Infralittoral mapping around an oceanic archipelago using MERIS FR satellite imagery and deep kelp observations: A new tool for assessing MPA coverage targets

Amorim, Patrícia; Atchoi, Elizabeth; Berecibar, Estíbaliz; Tempera, Fernando

doi:10.1016/j.seares.2014.10.002

Cited by 8 publications

(5 citation statements)

References 21 publications

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“…On the one hand, the macroalgal assemblage structure of the Azores resembles that of warm temperate areas of the north-eastern Atlantic and Mediterranean (Guiry & Guiry, 2017) dominated by species such as Z. tournefortti, H. scoparia, H. filicina and C. caespitosa. Although there are kelp populations, these are restricted to certain deep-water biotopes (Amorim et al, 2015). On the other hand, Cape Verde supports an assemblage of macroalgae dominated by tropical taxa, e.g.…”

Section: Discussionmentioning

confidence: 99%

Shallow subtidal macroalgae in the North-eastern Atlantic archipelagos (Macaronesian region): a spatial approach to community structure

Sangil

Martins

Hernández

et al. 2018

European Journal of Phycology

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Shallow subtidal macroalgal communities in the North-eastern Atlantic archipelagos (Azores, Madeira, Canaries and Cape Verde) were studied in order to identify their spatial organization patterns and the main drivers of change. Fifteen islands and 145 sites across 15º of latitude and 2850 km were sampled. We found high spatial variability across the scales considered (archipelago, island and site). The structure of macroalgal communities differed among archipelagos, except between Madeira and the Canaries, which were similar. Across a latitudinal gradient, macroalgal communities in the Azores were clearly separated from the other archipelagos; communities in Madeira and the Canaries occupied an intermediate position, while those in Cape Verde appeared at the opposite end of the gradient. In the Azores, species with warm-temperate affinities dominated communities. Cape Verde communities were, in contrast, dominated by tropical taxa, whereas in the subtropical Canaries and Madeira there was a mixture of species with colder and warmer affinities. Apart from crustose coralline algae, the Dictyotales were the group with greatest cover; larger and longer-lived species were progressively replaced by short-lived species along a latitudinal gradient from north to south. The perennial species Zonaria tournefortii dominated the sea-bottom in the Azores, the semiperennial Lophophora variegata in the Canaries, the filamentous algae in Madeira and the ephemeral Dictyota dichotoma in Cape Verde. We hypothesized that the differences among archipelagos could be explained by synergies between temperature and herbivory, which increased in diversity southwards, especially in Cape Verde. This was supported by the predominance of noncrustose macroalgae in the Azores and of crustose macroalgae in Cape Verde, as would be predicted from the greater herbivore activity. At the scale of islands and sites, the same set of environmental variables drove differences in macroalgal community structure across all the Macaronesian archipelagos.

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Section: Discussionmentioning

confidence: 99%

Shallow subtidal macroalgae in the North-eastern Atlantic archipelagos (Macaronesian region): a spatial approach to community structure

Sangil

Martins

Hernández

et al. 2018

European Journal of Phycology

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“…The adjoining island flanks drop steeply to depths averaging 2000 m limiting infralittoral grounds to a area of only 895 km 2 (Amorim et al. 2015). Similarly, among the 400 seamounts found in the region (Morato et al.…”

Section: Methodsmentioning

confidence: 99%

Range Extension of Mesophotic Kelps (Ochrophyta: Laminariales and Tilopteridales) in the Central North Atlantic: Opportunities for Marine Forest Research and Conservation

Tempera

Milla-Figueras

Sinde-Mano

et al. 2021

Journal of Phycology

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Kelp was first recorded for the remote warm‐temperate Azores archipelago (central North Atlantic) in 1971, when a few Laminaria specimens were collected on the Formigas Bank at depths beyond conventional SCUBA diving reach. A shortage of technical means and projects targeting mesophotic environments has since kept this offshore marine protected area as the single known kelp occurrence site. Here, we present new kelp records collected on previously unexplored mesophotic reefs using remote imaging systems, open‐ and closed‐circuit SCUBA diving, and fisheries bycatch information. The new data extend the known distribution range of kelp in the Azores 350 km to the west and 25 km to the southwest, henceforth including several island shelves in the eastern and central Azores. In addition to the previously recorded Laminaria ochroleuca, kelp specimens with a morphology akin to Phyllariopsis brevipes subsp. brevipes are also reported. For the first time, seabed imagery is used to document the depth‐wise diversity of the Azores kelp beds and their associated biota. Our findings emphasize the poor knowledge that persists in regard to Macaronesia’s mesophotic environments located beyond conventional SCUBA diving limits. The new on‐shelf kelp occurrences add conservation value to coastal areas and should facilitate island‐based research. However, their greater proximity to land‐based impacts and exposure to climate change also raise management needs.

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“…As demonstrated by others, the observation of higher densities of large plants at the kelp forest and lower densities of small plants at the maërl bed (biotope 5) indicates size (and density) stratification with depth as a function of available light on the bottom (Markager and Sand-Jensen, 1992;Gattuso et al, 2006). In L. ochroleuca surveys on the Formigas Bank (Azores), the highest densities (kelp forest) occurred between 41.5 and 64.3 m depth (yearly-averaged percentage of light ranges of 6.0-2.2% FR PAR and 9.5-3.7% FR 490 ) and at lower zones from 47.6 to 81.6 m dense to sparse plants (5.4-0.9% FR PAR and 8.8-1.6% FR 490 ) were seen at the bottom (Amorim et al, 2015). Despite deeper, the new kelp forest was exposed to higher light levels (9.3-4.9% FR 490 ) and 1% of light level was not even achieved at the maërl bed (3.5-2.3% FR 490 ), which reflects well the longdistance range (>100 m depth) of sunlight penetration in the ridge because of the exceptional clear waters in Madeira (Teira et al, 2005).…”

Section: Top Of the Ridgementioning

confidence: 99%

Benthic community zonation from mesophotic to deep sea: Description of first deep-water kelp forest and coral gardens in the Madeira archipelago (central NE Atlantic)

et al. 2022

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The Madeira archipelago has a unique underwater landscape that is 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.

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Infralittoral mapping around an oceanic archipelago using MERIS FR satellite imagery and deep kelp observations: A new tool for assessing MPA coverage targets

Cited by 8 publications

References 21 publications

Shallow subtidal macroalgae in the North-eastern Atlantic archipelagos (Macaronesian region): a spatial approach to community structure

Shallow subtidal macroalgae in the North-eastern Atlantic archipelagos (Macaronesian region): a spatial approach to community structure

Range Extension of Mesophotic Kelps (Ochrophyta: Laminariales and Tilopteridales) in the Central North Atlantic: Opportunities for Marine Forest Research and Conservation

Benthic community zonation from mesophotic to deep sea: Description of first deep-water kelp forest and coral gardens in the Madeira archipelago (central NE Atlantic)

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