Spatial and temporal variation of planktonic cnidarian density in subtropical waters of the Southern Brazilian Bight

2014 ◽  
Vol 94 (7) ◽  
pp. 1387-1400 ◽  
Author(s):  
Renato Mitsuo Nagata ◽  
Miodeli Nogueira Júnior ◽  
Frederico Pereira Brandini ◽  
Maria Angélica Haddad
Keyword(s):  
Temporal Variation ◽  
High Latitude ◽  
Seasonal Dynamics ◽  
Temporal Variations ◽  
Spatial And Temporal Variation ◽  
Seasonal Patterns ◽  
Southern Brazil ◽  
Coastal Species ◽  
Estuarine Coastal ◽  
Inner Continental Shelf

The spatial and temporal variations of planktonic cnidarians were studied across the inner continental shelf (≤40 m) off the State of Paraná in southern Brazil. Monthly zooplankton samples were taken between November 1997 and March 1999 at five stations. The holoplanktonicLiriope tetraphyllaandMuggiaea kochidominated during the entire period, comprising >80% of the specimens. The coast–ocean gradient became evident due to a near-coastal (≤20 m) assemblage formed byL. tetraphylla, Solmaris coronaand meroplanktonic medusae, and a distinct outer (25–40 m) assemblage formed by the medusaeCorymorpha gracilisandAglaura hemistomaand siphonophores. The estuarine runoff during warm rainy periods lowered the salinity (~30) at the inner stations (1, 2 and 3), providing appropriate conditions for the estuarine/coastal species. Wind-driven onshore advection of outer-shelf species to the inner isobaths occurred from late autumn to winter, when the rainfall decreased and salinity increased (>35). Population peaks occurred in both summer and winter at the inner stations. For most species, the seasonal patterns were inconsistent with other studies conducted in the Southern Brazilian Bight, suggesting irregular and unpredictable seasonal distributions of abundance. Whereas in high-latitude ecosystems the dynamics of cnidarian populations follows the seasonal productivity cycle, here, complex hydrographic processes seem to be more important in determining the structure and seasonal dynamics of this community.

scholarly journals Spatial and temporal variation in pH, alkalinity and conductivity in surface runoff and groundwater for the Upper River Severn catchment

1997 ◽  
Vol 1 (3) ◽  
pp. 697-715 ◽  
Author(s):  
T. Hill ◽  
C. Neal
Keyword(s):  
Temporal Variation ◽  
Ground Water ◽  
Field Measurements ◽  
Temporal Variations ◽  
Spatial And Temporal Variation ◽  
Flow Conditions ◽  
Land Usage ◽  
Load Analysis ◽  
Stream Waters ◽  
Upland Catchments

Abstract. Measurements of pH, alkalinity and electrical conductivity are used to examine the extent of the spatial and temporal variation in stream and ground water chemistry for the Upper Severn catchment, Plynlimon. Wide temporal variations in stream waters broadly reflect flow conditions and complex soil and ground water interactions but not soil type, land usage or geology. The results have major implications for the use of critical load analysis and the development and application of models in upland catchments. They point to the value of field measurements for assessing the environmental management of upland catchments, rather than the present use of over simplistic or inappropriate models.

scholarly journals Temporal Variation Dominates in Local Carabid Beetle Communities in Korean Mountains

Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1019
Author(s):  
Yonghwan Park ◽  
Taewoong Jang ◽  
Jongkuk Kim ◽  
Su-Kyung Kim ◽  
Il-Kwon Kim ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Temporal Variation ◽  
Spatial Scales ◽  
Temporal Variations ◽  
Carabid Beetle ◽  
Spatial And Temporal Variation ◽  
Mountain Range ◽  
Insect Communities ◽  
Local Climate ◽  
Study Sites

Spatial and temporal variation in ecological environments may result in spatial and temporal variation in communities. Temporal studies of biodiversity are essential for forecasting future changes in community structure and ecosystem function. Therefore, determining the mechanisms that drive temporal change in communities remains an important and interesting challenge in ecology. We quantified spatial and temporal variations in carabid beetle communities and site-specific environmental factors for 5 years at nine study sites on three mountains in the Baekdudaegan Mountain Range, Korea. Carabid beetle communities exhibited significant temporal variation, which was larger than spatial variations between and within mountains. Environmental factors mostly varied between sites within mountains. Community variation was only weakly associated with environmental factors at wide scales, i.e., between sites on three mountains, but was strongly associated at narrow spatial scales, i.e., between sites within one mountain. Our results indicate that temporal variation in communities occurs in response to variations in the local climate, and that the patterns of temporal variation differ between mountains. Thus, temporal surveys of insect communities and climates at local scales are important for predicting temporal changes in the communities.

scholarly journals Temporal variation of sandy beach macrofauna at two sites with distinct environmental conditions on Cassino Beach, extreme southern Brazil

2008 ◽  
Vol 56 (4) ◽  
pp. 257-270 ◽  
Author(s):  
Pedro de Sá Rodrigues da Silva ◽  
Luciano Peyrer das Neves ◽  
Carlos Emílio Bemvenuti
Keyword(s):  
Temporal Variation ◽  
Dominant Species ◽  
Sandy Beach ◽  
Temporal Variations ◽  
Sandy Beaches ◽  
Subtidal Zone ◽  
Low Density ◽  
Environmental Condition ◽  
Southern Brazil ◽  
Low Intensity

Temporal variations of the macrofauna of sandy beaches have been related to variations in the beach morphodynamics and also to the population dynamics of dominant species. The aim of this article is to describe the temporal variation of the intertidal macrofauna at two sites with distinct environmental condition on Cassino Beach, extreme southern Brazil. At each site three transect lines 50 m apart were defined perpendicular to the shore line, from which samples were collected monthly in triplicate at 4 intertidal levels (10 m apart) from June 2004 to May 2005. During winter a generally low density was observed, due to the absence of recruitments and to the mud deposition, which occurred just before sampling (in April 2004), and to low intensity stranding events. Spring witnessed a population explosion of Scolelepis gaucha, a migration of Mesodesma mactroides adults from the subtidal zone, and a strong stranding event. In the summer, recruitment of M. mactroides, Donax hanleyanus and Emerita brasiliensis was observed. Fall was characterized by low densities, except for D. hanleyanus recruitment. The macrofauna at both sites showed a striking seasonal variation in density and diversity, perhaps attributable to the recruitment of numerically dominant species and physical disturbances (stranding and mud deposition).

scholarly journals The effects of spatial and temporal replicate sampling on eDNA metabarcoding

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7335 ◽  
Author(s):  
Kevin K. Beentjes ◽  
Arjen G. C. L. Speksnijder ◽  
Menno Schilthuizen ◽  
Marten Hoogeveen ◽  
Berry B. van der Hoorn
Keyword(s):  
Spatial Distribution ◽  
Temporal Variation ◽  
Operational Taxonomic Unit ◽  
Taxonomic Diversity ◽  
Time Frame ◽  
Temporal Variations ◽  
Spatial And Temporal Variation ◽  
Small Scale ◽  
Time Intervals ◽  
Population Turnover

Background The heterogeneous nature of environmental DNA (eDNA) and its effects on species detection and community composition estimates has been highlighted in several studies in the past decades. Mostly in the context of spatial distribution over large areas, in fewer occasions looking at spatial distribution within a single body of water. Temporal variation of eDNA, similarly, has mostly been studied as seasonality, observing changes over large periods of time, and often only for small groups of organisms such as fish and amphibians. Methods We analyzed and compared small-scale spatial and temporal variation by sampling eDNA from two small, isolated dune lakes for 20 consecutive weeks. Metabarcoding was performed on the samples using generic COI primers. Molecular operational taxonomic unit (MOTUs) were used to assess dissimilarities between spatial and temporal replicates. Results Our results show large differences between samples taken within one lake at one point in time, but also expose the large differences between temporal replicates, even those taken only 1 week apart. Furthermore, between-site dissimilarities showed a linear correlation with time frame, indicating that between-site differences will be inflated when samples are taken over a period of time. We also assessed the effects of PCR replicates and processing strategies on general patterns of dissimilarity between samples. While more inclusive PCR replicate strategies lead to higher richness estimations, dissimilarity patterns between samples did not significantly change. Conclusions We conclude that the dissimilarity of temporal replicates at a 1 week interval is comparable to that of spatial replicate samples. It increases, however, for larger time intervals, which suggests that population turnover effects can be stronger than community heterogeneity. Spatial replicates alone may not be enough for optimal recovery of taxonomic diversity, and cross-comparisons of different locations are susceptible to inflated dissimilarities when performed over larger time intervals. Many of the observed MOTUs could be classified as either phyto- or zooplankton, two groups that have gained traction in recent years as potential novel bio-indicator species. Our results, however, indicate that these groups might be susceptible to large community shifts in relatively short periods of time, highlighting the need to take temporal variations into consideration when assessing their usability as water quality indicators.

scholarly journals Spatial and temporal variation in the canopy cover in a tropical semi-deciduous forest

2001 ◽  
Vol 44 (3) ◽  
pp. 269-276 ◽  
Author(s):  
Edmilson Bianchini ◽  
José A. Pimenta ◽  
Flavio A. M. dos Santos
Keyword(s):  
Temporal Variation ◽  
Environmental Heterogeneity ◽  
Deciduous Forest ◽  
Structural Characteristics ◽  
Canopy Cover ◽  
Temporal Variations ◽  
Spatial And Temporal Variation ◽  
Flooded Area ◽  
Individual Trees ◽  
Flooded Areas

This study was developed in the Mata dos Godoy State Park (23° 27’S, 51° 15’W) South Brazil which present great environmental heterogeneity when its north portion (ridge) is compared with the southern portion (valley), where there are some flooded areas. The forest formation is classified as tropical semi-deciduous forest. Spatial and temporal variations in the degree of the canopy cover were compared at flooded and unflooded sites. The measures were taken seasonally in 100m² plots using a spherical densiometer from spring 1995 to winter 1996. The flooded area was more open and lighter and had a greater spatial and temporal variation in the canopy cover than the unflooded areas. The greater heterogeneity in the flooded area could be due to structural characteristics of the canopy (greater spacing between individual trees, lower canopy and less stratified canopy), more frequent natural disturbances and a greater degree of deciduousness. These causes seemed to be related to the presence of the river and flooding.

scholarly journals Information-based mid-upper tropospheric methane derived from Atmospheric Infrared Sounder (AIRS) and its validation

2009 ◽  
Vol 9 (4) ◽  
pp. 16331-16360 ◽  
Author(s):  
X. Xiong ◽  
C. Barnet ◽  
J. Wei ◽  
E. Maddy
Keyword(s):  
Temporal Variation ◽  
High Latitude ◽  
A Priori ◽  
Thermal Infrared ◽  
Lapse Rate ◽  
Spatial And Temporal Variation ◽  
Aircraft Measurements ◽  
Infrared Sensors ◽  
Atmospheric Infrared Sounder ◽  
Temperature Lapse Rate

Abstract. Atmospheric Infrared Sounder (AIRS) measurements of methane (CH4) generally contain about 1.0 degree of freedom and are therefore dependent on a priori assumptions about the vertical methane distribution as well as the temperature lapse rate and the amount of moisture. Thus it requires that interpretation and/or analysis of the CH4 spatial and temporal variation based on the AIRS retrievals need to use the averaging kernels (AK). To simplify the use of satellite retrieved products for scientific analysis, a method based on the information content of the retrievals is developed, in which the AIRS retrieved CH4 in the layer from 50 to 250 hPa below the tropopause is used to characterize the mid-upper tropospheric CH4 in the mid-high latitude regions. The basis of this method is that in the mid-high latitude regions the maximum sensitive layers of AIRS to CH4 have a good correlation with the tropopause heights, and these layers are usually between 50 and 250 hPa below the tropopause. Validation using the aircraft measurements from NOAA/ESRL/GMD and the campaigns INTEX-A and -B indicated that the correlation of AIRS mid-upper tropospheric CH4 with aircraft measurements is ~0.6–0.7, and its the bias and rms difference are less than ±1% and 1.2%, respectively. Further comparison of the CH4 seasonal cycle indicated that the cycle from AIRS mid-upper tropospheric CH4 is in a reasonable agreement with NOAA aircraft measurements. This method provides a simple way to use the thermal infrared sounders data to approximately analyze the spatial and temporal variation CH4 in the upper free tropospere without referring the AK. This method is applicable to derive tropospheric CH4 as well as other trace gases for any thermal infrared sensors.

Effect of morphodynamics on the spatial and temporal variation of macrofauna on three sandy beaches, Rio de Janeiro State, Brazil

2001 ◽  
Vol 81 (3) ◽  
pp. 369-375 ◽  
Author(s):  
Valéria Gomes Veloso ◽  
Ricardo Silva Cardoso
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Temporal Variation ◽  
Abundant Species ◽  
Temporal Variations ◽  
Sandy Beaches ◽  
Spatial And Temporal Variation ◽  
Total Density ◽  
Beach Width ◽  
Slope Beach

Three exposed sandy beaches were selected to compare fluctuations in density of the most abundant species, and to verify the influence of spatial and temporal variations on the community structure. Sampling was carried out every three months, from June 1993 to May 1995, on Fora, Prainha, and Boqueirão Beaches. The first two beaches were classified by Dean's morphodynamic index (Ω) as intermediate, and the last as reflective. Slope, beach width and median grain size were significantly different among the beaches. Two-way analysis of variance revealed significant differences in species richness only among the beaches. No significant differences in density of the macrofauna between beaches and season were observed. However, Prainha Beach showed a higher temporal variation of the density of the macrofauna (and higher standard deviation) than the other two beaches. Emerita brasiliensis (Crustacea: Decapoda), Excirolana braziliensis (Crustacea: Isopoda), and Pseudorchestoidea brasiliensis (Crustacea: Amphipoda) were the most abundant species. Canonical correspondence analysis calculated the influence of the temporal variation as 27·5%; the influence of the environmental variation on community structure was 20·9%. The results suggest that in spite of the long-term fluctuations in species density, the beaches did not have temporal differences in the species richness and total density macrofauna during the study period.

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