scholarly journals Spatial and temporal distribution in density and biomass of two Pseudodiaptomus species (Copepoda: Calanoida) in the Caeté river estuary (Amazon region - North of Brazil)

2006 ◽  
Vol 66 (2a) ◽  
pp. 421-430 ◽  
Author(s):  
A. Magalhães ◽  
R. M. Costa ◽  
T. H. Liang ◽  
L. C. C. Pereira ◽  
M. J. S. Ribeiro
Keyword(s):  
Salinity Gradient ◽  
River Estuary ◽  
Temporal Distribution ◽  
Dry Weight ◽  
Temporal Variations ◽  
Spatial And Temporal Distribution ◽  
Regression Parameters ◽  
North Brazil ◽  
Density And Biomass ◽  
Copepod Biomass

Spatial and temporal density and biomass distribution of the planktonic copepods Pseudodiaptomus richardi and P. acutus along a salinity gradient were investigated in the Caeté River Estuary (North-Brazil) in June and December, 1998 (dry season) and in February and May, 1999 (rainy season). Copepod biomass was estimated using regression parameters based on the relation of dry weight and body length (prosome) of adult organisms. The Caeté River Estuary was characterized by high spatial and temporal variations in salinity (0.8-37.2‰). Exponential length-weight relationships were observed for both Pseudodiaptomus species. Density and biomass values oscillated between 0.28-46.18 ind. m-3 and 0.0022-0.3507 mg DW. m-3 for P. richardi; and between 0.01-17.02 ind. m-3 and 0.0005-0.7181 mg DW. m-3 for P. acutus. The results showed that the contribution of P. richardi for the secondary production in the Caeté River Estuary is more important in the limnetic zone than in other zones where euhaline-polyhaline regimes were predominant. However, it was not possible to observe a clear pattern of spatial and temporal distribution for P. acutus.

scholarly journals Distribution and density of the mollusk Donax striatus (Linnaeus, 1767) in a tropical estuarine region in the brazilian semi-arid

2015 ◽  
Vol 75 (4) ◽  
pp. 914-922 ◽  
Author(s):  
E. L. Medeiros ◽  
G. V. Fernandes ◽  
G. G. Henry-Silva
Keyword(s):  
Intertidal Zone ◽  
Significant Positive Correlation ◽  
River Estuary ◽  
Temporal Distribution ◽  
Average Density ◽  
Spatial And Temporal Distribution ◽  
Tropical Estuarine ◽  
Sampling Points ◽  
Estuarine Region ◽  
Semi Arid

Abstract This study evaluated the spatial and temporal distribution and density of the bivalve Donax striatus, at beaches close to the Apodi/Mossoró River estuary, through, six semiannual sampling campaigns were performed between April/2009 and October/2011. The sampled area was delimited by 20 transects that were laid perpendicular to the beach line and extended over 300 m in the intertidal zone. Seven sampling points were established in each transect, organisms and sediment were collected, and water temperature and salinity were recorded. The highest D. striatus average density (103 individuals.m–2) was observed in April/2009 and the lowest (18 individuals.m–2) in October/2010. The highest D. striatus densities occurred in beaches further from the estuarine region as demonstrated by a significant positive correlation (r2 = 0.67 and p = 0.0007). The D. striatus densities presented significant negative correlations with the percentages of organic matter in the water. This species demonstrated an aggregated distribution in the studied area.

scholarly journals Spatial and Temporal Distribution of a Multiple Gear Fishing Fleet Exploiting the Caribbean Sea and North Brazil Shelf Large Marine Ecosystems

2020 ◽  
Vol 12 (2) ◽  
pp. 100-112
Author(s):  
Carolina Mercedes Laurent Singh ◽  
Jamerson Aguiar‐Santos ◽  
Efrem Jorge Gondim Ferreira ◽  
Eucaris del Carmen Evaristo ◽  
Carlos Edwar de Carvalho Freitas
Keyword(s):  
Temporal Distribution ◽  
Caribbean Sea ◽  
Marine Ecosystems ◽  
Spatial And Temporal Distribution ◽  
Fishing Fleet ◽  
Large Marine Ecosystems ◽  
North Brazil ◽  
The Caribbean

scholarly journals Characterizing Uncertainties in Atmospheric Inversions of Fossil Fuel CO<sub>2</sub> Emissions in California

2018 ◽  
Author(s):  
Kieran Brophy ◽  
Heather Graven ◽  
Alistair J. Manning ◽  
Emily White ◽  
Tim Arnold ◽  
...  
Keyword(s):  
Fossil Fuel ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Temporal Distribution ◽  
Temporal Variations ◽  
Potential Effect ◽  
Spatial And Temporal Distribution ◽  
Transport Models ◽  
Pseudo Data ◽  
Atmospheric Inversions

Abstract. Atmospheric inverse modelling has become an increasingly useful tool for evaluating emissions of greenhouse gases including methane, nitrous oxide and synthetic gases such as hydrofluorocarbons (HFCs). Atmospheric inversions for emissions of CO2 from fossil fuel combustion (ffCO2) are currently being developed. The aim of this paper is to investigate potential errors and uncertainties related to the spatial and temporal prior representation of emissions and modelled atmospheric transport for the inversion of ffCO2 emissions in the U.S. state of California. We perform simulation experiments based on a network of ground-based observations of CO2 concentration and radiocarbon in CO2 (a tracer of ffCO2), combining prior (bottom-up) emission models and transport models currently used in many atmospheric studies. The potential effect of errors in the spatial and temporal distribution of prior emission estimates is investigated in experiments by using perturbed versions of the emissions estimates used to create the pseudo data. The potential effect of transport error was investigated by using three different atmospheric transport models for the prior and pseudo data simulations. We find that the magnitude of biases in posterior state-total emissions arising from errors in the spatial and temporal distribution in prior emissions in these experiments are 1–15 % of posterior state-total emissions, and generally smaller than the 2-σ uncertainty in posterior emissions. Transport error in these experiments introduces biases of −10 % to +6 % in posterior state-total emissions. Our results indicate that uncertainties in posterior state-total ffCO2 estimates arising from the choice of prior emissions or atmospheric transport model are on the order of 15 % or less for the ground-based network in California we consider. We highlight the need for temporal variations to be included in prior emissions, and for continuing efforts to evaluate and improve the representation of atmospheric transport for regional ffCO2 inversions.

scholarly journals Status of the population structure of the mangrove crab Ucides cordatus (Decapoda: Ocypodidae) on the Piraquê-açu River estuary, Espírito Santo, Brazil

2010 ◽  
Vol 58 (2) ◽  
pp. 81-92 ◽  
Author(s):  
Rita de Cássia Conti ◽  
Rosebel Cunha Nalesso
Keyword(s):  
Salinity Gradient ◽  
Carapace Width ◽  
River Estuary ◽  
Temporal Distribution ◽  
Mangrove Forests ◽  
Ucides Cordatus ◽  
Management Actions ◽  
Mangrove Crab ◽  
Crab Density ◽  
The Mean

The land crab Ucides cordatus is a keystone species of neotropical mangrove forests and an important resource of the artisanal fisheries. The spatial and temporal distribution of U. cordatus in the mangrove area of the Piraquê-açu river estuary was determined following a longitudinal estuarine salinity gradient (lower, middle, upper estuary) and along the vertical intertidal gradient. The numbers of open and closed burrows were counted monthly on fixed transects, the inhabiting crabs were caught, sexed and the carapace width measured, during 1 year. The mean crab density was 2.5 ind.m-². The highest crab density (3.9 ind.m-²), linked to high numbers of juvenile crabs, was found on the upper estuary and correlated with lower salinities. High intertidal levels had higher crab densities than lower intertidal levels, except in the upper estuary. Males were smaller than females; the mean carapace width of the population was 4.89 cm, below the minimum legal harvesting size (6 cm). The predominance of females over males at some sites (especially close to villages) brought out the advanced level of overfishing of this U. cordatus population and highlights the urgent need of management actions.

scholarly journals SPATIAL AND TEMPORALVARIATION OF DISSOLVED INORGANIC NUTRIENTS, AND CHLOROPHYLL-α IN A TROPICAL ESTUARY IN NORTHEASTERN BRAZIL: DYNAMICS OF NUTRIENT REMOVAL

2015 ◽  
Vol 63 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Maria Aparecida Macedo Silva ◽  
Marcelo F. L. Souza ◽  
Paulo C. Abreu
Keyword(s):  
Nutrient Removal ◽  
Organic Phosphorus ◽  
Inorganic Nitrogen ◽  
Salinity Gradient ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
River Estuary ◽  
Temporal Distribution ◽  
Northeastern Brazil ◽  
Nutrient Concentrations

Monthly sampling campaigns were carried out between February 2010 and January 2011 to evaluate the spatial and temporal distribution of nutrients (ammonium, nitrite, nitrate, dissolved organic nitrogen, phosphate, dissolved organic phosphorus and silicate) and chlorophyll-α along a salinity gradient in the tropical Cachoeira River estuary, subject to the untreated effluents of a sewage treatment plant (STP). During the study period the lowest and highest river discharge occurred in February and April 2010, respectively. High river outflow promoted increased concentrations of inorganic nitrogen and silicate but did not affect the concentration of phosphate. Based on the chlorophyll-α concentration the estuary may be classified as eutrophic / hypereutrophic in its inner portion and mesotrophic in the lower region. The inner portion is more affected by the nutrient load carried out by the river and STP, while dilution by seawater contributed to the reduction of the nutrient concentrations in the lower reaches of the estuary. The results indicate that nutrient uptake by the phytoplankton is the most effective dissolved inorganic nutrient removal processes, especially for phosphate. Mixing diagrams suggest that the coupling of nitrification and denitrification processes is also responsible for the elimination of nitrogen from this ecosystem.

scholarly journals Spatial and temporal variations in algal phosphorus in Taihu Lake

2021 ◽  
Author(s):  
Yu Zhang ◽  
Wei Zhu ◽  
Ruochen Wang ◽  
Gangyu Feng ◽  
Zongpu Xue ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Taihu Lake ◽  
Phosphorus Content ◽  
Temporal Distribution ◽  
Temporal Variations ◽  
Spatial And Temporal Distribution ◽  
Concentration Data ◽  
The West ◽  
New Information ◽  
Intracellular Phosphorus

Abstract Phosphorus circulation in Taihu Lake has attracted extensive attention, but the contribution of Microcystis to phosphorus circulation in this area is unknown. In this study, the phosphorus concentrations in algal samples collected from the lake in 2015–2016 were determined in the laboratory. From the concentration data, the total quantity of algal phosphorus was calculated and the seasonal variations in algal phosphorus were examined. The results indicated that the intracellular phosphorus content of Microcystis in Taihu varied from 0.044 to 0.130 pg/cell and tended to be high in spring and low in summer. The total amount of algal phosphorus in Taihu Lake ranged between 7.78 and 97.32 t over the study period. Algal phosphorus only accounted for between 1.5 and 18.5% of the phosphorus stock in the water. Because Microcystis accumulated downwind, there was a tendency for the total phosphorus concentrations to be low in the east of the lake and high in the west of the lake. This new information about the spatial and temporal distribution of algal phosphorus contributes to our understanding of how phosphorus in Microcystis contributes to phosphorus circulation in Taihu Lake.

scholarly journals Comparison of HPLC Pigment Analysis and Microscopy in Phytoplankton Assessment in the Seomjin River Estuary, Korea

2020 ◽  
Vol 12 (4) ◽  
pp. 1675
Author(s):  
Minji Lee ◽  
Nam-Il Won ◽  
Seung Ho Baek
Keyword(s):  
Water Movement ◽  
Salinity Gradient ◽  
River Estuary ◽  
Temporal Distribution ◽  
Microscopic Analysis ◽  
Carotenoid Pigments ◽  
Freshwater Species ◽  
Pigment Analysis ◽  
Phytoplankton Communities ◽  
Seomjin River

The distribution of microalgal species in estuaries shows marked gradients because of the mixing of marine and fresh water during tidal exchanges. To assess the spatio-temporal distribution of phytoplankton in the Seomjin River estuary (SRE), Korea, we investigated the seasonal phytoplankton communities along a salinity gradient in the estuary using both high performance liquid chromatography (HPLC) pigment analysis and light microscopy. Both types of analysis indicated that marine planktonic diatoms generally dominated at downstream sites having salinities >10, whereas freshwater species dominated at upstream sites having salinities <5. High levels of the pigments fucoxanthin and alloxanthin were found at upstream sites in the SRE in late spring. During summer, relatively high levels of the pigment peridinin were present in downstream areas of the SRE, and relatively high levels of diatoms occurred in upstream areas. In autumn, small Cryptomonas species were found in high abundance based on microscopic analysis, while CHEMTAX analysis of photosynthetic pigments showed relatively high concentrations of the diatom pigment fucoxanthin, implying the co-occurrence of a small unidentified phytoplankton. During winter, when the estuarine waters were well mixed, both the microscopic and CHEMTAX analyses showed that diatoms dominated at most stations. Seasonal and horizontal gradients in environmental conditions were clearly influenced by the salinity and nutrient loadings, especially the nitrate+nitrite and silicate concentrations. In particular, the ratio of photoprotective carotenoid pigments (PPCs) to photosynthetic carotenoid pigments (PSCs) was relatively low during all four seasons. This was predominately because of the high productivity of diatoms, which have a very low ratio of PPCs to PPSs. The SRE is a favorable habitat for diatoms because it is a high turbulence area having rapid water movement as a result of tidal changes. Overall, there was consistency in the data derived from the microscopy and chemotaxonomy analyses, suggesting that both methods are useful for analysis of the phytoplankton community structure in this complex estuarine and coastal water ecosystem.

scholarly journals Environmental influences on the spatial and temporal distribution of the puffer fish Sphoeroides greeleyi and Sphoeroides testudineus in a Brazilian subtropical estuary

2009 ◽  
Vol 7 (2) ◽  
pp. 275-282 ◽  
Author(s):  
Luís Fernando Fávaro ◽  
Elton Celton de Oliveira ◽  
Augusto de Oliveira Brunow Ventura ◽  
Nelsy Fenerich Verani
Keyword(s):  
Abiotic Factors ◽  
Temporal Distribution ◽  
Temporal Variations ◽  
Environmental Data ◽  
Spatial Gradient ◽  
Spatial And Temporal Distribution ◽  
Environment Impact ◽  
Monthly Basis ◽  
The North ◽  
Puffer Fish

The spatial and temporal distribution of Sphoeroides greeleyi and Sphoeroides testudineus were established from collections (biological material and environmental data) conducted on a monthly basis from May 2000 to April 2001 in intertidal areas along the north-south axis of the estuarine complex of Paranaguá, Paraná State. In addition to characterizing a north-south spatial gradient, which fluctuates seasonally, the variation in the abiotic factors made possible the division of the estuary into three regions: north, central and south. Spatially, it was found that the number of individuals declines significantly for both species in the north-south direction of the estuary. Moreover, significant differences were found in the size of individuals across the estuarine regions. The largest S. greeleyi individuals were caught in the north, as well as the smallest S. testudineus individuals. The catches with the highest numbers of puffer fish occurred from late spring to early autumn, coinciding with the occurrence of specimens of smaller size and lower mean body mass. The results indicate that spatial and temporal variations in the environment impact the distribution patterns of both puffer fish species, suggesting that the co-occurrence of closely related species functions as a modulating factor in that distribution.

Spatio-Temporal Persistence of the Abra Alba-Pectinaria Koreni Muddy-Fine Sand Community of the Eastern Bay of Seine

1997 ◽  
Vol 77 (4) ◽  
pp. 1165-1185 ◽  
Author(s):  
E. Thiébaut ◽  
L. Cabioch ◽  
J.-C. Dauvin ◽  
C. Retiere ◽  
F. Gentil
Keyword(s):  
Dominant Species ◽  
Salinity Gradient ◽  
Food Limitation ◽  
Temporal Stability ◽  
Fine Sand ◽  
Temporal Variations ◽  
Total Density ◽  
Factorial Correspondence Analysis ◽  
Spatio Temporal ◽  
Density And Biomass

The spatial distribution and temporal variations of the Abra alba-Pectinaria koreni community from the eastern part of the Bay of Seine were investigated through four winter surveys (1986, 1987, 1988 and 1991). A grid of 40–67 stations was sampled each year using a Hamon grab (0·25 m-2) for macrofauna collection and sediment analysis. The fauna was dominated by polychaetes and in a lower part by molluscs and echinoderms. Although species richness with ~100 species collected during each survey was high, total density and biomass (±SE) resulted principally from about ten dominant species, and varied between 846·9 ±163·5 and 1135·3 ±186·7 ind m-2 and 23·52 ±4·41 and 27·48 ±4·45 g m-2respectively. The dominant species were patchily distributed and exhibited weak spatio-temporal fluctuations except the two bivalves A. alba and Cultellus pellucidus. Factorial correspondence analysis (FCA) of the distribution of main species among stations and automatic hierarchical classification identified five faunal assemblages which were relatively stable in space and time. The temporal stability of the community could be generated by processes of larval retention near parental population, and sediment stabilization induced by the low abundance of deposit feeders and the high densities of the tube-dwelling polychaete Owenia fusiformis. While the sediment variables were a poor indicator of the spatial structure of the community, the salinity gradient off the Seine Estuary and post-settlement processes (e.g. food limitation and postlarval drifting) have been proposed to explain it. Comparison with an earlier survey (i.e. 1971) suggested a degree of long-term persistence of the community structure in qualitative and quantitative terms.

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