scholarly journals Population parameters and the relationships between environmental factors and abundance of the Acetes americanus shrimp (Dendrobranchiata: Sergestidae) near a coastal upwelling region of Brazil

2015 ◽  
Vol 63 (3) ◽  
pp. 229-238
Author(s):  
Ana Paula Freitas dos Santos ◽  
Sabrina Morilhas Simões ◽  
Gabriel Lucas Bochini ◽  
Cinthia Helena Costa ◽  
Rogerio Caetano da Costa
Keyword(s):  
Population Dynamics ◽  
Sexual Dimorphism ◽  
Environmental Factors ◽  
Primary Productivity ◽  
Low Temperatures ◽  
Coastal Upwelling ◽  
Statistical Correlation ◽  
Individual Growth ◽  
Otter Trawl ◽  
Population Parameters

AbstractThe population dynamics of Acetes americanus was investigated, focusing on the sex ratio, individual growth, longevity, recruitment and relationship between abundance and environmental factors in the region of Macaé, strongly influenced by coastal upwelling. Otter trawl net samplings were performed from July 2010 to June 2011 at two points (5 m and 15 m). Nearly 19,500 specimens, predominantly females (77.15%), were captured. Their sizes, larger than that of males, indicated sexual dimorphism. Shrimps at lower latitudes present larger sizes and longer longevity than those from higher latitudes. This difference is probably due to low temperatures and high primary productivity. Though no statistical correlation was found between abundance and environmental factors, the species was more abundant in temperatures closer to 20.0º C and in months with high chlorophyll-a levels. Due to the peculiar characteristics of this region, A. americanusshowed greater differences in size and longevity than individuals sampled in other studies undertaken in the continental shelf of Southeast Brazil.

scholarly journals EFFECT ON 6-BAP CATALASE ACTIVITY IN TOMATO PLANTS UNDER CONDITIONS OF TEMPERATURE STRESS

2015 ◽  
Vol 4 (2) ◽  
pp. 96-99
Author(s):  
Tatyana Stepanovna Kolmykova ◽  
Ekaterina Vladimirovna Klokova ◽  
Elvera Shagidulovna Sharkaeva
Keyword(s):  
Enzyme Activity ◽  
Antioxidant Enzymes ◽  
Environmental Factors ◽  
Catalase Activity ◽  
Low Temperatures ◽  
High Ability ◽  
Tomato Plants ◽  
Resistance To Stress ◽  
Primary Antioxidant ◽  
A Minor

Activity of the antioxidant system is one of the mechanisms for the protection of plants against adverse environmental factors. Catalase - a primary antioxidant enzymes. Her change may serve as an indicator of plant resistance to stress. Studied catalase activity in tomato plants of different varieties under the action of low temperatures and cytokinin 6-BAP preparation. The object of investigation used 24- and 27-day-old tomato plant varieties Podarochnyi, Patrice, Volgogradskyi. Found that under the action of low temperatures, the decrease in positive catalase activity: 10-30% at 10 C and 40-60% at a temperature of 3 C as compared with non-refrigerated plants. Less resistant to hyperthermia were plant varieties Patrice. With increasing length of vegetation at a temperature of 25 C in 27-day-old tomato plants resulted in a minor increase in the activity of the enzyme. After the end of the cooling observed recovery of enzyme activity only at grades Podarochnyi and Patrice. This indicates that the indicated tomato varieties possess a high ability to restore metabolic processes. Using 6-regulator cytokinin BAP increased catalase activity in tomato plants as prolonged or momentary cooling. Especially responsive to the drug were plant varieties Patrice and Volgogradskyi. And 6-BAP helped repair catalase activity in 27-day-old plants in the aftereffect of cold stress. Were more sensitive plant varieties Podarochnyi.

scholarly journals Investigation of the abundance, distribution and composition of microplastics at coastal upwelling sites in the Atlantic Ocean

2016 ◽  
Author(s):  
La Daana K Kanhai ◽  
Rick Officer ◽  
Ian O'Connor ◽  
Richard C Thompson
Keyword(s):  
Atlantic Ocean ◽  
Surface Waters ◽  
Primary Productivity ◽  
Null Hypothesis ◽  
Latitudinal Gradient ◽  
Coastal Upwelling ◽  
Abundance Distribution ◽  
Significant Difference ◽  
Benguela Upwelling ◽  
Canary Upwelling

Microplastics are an issue of international concern due to the fact that these substances may potentially threaten biota by (i) causing physical harm, (ii) transporting persistent, bioaccumulating and toxic (PBT) substances and, (iii) leaching plastic additives. Within the world’s oceans, areas which experience coastal upwelling are biota rich due to their high levels of primary productivity. The assessment of microplastic presence in areas which experience coastal upwelling is vital as it will indicate whether microplastics are an issue of concern in areas which support key biological resources. The null hypothesis of the present study is that microplastic abundance will be lower in areas where there is upwelling. As such, the present study aims to investigate whether microplastic abundance in upwelled areas in the Atlantic Ocean is significantly different from non-upwelled areas. Based on an opportunistic voyage aboard the RV Polarstern, microplastics will be sampled in sub-surface waters along a diverse latitudinal gradient in the Atlantic Ocean i.e. from Bremerhaven (Germany) to Cape Town (South Africa). Based on the proposed route, it will be possible to determine microplastic levels at two areas of coastal upwelling in the Atlantic Ocean (i) Canary Upwelling Ecosystem (CUE) and (ii) Benguela Upwelling Ecosystem (BUE). The results will then be analysed to determine whether there was a statistically significant difference between ‘upwelled areas’ and ‘non-upwelled areas’.

scholarly journals Seasonal dynamics of <I>Pseudocalanus minutus elongatus</I> and <I>Acartia spp.</I> in the southern Baltic Sea (Gdańsk Deep) – numerical simulations

2006 ◽  
Vol 3 (4) ◽  
pp. 1157-1202
Author(s):  
L. Dzierzbicka-Głowacka ◽  
L. Bielecka ◽  
S. Mudrak
Keyword(s):  
Population Dynamics ◽  
Baltic Sea ◽  
Seasonal Dynamics ◽  
Egg Production ◽  
Phytoplankton Bloom ◽  
Individual Growth ◽  
Initial Development ◽  
Southern Baltic Sea ◽  
Gdansk Deep ◽  
Southern Baltic

Abstract. A population dynamics model for copepods is presented describing a seasonal dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the southern Baltic Sea (Gdansk Deep). The copepod model was coupled with an one-dimensional physical and biological upper layer model for nutrients (total inorganic nitrogen, phosphate), phytoplankton, microzooplankton and an early juvenile of herring as predator. In this model, mesozooplankton (herbivorous copepods) has been introduced as animals having definite patterns of growth in successive stages, reproduction and mortality. The populations are represented by 6 cohorts in different developmental stages, thus assuming, that recruitment of the next generation occurs after a fixed period of adult life. The copepod model links trophic processes and population dynamics, and simulates individual growth within cohorts and the changes in biomass between cohorts. The simulations of annual cycles of copepods contain one complete generation of Pseudocalanus and two generations of Acartia in the whole column water, and indicate the importance of growth of older stages of 6 cohorts each species to total population biomass. The peaks of copepods biomass, main, at the turn of June and July for Pseudocalanus and smaller, in July for Acartia, lag that phytoplankton by ca. two mouths due to growth of cohorts in successive stages and egg production by females. The numerical results show that the investigated species could not be the main factor limiting the spring phytoplankton bloom in the Gdansk Deep, because the initial development was slow for Acartia and faster for Pseudocalanus, but main development formed after the bloom, in both cases. However, the simulated microzooplankton biomass was enough high to conclude, in our opinion, that, in this case, it was major cause limiting phytoplankton bloom. Model presented here is a next step in understanding how the population dynamics of a dominant species in the southern Baltic Sea interact with the environment.

Modeling Crime Density with Population Dynamics in Space and Time: An Application of Assault in Gangnam, South Korea

2020 ◽  
pp. 001112872094803
Author(s):  
Yeondae Jung ◽  
Yongwan Chun ◽  
Kamyoung Kim
Keyword(s):  
Population Dynamics ◽  
Environmental Factors ◽  
Violent Crime ◽  
Subway Station ◽  
Factors Associated ◽  
Residential Population ◽  
Economic Control ◽  
Time Periods ◽  
Residential Use ◽  
Ambient Population

The current study explores populational and environmental factors associated with violent crime. Specifically, it compares ambient and residential populations with regard to their association with assault density at a fine spatial and temporal unit in a city with socio-economic control variables. The results show that the ambient population are consistently associated with the level of assaults throughout the four time periods in a day, while residential population does not contribute much to explaining its variation. In addition, we also find that the percentage of single-member households and the distance to the nearest subway station are constantly associated with assault density, while the proportion of non-residential use and the land price are partially associated.

scholarly journals Sexual dimorphism in species of Schistura (Teleostei: Nemacheilidae) from the Mae Khlong basin and peninsular Thailand

Zootaxa ◽  
2012 ◽  
Vol 3586 (1) ◽  
pp. 353 ◽  
Author(s):  
RUNGTHIP PLONGSESTHEE ◽  
F. WILLIAM H. BEAMISH ◽  
LAWRENCE M. PAGE
Keyword(s):  
Sexual Dimorphism ◽  
Environmental Factors ◽  
The Other ◽  
Sexually Dimorphic ◽  
Morphometric Characteristics ◽  
Pectoral Fin ◽  
Caudal Fin

Sexually dimorphic characteristics are described for four species of Schistura from the Mae Khlong basin and peninsularThailand. Males of S. mahnerti have a suborbital flap and rows of unculi on the upper surfaces of the pectoral-fin rays.Females of S. mahnerti have a suborbital groove. None of the morphological measurements differ significantly betweenmales and females of S. mahnerti. In the other three species, S. aurantiaca, S. cf. aurantiaca, and S. sexcauda, all indi-viduals lack the flap or groove, but most males have a conspicuous black botch on the procurrent rays of the upper lobeof the caudal fin, a feature absent in most females. Some morphometric characteristics vary between sexes of these spe-cies. Sexually dimorphic traits presumably have a function related to reproduction; however, little is known about reproduction in Schistura, and variation in morphology in relation to habitat or other environmental factors has not been studied.

scholarly journals Factors affecting the abundance of age-0 Atlantic menhaden (Brevoortia tyrannus) in Chesapeake Bay

2016 ◽  
Vol 73 (9) ◽  
pp. 2238-2251 ◽  
Author(s):  
Edward D. Houde ◽  
Eric R. Annis ◽  
Lawrence W. Harding ◽  
Michael E. Mallonee ◽  
Michael J. Wilberg
Keyword(s):  
Environmental Factors ◽  
Primary Production ◽  
Chesapeake Bay ◽  
Primary Productivity ◽  
Atlantic Menhaden ◽  
Strongly Correlated ◽  
Brevoortia Tyrannus ◽  
Factors Affecting ◽  
Chl A ◽  
Low Levels

Abstract The abundance of prerecruit, age-0 Atlantic menhaden (Brevoortia tyrannus), declined to low levels in Chesapeake Bay in the 1990s, after two decades of high abundances in the 1970s–1980s. Environmental factors and trophodynamics were hypothesized to control age-0 menhaden abundance. Data on age-0 menhaden abundance from seine and trawl surveys were analysed with respect to primary productivity, chlorophyll a (Chl a), and environmental variables. Abundance from 1989 to 2004 was strongly correlated with metrics of primary production and euphotic-layer Chl a, especially during spring months when larval menhaden transform into filter-feeding, phytoplanktivorous juveniles. Correlation, principal components, and multiple regression analyses were conducted that identified factors associated with age-0 menhaden abundance. Primary production, Chl a, and variables associated with freshwater flow, e.g. Secchi disk depth and zooplankton assemblages, were correlated with age-0 menhaden abundance. Lengths of age-0 menhaden were positively related to mean levels of annual primary production. However, lengths were negatively related to age-0 menhaden abundance, indicating that growth may be density-dependent. The identified relationships suggest that numbers of menhaden larvae ingressing to Chesapeake Bay and environmental factors that subsequently control primary productivity and food for juveniles within the Bay may control recruitment levels of Atlantic menhaden.

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