The Alboran Sea circulation and its biological response: A review

Abstract

The oceanography of the Alboran Sea (AS) has been the subject of intensive research for decades. Chief among the reasons for this interest is the variety of physical processes taking place in the basin, spanning from coastal upwelling, dynamic of density fronts, internal waves, and strong meso- and submesoscale turbulence. Historical fieldwork and an increasing number of numerical studies in recent years have led to a more complete—although more dispersed—description and knowledge of process dynamics in the AS and their role in shaping primary productivity and regional fisheries resources. In this review, we summarize and put together old and new research to get an updated picture of the AS circulation and its variability at different time scales, with an emphasis on physical–biological interactions. As part of the review, we identify gaps in our understanding regarding the physical drivers for seasonal and for rapid transitions between the most recurrent one-gyre and two-gyre modes of circulation of the AS. We also point at possible research strategies based on end-to-end regional biophysical modeling to gain new insights into past and present physical control on fisheries resources and for assessing plausible climate change impacts on the AS ecosystem.

Vigorous vertical mixing supports biological production in the mesoscale Tsugaru Gyre

“…These calculations suggest that uxes at the rear of the sill potentially contribute to production in the downstream region spreading out about daily advection, although a more detailed study is needed in the future, including contributions from reproduction. The Tsugaru Gyre is a productive shing ground [37][38][39] ; hence, this study greatly advances our knowledge of nutrient supply hotspots, which are key areas for the ecosystem of this area, and its monitoring in the region aligns with that of other regions, including the Alboran Sea circulation 40 .…”

In Situ Observations of the Small‐Scale Dynamics at Camarinal Sill—Strait of Gibraltar

“…A hydraulic transition from subcritical to supercritical flow is associated with much instability usually related to a plunge of the isopycnals. The transition from supercritical to subcritical triggers a hydraulic jump (see Figure 5 of Sánchez‐Garrido and Nadal (2022)). The distinction between these states is based on the Froude number F , generally computed as the local composite Froude number $${G}^{2}={F}_{1}^{2}+{F}_{2}^{2}$$ where $${F}_{i}^{2}={U}_{i}^{2}/\left({g}^{\prime }{h}_{i}\right)$$, with i stands for layers 1 and 2 and g ′ the reduced gravity defined as $$g\left({\rho }_{2}-{\rho }_{1}\right)/\bar{\rho }$$, ρ i the density of layer i and $$\bar{\rho }$$ the averaged density.…”

Evidence of Reflected Internal Solitary Waves in the Strait of Gibraltar

“…The shoaling of ISWs is known to be an important source of mixing along continental shelves of many regions (Jeans & Sherwin, 2001; Lamb, 2014; Laurent et al., 2011). This mechanism is therefore likely responsible for a significant part of the mixing along the continental shelf in the SoG (Vlasenko et al., 2009), impacting the biological production (Sánchez‐Garrido & Nadal, 2022; Vázquez et al., 2009) but it has yet not been addressed (Wesson & Gregg, 1994). Exhibiting these new wave patterns represents a step forward in our understanding of SoG dynamics, and requires a more thorough description of the interaction between the ISWs and continental slope, particularly the Moroccan slope.…”