Seamounts of the Azores

Seamounts are common topographic features in the EEZ of the Azores. The archipelago of the Azores is composed of 9 volcanic islands distributed in 3 groups in the north-eastern Atlantic. The size of the Azores EEZ is about 1 000 000 km2, with an average depth of about 3,000 meters. The large occurrence of seamounts is imputable to the volcanic and tectonically active seafloor, typical of this region.

A total of 63 large (height exceeding 1000 meters) and 398 small (height comprised between 200 and 1000 meters) seamounts have been described in the Azorean EEZ, with a density of 3.3 peaks per 1000 km2 and a mean abundance of 0.42 and 0.07 small and large seamounts, respectively, per 1000 km2. Most of the seamounts have deep summits, between 800 to 1500m.

The Azorean seamounts ecosystems are of considerable biological interest and are extremely important also at the economic and, indirectly, social level.

They are hotspots of marine life: shallow seamounts act as aggregating sites for some marine predators.

The fish skipjack (Katsuwonus pelamis), bigeye tuna (Thunnus obesus), the common dolphin (Delphinus delphis) and the Cory’s shearwater (Calonectris diomedea borealis) have been recorded to be more abundant close to some shallow water seamount summits (shallower than 400 m depth).

via Seamounts in the Azores.

Welcome to Seabed Habitats

Welcome to Seabed Habitats- The newest blog about everything to do with marine habitats.The marine realm is such a dynamic system and is very much an “unexplored wilderness.” Being a relatively new science (with most sub-disciplines being only 50-120 years old), a lot of work is being done to gain a thorough understanding. With technological advances happening rapidly, there are always new methods to try out and new equipment to test. With research being so interdisciplinary in nature, spanning a range of areas such as marine ecology, marine geology, coastal processes, geophysics, oceanography, hydrography, remote sensing, surveying, GIS.. This blog attempts to keep you up to date on the latest developments in the field. From new research ideas to images to the latest technology- all can be discussed here.

Maërl

What is Maërl?

ResearchBlogging.org

Maërl refers to a group of free-living coralline red algae belonging to the Class Rhodophyta. The term “Maërl” is a Breton term with there even being a festival about maerl in Brittany. Maërl beds form a complex three-dimensional habitat and have been found to harbour greater diversity of life in comparison to surrounding habitats. As a result they are protected under the EU Habitats Directive, with two maërl forming species, Phymatolithon calcareum (Pallas) W.H.Adey & D.L.McKibbin, 1970., Lithothamnion corallioides (P.L.Crouan & H.M.Crouan) P.L.Crouan & H.M.Crouan, 1867, found in under Annex V. In many cases, maërl is also given protection under Annex 1 of the EU Habitats directive as a sub-feature habitat and as an indicator of a biodiversity hotspot.

Distribution of maërl in the British Isles- NBN Map- Phymatolithon calcareum Common Maërl

UK Marine SACs Document

Maërl Beds in the Fal Estuary with Harbour crab - Liocarcinus depurator

Biogenic Beach Sediments

Biogenic gravel beaches made of dead or fossil maërl deposits can be found adjacent to live maërl habitats.
Trá an Doilín, Ireland

Many different growth forms result in different grain shapes of the thalli.
Phymatolithon calcareum

Intertidal Maërl

Muckinish Bay in County Clare has maerl beds which are only exposed during the low spring tide.

Subtidal Maërl

Subtidally, maërl free living and forms branches

 

Maërl megaripples

Where currents are strong enough, or due to disturbance due storm-waves, maërl megaripples can form (asymmetric for currents-formed ripples and symmetric wave-formed ripples) Here is some rare footage of maerl mega ripples in Northern Ireland:

Image credits

(1) Maërl beds in the Fal Estuary with harbour crab – Liocarcinus depurator: Image credit to Ross Bullimore
(2) Trá an Doilín, Ireland Seabed Habitats
(3) Phymatolithon calcareum, Image credit to Malcolm Storey www.bioimages.org.uk
(4) Muckinish Bay, County Clare, Image credit to Seabed Habitats
(5) Maërl Megaripples, Diver footage courtesy of Joe Breen of the Northern Ireland Environment Agency (NIEA)

Welcome

Welcome to Seabed Habitats- The newest blog about everything to do with marine habitats.The marine realm is such a dynamic system and is very much an “unexplored wilderness.” Being a relatively new science (with most sub-disciplines being only 50-120 years old), a lot of work is being done to gain a thorough understanding. With technological advances happening rapidly, there are always new methods to try out and new equipment to test. With research being so interdisciplinary in nature, spanning a range of areas such as marine ecology, marine geology, coastal processes, geophysics, oceanography, hydrography, remote sensing, surveying, GIS.. This blog attempts to keep you up to date on the latest developments in the field. From new research ideas to images to the latest technology- all can be discussed here.

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