Ana Martins
Associate Professor of Oceanography at the Department of Oceanography and Fisheries at the University of the Azores (UAc). Responsible for the Oceanography team at UAc since 2000. Founder and integrated member of the OKEANOS Institute at UAc. Directs/ed undergraduate and graduate programs at UAc. Responsible for the coordination/teaching of more than 20 courses in Ocean Sciences fields at UAc. Some appointments: Member of the Program Committee: SPIE Remote Sensing Ocean, Sea Ice, Coastal Waters, and Large Water Regions.
Address: Department of Oceanography and Fisheries, University of the Azores, Rua Professor Doutora Frederico Machado, 9901-862, Horta, Azores, Portugal
Address: Department of Oceanography and Fisheries, University of the Azores, Rua Professor Doutora Frederico Machado, 9901-862, Horta, Azores, Portugal
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Papers by Ana Martins
characterised by narrow shelves, steep slopes and a large submarine tributary
system that boosts primary productivity in oligotrophic waters and thus offers a
potential for hotspots of biodiversity. Despite this, there have been limited
deep-water exploration activities with less than five expeditions since the
1960s. Here, we investigated the seabed on the southern side of the
Madeira-Desertas Ridge using a manned submersible along a 3.8 km long
transect starting at 366 m depth up the ridge shelf until its top at 73 m. Benthic
habitats and community composition were documented with video along a
depth gradient from mesophotic to deep sea. Six distinct biotopes were
recognised (three deeper, and three shallower than 115 m depth). Our results
showed a rich biodiversity with deep biotopes characterised by sponges and
non-reef-building corals (e.g., Pachastrella monilifera, Viminella flagellum,
Eunicella verrucosa) and shallow biotopes comprising macroalgae and the
gorgonian Paramuricea cf. grayi. The pronounced benthic zonation reflects the steep environmental gradient that includes high topographic variation,
heterogeneous substrates, and bidirectional regular wave-motion at the
shallow mesophotic part. Together with biotic factors, such as low density of
sea urchins and presence of predatory fish, this environment with unusual deep
light penetration, a mesoscale cyclonic eddy, and deep wave-motion, has
allowed the establishment of a mature deep-water kelp population of
Laminaria ochroleuca in the plateau (max. >100 individuals p/100 m2). At the
same time, a conspicuous coral fauna was observed on a wide range of soft to
hard bottoms with several species taking advantage of the favourable
hydrodynamic regime and seawater properties together with substratum
availability to create coral gardens. These habitats were previously not known
from Madeira, and their newfound discovery in the archipelago merit further
investigation and protection.
Here, we address this challenge and quantify algal blooms’ turnover using a combination of satellite and in situ data, which allows identification of a relatively stable oceanic patch that is subject to little mixing with its surroundings. Using a newly developed multisatellite Lagrangian diag- nostic, we decouple the contributions of physical and bio- logical processes, allowing quantification of a complete life cycle of a mesoscale (w10–100 km) bloom of coccolitho- phores in the North Atlantic, from exponential growth to its rapid demise. We estimate the amount of organic carbon produced during the bloom to be in the order of 24,000 tons, of which two-thirds were turned over within 1 week. Complimentary in situ measurements of the same patch area revealed high levels of specific viruses infecting cocco- lithophore cells, therefore pointing at the importance of viral infection as a possible mortality agent. Application of the newly developed satellite-based approaches opens the way for large-scale quantification of the impact of diverse environmental stresses on the fate of phytoplankton blooms and derived carbon in the ocean.
characterised by narrow shelves, steep slopes and a large submarine tributary
system that boosts primary productivity in oligotrophic waters and thus offers a
potential for hotspots of biodiversity. Despite this, there have been limited
deep-water exploration activities with less than five expeditions since the
1960s. Here, we investigated the seabed on the southern side of the
Madeira-Desertas Ridge using a manned submersible along a 3.8 km long
transect starting at 366 m depth up the ridge shelf until its top at 73 m. Benthic
habitats and community composition were documented with video along a
depth gradient from mesophotic to deep sea. Six distinct biotopes were
recognised (three deeper, and three shallower than 115 m depth). Our results
showed a rich biodiversity with deep biotopes characterised by sponges and
non-reef-building corals (e.g., Pachastrella monilifera, Viminella flagellum,
Eunicella verrucosa) and shallow biotopes comprising macroalgae and the
gorgonian Paramuricea cf. grayi. The pronounced benthic zonation reflects the steep environmental gradient that includes high topographic variation,
heterogeneous substrates, and bidirectional regular wave-motion at the
shallow mesophotic part. Together with biotic factors, such as low density of
sea urchins and presence of predatory fish, this environment with unusual deep
light penetration, a mesoscale cyclonic eddy, and deep wave-motion, has
allowed the establishment of a mature deep-water kelp population of
Laminaria ochroleuca in the plateau (max. >100 individuals p/100 m2). At the
same time, a conspicuous coral fauna was observed on a wide range of soft to
hard bottoms with several species taking advantage of the favourable
hydrodynamic regime and seawater properties together with substratum
availability to create coral gardens. These habitats were previously not known
from Madeira, and their newfound discovery in the archipelago merit further
investigation and protection.
Here, we address this challenge and quantify algal blooms’ turnover using a combination of satellite and in situ data, which allows identification of a relatively stable oceanic patch that is subject to little mixing with its surroundings. Using a newly developed multisatellite Lagrangian diag- nostic, we decouple the contributions of physical and bio- logical processes, allowing quantification of a complete life cycle of a mesoscale (w10–100 km) bloom of coccolitho- phores in the North Atlantic, from exponential growth to its rapid demise. We estimate the amount of organic carbon produced during the bloom to be in the order of 24,000 tons, of which two-thirds were turned over within 1 week. Complimentary in situ measurements of the same patch area revealed high levels of specific viruses infecting cocco- lithophore cells, therefore pointing at the importance of viral infection as a possible mortality agent. Application of the newly developed satellite-based approaches opens the way for large-scale quantification of the impact of diverse environmental stresses on the fate of phytoplankton blooms and derived carbon in the ocean.