A high-resolution hydrodynamic-biogeochemical coupled model of the Gulf of Cadiz – Alboran Sea region.

Abstract

The southern Iberia regional seas comprise the Gulf of Cadiz and the Alboran Sea sub-basins connected by the narrow Strait of Gibraltar. Both basins are very different in their hydrological and biological characteristics but are, also, tightly connected to each other. Integrative studies of the whole regional oceanic system are scarce and difficult to perform due to the relative large area to cover and the different relevant time-scales of the main forcing in each sub-basin. Here we propose, for the first time, a fully coupled, 3D, hydrodynamic-biogeochemical model that covers, in a single domain (~2km resolution) both marine basins for a 20-year simulation (1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008). Model performance is assessed against available data in terms of spatial and temporal distribution of biological variables. In general, the proposed model is able to represent the climatological distribution of primary and secondary producers and also the main seasonality of primary production in the various sub-regions of the analyzed basins. Potential causes of the observed mismatches between model and data are identified and some solutions are proposed for future model development. We conclude that most of these mismatches could be attributed to the missing tidal forcing in the actual model configuration. This model is a first step towards obtaining a meaningful tool to study past and future oceanographic conditions in this important marine region, which constitutes the unique connection between the Mediterranean Sea and the open ocean.

Palaeohydrological changes over the last 50 ky in the central Gulf of Cadiz: complex forcing mechanisms mixing multi-scale processes

“…Contrary to the Gulf of Cadiz, no important river discharges are noticeable today in the Alboran Sea and the continental shelf is narrower. Primary productivity in the Alboran Sea mainly results today from the inflow of Atlantic waters through the Strait of Gibraltar, while marsh and riverine influence in coastal zones from the Gulf of Cadiz is particularly high (Macías et al, 2014). This could explain the predominance of L. machaerophorum in core MD99-2339, while N. labyrinthus will preferentially characterize MD95-2043.…”

A Method to Establish Marine Bio-Regions in the Pelagic Ecosystem Based on Phytoplanktonic Communities. Aplication to the Southern Spanish Coast

“…On one hand, there is an intense mixing of Atlantic and Mediterranean waters within the Strait of Gibraltar favoured by the strong velocity shear between both currents and the large vertical displacements associated to internal tides (Bolado-Penagos et al, 2023). This mixing is able to fertilize the Atlantic Waters flowing into the Alboran Sea, enhancing the primary production of the surface waters that flow in a northeast direction into the Alboran Sea, approaching its northern coast (Macías et al, 2007(Macías et al, , 2014. On the other, two cyclonic circulation cells close to the northern coast of the Alboran Sea would favour the upwelling of sub-surface waters, injecting nutrients at the euphotic layer (Vargas-Yáñez et al, 2019;García--Martínez et al, 2019a, 2019b.…”

Modelling the Mediterranean pelagic ecosystem using the POSEIDON ecological model. Part I: Nutrients and chlorophyll-a dynamics

“…Ligurian Sea) where the vertical transport of nutrients enriches the euphotic zone during winter, and c) in coastal areas enriched by large river outflow (i.e. Gulf of Lion, Adriatic and North Aegean Seas; Polimene et al, 2006;Siokou-Frangou et al, 2010;Macias et al, 2014Macias et al, , 2018. However, Chl-a concentration and primary production are very low in the uppermost layers over the entire annual cycle, with the exception of the short period during late winter mixing events, and can only be sustained at the top of the nutricline, where a deep chlorophyll maximum (DCM) is found (Siokou-Frangou et al, 2010).…”