Influence of upwelling events on the estuaries of the north-western coast of the Iberian Peninsula

2013 ◽  
Vol 64 (12) ◽  
pp. 1123 ◽  
Author(s):  
I. Alvarez ◽  
J. M. Dias ◽  
M. deCastro ◽  
N. Vaz ◽  
M. C. Sousa ◽  
...  
Keyword(s):  
Primary Production ◽  
Iberian Peninsula ◽  
Biological Diversity ◽  
Coastal Upwelling ◽  
Western Coast ◽  
External Forcing ◽  
Ria De Aveiro ◽  
The North ◽  
Upwelled Water ◽  
Ría De Vigo

Coastal upwelling is one of the best studied oceanographic phenomena because of its effects on primary production. The western coast of the Iberian Peninsula has high biological diversity, mainly due to this primary production. In this study, the response of salinity and temperature to the occurrence of upwelling was analysed at the Ria de Vigo– and Ria de Aveiro–ocean boundary over the course of a year. Both systems were influenced by similar external forcing, but the response of thermohaline properties differed. Salinity and temperature were dependent on external forcing throughout the water column at Ria de Aveiro, whereas near-bed measurements revealed the presence of upwelled water at Ria de Vigo. Eastern North Atlantic Central Water was observed during spring–summer (summer) at the southern (northern) mouth of Ria de Vigo, but it was not observed at Ria de Aveiro. This difference may be due to the shallowness and narrowness of the Ria de Aveiro mouth, which can limit the entrance of ocean water. The trends found are unlikely to be unique, suggesting that geomorphologic characteristics of system–ocean boundaries determine how physical processes occurring in adjacent coastal areas impact estuarine properties.

scholarly journals External forcing mechanisms controlling the North Atlantic coastal upwelling regime during the mid-Holocene

Geology ◽  
2020 ◽  
Author(s):  
Armand Hernández ◽  
Mário Cachão ◽  
Pedro Sousa ◽  
Ricardo M. Trigo ◽  
Jürg Luterbacher ◽  
...  
Keyword(s):  
North Atlantic ◽  
Coastal Upwelling ◽  
Marine Ecosystem ◽  
External Forcing ◽  
The North ◽  
New Findings ◽  
The North Atlantic ◽  
Eastern North Atlantic ◽  
Forcing Mechanisms ◽  
The Impact

Nearshore upwelling along the eastern North Atlantic margin regulates regional marine ecosystem productivity and thus impacts blue economies. While most global circulation models show an increase in the intensity and duration of seasonal upwelling at high latitudes under future human-induced warmer conditions, projections for the North Atlantic are still ambiguous. Due to the low temporal resolution of coastal upwelling records, little is known about the impact of natural forcing mechanisms on upwelling variability. Here, we present a microfossil-based proxy record and modeling simulations for the warmest period of the Holocene (ca. 9–5 ka) to estimate the contribution of the natural variability in North Atlantic upwelling via atmospheric and oceanic dynamics. We found that more frequent high-pressure conditions in the eastern North Atlantic associated with solar activity and orbital parameters triggered upwelling variations at multidecadal and millennial time scales, respectively. Our new findings offer insights into the role of external forcing mechanisms in upwelling changes before the Anthropocene, which must be considered when producing future projections of midlatitude upwelling activity.

The use of a mathematical model to evaluate mercury accumulation in sediments and recovery time in a coastal lagoon (Ria de Aveiro, Portugal)

1998 ◽  
Vol 37 (6-7) ◽  
pp. 33-38 ◽  
Author(s):  
S. N. Abreu ◽  
M. E. Pereira ◽  
A. C. Duarte
Keyword(s):  
Mathematical Model ◽  
Recovery Time ◽  
Surface Sediments ◽  
Mercury Accumulation ◽  
Western Coast ◽  
Ria De Aveiro ◽  
Economic Role ◽  
The North ◽  
Surrounding Areas ◽  
North Western

The urge of restoration and management of vital ecosystems (mainly those that affect directly human health) has become one of the most requested priorities. Ria de Aveiro (a lagoon on the north-western coast of Portugal) has an important economic role in local and surrounding areas due to its variety of resources. Studies have shown that there is an effective risk of hindering traditional activities due to high levels of mercury. Mercury concentrations in 1985 ranged from 0.7 μg g−1 to 850 μg g−1 in surface sediments and concentrations up to 25 μg g−1 fresh weight in fishes. A mathematical model (ECoS) was used to perform a simulation of mercury accumulation in surface sediments along the most contaminated channel from the beginning of the industrial discharges (in the 50's) until present days and recovery time for a zero mercury discharge from 1995 until 2045. The model shows that the amount of mercury in the surface sediments would decrease exponentially due to both deposition of mercury free particles and ressuspension of less and less contaminated particles. The model estimated levels actually measured along the channel and evaluated that, even after 40 years, mercury concentration would be approximately 50 μg g−1 in the most contaminated section of that channel if the discharges were discontinued now.

scholarly journals ARUS SELATAN JAWA

OSEANA ◽  
2017 ◽  
Vol 42 (3) ◽  
pp. 1-8
Author(s):  
Dewi Surinati ◽  
Jaka Harry Mulyanto Wijaya
Keyword(s):  
Indian Ocean ◽  
West Coast ◽  
Coastal Upwelling ◽  
Convergence Zone ◽  
Western Coast ◽  
The North ◽  
Seasonal Basis ◽  
The Indian Ocean ◽  
North And South

SOUTH JAVA CURRENT. Indian Ocean is influenced by the monsoon cycle. Monsoon cycle that occurs in the Indian Ocean influences the current patterns. Since a very strong westerlies occurs in The Tropical Convergence Zone (TCZ) at the equator, wyrtki jet is formed in the 40° - 80° W Indian Ocean on a transitional season. Its branchs are possibly formed when the wyrtki jet is in the equatorial west coast of Sumatra to the north and south along the western coast of Sumatra which eventually creates South Java Current (SJC). SJC flows southeastward during December–April and northwestward during June–October, when it is associated with coastal upwelling. SJC develop upwelling on a seasonal basis.

scholarly journals Significance of nanophytoplankton photosynthesis and primary production in a coastal upwelling system (Ría de Vigo, NW Spain)

1999 ◽  
Vol 183 ◽  
pp. 13-27 ◽  
Author(s):  
GH Tilstone ◽  
FG Figueiras ◽  
EG Fermín ◽  
B Arbones
Keyword(s):  
Primary Production ◽  
Coastal Upwelling ◽  
Nw Spain ◽  
Upwelling System ◽  
Ría De Vigo

scholarly journals Mechanisms controlling primary and new production in a global ecosystem model – Part I: The role of the large-scale upper mixed layer variability

2006 ◽  
Vol 3 (4) ◽  
pp. 1065-1113
Author(s):  
E. E. Popova ◽  
A. C. Coward ◽  
G. A. Nurser ◽  
B. de Cuevas ◽  
M.J.R. Fasham ◽  
...  
Keyword(s):  
Primary Production ◽  
Mixed Layer ◽  
North Atlantic ◽  
Ecosystem Model ◽  
Ecosystem Dynamics ◽  
Global Ocean ◽  
External Forcing ◽  
The North ◽  
The North Atlantic ◽  
Upper Mixed Layer

Abstract. A global general circulation model coupled to a simple six-compartment ecosystem model is used to study the extent to which global variability in primary and export production can be realistically predicted on the basis of advanced parameterizations of upper mixed layer physics, without recourse to introducing extra complexity in model biology. The ''K profile parameterization'' (KPP) scheme employed, combined with 6-hourly external forcing, is able to capture short-term periodic and episodic events such as diurnal cycling and storm-induced deepening. The model realistically reproduces various features of global ecosystem dynamics that have been problematic in previous global modelling studies, using a single generic parameter set. The realistic simulation of deep convection in the North Atlantic, and lack of it in the North Pacific and Southern Oceans, leads to good predictions of chlorophyll and primary production in these contrasting areas. Realistic levels of primary production are predicted in the oligotrophic gyres due to high frequency external forcing of the upper mixed layer (accompanying paper Popova et al., 2006) and novel parameterizations of zooplankton excretion. Good agreement is shown between model and observations at various JFOFS time series sites: BATS, KERFIX, Papa and station India. One exception is that the high zooplankton grazing rates required to maintain low chlorophyll in high-nutrient low-chlorophyll and oligotrophic systems lessened agreement between model and data in the northern North Atlantic, where mesozooplankton with lower grazing rates may be dominant. The model is therefore not globally robust in the sense that additional parameterizations were needed to realistically simulate ecosystem dynamics in the North Atlantic. Nevertheless, the work emphasises the need to pay particular attention to the parameterization of mixed layer physics in global ocean ecosystem modelling as a prerequisite to increasing the complexity of ecosystem models.

scholarly journals Influence of atmospheric modes on coastal upwelling along the western coast of the Iberian Peninsula, 1985 to 2005

2008 ◽  
Vol 36 ◽  
pp. 169-179 ◽  
Author(s):  
M deCastro ◽  
M Gómez-Gesteira ◽  
MN Lorenzo ◽  
I Alvarez ◽  
AJC Crespo
Keyword(s):  
Iberian Peninsula ◽  
Coastal Upwelling ◽  
Western Coast

scholarly journals The fate of upwelled nitrate off Peru shaped by submesoscale filaments and fronts

2020 ◽  
Author(s):  
Jaard Hauschildt ◽  
Soeren Thomsen ◽  
Vincent Echevin ◽  
Andreas Oschlies ◽  
Yonss Saranga José ◽  
...  
Keyword(s):  
Primary Production ◽  
Coastal Upwelling ◽  
Nutrient Transport ◽  
Model Simulations ◽  
Fresh Organic Matter ◽  
Upwelled Water ◽  
Vertical Scale ◽  
Nitrate Concentrations ◽  
Additional Value ◽  
Offshore Transport

Abstract. Filaments and fronts play a crucial role for a net offshore and downward nutrient transport in Eastern Boundary Upwelling Regions (EBUS) and thereby reduce primary production. Often studies are either based on observations or model simulations but seldom both approaches are combined quantitatively to assess the importance of filaments for primary production and nutrient transport. Here we combine targeted interdisciplinary shipboard observations of a cold filament off Peru with submesoscale-permitting (1/45°) coupled physical (CROCO) and biogeochemical (PISCES) model simulations to (i) evaluate the model simulations in detail, including the timescales of biogeochemical modification of the newly upwelled water and (ii) quantify the net effect of submesoscale fronts and filaments on primary production of the Peruvian upwelling system. The observed filament contains relatively cold, fresh and nutrient-rich waters originating in the coastal upwelling. Enhanced nitrate concentrations and offshore velocities of up to 0.5 m s−1 within the filament suggest an offshore transport of nutrients. Surface chlorophyll in the filament is a factor 4 lower than at the upwelling front while surface primary production is a factor 2 higher, highlighting the additional value of direct rate measurements for model validation. The simulation exhibits filaments that are similar in horizontal and vertical scale compared to the observed filament. Nitrate concentrations and primary pro- duction within filaments in the model are comparable to observations as well, justifying further analysis of nitrate uptake and subduction using the model. Virtual Lagrangian floats were released in the subsurface waters along the shelf and biogeochemical variables tracked along the trajectories of floats upwelled near the coast. In the submesoscale-permitting (1/45°) simulation 43.0 % of upwelled floats and 40.6 % of upwelled nitrate is subducted within 20 days after upwelling, which corresponds to an increase of nitrate subduction compared to a mesoscale-resolving (1/9°) simulation by 13.9 %. This suggests that submesoscale processes further reduce primary production by amplifying the downward and offshore export of nutrients found in previous mesoscale studies, which are thus likely to underestimate the reduction in primary production due to eddy-fluxes. Moreover, this downward and offshore transport could also enhance the export of fresh organic matter below the photic zone and thereby potentially stimulate microbial activity in the upper offshore oxygen minimum zone.

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