scholarly journals Hydrological connectivity: an introduction to the concept

2020 ◽  
Vol 92 (1) ◽  
Author(s):  
Matija Zorn ◽  
Mauro Hrvatin ◽  
Drago Perko
Keyword(s):  
Temporal Variability ◽  
Hydrological Connectivity ◽  
Spatial And Temporal Variability ◽  
Fluvial System ◽  
Environmental Sciences ◽  
River Floodplain ◽  
Water And Sediment ◽  
Multiple Dimensions ◽  
Subsurface Waters ◽  
Surface And Subsurface Waters

The concept of connectivity, especially hydrological connectivity, is used in Earth and environmental sciences as a term and as a conceptual framework for addressing spatial and temporal variability in runoff and sediment transport. Hydrological connectivity can be defined as the transfer of water and sediment through a fluvial system or a dynamic linkage between surface and subsurface waters flowing through a landscape. Five forms of hydrological connectivity may be distinguished: stream-hillslope connectivity, river-floodplain connectivity, stream-lake connectivity, longitudinal or upstream-downstream connectivity, and stream-groundwater connectivity. All of them are interconnected. Hydrological connections are not only unidirectional but cover multiple dimensions and operate across different temporal scales. As a framework, connectivity is useful for understanding spatial variations in runoff. //   Pojem povezljivosti, zlasti hidrološke povezljivosti, se v vedah o Zemlji in okolju uporablja kot strokovni izraz in kot konceptualni okvir za obravnavo prostorske ter časovne spremenljivosti v pretoku vode in prenosu gradiva. Hidrološko povezljivost lahko opredelimo kot prenašanje vode in sedimentov skozi rečni sistem ali kot dinamično povezavo med nadzemnimi in podzemnimi vodami, ki tečejo skozi pokrajino. Razlikujemo lahko pet oblik hidrološke povezljivosti: povezljivost med vodotokom in pobočjem, povezljivost med vodotokom in njegovim poplavnim območjem, povezljivost med vodotokom in jezerom, vzdolžno povezljivost med vodotokovim povirnim in izlivnim delom ter povezljivost med vodotokom in podzemno vodo. Vse so med sabo povezane. Vodne povezave niso samo enosmerne, ampak imajo več razsežnosti glede na prostor in čas. Kot okvir je povezljivost koristna za razumevanje prostorskih razlik pri odtoku.

scholarly journals Spatial and temporal variability in coccolithophore abundance and distribution in the NW Iberian coastal upwelling system

2018 ◽  
Vol 15 (1) ◽  
pp. 245-262 ◽  
Author(s):  
Blanca Ausín ◽  
Diana Zúñiga ◽  
Jose A. Flores ◽  
Catarina Cavaleiro ◽  
María Froján ◽  
...  
Keyword(s):  
Water Column ◽  
Environmental Conditions ◽  
Temporal Variability ◽  
Coastal Upwelling ◽  
Spatial And Temporal Variability ◽  
Upwelling System ◽  
Subsurface Waters ◽  
Shelf Station ◽  
Abundance And Distribution ◽  
Upwelling Event

Abstract. A systematic investigation of the spatial and temporal variability in coccolithophore abundance and distribution through the water column of the NW Iberian coastal upwelling system was performed. From July 2011 to June 2012, monthly sampling at various water depths was conducted at two parallel stations located at 42∘ N. Total coccosphere abundance was higher at the outer-shelf station, where warmer, nutrient-depleted waters favoured coccolithophore rather than phytoplanktonic diatom blooms, which are known to dominate the inner-shelf location. In seasonal terms, higher coccosphere and coccolith abundances were registered at both stations during upwelling seasons, coinciding with high irradiance levels. This was typically in conjunction with stratified, nutrient-poor conditions (i.e. relaxing upwelling conditions). However, it also occurred during some upwelling events of colder, nutrient-rich subsurface waters onto the continental shelf. Minimum abundances were generally found during downwelling periods, with unexpectedly high coccolith abundance registered in subsurface waters at the inner-shelf station. This finding can only be explained if strong storms during these downwelling periods favoured resuspension processes, thus remobilizing deposited coccoliths from surface sediments, and hence hampering the identification of autochthonous coccolithophore community structure. At both locations, the major coccolithophore assemblages were dominated by Emiliania huxleyi, small Gephyrocapsa group, Gephyrocapsa oceanica, Florisphaera profunda, Syracosphaera spp., Coronosphaera mediterranea, and Calcidiscus leptoporus. Ecological preferences of the different taxa were assessed by exploring the relationships between environmental conditions and temporal and vertical variability in coccosphere abundance. These findings provide relevant information for the use of fossil coccolith assemblages in marine sediment records, in order to infer past environmental conditions, of particular importance for Paleoceanography. Both E. huxleyi and the small Gephyrocapsa group are proposed as proxies for the upwelling regime with a distinct affinity for different stages of the upwelling event: E. huxleyi was associated with warmer, nutrient-poor and more stable water column (i.e. upwelling relaxation stage) while the small Gephyrocapsa group was linked to colder waters and higher nutrient availability (i.e. early stages of the upwelling event), similarly to G. oceanica. Conversely, F. profunda is suggested as a proxy for the downwelling regime and low-productivity conditions. The assemblage composed by Syracosphaera pulchra, Coronosphaera mediterranea, and Rhabdosphaera clavigera may be a useful indicator of the presence of subtropical waters conveyed northward by the Iberian Poleward Current. Finally, C. leptoporus is proposed as an indicator of warmer, saltier, and oligotrophic waters during the downwelling/winter regime.

scholarly journals Spatial and temporal variability in coccolithophore abundance and distribution in the NW Iberian coastal upwelling system

2017 ◽  
Author(s):  
Blanca Ausín ◽  
Diana Zúñiga ◽  
Jose Abel Flores ◽  
Catarina Cavaleiro ◽  
María Froján ◽  
...  
Keyword(s):  
Water Column ◽  
Environmental Conditions ◽  
Temporal Variability ◽  
Coastal Upwelling ◽  
Relevant Information ◽  
High Irradiance ◽  
Spatial And Temporal Variability ◽  
Upwelling System ◽  
Subsurface Waters ◽  
Abundance And Distribution

Abstract. For the first time a systematic investigation of the coccolithophore ecology based on the spatial and temporal variability in their abundance and distribution through the water column was performed for the NW Iberian coastal upwelling system. From July 2011 to June 2012 monthly sampling at different water depths was conducted at two stations located along the 42º N parallel. Total coccolithophore abundances were higher at the offshore station where warmer and nutrient–depleted waters favoured coccolithophore rather than diatom blooming, the other phytoplankton group that is known to be dominant at the onshore location. In seasonal terms, coccolithophore blooms were registered at both stations during upwelling seasons, coinciding with high irradiance levels and generally in conjunction with stratified and nutrient–poor conditions in the water column, but also when colder and nutrient–rich subsurface waters upwelled onto the continental shelf. On the contrary, despite minimum abundances were generally found during downwelling periods, unexpectedly high coccolithophore abundances were registered in subsurface waters at the onshore station. This finding was only explained if strong storms during downwelling periods favoured resuspension processes, thus remobilizing deposited coccoliths from surface sediments, and hence hampering the identification of the autochthonous coccolithophore community structure. Major composition of coccolithophore assemblages at both locations was dominated by Emiliania huxleyi, small Gephyrocapsa group, Gephyrocapsa oceanica, Florisphaera profunda, and Syracosphaera spp. Ecological preferences of the different taxa were assessed by exploring the relationships between environmental conditions and temporal and vertical variability in coccolithophore abundance. Our findings will provide relevant information in regards to the use of fossil coccolithophore assemblages in marine sediment records to infer environmental conditions in the past, which is of particular relevance in Paleoceanography. E. huxleyi and the small Gephyrocapsa group are proposed as proxies for the upwelling regime and high primary production. Conversely, F. profunda is suggested as a proxy for the downwelling regime and low productivity conditions. Finally, the assemblage composed by Syracosphaera pulchra, Coronosphaera mediterranea, and Rhabdosphaera clavigera may be used as a useful indicator of the presence of warm and nutrient–poor southerly waters conveyed by the Iberian Poleward Current.

Response of Corn Grain Yield to Spatial and Temporal Variability in Emergence

Crop Science ◽  
2004 ◽  
Vol 44 (3) ◽  
pp. 847 ◽  
Author(s):  
Weidong Liu ◽  
Matthijs Tollenaar ◽  
Greg Stewart ◽  
William Deen
Keyword(s):  
Grain Yield ◽  
Temporal Variability ◽  
Spatial And Temporal Variability ◽  
Corn Grain ◽  
Corn Grain Yield

Hydrological connectivity drives the propagule pressure of Limnoperna fortunei (Dunker, 1857) in a tropical river–floodplain system

Hydrobiologia ◽  
2021 ◽  
Vol 848 (9) ◽  
pp. 2043-2053 ◽  
Author(s):  
Vanessa Ernandes de Amo ◽  
Jéssica Ernandes-Silva ◽  
Dieison André Moi ◽  
Roger Paulo Mormul
Keyword(s):  
Propagule Pressure ◽  
Hydrological Connectivity ◽  
Limnoperna Fortunei ◽  
Tropical River ◽  
River Floodplain
Sign in / Sign up

Export Citation Format

Share Document