Consulta: subjectFacets:"Seasonal variability"
Registros recuperados: 20
Data/hora: 09/06/2024 12:39:19

Сезонные изменения  концентрации хлорофилла “а” и отношения органический  углерод / хлорофилл “а”в  фитопланктоне прибрежных вод  Черного моря в районе Севастополя по результатам исследований в 2000 – 2001 гг.
Provedor de dados: 13
Autores: Стельмах, Л. В.; Бабич, И. И.; Ляшенко, С. В.
На основе  данных, полученных на трех станциях   в прибрежных водах Черного моря  в районе  Севастополя в 2000 – 2001 гг , представлена сезонная динамика  концентрации хлорофилла “a” в планктоне и отношения С/Хл”a” в микро- и наннофитопланктоне поверхностных вод.  В  течение года эти  показатели изменялись более, чем на порядок.  Так, концентрация хлорофилла “а”  изменялась от 0,21 до 14,28 мг. м-3 и достигала максимальных значений в весенний и осенний периоды, что обусловлено “цветением” диатомовых водорослей Chaetoceros socialis весной и Cerataulina bergonii осенью.  Максимальные значения отношения С/Хл”a”  (158  - 183 ) были получены в летний период (в июле), когда в фитопланктоне доминировали пирофитовые водоросли, минимальные значения (13 –20)...
Tipo: Journal Contribution
Palavras-chave: Фитопланктон; Хлорофилл "a"; Диатомовые водоросли; Пирофитовые водоросли; Chlorophyll “a”; Seasonal variability; Phytoplankton; Pyrrophyta Seasonal variations Phytoplankton Chlorophylls Diatoms Phytoplankton Chlorophylls Diatoms http://aims.fao.org/aos/agrovoc/c_13344 http://aims.fao.org/aos/agrovoc/c_1577 http://aims.fao.org/aos/agrovoc/c_32657.
Ano: 2002
URL: http://repository.ibss.org.ua/dspace/handle/99011/411

Seasonal variability on the structure of sublittoral macrozoobenthic association in the Patos Lagoon estuary, southern Brazil
Provedor de dados: 76
Autores: Colling,Leonir A.; Bemvenuti,Carlos E.; Gandra,Michel S.
The aim of this study is to analyze and relate the spatial-temporal variability of macrozoobenthic assemblages to bottom characteristics and salinity fluctuations, in an estuarine shallow water region of Patos Lagoon. Monthly samples, between September 2002 and August 2003, were taken on six sampling stations (distant 90 m). Three biological samples with a 10 cm diameter corer, one sample for sediment analysis, fortnightly bottom topography measurements, and daily data of temperature and salinity were taken from each station. Two biotic and environmental conditions were identified: the first corresponding to spring and summer months, with low macrozoobenthos densities, low values of salinity, small variations in bottom topographic level and weak...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Seasonal variability; Benthos; Estuary; Abiotic variables; Sublittoral habitats.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212007000300007

Temporal dynamics of a fish community in the lower portion of a tidal creek, Pando sub-estuarine system, Uruguay
Provedor de dados: 76
Autores: Gurdek,Rodrigo; Acuña-Plavan,Alicia.
ABSTRACT Estuaries are highly dynamic ecosystems subjected to variability of their fish communities over different time scales. The nearshore fish community of the lower Pando estuary, a temperate sub-system of the Río de la Plata estuary, was sampled from May 2002 to June 2003. A total of 2,165 fishes, represented by 16 species were caught by seine netting. Captures were dominated by juveniles (&gt;90%), as well as by the sciaenid Micropogonias furnieri (Desmarest, 1823) (82.8%). The fish community showed high seasonal variability, with the greatest diversity and biomass in summer and spring and the highest species richness during summer. Lowest values of all community parameters occurred in winter and autumn, seasons that presented the highest similarity...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ichthyofauna; Community parameters; Seasonal variability; Diel variability; Sub-estuary.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212017000100203

Fish assemblage structure in a port region of the Amazonic coast
Provedor de dados: 76
Autores: Silva,Marcelo H. L.; Torres Júnior,Audálio R.; Castro,Antonio C. L.; Azevedo,James W. J.; Ferreira,Cássia F. C.; Cardoso,Rayssa L.; Nunes,Jorge L. S.; Carvalho-Neta,Raimunda N. F.
ABSTRACT: The fish assemblage structure in a port area in São Marcos Bay (Amazonic coast) was evaluated based on the spatial and temporal distributions to identify potential changes in response to anthropic pressure increases associated with industrial and port activities in region. The samples were taken between March 2011 and November 2015. The ichthyofauna was represented by a total of 56 species, distributed in 15 orders and 29 families. Captures were dominated by Genyatremus luteus (Bloch, 1790), but Sciades proops (Valenciennes, 1840) was the most representative in terms of biomass. Seasonal distributions of fish assemblage did not reveal significant differences. However, there was a difference between catch sites, abundance, biomass and Shannon...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ichthyofauna; Estuary; Seasonal variability; Spatial patterns; Maranhão Amazon.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212018000100218

Seasonal and inter-annual ONSET Sea Surface Temperature variability along the northern coast of the Gulf of Guinea
Provedor de dados: 5
Autores: Sohou, Z.; Koné, V.; Da-allada, Y.c.; Djakouré, S.; Bourlès, Bernard; Racape, Virginie; Degbe, G.; Adje, C.
The aim of this study is to characterize the coastal upwelling variability at seasonal and inter-annual time scales in the northern Gulf of Guinea (NGoG) using Sea Surface Temperature (SST) collected with autonomous “ONSET” thermometers. Results show that the ONSET SST data are suitable for numerical model evaluation, and provide relevant information in addition to satellite and reanalysis data at seasonal cycle. The minor and major coastal upwellings are present in all the products. The inter-annual SST variability is more pronounced in the western part of the region (Côte d’Ivoire and Ghana) than in the eastern part (Benin and Nigeria). The pattern differences between the west and the east of the region highlight a large spatial variability of the SST in...
Tipo: Text
Palavras-chave: Sea Surface Temperature; ONSET data; Gulf of Guinea; Coastal upwelling; Seasonal variability; Inter-annual variability.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00607/71885/70583.pdf

Seasonal Mesoscale and Submesoscale Eddy Variability along the North Pacific Subtropical Countercurrent
Provedor de dados: 5
Autores: Qiu, Bo; Chen, Shuiming; Klein, Patrice; Sasaki, Hideharu; Sasai, Yoshikazu.
Located at the center of the western North Pacific Subtropical Gyre, the Subtropical Countercurrent (STCC) is not only abundant in mesoscale eddies, but also exhibits prominent submesoscale eddy features. Output from a 1/30 degrees high-resolution OGCM simulation and a gridded satellite altimetry product are analyzed to contrast the seasonal STCC variability in the mesoscale versus submesoscale ranges. Resolving the eddy scales of &gt;150 km, the altimetry product reveals that the STCC eddy kinetic energy and rms vorticity have a seasonal maximum in May and April, respectively, a weak positive vorticity skewness without seasonal dependence, and an inverse (forward) kinetic energy cascade for wavelengths larger (shorter) than 250 km. In contrast, the...
Tipo: Text
Palavras-chave: Circulation/ Dynamics; Eddies; Instability; Mesoscale processes; Observational techniques and algorithms; Altimetry; Models and modeling; Ocean models; Variability; Seasonal variability.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00245/35588/34142.pdf

Modeled mixed-layer salinity balance in the Gulf of Guinea: seasonal and interannual variability
Provedor de dados: 5
Autores: Da-allada, Casimir Yelognisse; Du Penhoat, Yves; Jouanno, Julien; Alory, Gael; Hounkonnou, Norbert Mahouton.
A regional numerical simulation and observations were used to investigate the various processes controlling mixed-layer salinity balance on seasonal and interannual time scales in the Gulf of Guinea. Processes were quantified using a mixed-layer salt budget. Model results correctly reproduced the mean, phase, and amplitude of observed seasonal near-surface salinity. The results indicated that on seasonal time scales, the mixed-layer salinity balance differed from one region to another. The surface salinity seasonal cycle was characterized by strong salinization during May for coastal areas north and south of the equator. Model results suggested that vertical mixing controls the mixed-layer salinity increase at the equator during May, while both vertical...
Tipo: Text
Palavras-chave: Sea surface salinity; Gulf of guinea; Model; Mixed-layer budget; Seasonal variability; Interannual variability.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00242/35333/36310.pdf

The Biological Pump and Seasonal Variability of pCO(2) in the Southern Ocean: Exploring the Role of Diatom Adaptation to Low Iron
Provedor de dados: 5
Autores: Person, Roland; Aumont, Olivier; Levy, M.
Iron is known to limit primary production in the Southern Ocean (SO). To cope with the lack of this micronutrient, diatoms, a dominant phytoplankton group in this oceanic region, have been shown in cultures to have developed an original adaptation strategy to maintain efficient growth rates despite very low cellular iron quotas, even in low light conditions. Using a global ocean biogeochemical model, we explored the consequences of this physiological adaptation for the biological pump and the seasonal variability of both surface chlorophyll concentrations and surface partial pressure of carbon dioxide (pCO(2)) in this key region for global climate. In the model, we implemented a low intracellular Fe:C requirement in the SO for diatoms uniquely. This...
Tipo: Text
Palavras-chave: Southern Ocean; Diatoms; Physiological adaptation; Biological pump; PCO(2); Seasonal variability.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00673/78490/80817.pdf

Analysis of salinity measurements near islands on the French continental shelf of the Bay of Biscay
Provedor de dados: 5
Autores: Lazure, Pascal; Jegou, Anne-marie; Kerdreux, Michel.
The Bay of Biscay is characterised by large fresh water inputs from two major rivers, the Loire and the Gironde, with a mean discharge of about 900 m(3)/s. To describe the spatial and temporal variability of the Loire and Gironde plumes, continuous salinity measurements were made at 4 locations on French coastal islands over periods lasting at least two years. These islands are located at a distance from the large local gradients linked to local inputs. Whereas sea surface salinity in the centre of the Bay of Biscay is 35.6, salinities at the coast vary between about 35 in summer to occasionally less than 30 in late winter or in spring. Minimum salinities do not occur at the same time along the coast, indicating a strong spatial gradient. Near the Loire...
Tipo: Text
Palavras-chave: Bay of Biscay; Continental shelf; River plume; Seasonal variability; Salinity; Hydrology.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-3957.pdf

Interaction between marine populations and fishing activities: temporal patterns of landings of La Rochelle trawlers in the Bay of Biscay
Provedor de dados: 5
Autores: Poulard, Jean-charles; Leaute, Jean-pierre.
Marine populations are distributed heterogeneously in space and time because of the diversity of habitats and the requirements of species life cycles. Human exploitation of these resources also varies as a function of space, time and the type of fishing activities performed. These three factors determine fishing strategy at different levels of integration. The purpose of this study was to describe and analyse, with respect to different time scales, the relations between the modalities of resource exploitation and the biological or demographic characteristics of the species involved. These investigations relate to the more general task of acquiring the basic knowledge needed for spatialised management of fishing effort. A fleet of trawlers from La Rochelle,...
Tipo: Text
Palavras-chave: Atlantic ocean; Bay of Biscay; Seasonal variability; Multiple factor analysis; Bottom trawlers; Landings.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/2002/publication-1397.pdf

Silicon utilization by sponges: an assessment of seasonal changes
Provedor de dados: 5
Autores: Lopez-acosta, Maria; Leynaert, Aude; Coquille, Valerie; Maldonado, Manuel.
Awareness that sponges are relevant silicic acid (DSi) users is growing; however, understanding how their DSi consumption kinetics perform is still limited. We investigated the effects that seasonal changes in a temperate ecosystem (Bay of Brest, France) have on the DSi consumption of 2 dominant sponge species: Hymeniacidon perlevis and Tethya citrina. The results indicated that while both species increased their rate of DSi utilization with DSi availability following saturable Michaelis-Menten kinetics, only the kinetics of T. citrina shifted seasonally. This species consumed DSi at a higher rate in autumn than in summer. Surprisingly, the increase in DSi utilization did not involve an increase in net affinity for DSi but rather augmentation of both the...
Tipo: Text
Palavras-chave: Silicic acid; Silicon consumption kinetics; Siliceous sponges; Seasonal variability.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00616/72772/72246.pdf

Hydrographical variability on the French continental shelf in the Bay of Biscay, during the 1990s
Provedor de dados: 5
Autores: Puillat, Ingrid; Lazure, Pascal; Jegou, Anne-marie; Lampert, Luis; Miller, P.
A synthesis of 9 years of hydrographic measurements, acquired during approximately 25 cruises (1992-2000) on the French continental shelf of the Bay of Biscay, is presented. The main focus is upon salinity distribution, as it is little known in this area. The whole of the data set covers I I months of the year, with some sampling fields repeated several times a year, for multiple years. This time-series allows temperature and salinity distributions to be studied together with their seasonal, inter-annual and mesoscale variability.   The seasonal trend in temperature can be described in three stages, which are in agreement with past studies. Thermal stratification occurs between May and mid-September in a layer similar to 50 m in thickness, whereas the...
Tipo: Text
Palavras-chave: Upwelling; Cold pool; River plumes; Seasonal variability; Salinity; Hydrography.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/2004/publication-779.pdf

Seasonal Carbon Dynamics in the Near‐Global Ocean
Provedor de dados: 5
Autores: Keppler, L.; Landschützer, P.; Gruber, N.; Lauvset, S. K.; Stemmler, I.
The seasonal cycle represents one of the largest signals of dissolved inorganic carbon (DIC) in the ocean, yet these seasonal variations are not well established at a global scale. Here, we present the Mapped Observation‐Based Oceanic DIC (MOBO‐DIC) product, a monthly DIC climatology developed based on the DIC measurements from GLODAPv2.2019 and a two‐step neural network method to interpolate and map the measurements. MOBO‐DIC extends from the surface down to 2,000 m and from 65°N to 65°S. We find the largest seasonal amplitudes of surface DIC in the northern high‐latitude Pacific (∼30 to &gt;50 μmol kg−1). Surface DIC maxima occur in hemispheric spring and minima in fall, driven by the input of DIC into the upper ocean by mixing during winter, and net...
Tipo: Text
Palavras-chave: DIC; Seasonal variability; Neural networks; SOM&amp;#8208; FFN; Monthly climatology; NCP.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00668/78016/80262.pdf

Seasonal variability in microplanktonic biomasses in the Gironde dilution plume (Bay of Biscay): relative importance of bacteria
Provedor de dados: 5
Autores: Artigas, Lf.
Bacterial and phytoplankton biomasses were estimated in a four-year study along a saline gradient (the dilution plume of the Gironde estuary on the Aquitanian continental shelf), by measuring bacterial abundance and mean cell volumes (epifluorescence counts) and chlorophyll-a concentrations tin vitro fluorescence). The spatial and temporal distribution of phytoplankton enabled us to determine the seasonal succession of algal blooms, sprouting in the marine waters of the inner shelf in early spring (picoplanktonic forms), reaching their annual maximum (10 mu g L-1) in plume waters in advanced spring, and moving to estuarine waters in the summer (&gt; 20 mu m forms). Bacterial biomasses followed mainly a decreasing dilution gradient, especially in winter and...
Tipo: Text
Palavras-chave: Bactéries; Phytoplancton; Rapport des biomasses microbiennes; Variabilité saisonnière; Panache de dilution girondin; Bacterioplankton; Phytoplankton; Microbial biomass ratio; Seasonal variability; Gironde dilution plume.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00325/43659/43210.pdf

Numerical study of the annual and semi-annual fluctuations in the deep equatorial Atlantic Ocean
Provedor de dados: 5
Autores: Thierry, Virginie; Treguier, Anne-marie; Mercier, Herle.
Using idealized and realistic high-resolution primitive equation models, we explore the annual and semi-annual period fluctuations in the deep equatorial Atlantic Ocean. The deep seasonal variability derives its energy from the equatorial zonal wind stress component and the wind energy reaches the deep layers by means of vertically propagating Kelvin and Rossby waves. The first meridional mode (l = 1) annual Rossby wave reaches the western boundary while the other Rossby waves directly propagate toward the bottom. A deep Kelvin wave is generated by the reflection of the incoming l = 1 annual Rossby wave at the western boundary. Due to the complexity of the surface layers in the non-linear simulations, one cannot separate the waves generated at the...
Tipo: Text
Palavras-chave: Wind driven circulation; Seasonal variability; Equatorial waves.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/publication-670.pdf

Food resource partitioning in a fish community of the central Amazon floodplain
Provedor de dados: 83
Autores: Mérona,Bernard de; Rankin-de-Mérona,Judy.
Diets of most of fish species inhabiting a floodplain lake in central Amazonia were studied over a two years and half period. Based on the percentage of relative occurrence of 11 major food categories a classification of species in 11 feeding guilds is proposed. Many species were found to be specialized feeders. Fish, detritus and insects were the most important food resources supporting the fish community in both seasons, but the proportions of fruits, invertebrates and fish were reduced during the low water season. At the community level mean diet overlap between species was low, suggesting efficient resource partitioning within the community. However mean overlap between unspecialized feeders was high. Based on the 23 most abundant species belonging to...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Varzea lake; Fishes; Diet; Overlap; Seasonal variability.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252004000200004

Temporal variability of nitrogen and phosphorus concentrations in a German catchment: water sampling implication
Provedor de dados: 91
Autores: Pott,Cristiano A.; Jadoski,Sidnei O.; Schmalz,Britta; Hörmann,Georg; Fohrer,Nicola.
Daily time series were used to verify the temporal variability and to characterize the nitrogen (N) and phosphorus (P) pollution in a 462 km² catchment of the Stör river, a typical rural lowland catchment in Germany. Also, this study aimed to identify the best sampling frequency of pollution by N and P. Total phosphorus (TP), soluble orthophosphate-phosphorus (PO4-P), particulate-phosphorus (PP), total nitrogen (TN), nitrate-nitrogen (NO3-N) ammonium-nitrogen (NH4-N) and total suspended sediment (TSS) were analysed. Daily monitoring from August 8, 2009 until August 10, 2011 was conducted with an automatic water sampler at the outlet of the catchment. The results show a seasonal variability of water quality parameters with more N and P concentration in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Water quality; Nitrate; Phosphate; Autocorrelation; Automatic water sampler; Seasonal variability.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662014000800005

Seasonal variability of planktonic copepods (Copepoda: Crustacea) in a tropical estuarine region in Brazil
Provedor de dados: 103
Autores: Dias,Cristina de Oliveira; Araujo,Adriana Valente de; Bonecker,Sérgio Luiz Costa.
The Caravelas River estuary and adjacent coastal region were studied during the rainy and dry seasons of 2003-2004 to assess the copepod community structure. Abiotic and biotic parameters were measured, and the total density, frequency and percentage of copepod taxa were determined for each sampling period. Copepod densities showed significant differences between sampling periods, with higher densities in the rainy seasons (Mean: 90,941.80 ind.m-3; S.D.: 26,364.79). The sampling stations located to the north and south, in the coastal region adjacent to the Caravelas River estuary presented the lowest copepod density values. The copepod assemblage was composed mainly of estuarine and estuarine/coastal copepods. The seasonal variations in temperature and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Coastal region; Northeast Brazil; Seasonal variability; Tropical zone; Zooplankton.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702009000400015

Annual and daily patterns of calling activity in male Scinax fuscomarginatus (Anura: Hylidae) from Central Brazil
Provedor de dados: 103
Autores: Souza,Antonio Olímpio de; Oliveira,Seixas Rezende; Dias,Gardênia Proto; Bastos,Rogério Pereira; Morais,Alessandro Ribeiro de.
ABSTRACT Bioacoustics is an effective way of recording detailed data during population surveys and monitoring. In the present study, we used an automated digital recorder (ADR) to describe the temporal variation in the calling activity of Scinax fuscomarginatus (Lutz, 1925) in central Brazil. We also evaluated the role of climatic variables (air temperature and precipitation) on calling activity by using a Generalized Additive Model (GAM). We conducted the recordings at five ponds in the Cerrado savanna of Rio Verde Municipality, in Goiás state between November 2013 and October 2014. The analysis of the 43.2 hours of acoustic recording showed that S. fuscomarginatus has a prolonged breeding pattern. The ADR provides a fine-scale description of the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Acoustic survey; Anurans; Automated recording; Breeding period; Phenology; Seasonal variability; Vocalization behavior.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702020000100328

Abiotic factors influencing tropical dry forests regeneration
Provedor de dados: 52
Autores: Ceccon,Eliane; Huante,Pilar; Rincón,Emanuel.
Tropical dry forests represent nearly half the tropical forests in the world and are the ecosystems registering the greatest deterioration from the anthropogenic exploitation of the land. This paper presents a review on the dynamics of tropical dry forests regeneration and the main abiotic factors influencing this regeneration, such as seasonal nature, soil fertility and humidity, and natural and anthropic disturbances. The main purpose is to clearly understand an important part of TDF succession dynamics.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Tropical dry forests; Regeneration; Disturbances; Seasonal variability; Fertility; Moisture.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132006000300016