankton biomass accumulation show no correlation with cell division rates. Consequently, factors controlling plankton blooms remain highly controversial...

2002
J.M.G. Vilar R. V. Sole J. M. Rubi

Plankton is the productive base of aquatic ecosystems and plays a major role in the global control of atmospheric carbon dioxide. Nevertheless, after intensive study, the factors that drive its spatial distribution are still far from being clear. The models proposed so far show very limited agreement with actual data as many of their results are not consistent with field observations. Here we s...

2010
Rubao Ji Martin Edwards David L. Mackas Jeffrey A. Runge Andrew C. Thomas

Increasing availability and extent of biological ocean time series (from both in situ and satellite data) have helped reveal significant phenological variability of marine plankton. The extent to which the range of this variability is modified as a result of climate change is of obvious importance. Here we summarize recent research results on phenology of both phytoplankton and zooplankton. We ...

Journal: :Applied and environmental microbiology 2003
Erin K Lipp Irma N G Rivera Ana I Gil Eric M Espeland Nipa Choopun Valérie R Louis Estelle Russek-Cohen Anwar Huq Rita R Colwell

Seawater and plankton samples were collected over a period of 17 months from November 1998 to March 2000 along the coast of Peru. Total DNA was extracted from water and from plankton grouped by size into two fractions (64 micro m to 202 micro m and >202 micro m). All samples were assayed for Vibrio cholerae, V. cholerae O1, V. cholerae O139, and ctxA by PCR. Of 50 samples collected and tested, ...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید