Seasonal variation in benthic invertebrate recolonization of small-scale disturbances in a subtropical Florida lake

Hydrobiologia ◽  
1985 ◽  
Vol 124 (3) ◽  
pp. 211-221 ◽  
Author(s):  
Andrea Fuller ◽  
Bruce C. Cowell
Keyword(s):  
Seasonal Variation ◽  
Benthic Invertebrate ◽  
Small Scale

The response of soil enzyme activity to seasonal and microtopographical variations in the sedge peatlands in Changbai Mountain, China

2020 ◽  
Author(s):  
Ming Wang
Keyword(s):  
Enzyme Activity ◽  
Seasonal Variation ◽  
Enzyme Activities ◽  
Soil Enzyme ◽  
Changbai Mountain ◽  
Soil Enzyme Activity ◽  
Small Scale ◽  
P Availability ◽  
Soil Enzyme Activities ◽  
Significant Difference

<p>Hummock-hollow microtopography is a common feature in northern peatlands. It<br>creates microsites of variable hydrology, vegetation, and soil biogeochemistry, thus affect soil C<br>cycling in peatlands at the local scale. This study investigated effects of microtopography on soil<br>enzyme (β-1,4-glucosidase (βG), β-1,4-N-acetylglucosaminidase (NAG), acid phosphatase (AP)<br>and peroxidase (PER)) activities and environment variables as well as their relationships in a<br>typical sedge peatland in Changbai Mountain, northeast of China. Our results showed that the<br>enzyme activities in the sedge peatland significantly varied across seasons and microtopographical<br>positions. Soil enzyme activities in hummocks exhibited more obvious seasonal variation than<br>hollows, with the βG, AP and PER activities presented a distinct valley in summer and the<br>maximum values occurred in Spring or Autumn. Soil hydrolase (βG, NAG and AP) activities in<br>hummocks were significantly higher compared to hollows, while soil oxidase (PER enzyme)<br>activity in hollows was higher than hummocks. The NMDS analysis revealed that the influence<br>degree of microtopography on the enzyme activities was higher than that of seasonal variation.<br>Redundancy analysis (RDA) indicated that the variations of soil enzyme activities in the peatland<br>were related to environmental variables, especially to water table depth (WTD), soil temperature<br>(ST), SOC, N availability and P availability. Furthermore, correlation analysis showed that the<br>three hydrolase (BG, NAG and AP) activities were positively correlated with soil TN, SOC and<br>C/N, and negatively correlated with WTD and TP. On the contrast, the PER activities were<br>positively correlated with TP, and negatively correlated with ST, SOC and C/N. The present<br>study demonstrated that small scale topographic heterogeneity created by hummock cause habitat<br>heterogeneity and thus lead to significant difference of soil enzyme activity between hummock<br>and hollow in the sedge peatlands. This finding provides further evidence of the importance of<br>peatland microtopography to C cycling and has direct implications for scaling biogeochemical<br>processes to the ecosystem level.</p>

Mesoscale Spectra of Mars’s Atmosphere Derived from MGS TES Infrared Radiances

2007 ◽  
Vol 64 (5) ◽  
pp. 1717-1726 ◽  
Author(s):  
Takeshi Imamura ◽  
Yasuhiro Kawasaki ◽  
Tetsuya Fukuhara
Keyword(s):  
Seasonal Variation ◽  
Large Scale ◽  
Thermal Emission ◽  
The Other ◽  
Small Scale ◽  
High Latitudes ◽  
Mars Global Surveyor ◽  
Infrared Radiance ◽  
Infrared Radiances ◽  
Radiance Data

Abstract Wavenumber spectra of the atmospheric potential energy of Mars at mesoscales (wavelengths of 64–957 km) were obtained as a function of latitude, season, and Martian year using infrared radiance data obtained by the Thermal Emission Spectrometer (TES) onboard the Mars Global Surveyor (MGS) spacecraft. Spectral slopes tend to be flatter at smaller scales, and the slopes are usually flatter than −1 near small-scale ends. Near large-scale ends, the spectra sometimes show prominent steepening with slopes from −2 to −3. The power peaks in the high latitudes in winter and equinoxes, suggesting that eddies are generated preferentially in baroclinic zones. The seasonal variation at each latitude band, on the other hand, tends to be obscured by large interannual variability. An enhancement in the power was observed around the storm tracks in the Southern Hemisphere. Spectra of the terrestrial stratosphere were also obtained with a similar method from data taken by the Aura satellite and compared to the results for Mars.

scholarly journals Small-scale spatial heterogeneity and seasonal variation in a population of a cave-dwelling Mediterranean mysid

1996 ◽  
Vol 18 (5) ◽  
pp. 659-671 ◽  
Author(s):  
Marta Ribes ◽  
Rafel Coma ◽  
Mikel Zabala ◽  
Josep-Maria Gili
Keyword(s):  
Seasonal Variation ◽  
Spatial Heterogeneity ◽  
Small Scale

Implications of seasonal variation for biomonitoring with predictive models in the Fraser River catchment, British Columbia

2001 ◽  
Vol 58 (7) ◽  
pp. 1411-1417 ◽  
Author(s):  
Pamela F Reece ◽  
Trefor B Reynoldson ◽  
John S Richardson ◽  
David M Rosenberg
Keyword(s):  
Seasonal Variation ◽  
Test Site ◽  
Benthic Invertebrate ◽  
Large River ◽  
Reference Condition ◽  
Taxonomic Resolution ◽  
Reference Database ◽  
Fraser River ◽  
River Catchment ◽  
Invertebrate Assemblage

Reference-condition models for the Fraser River catchment were developed using samples collected during the autumn of 1994, 1995, and 1996. The goal of this study was to examine applicability to the reference-condition models of samples collected in other seasons and the effect of taxonomic resolution (genus and family) on model sensitivity to seasonal variation in the benthic invertebrate assemblage. Samples from eight streams representing interior, coastal, and large-river habitats were collected in spring, summer, autumn, and winter of 1995 and in spring of 1996. The benthic invertebrate assemblage changed seasonally such that the models could not be used for seasons other than autumn. The models were equally sensitive to seasonal variation when genus-level or family-level data were used. We recommend that test samples (i.e., samples collected from disturbed sites and meant for comparison with the reference database) be collected either during the autumn or over multiple sampling dates to reduce the possibility that seasonal shifts or stochastic events will lead to erroneous conclusions about the state of a test site.

scholarly journals Biogeographic classification of the Caspian Sea

2014 ◽  
Vol 11 (22) ◽  
pp. 6451-6470 ◽  
Author(s):  
F. Fendereski ◽  
M. Vogt ◽  
M. R. Payne ◽  
Z. Lachkar ◽  
N. Gruber ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Caspian Sea ◽  
Benthic Invertebrate ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Agglomerative Clustering ◽  
The Caspian Sea ◽  
Surface Salinity ◽  
Chl A

Abstract. Like other inland seas, the Caspian Sea (CS) has been influenced by climate change and anthropogenic disturbance during recent decades, yet the scientific understanding of this water body remains poor. In this study, an eco-geographical classification of the CS based on physical information derived from space and in situ data is developed and tested against a set of biological observations. We used a two-step classification procedure, consisting of (i) a data reduction with self-organizing maps (SOMs) and (ii) a synthesis of the most relevant features into a reduced number of marine ecoregions using the hierarchical agglomerative clustering (HAC) method. From an initial set of 12 potential physical variables, 6 independent variables were selected for the classification algorithm, i.e., sea surface temperature (SST), bathymetry, sea ice, seasonal variation of sea surface salinity (DSSS), total suspended matter (TSM) and its seasonal variation (DTSM). The classification results reveal a robust separation between the northern and the middle/southern basins as well as a separation of the shallow nearshore waters from those offshore. The observed patterns in ecoregions can be attributed to differences in climate and geochemical factors such as distance from river, water depth and currents. A comparison of the annual and monthly mean Chl a concentrations between the different ecoregions shows significant differences (one-way ANOVA, P < 0.05). In particular, we found differences in phytoplankton phenology, with differences in the date of bloom initiation, its duration and amplitude between ecoregions. A first qualitative evaluation of differences in community composition based on recorded presence–absence patterns of 25 different species of plankton, fish and benthic invertebrate also confirms the relevance of the ecoregions as proxies for habitats with common biological characteristics.

scholarly journals Bio-geographic classification of the Caspian Sea

2014 ◽  
Vol 11 (3) ◽  
pp. 4409-4450
Author(s):  
F. Fendereski ◽  
M. Vogt ◽  
M. R. Payne ◽  
Z. Lachkar ◽  
N. Gruber ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Caspian Sea ◽  
Benthic Invertebrate ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Rank Test ◽  
Agglomerative Clustering ◽  
The Caspian Sea ◽  
Surface Salinity

Abstract. Like other inland seas, the Caspian Sea (CS) has been influenced by climate change and anthropogenic disturbance during recent decades, yet the scientific understanding of this water body remains poor. In this study, an eco-geographical classification of the CS based on physical information derived from space and in-situ data is developed and tested against a set of biological observations. We used a two-step classification procedure, consisting of (i) a data reduction with self-organizing maps (SOMs) and (ii) a synthesis of the most relevant features into a reduced number of marine ecoregions using the Hierarchical Agglomerative Clustering (HAC) method. From an initial set of 12 potential physical variables, 6 independent variables were selected for the classification algorithm, i.e., sea surface temperature (SST), bathymetry, sea ice, seasonal variation of sea surface salinity (DSSS), total suspended matter (TSM) and its seasonal variation (DTSM). The classification results reveal a robust separation between the northern and the middle/southern basins as well as a separation of the shallow near-shore waters from those off-shore. The observed patterns in ecoregions can be attributed to differences in climate and geochemical factors such as distance from river, water depth and currents. A comparison of the annual and monthly mean Chl a concentrations between the different ecoregions shows significant differences (Kruskal–Wallis rank test, P < 0.05). In particular, we found differences in phytoplankton phenology, with differences in the date of bloom initiation, its duration and amplitude between ecoregions. A first qualitative evaluation of differences in community composition based on recorded presence-absence patterns of 27 different species of plankton, fish and benthic invertebrate also confirms the relevance of the ecoregions as proxies for habitats with common biological characteristics.

scholarly journals Spatio-temporal epidemiology of Campylobacter jejuni enteritis, in an area of Northwest England, 2000–2002

2010 ◽  
Vol 138 (10) ◽  
pp. 1384-1390 ◽  
Author(s):  
E. GABRIEL ◽  
D. J. WILSON ◽  
A. J. H. LEATHERBARROW ◽  
J. CHEESBROUGH ◽  
S. GEE ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Seasonal Variation ◽  
Campylobacter Jejuni ◽  
Genetic Model ◽  
Spatial Clustering ◽  
Small Scale ◽  
Temporal Clustering ◽  
Significant Seasonal Variation ◽  
Spatio Temporal ◽  
Temporal Interaction

SUMMARYA total of 969 isolates of Campylobacter jejuni originating in the Preston, Lancashire postcode district over a 3-year period were characterized using multi-locus sequence typing. Recently developed statistical methods and a genetic model were used to investigate temporal, spatial, spatio-temporal and genetic variation in human C. jejuni infections. The analysis of the data showed statistically significant seasonal variation, spatial clustering, small-scale spatio-temporal clustering and spatio-temporal interaction in the overall pattern of incidence, and spatial segregation in cases classified according to their most likely species-of-origin.

scholarly journals Seasonal small-scale variation in distribution among depth zones in a coastal Baltic Sea fish assemblage

2015 ◽  
Vol 72 (8) ◽  
pp. 2374-2384 ◽  
Author(s):  
N. Mustamäki ◽  
H. Jokinen ◽  
M. Scheinin ◽  
E. Bonsdorff ◽  
J. Mattila
Keyword(s):  
Seasonal Variation ◽  
Fish Assemblage ◽  
Juvenile Fish ◽  
Late Summer ◽  
Early Summer ◽  
Small Scale ◽  
Fish Assemblage Structure ◽  
Adult Fish ◽  
Depth Zone ◽  
Small Depth

Abstract We studied seasonal and small-scale spatial variation in fish assemblage structure in the northern Baltic Proper archipelago. The study was conducted in a shallow coastal basin during three consecutive production-seasons. The structure of the fish assemblage changes significantly seasonally, from early summer (May–June) to late summer (August–September), and spatially over short distances (ca. 500 m) and small depth intervals (ca. 5 m) in an area without physical barriers. The magnitude of the seasonal variation was depth zone-specific, indicating that seasonal patterns from a given depth zone cannot be directly extrapolated to adjacent ones, let alone to a whole water body. In early summer, the adult fish displayed spawning aggregations, and their abundance was highest closest to the shoreline. In late summer, the adult fish were more evenly distributed and the assemblage was dominated by high abundances of juvenile fish. The results underline the importance of including several spatial and temporal scales into studies on fish distribution. The resulting patterns from such studies may appear idiosyncratic unless the nature and magnitude of seasonal variation and small-scale depth zone distribution are taken into account.

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