Miguel Angel Ahumada-Sempoal

Prof. Miguel Angel Ahumada-Sempoal


Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 August 2018 in PLOS ONE
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BLBertrand D Lequeux
Bertrand D Lequeux
MAMiguel Angel Ahumada-Sempoal
Miguel Angel Ahumada-Sempoal
ALAndrés López-Pérez
Andrés López-Pérez
CRCristóbal Reyes-Hernández
Cristóbal Reyes-Hernández
There are many marine protected areas (MPAs) containing coral reef aggregations in the eastern Pacific region. However, the connectivity of corals between MPAs is still poorly known, especially in the Marine Conservation Corridor of the Eastern Tropical Pacific (MCCETP). Here, we assess the potential connectivity of corals across equatorial eastern Pacific MPAs through a Lagrangian particle-tracking algorithm coupled offline with an ocean-circulation numerical model. Connectivity metrics and graph theory were used to analyze the networks and highlight those MPAs that are critical for maintaining the connectivity of corals across the region. Our results show that the equatorial eastern Pacific MPAs form a relatively well-connected network, at least 40% of coral larvae released per year end up within the boundaries of an MPA. MPAs like Malpelo and Gorgona islands included in the MCCETP were found to be critical for connectivity of corals because of their high betweenness centrality and potential role as stepping-stones between coastal MPAs and offshore MPAs such as the Galapagos Islands. Two pelagic larval duration (PLD) scenarios (40 and 130 days) indicate a quasi-unidirectional larval flow from coastal MPAs toward oceanic MPAs, where the only resilient MPAs (Coiba and Malpelo islands) depend mostly on subsidiary recruitment from MPAs located along the coast of Costa Rica, Panama and Colombia. In the two PLD scenarios, Cocos Island maintains a very low resilience potential. Our results indicate the imperative need to include coastal MPAs in the MCCETP network initiative, since connectivity and resilience of coral reefs in the equatorial eastern Pacific region rely heavily on coastal MPAs.

28 November 2011 in Sensors
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NBNixon Bahamon
Nixon Bahamon
Jacopo AguzziJacopo Aguzzi
Jacopo Aguzzi
RBRaffaele Bernardello
Raffaele Bernardello
MAMiguel Angel Ahumada-Sempoal
Miguel Angel Ahumada-Sempoal
JPJoan Puigdefabregas
Joan Puigdefabregas
ACAntonio Cruzado
Antonio Cruzado
The new pelagic Operational Observatory of the Catalan Sea (OOCS) for the coordinated multisensor measurement of atmospheric and oceanographic conditions has been recently installed (2009) in the Catalan Sea (41°39'N, 2°54'E; Western Mediterranean) and continuously operated (with minor maintenance gaps) until today. This multiparametric platform is moored at 192 m depth, 9.3 km off Blanes harbour (Girona, Spain). It is composed of a buoy holding atmospheric sensors and a set of oceanographic sensors measuring the water conditions over the upper 100 m depth. The station is located close to the head of the Blanes submarine canyon where an important multispecies pelagic and demersal fishery gives the station ecological and economic relevance. The OOCS provides important records on atmospheric and oceanographic conditions, the latter through the measurement of hydrological and biogeochemical parameters, at depths with a time resolution never attained before for this area of the Mediterranean. Twenty four moored sensors and probes operating in a coordinated fashion provide important data on Essential Ocean Variables (EOVs; UNESCO) such as temperature, salinity, pressure, dissolved oxygen, chlorophyll fluorescence, and turbidity. In comparison with other pelagic observatories presently operating in other world areas, OOCS also measures photosynthetic available radiation (PAR) from above the sea surface and at different depths in the upper 50 m. Data are recorded each 30 min and transmitted in real-time to a ground station via GPRS. This time series is published and automatically updated at the frequency of data collection on the official OOCS website (http://www.ceab.csic.es/~oceans). Under development are embedded automated routines for the in situ data treatment and assimilation into numerical models, in order to provide a reliable local marine processing forecast. In this work, our goal is to detail the OOCS multisensor architecture in relation to the coordinated capability for the remote, continuous and prolonged monitoring of atmospheric and oceanographic conditions, including data communication and storage. Accordingly, time series of measurements for a number of biological parameters will be presented for the summer months of 2011. Marine hindcast outputs from the numerical models implemented for simulating the conditions over the study area are shown. The strong changes of atmospheric conditions recorded in the last years over the area have altered the marine conditions of living organisms, but the dimension of the impact remains unclear. The OOCS multisensor coordinated monitoring has been specifically designed to address this issue, thus contributing to better understand the present environmental fluctuations and to provide a sound basis for a more accurate marine forecast system.

16 December 2019 in Ocean Science
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MCMorane Clavel-Henry
Morane Clavel-Henry
Jordi Solé OlléJordi Solé Ollé
Jordi Solé Ollé
MAMiguel Angel Ahumada-Sempoal
Miguel Angel Ahumada-Sempoal
NBNixon Bahamon
Nixon Bahamon
FBFlorence Briton
Florence Briton
JCJoan B. Company
Joan B. Company
Marine biophysical models can be used to explore the displacement of individuals in and between submarine canyons. Mostly, the studies focus on the shallow hydrodynamics in or around a single canyon. In the northwestern Mediterranean Sea, knowledge of the deep-sea circulation and its spatial variability in three contiguous submarine canyons is limited. We used a Lagrangian framework with three-dimensional velocity fields from two versions of the Regional Ocean Modeling System (ROMS) to study the deep-bottom connectivity between submarine canyons and to compare their influence on the particle transport. From a biological point of view, the particles represented eggs and larvae spawned by the deep-sea commercial shrimp Aristeus antennatus along the continental slope in summer. The passive particles mainly followed a southwest drift along the continental slope and drifted less than 200 km considering a pelagic larval duration (PLD) of 31 d. Two of the submarine canyons were connected by more than 27 % of particles if they were released at sea bottom depths above 600 m. The vertical advection of particles depended on the depth where particles were released and the circulation influenced by the morphology of each submarine canyon. Therefore, the impact of contiguous submarine canyons on particle transport should be studied on a case-by-case basis and not be generalized. Because the flows were strongly influenced by the bottom topography, the hydrodynamic model with finer bathymetric resolution data, a less smoothed bottom topography, and finer sigma-layer resolution near the bottom should give more accurate simulations of near-bottom passive drift. Those results propose that the physical model parameterization and discretization have to be considered for improving connectivity studies of deep-sea species.

6 May 2020 in Sensors
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NBNixon Bahamon
Nixon Bahamon
Jacopo AguzziJacopo Aguzzi
Jacopo Aguzzi
MAMiguel Angel Ahumada-Sempoal
Miguel Angel Ahumada-Sempoal
RBRaffaele Bernardello
Raffaele Bernardello
CRCharlotte Reuschel
Charlotte Reuschel
ACAntonio Cruzado
Antonio Cruzado
Since 2014, the global land and sea surface temperature has scaled 0.23 °C above the decadal average (2009–2018). Reports indicate that Mediterranean Sea temperatures have been rising at faster rates than in the global ocean. Oceanographic time series of physical and biogeochemical data collected from an onboard and a multisensor mooring array in the northwestern Mediterranean Sea (Blanes submarine canyon, Balearic Sea) during 2009–2018 revealed an abrupt temperature rising since 2014, in line with regional and global warming. Since 2014, the oligotrophic conditions of the water column have intensified, with temperature increasing 0.61 °C on the surface and 0.47 °C in the whole water column in continental shelf waters. Water transparency has increased due to a decrease in turbidity anomaly of −0.1 FTU. Since 2013, inshore chlorophyll a concentration remained below the average (−0.15 mg·l−1) and silicates showed a declining trend. The mixed layer depth showed deepening in winter and remained steady in summer. The net surface heat fluxes did not show any trend linked to the local warming, probably due to the influence of incoming offshore waters produced by the interaction between the Northern Current and the submarine canyon. Present regional and global water heating pattern is increasing the stress of highly diverse coastal ecosystems at unprecedented levels, as reported by the literature. The strengthening of the oligotrophic conditions in the study area may also apply as a cautionary warning to similar coastal ecosystems around the world following the global warming trend.

23 February 2017 in Latin American Journal of Aquatic Research
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MAMaría del Carmen Alejo-Plata
María del Carmen Alejo-Plata
MAMiguel Angel Ahumada-Sempoal
Miguel Angel Ahumada-Sempoal
JGJosé Luis Gómez-Márquez
José Luis Gómez-Márquez
AAAdrián Felipe González Acosta
Adrián Felipe González Acosta
Carcharhinus falciformis is an abundant oceanic species, which occurs in equatorial and tropical zones, with an important catch in the Atlantic and Pacific coasts of Mexico. Samples were taken from December 2000 to December 2007 in four landing sites of the artisanal fleet on the coast of Oaxaca. During the period of study 1236 specimens (602 females and 634 males) of C. falciformis were registered. Total length (TL) ranged from 49 to 217 cm for females (mean = 111.3 cm) and from 59 to 265 cm for males (mean = 111.7 cm). The sex ratio of females to males was 1:1 ( 2 0.05 = 0.78, P > 0.05). The present data suggest a size at first sexual maturity of about 184.8 cm TL for females and 178.5 cm TL for males. The catches were composed mainly of young. In the 52 gravid females examined, the average number of embryos per female was seven; with a range of 3-14 embryos. Mean TL of embryos ranged from 10 to 66 cm with evidence of seasonal changes in the size structure. Results obtained showed that C. falciformis gives birth most of the year, with the highest proportion of births during the rainy season (May to October).