scholarly journals Displacement of diverse ichthyoplankton assemblages by a coastal upwelling event on the Sydney shelf

1999 ◽  
Vol 176 ◽  
pp. 49-62 ◽  
Author(s):  
KA Smith ◽  
IM Suthers
Keyword(s):  
Coastal Upwelling ◽  
Upwelling Event

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 Real-Time Observations of a Coastal Upwelling Event Using Innovative Technologies

2002 ◽  
Author(s):  
Jeffrey D. Paduan ◽  
Steven R. Ramp ◽  
Leslie K. Rosenfeld
Keyword(s):  
Real Time ◽  
Coastal Upwelling ◽  
Innovative Technologies ◽  
Upwelling Event

Evolution of a coastal upwelling event during summer 2004 in the southern Taiwan Strait

2011 ◽  
Vol 30 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Caiyun Zhang ◽  
Huasheng Hong ◽  
Chuanmin Hu ◽  
Shaoling Shang
Keyword(s):  
Coastal Upwelling ◽  
Taiwan Strait ◽  
Southern Taiwan ◽  
Upwelling Event

A Rarely Witnessed Summertime Upwelling Event northwest off the Hainan Island

2020 ◽  
Author(s):  
Ai-Jun Pan ◽  
Fang-fang Kuang ◽  
Kai Li ◽  
Xu Dong
Keyword(s):  
Coastal Upwelling ◽  
Hainan Island ◽  
Heat Fluxes ◽  
Tidal Mixing ◽  
Coastal Current ◽  
Beibu Gulf ◽  
Surface Heat Fluxes ◽  
Upwelled Water ◽  
Basin Scale ◽  
Upwelling Event

<p>A field survey revealed a rare realization of upwelling event in the northwestern Hainan Island (UNWHI) on July 24, 2015. Model experiments suggest that the UNWHI is not locally generated, but can be treated as northward extension of the upwelling southwest off Hainan Island (USWHI) under favorable wind conditions. Therefore, presence of the USWHI is vital for the UNWHI occurrence. Tidal mixing is testified to be the primary driving force for the USWHI, whilst southerly winds plays an essential role in the induction of the UNWHI. Moreover, it is demonstrated that the UNWHI is not a stable, but intermittent coastal upwelling system. Shallow basin of the Beibu Gulf makes the interior circulation vulnerable to local monsoon changes. Given the favorable southerly winds, a cyclonic gyre northwest off Hainan Island will be induced and which, leads to northward coastal current and consequently, the UNWHI is to be formed due to the northward transport of the USWHI. Conversely, the UNWHI vanishes during northerly winds period, because the basin-scale anticyclonic gyre results in a southward current west off the Hainan Island and which, acts to push the upwelled water of the USWHI offshore and away from the northwestern Hainan Island. In addition, our diagnostics indicates that contributions from surface heat fluxes to the UNWHI occurrence is negligible. Besides, it also reminds us that application of a high-frequency, much closer to reality wind field is necessary for the coastal upwelling simulation. </p>

scholarly journals Seasonal coastal upwelling in the Bali Strait: a model study

2021 ◽  
Vol 944 (1) ◽  
pp. 012055
Author(s):  
A Suprianto ◽  
A S Atmadipoera ◽  
J Lumban-Gaol
Keyword(s):  
Chlorophyll A ◽  
Coastal Upwelling ◽  
Fish Distribution ◽  
Sea Surface ◽  
Monsoon Period ◽  
Easterly Wind ◽  
Chl A ◽  
Model Study ◽  
Velocity Surface ◽  
Upwelling Event

Abstract Bali Strait is part of fisheries management zone (WPP 573), where abundant fishery potential, of lemuru fish commodity. Here, physical oceanographic setting such as upwelling event plays an important role on maintaining high primary productivity and lemuru fish distribution. This study aims to describe physical process and dynamics of seasonal coastal upwelling using time-series datasets (2008 and 2014) of temperature, salinity, current velocity, surface chlorophyll-a (chl-a) from INDESO model and satellite imagery. The results showed that upwelling in the Bali Strait only during the southeast monsoon period when the south-easterly wind force surface Ekman drift of about 5.5 × 10−3 Sv flowing south-eastward (toward offshore). Upwelling event is characterized by minimum parameter of sea surface temperature (24.93 °C), and sea level anomaly (0.75 m), but maximum of surface chlorophyll-a (1.33 mg/m3). Furthermore, isotherm of 26 °C and Isohaline 33.7 psu are outcropped at sea surface in the center of upwelling zone. In contrast, during the nortwest monsoon period these isolines remain at deeper layer of about 80-90 m depth. Mean temperature-based upwelling index during peak of upwelling in August (1.19±0.19 °C). Upwelling impact on high abundance of lemuru fish (Sardinella sp.) production two month later after peak of chl-a.

Real-Time Observations of a Coastal Upwelling Event Using Innovative Technologies

2001 ◽  
Author(s):  
Jeffrey D. Raduan ◽  
Steven R. Ramp ◽  
Leslie K. Rosenfeld
Keyword(s):  
Real Time ◽  
Coastal Upwelling ◽  
Innovative Technologies ◽  
Upwelling Event
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