Short-term temporal variation in population structure of two harpacticoid copepods, Zausodes arenicolus and Paradactylopodia brevicornis

1984 ◽  
Vol 84 (1) ◽  
pp. 53-63 ◽  
Author(s):  
J. C. Kern ◽  
S. S. Bell
Keyword(s):  
Population Structure ◽  
Temporal Variation ◽  
Short Term ◽  
Harpacticoid Copepods

Characterizing population structure of coral-associated fauna from mesophotic and shallow habitats in the Caribbean

2018 ◽  
Vol 99 (3) ◽  
pp. 619-629 ◽  
Author(s):  
Alex J. Veglia ◽  
Nicholas M. Hammerman ◽  
Carlos R. Rivera Rosaly ◽  
Matthew Q. Lucas ◽  
Alexandra Galindo Estronza ◽  
...  
Keyword(s):  
Population Structure ◽  
Puerto Rico ◽  
Marine Invertebrates ◽  
Geographic Distance ◽  
Harpacticoid Copepod ◽  
Coi Gene ◽  
Mitochondrial Coi ◽  
Symbiotic Relationships ◽  
Harpacticoid Copepods ◽  
Obligate Symbiont

Symbiotic relationships are a common phenomenon among marine invertebrates, forming both obligatory and facultative dependencies with their host. Here, we investigate and compare the population structure of two crustacean species associated with both shallow and mesophotic ecosystems: an obligate symbiont barnacle (Ceratoconcha domingensis), of the coral Agaricia lamarcki and a meiobenthic, free-living harpacticoid copepod (Laophontella armata). Molecular analyses of the Cytochrome Oxidase Subunit I (COI) gene revealed no population structure between mesophotic and shallow barnacle populations within south-west Puerto Rico (ΦST = 0.0079, P = 0.33). The absence of population structure was expected due to the pelagic naupliar larvae of the barnacles and the connectivity patterns exhibited by the coral itself within the same region. Laophontella armata exhibited significant structure based on the mitochondrial COI gene between the mesophotic reef ecosystem of El Seco, Puerto Rico and mangrove sediments of Curaçao (ΦST = 0.2804, P = 0.0). The El Seco and Curaçao copepods shared three COI haplotypes despite the obligatory benthic development of harpacticoid copepods and the geographic distance between the two locations. Three other COI haplotypes from El Seco exhibited higher than expected (up to 7%) intra-species variability, potentially representing three new cryptic species of harpacticoid copepods or rare, deeply divergent lineages of L. armata. This result is evidence for the urgent need of a deeper investigation into the meiofauna diversity associated with mesophotic coral ecosystems (MCEs), arguably the most diverse metazoan component of MCEs.

Short-term growth (RNA/DNA ratio) of yellow perch (Perca flavescens) in relation to environmental influences and spatio-temporal variation in a shallow fluvial lake

2007 ◽  
Vol 64 (12) ◽  
pp. 1646-1655 ◽  
Author(s):  
Hélène Glémet ◽  
Marco A Rodríguez
Keyword(s):  
Temporal Variation ◽  
Water Level ◽  
Yellow Perch ◽  
Perca Flavescens ◽  
Negative Influence ◽  
Water Levels ◽  
Short Term ◽  
Ecological Processes ◽  
Flood Pulse Concept ◽  
Spatio Temporal

Shallow fluvial lakes are heterogeneous ecosystems in which marked spatio-temporal variation renders difficult the analysis of key ecological processes, such as growth. In this study, we used generalized additive modelling of the RNA/DNA ratio, an index of short-term growth, to investigate the influence of environmental variables and spatio-temporal variation on growth of yellow perch (Perca flavescens) in Lake St. Pierre, Quebec, Canada. Temperature and water level had seemingly stronger effects on short-term growth than seasonal change or spatial variation between and along the lakeshores. Consistent with previous studies, the maximum RNA/DNA ratio was found at 20.5 °C, suggesting that our approach provides a useful tool for estimating thermal optima for growth in the field. The RNA/DNA ratio showed a positive relationship with water level, as predicted by the flood pulse concept, a finding with implications for ecosystem productivity in fluvial lakes. The RNA/DNA ratio was more variable along the north than the south shore, possibly reflecting exposure to more differentiated water masses. The negative influence of both high temperatures and low water levels on growth points to potential impacts of climatic change on fish production in shallow fluvial lakes.

Short term spatial and temporal variation of phytoplankton in a shallow tropical oligotrophic reservoir, southeast Brazil

Hydrobiologia ◽  
2005 ◽  
Vol 542 (1) ◽  
pp. 235-247 ◽  
Author(s):  
Maria Rosélia Marques Lopes ◽  
Carlos E. de M. Bicudo ◽  
M. Carla Ferragut
Keyword(s):  
Temporal Variation ◽  
Spatial And Temporal Variation ◽  
Short Term ◽  
Southeast Brazil

Short-term spatial and temporal variation of sediment oxygen dynamics in a tropical tidal salt flat

2011 ◽  
Vol 19 (5) ◽  
pp. 389-395 ◽  
Author(s):  
Vinícius Peruzzi de Oliveira ◽  
Luiz Fernando Jardim Bento ◽  
Alex Enrich Prast
Keyword(s):  
Temporal Variation ◽  
Spatial And Temporal Variation ◽  
Short Term ◽  
Salt Flat ◽  
Oxygen Dynamics

Removing Time Variation with the Anti-Hebbian Differential Synapse

1991 ◽  
Vol 3 (3) ◽  
pp. 312-320 ◽  
Author(s):  
Graeme Mitchison
Keyword(s):  
Temporal Variation ◽  
Time Variation ◽  
Synaptic Weight ◽  
Receptive Fields ◽  
Learning Rule ◽  
Temporal Changes ◽  
Short Term ◽  
Conservation Condition ◽  
Rule Changes ◽  
Synaptic Learning

I describe a local synaptic learning rule that can be used to remove the effects of certain types of systematic temporal variation in the inputs to a unit. According to this rule, changes in synaptic weight result from a conjunction of short-term temporal changes in the inputs and the output. Formally, This is like the differential rule proposed by Klopf (1986) and Kosko (1986), except for a change of sign, which gives it an anti-Hebbian character. By itself this rule is insufficient. A weight conservation condition is needed to prevent the weights from collapsing to zero, and some further constraint—implemented here by a biasing term—to select particular sets of weights from the subspace of those which give minimal variation. As an example, I show that this rule will generate center-surround receptive fields that remove temporally varying linear gradients from the inputs.

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