Spatial and temporal variation in littoral-zone benthic invertebrates from three south-central Ontario lakes

1995 ◽  
Vol 52 (7) ◽  
pp. 1406-1420 ◽  
Author(s):  
R. A. Reid ◽  
K. M. Somers ◽  
S. M. David
Keyword(s):  
Temporal Variation ◽  
Benthic Invertebrates ◽  
Seasonal Changes ◽  
Littoral Zone ◽  
Spatial And Temporal Variation ◽  
South Central ◽  
Temporal Factors ◽  
Follow Up Studies ◽  
Spatial Differences

Surveys of benthic invertebrates have revealed patterns attributed to the impacts of acid deposition. Unfortunately, these patterns may be confounded by temporal variation that will affect follow-up studies of the recovery of these communities. Here, we assess spatial and temporal variation in time-limited, kick-and-sweep collections of littoral-zone benthos. Spatial variation comprised five sites representing the predominant nearshore substrates in each of three lakes. Temporal variation spanned a different scale in each lake with five sites sampled: (i) twice on the same day, (ii) once a week for 3 weeks, and (iii) four times through the ice-free season. Variation was quantified using a model II analysis of variance. Spatial differences predominated in same-day samples (60.4% of the variation on average) and those collected over a 3-week period (46.1%). In contrast, samples collected over the ice-free season revealed that spatial and temporal factors accounted for 9.4 and 25.6% of the variation. We conclude that our collections of littoral macrobenthos are highly repeatable if sampling is restricted to short periods (e.g., 3 weeks). Surveys spanning longer periods may incorporate considerable temporal variation from seasonal changes in abundance.

scholarly journals Spatial and temporal variation of fish assemblage associated with aquatic macrophyte patches in the littoral zone of the Ayapel Swamp Complex, Colombia

2017 ◽  
Vol 29 (0) ◽  
Author(s):  
Carlos Mario Marín Avendaño ◽  
Néstor Jaime Aguirre Ramírez
Keyword(s):  
Temporal Variation ◽  
Environmental Conditions ◽  
Fish Assemblage ◽  
Littoral Zone ◽  
Aquatic Macrophyte ◽  
Abundant Species ◽  
Assemblage Structure ◽  
Spatial And Temporal Variation ◽  
Suitable Habitat ◽  
Fish Assemblage Structure

Abstract: Aim The purpose of the present study was to examine spatial and temporal variation in fish assemblage structure associated with aquatic macrophytes in the littoral zone of the ASC. Methods Specimens were caught between January 2008 and February 2009, over four limnimetric moments, using both cast net and seine net. Data on the temperature, electrical conductivity, pH and dissolved oxygen was recorded for the characterization of the water mass in the sites. Results A total of 34,151 specimens from 44 species were collected. The most abundant species were Eigenmannia virescens, Astyanax caucanus, Astyanax fasciatus, Roeboides dayi and Cyphocharax magdalenae, which together accounted for more than 75% of the sample. Temporal and spatial comparisons showed variation in the environmental conditions and highlighted the existence of heterogeneous abiotic conditions (p<0.05). However, the multiple comparisons test showed the existence of homogeneous spatial conditions (p>0.05) regarding the fish assemblage structure. The multivariate analysis showed no significant relationship between existing environmental conditions and the fish assemblage (p=0.04). The analysis also showed the absence of a relationship between the fish assemblage and environmental variables with respect to the flood pulse and sampling sites (p>0.05). Conclusion The uniformity of the fish communities that inhabit aquatic macrophyte patches in the littoral region of the ASC may be related to the availability of suitable habitat in structural terms, that probably supports a more abundant and varied wildlife.

Temporal and spatial variability in elemental composition of otoliths: implications for determining stock identity and connectivity of populations

2002 ◽  
Vol 59 (4) ◽  
pp. 669-679 ◽  
Author(s):  
Bronwyn M Gillanders
Keyword(s):  
Temporal Variation ◽  
Elemental Composition ◽  
Juvenile Fish ◽  
Spatial And Temporal Variation ◽  
Otolith Chemistry ◽  
Temporal And Spatial Variability ◽  
Spatial Differences ◽  
Elemental Fingerprint ◽  
Temporal And Spatial ◽  
Over Time

Interannual variability in elemental composition of otoliths may confound spatial interpretations. The elemental fingerprints of otoliths of juvenile fish were determined for fish collected from 12 to 15 estuaries in each of three consecutive recruitment years to determine temporal variation in otolith chemistry for each estuary. It was also examined whether there is overlap in elemental fingerprints of fish collected in different years and from different estuaries that may confound subsequent spatial comparisons. Significant differences in otolith chemistry were found among years for individual elements (lithium, manganese, strontium, and barium) and for multi-element fingerprints. Some estuaries showed large variation in multi-element fingerprints among years, whereas others showed little variation among years. There was some overlap of elemental fingerprints of different estuaries, but these were not always for fish collected in the same year. The significant spatial and temporal variation in elemental fingerprints meant that it was possible to confound spatial differences with temporal differences. Therefore, if the natal estuary of the adults is to be determined, a library of elemental fingerprints needs to be built up over time for each estuary rather than a single year-class of juveniles being used as the elemental fingerprint for a number of year-classes of adults.

What graduate follow-up studies can tell us

2000 ◽  
Vol 34 (12) ◽  
pp. 976-977 ◽  
Author(s):  
Linda H Distlehorst
Keyword(s):  
Follow Up Studies

Beurteilung der Adriamycin-Kardiotoxizität mittels der Äquilibrium-Radionuklid-Ventrikulographie

1987 ◽  
Vol 26 (05) ◽  
pp. 206-211 ◽  
Author(s):  
P. Knesewitsch ◽  
N. H. Göldel ◽  
S. Fritsch ◽  
E. Moser
Keyword(s):  
Left Ventricular ◽  
Peak Filling Rate ◽  
Base System ◽  
Filling Rate ◽  
Time To Peak ◽  
Ejection Rate ◽  
Follow Up Studies ◽  
Pathologic Findings ◽  
Peak Ejection Rate

Results of 606 equilibrium radionuclide ventriculographies (ERNV) performed in 348 non-selected patients receiving Adriamycin (ADM) therapy were stored in a data base system. The aim of the study was to assess the influence of a potential cardiotoxic therapy on left ventricular pump function. Increasing ADM doses yielded a significant (p <0.05) decrease of the resting ejection fraction (R-gEF), the peak ejection rate and the peak filling rate. Enddiastolic and endsystolic volumes increased significantly. Stroke volume, heart rate and time to peak filling rate did not change significantly. 368 follow-up studies were performed in 128 patients: 65/128 patients presented a decrease of R-gEF, but only in 45 of these patients R-gEF values fell into the pathologic range. In 44 of these follow-ups, R-gEF remained unchanged. In 19 patients, a R-gEF increase was observed. At the beginning of ADM therapy 14% of the patients had subnormal R-gEF values. With increasing ADM doses pathologic findings increased to 86% in patients with ADM doses higher than 500 mg/m2.

Synthesis and Biological Evaluation of the Antimicrobial Natural Product Lipoxazolidinone A

2018 ◽  
Author(s):  
Jonathan J. Mills ◽  
Kaylib R. Robinson ◽  
Troy E. Zehnder ◽  
Joshua G. Pierce
Keyword(s):  
Natural Products ◽  
Natural Product ◽  
Mechanism Of Action ◽  
Marine Natural Products ◽  
Biological Evaluation ◽  
Lead Compounds ◽  
Follow Up Studies ◽  
Initial Resistance ◽  
Synthesis And Biological Evaluation

The lipoxazolidinone family of marine natural products, with an unusual 4-oxazolidinone heterocycle at their core, represents a new scaffold for antimicrobial discovery; however, questions regarding their mechanism of action and high lipophilicity have likely slowed follow-up studies. Herein, we report the first synthesis of lipoxazolidinone A, 15 structural analogs to explore its active pharmacophore, and initial resistance and mechanism of action studies. These results suggest that 4-oxazolidinones are valuable scaffolds for antimicrobial development and reveal simplified lead compounds for further optimization.

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