scholarly journals The relationship between plankton, capelin, and cod under different temperature conditions

2005 ◽  
Vol 62 (7) ◽  
pp. 1281-1292 ◽  
Author(s):  
E.L. Orlova ◽  
V.D. Boitsov ◽  
A.V. Dolgov ◽  
G.B. Rudneva ◽  
V.N. Nesterova
Keyword(s):  
Species Distribution ◽  
Phytoplankton Bloom ◽  
Calanus Finmarchicus ◽  
Feeding Intensity ◽  
Sea Temperature ◽  
Northern Areas ◽  
Calanus Glacialis ◽  
Reproductive Processes ◽  
The Relationship ◽  
Prey Overlap

Abstract On the basis of data from cold (1982 and 1987) and warm summers (1983, 1984, 1990, and 1992), we explore the relationship between the phytoplankton bloom and the timing and intensity of the zooplankton bloom. In warm years, there is more overlap in the time between the zooplankton and the phytoplankton bloom. In northern areas (76–78°N) with seasonal ice, the phytoplankton bloom and reproductive processes in Calanus finmarchicus and Calanus glacialis continue well into August, evidenced by the presence of an abundance of nauplii and younger copepodites. We analyse feeding intensity of capelin and its distribution relative to food availability and capelin abundance. The extent to which feeding areas of cod and capelin, its major prey, overlap is subject to the abundance of these species, distribution of zooplankton, and sea temperature in a given year.

scholarly journals On What Do the Homeless Base Their Happiness?

Healthcare ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1512
Author(s):  
Yaiza Cano-González ◽  
Carmen Portillo-Sotelo ◽  
María del Mar Rodríguez-del-Águila ◽  
María Paz García-Caro ◽  
Ana M. Núñez-Negrillo ◽  
...  
Keyword(s):  
Content Analysis ◽  
Satisfaction With Life ◽  
Homeless People ◽  
Self Esteem ◽  
Homeless Persons ◽  
Structured Interviews ◽  
Support Strategies ◽  
Northern Areas ◽  
The Relationship ◽  
The City

Objective: To determine the relationship between the characteristics and experiences of homeless persons and their state of happiness as a basis for designing appropriate social support strategies. Design: Exploratory observational study with an analytical and descriptive qualitative design. Setting: Participants were contacted, administered with questionnaires, and interviewed in the street (central and northern areas of the city) or at the “Asociación Calor y Café” center in Granada (Spain) between April 2017 and February 2018. Participants: Selected by intentional sampling, 25 participants completed questionnaires in the first study and 14 of these were administered with questionnaires and interviewed in the second study. Method: General and specific questionnaires were administered to determine the state of happiness and other variables. Descriptive statistics were followed by an analysis of the relationships between variables and the content analysis of semi-structured interviews. Results: A feeling of happiness was described by 64% of participants and confirmed by a happiness scale score of 50%. Participants who felt satisfied with their life were 4.5-fold more likely to feel happy (p = 0.021). Expectations for the future were not associated with happiness or satisfaction with life. Content analysis of interviews revealed three main themes: conditions for happiness, own happiness/unhappiness, and self-esteem. Conclusions: Many homeless people describe themselves as feeling happy and satisfied with their life. Material aspects, affective situations, daily life concerns, and self-esteem predominate in their discourse on happiness.

scholarly journals Evaluating ecological uniqueness over broad spatial extents using species distribution modelling

2021 ◽  
Author(s):  
Gabriel Dansereau ◽  
Pierre Legendre ◽  
Timothée Poisot
Keyword(s):  
North America ◽  
Species Distribution ◽  
Rare Species ◽  
Beta Diversity ◽  
Species Distribution Modelling ◽  
Distribution Models ◽  
Science Data ◽  
Distribution Modelling ◽  
Ecological Uniqueness ◽  
The Relationship

Aim: Local contributions to beta diversity (LCBD) can be used to identify sites with high ecological uniqueness and exceptional species composition within a region of interest. Yet, these indices are typically used on local or regional scales with relatively few sites, as they require information on complete community compositions difficult to acquire on larger scales. Here, we investigate how LCBD indices can be used to predict ecological uniqueness over broad spatial extents using species distribution modelling and citizen science data. Location: North America. Time period: 2000s. Major taxa studied: Parulidae. Methods: We used Bayesian additive regression trees (BARTs) to predict warbler species distributions in North America based on observations recorded in the eBird database. We then calculated LCBD indices for observed and predicted data and examined the site-wise difference using direct comparison, a spatial autocorrelation test, and generalized linear regression. We also investigated the relationship between LCBD values and species richness in different regions and at various spatial extents and the effect of the proportion of rare species on the relationship. Results: Our results showed that the relationship between richness and LCBD values varies according to the region and the spatial extent at which it is applied. It is also affected by the proportion of rare species in the community. Species distribution models provided highly correlated estimates with observed data, although spatially autocorrelated. Main conclusions: Sites identified as unique over broad spatial extents may vary according to the regional richness, total extent size, and the proportion of rare species. Species distribution modelling can be used to predict ecological uniqueness over broad spatial extents, which could help identify beta diversity hotspots and important targets for conservation purposes in unsampled locations.

scholarly journals Feeding ecology of Serrasalmus gouldingi (Characiformes: Serrasalmidae) in the lower Anapu River region, Eastern Amazon, Brazil

2016 ◽  
Vol 46 (3) ◽  
pp. 259-270 ◽  
Author(s):  
Bruno da S. PRUDENTE ◽  
Pedro CARNEIRO-MARINHO ◽  
Roberta de M. VALENTE ◽  
Luciano F. de A. MONTAG
Keyword(s):  
Feeding Ecology ◽  
Diet Composition ◽  
Niche Breadth ◽  
Life Stage ◽  
Flood Pulse ◽  
Feeding Intensity ◽  
High Tendency ◽  
Flood Season ◽  
River Region ◽  
The Relationship

Abstract Studies on feeding ecology of fishes are important to understand the relationship between species and environmental seasonal variations. In tropical rivers, these relationships are mainly modeled by hydrological patterns. Thereby, this study aimed to assess the influence of fluviometric variation and life stage (juveniles and adults) in the feeding ecology of Serrasalmus gouldingi in the lower Anapu River region, located in Eastern Amazon, Pará, Brazil. Specimens were collected bimonthly, considering four different hydrological periods. We assessed the diet composition, feeding intensity and niche breadth of the species. Thirty-two dietary items were identified and grouped into ten categories. A total of 279 stomachs were analyzed, showing a predominance of fish fragments, followed by fruits and seeds. The diet composition of S. gouldingi differed only between drought and flood season, although it did not differ between juveniles and adults. An increase in feeding intensity was recorded during the rise in the water level, with a lower feeding intensity observed during transitional season. Serrasalmus gouldingi showed lower niche breadth during flood season, attributed to the high consumption of fruits and seeds, presenting an omnivorous diet with high tendency towards piscivory. Although less evident than in other Amazon watersheds, the flood pulse in the lower Anapu River region is an important factor influencing the feeding ecology of the species.

Relationship between the Southern Oscillation Index and Australian sugarcane yields

1994 ◽  
Vol 45 (7) ◽  
pp. 1557 ◽  
Author(s):  
I Kuhnel
Keyword(s):  
Southern Hemisphere ◽  
Southern Oscillation Index ◽  
Southern Oscillation ◽  
Significance Testing ◽  
The Past ◽  
Northern Areas ◽  
Eastern Australia ◽  
North Eastern ◽  
Sugarcane Yield ◽  
The Relationship

This study examines the relationship between the Southern Oscillation Index and the sugarcane yield anomalies at 27 mills in north-eastern Australia (Queensland) for the period 1950-1989. The major results of this work indicate that the SO1 alone seems to have only a limited value as predictor of total sugarcane yields over large areas (i.e. the whole of Queensland). However, on a smaller scale, the SO1 appears to be a useful indicator of yields for the northern sugarcane districts. In these northern areas, the highest correlations with the SO1 are reached during the southern hemisphere spring and summer months 6 to 11 months prior to the harvest. They are negative and explain about 40% of the total variance. They also suggest that a positive SO1 during the spring and summer months tends to be followed by lower-than-normal yields at the following harvest and vice versa. This signal is rather robust and withstands rigorous significance testing. Moreover, it appears that the relationship between the SO1 and the sugarcane yields has been relatively strong and stable for the past 40 years, but weakened substantially during the 1930-1940 period.

On the relationship between the vertical distribution-migration of zooplankton and the organic carbon flux, before, during and after convective events, in the open southern Adriatic Sea

2020 ◽  
Author(s):  
Mirna Batistić ◽  
Rade Garić ◽  
Stefano Miserocchi ◽  
Leonardo Langone ◽  
Laura Ursella ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Flux ◽  
Adriatic Sea ◽  
Phytoplankton Bloom ◽  
Sediment Traps ◽  
Zooplankton Abundance ◽  
Backscatter Signal ◽  
Organic Carbon Flux ◽  
Long Term Study ◽  
The Relationship

<p>The Southern Adriatic (SA) is the deepest part of the Adriatic Sea (1242 m) and one of three sites of open-sea deep convection in the Mediterranean. Due to winter convection events, the dense water formation processes in the open SA result in a homogenization of the water column, which determines the nutrient input into the euphotic zone, enhances phytoplankton growth and consequently, the abundance of zooplankton.</p><p>By analyzing zooplankton samples, together with acoustic data (ADCP) and data from sediment traps (at 125 m and 1150 m) taken in the SA from November 2015 to June 2016, we investigated the relationship between the distribution of zooplankton abundance and the flow of organic carbon in the deep open southern Adriatic Sea. During the pre-convection period (November 2015), the highest organic carbon flux (C org flux) was found at both depth (125 m, 1150 m), which is probably related to the autumn phytoplankton bloom and consequently an increase in zooplankton abundance. During the winter mixing phase, a lower C org flux was recorded in the upper trap samples which was a consequence of the reduced growth of phytoplankton and the transport of the cells to the deeper aphotic layers; where some increase of org C flux in the lower trap was recorded. Thus, the deepest layers were enriched leading to a minimum vertical zooplankton-migration (DVM). In spring, during the post-convection period (March, April), high abundance of mesozooplankton, mostly copepods, was registered in the upper layer, as well as an evident increase of C org flux. Other species than copepods (which remain at the food rich surface), probably ostracods and euphausiids, played a significant role in the DVM because they are more abundant in the deeper layers. The increase in C org flux in the upper samples in May is in accordance with a recorded salp bloom (also evident through a strong backscatter signal). Salp fecal pellets were observed to contribute significantly to vertical carbon flux in various ocean regions.</p><p>The relationship between vertical zooplankton distribution, zooplankton migration and carbon export has generally been poorly studied in the Adriatic Sea. Preliminary results for the open SA are presented here, but for more accurate knowledge of this topic, a long term study is needed.</p>

Life cycle of Calanus finmarchicus in the lower St. Lawrence Estuary: the imprint of circulation and late timing of the spring phytoplankton bloom

2001 ◽  
Vol 58 (4) ◽  
pp. 647-658 ◽  
Author(s):  
Stéphane Plourde ◽  
Pierre Joly ◽  
Jeffrey A Runge ◽  
Bruno Zakardjian ◽  
Julian J Dodson
Keyword(s):  
Population Dynamics ◽  
Life Cycle ◽  
Production Rate ◽  
Egg Production ◽  
Phytoplankton Bloom ◽  
Food Limitation ◽  
Calanus Finmarchicus ◽  
Lawrence Estuary ◽  
Egg Production Rate ◽  
St Lawrence Estuary

The life cycle of Calanus finmarchicus in the lower St. Lawrence estuary is described based on observations of female egg production rate, population stage abundance, and chlorophyll a biomass collected over 7 years (1991–1997) at a centrally located monitoring station. The mean seasonal pattern shows maximum abundance of females in May, but peak population egg production rate and naupliar (N3–N6) abundance occur in early July just after onset of the late spring – early summer phytoplankton bloom. The population stage structure is characterized by low summer abundance of early copepodite stages C1–C3 and high stage C5 abundance in autumn. Between 1994 and 1997, there was important interannual variation in both timing (up to 1 month) and amplitude (five- to eight-fold) of population reproduction. Patterns of seasonal increase of C5 abundance in autumn suggest interannual variations of both timing and magnitude of deep upstream advection of this overwintering stage. Thus, the main features of C. finmarchicus population dynamics in the central lower St. Lawrence Estuary are (i) late reproduction resulting from food limitation prior to the onset of the summer phytoplankton bloom, (ii) probable export of early developmental stages during summer, and (iii) advection into the central lower St. Lawrence Estuary of overwintering stage C5 in autumn from downstream regions. These results support the hypothesis that circulation, mainly driven by discharge from the St. Lawrence River and its tributaries, is a key factor governing population dynamics of C. finmarchicus in this region.

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