scholarly journals Morpho-Functional Traits Reveal Differences in Size Fractionated Phytoplankton Communities but Do Not Significantly Affect Zooplankton Grazing

2022 ◽  
Vol 10 (1) ◽  
pp. 182
Author(s):  
Jessica Titocci ◽  
Melanie Bon ◽  
Patrick Fink

The recent emergence of approaches based on functional traits allows a more comprehensive evaluation of the role of functions and interactions within communities. As phytoplankton size and shape are the major determinants of its edibility to herbivores, alteration or loss of some morpho-functional phytoplankton traits should affect zooplankton grazing, fitness and population dynamics. Here, we investigated the response of altered phytoplankton morpho-functional trait distribution to grazing by zooplankton with contrasting food size preferences and feeding behaviors. To test this, we performed feeding trials in laboratory microcosms with size-fractionated freshwater phytoplankton (3 size classes, >30 µm; 5–30 µm and <5 µm) and two different consumer types: the cladoceran Daphnia longispina, (generalist unselective filter feeder) and the calanoid copepod Eudiaptomus sp. (selective feeder). We observed no significant changes in traits and composition between the controls and grazed phytoplankton communities. However, community composition and structure varied widely between the small and large size fractions, demonstrating the key role of size in structuring natural phytoplankton communities. Our findings also highlight the necessity to combine taxonomy and trait-based morpho-functional approaches when studying ecological dynamics in phytoplankton-zooplankton interactions.

2007 ◽  
Vol 10 (12) ◽  
pp. 1170-1181 ◽  
Author(s):  
Elena Litchman ◽  
Christopher A. Klausmeier ◽  
Oscar M. Schofield ◽  
Paul G. Falkowski

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tiedo van Kuijk ◽  
Jacobus C. Biesmeijer ◽  
Berry B. van der Hoorn ◽  
Piet F. M. Verdonschot

AbstractBiological invasions by nonindigenous species can have negative effects on economies and ecosystems. To limit this impact, current research on biological invasions uses functional traits to facilitate a mechanistic understanding of theoretical and applied questions. Here we aimed to assess the role of functional traits in the progression of crayfish species through different stages of invasion and determine the traits associated with invasive success. A dataset of thirteen functional traits of 15 species currently occurring or available for sale in the Netherlands was evaluated. Six of these crayfish appeared invasive. Important traits distinguishing successful from unsuccessful invaders were a temperate climate in the native range, a medium to high egg count and producing more than one egg clutch per year. The most successful invaders had different functional trait combinations: Procambarus clarkii has a higher reproductive output, can migrate over longer distances and possesses a higher aggression level; Faxonius limosus is adapted to a colder climate, can reproduce parthenogetically and has broader environmental tolerances. Using a suit of functional traits to analyse invasive potential can help risk management and prevention. For example, based on our data Procambarus virginalis is predicted to become the next successful invasive crayfish in the Netherlands.


2012 ◽  
pp. 66-77 ◽  
Author(s):  
I. A. Lavrinenko ◽  
O. V. Lavrinenko ◽  
D. V. Dobrynin

The satellite images show that the area of marshes in the Kolokolkova bay was notstable during the period from 1973 up to 2011. Until 2010 it varied from 357 to 636 ha. After a severe storm happened on July 24–25, 2010 the total area of marshes was reduced up to 43–50 ha. The mean value of NDVI for studied marshes, reflecting the green biomass, varied from 0.13 to 0.32 before the storm in 2010, after the storm the NDVI decreased to 0.10, in 2011 — 0.03. A comparative analysis of species composition and structure of plant communities described in 2002 and 2011, allowed to evaluate the vegetation changes of marshes of the different topographic levels. They are fol­lowing: a total destruction of plant communities of the ass. Puccinellietum phryganodis and ass. Caricetum subspathaceae on low and middle marches; increasing role of halophytic species in plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. typicum on middle marches; some changes in species composition and structure of plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. festucetosum rubrae on high marches and ass. Parnassio palustris–Salicetum reptantis in transition zone between marches and tundra without changes of their syntaxonomy; a death of moss cover in plant communities of the ass. Caricetum mackenziei var. Warnstorfia exannulata on brackish coastal bogs. The possible reasons of dramatic vegetation dynamics are discussed. The dating of the storm makes it possible to observe the directions and rates of the succession of marches vegetation.


2004 ◽  
Vol 23 (2) ◽  
pp. 105-117 ◽  
Author(s):  
Vineeta D. Sharma

Due to the high incidence of fraud in Australia, regulatory reports suggest strengthening the monitoring role of the board of directors (BOD). These reports recommend greater independence and no duality (chairperson of the BOD should not be the CEO) on the BOD. While there is no Australian evidence, research evidence in the U.S. supports these suggested reforms. It is not clear whether the research evidence observed in the U.S. will generalize to the Australian setting because of contextual differences. This study extends the U.S. findings to the Australian context and investigates the relationship between two attributes of the BOD, independence and duality, and fraud. In addition, I examine whether institutional ownership plays a role in the context of fraud. The more highly concentrated institutional ownership in Australia suggests the presence of some relationship. Using a matched sample of fraud and no-fraud firms from 1988–2000, I find that as the percentage of independent directors and the percentage of independent institutional ownership increases, the likelihood of fraud decreases. As expected, the results show a positive relationship between duality and the likelihood of fraud. These results support the call for strengthening the composition and structure of the BOD in Australia.


2021 ◽  
Vol 22 (5) ◽  
pp. 2250
Author(s):  
Evita Athanasiou ◽  
Antonios N. Gargalionis ◽  
Fotini Boufidou ◽  
Athanassios Tsakris

The role of certain viruses in malignant brain tumor development remains controversial. Experimental data demonstrate that human herpesviruses (HHVs), particularly cytomegalovirus (CMV), Epstein–Barr virus (EBV) and human herpes virus 6 (HHV-6), are implicated in brain tumor pathology, although their direct role has not yet been proven. CMV is present in most gliomas and medulloblastomas and is known to facilitate oncomodulation and/or immunomodulation, thus promoting cancer cell proliferation, invasion, apoptosis, angiogenesis, and immunosuppression. EBV and HHV-6 have also been detected in brain tumors and high-grade gliomas, showing high rates of expression and an inflammatory potential. On the other hand, due to the neurotropic nature of HHVs, novel studies have highlighted the engagement of such viruses in the development of new immunotherapeutic approaches in the context of oncolytic viral treatment and vaccine-based strategies against brain tumors. This review provides a comprehensive evaluation of recent scientific data concerning the emerging dual role of HHVs in malignant brain pathology, either as potential causative agents or as immunotherapeutic tools in the fight against these devastating diseases.


2021 ◽  
Vol 30 (3) ◽  
pp. 148-153
Author(s):  
Roland Pika ◽  
Brid O'Brien ◽  
Jill Murphy ◽  
Kathleen Markey ◽  
Claire O'Donnell

Perioperative setting registered nurse first assistants (RNFAs) are described as non-medical practitioners who perform surgical interventions during surgery. They provide medical care to perioperative patients under the supervision of a consultant surgeon. First assistants in surgery can be an expanded perioperative nursing role. A review of the literature illuminates the need for continuous learning in developing skills in becoming competent RNFA practitioners and how they utilise acquired skills to assist, mentor and teach their colleagues within the perioperative setting. The RNFA is an advanced and expanded practice role. RNFAs contribute significantly to the provision of care within all phases of perioperative care (preoperative, intraoperative, postoperative). There is little literature on the role of the RNFA due to its relatively recent emergence in the healthcare sector and the small number of countries where it is implemented.


2021 ◽  
Vol 483 ◽  
pp. 118908
Author(s):  
Mizanur Rahman ◽  
Masum Billah ◽  
Md Obydur Rahman ◽  
Debit Datta ◽  
Muhammad Ahsanuzzaman ◽  
...  

2021 ◽  
Vol 41 (3) ◽  
pp. 485-498
Author(s):  
Sravanthi Kollu

Abstract The multilingual turn in literary studies emphasizes the fairly recent emergence of a monolingual attachment to language. While this rightly calls into question the academic focus on monolingual competencies and offers a substantial area of inquiry for scholars working with the linguistically diverse regions of South Asia, Africa, and the Middle East, this essay posits that the persistence of multilinguality among historical actors from these regions does not merit a shift away from monolingualism in contemporary scholarship. This argument derives from the claims analyzed in this essay, made by South Asian writers in colonial India, about the singularity of one's own language (swabhasha) and the writers' anxieties to protect this language from vulgar speech (gramyam). Building on contemporary work on the vernacular, the essay seeks to draw renewed attention to the role of speech in language debates in Telugu, a language whose particularity has not become a metonym either for the nation (like Hindi) or for a pan–South Indian identity (like Tamil). In tracing the movement from vulgar speech to proper language in this archive, this essay reframes vernacularity as an ethical compulsion premised on the common.


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