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- Macroalgas das Berlengas e Costa de Prata: Do conhecimento à utilizaçãoPublication . Franco, João N.; Lemos, Marco F.L.; Neto, João M.A Costa de Prata, região litoral compreendida entre Esmoriz (Aveiro) e Torres Vedras (Lisboa), caracteriza-se, a norte, pelo domínio de praias de areia fina cortadas pelos maciços rochosos da Serra da Boa Viagem, da Nazaré e de São Martinho do Porto. Já a sul de Peniche, dominam os afloramentos rochosos, submareais e intermareais, que frequentemente emergem do mar em imponentes arribas que vincam o limite continental. É nesta zona que podemos encontrar o arquipélago das Berlengas, um território insular que se encontra ao abrigo de um regime especial de proteção, a Reserva Marinha das Berlengas, bem conhecido pela sua riqueza natural.
- Where the grass is greenest in seagrass seascapes depends on life history and simple species traits of fishPublication . Eggertsen, Linda; Goodell, Whitney; Cordeiro, Cesar A. M. M.; Cossa, Damboia; Lucena, Marcos de; Berkström, Charlotte; Franco, Joao N.; Ferreira, Carlos E. L.; Bandeira, Salomão; Gullström, MartinTropical seagrass meadows are critical habitats for many fish species, yet few studies have investigated the influence of multiple scale-dependent factors and marine protected areas on seagrass fish species of differing life histories. We assessed the influence of fine-scale seagrass meadow characteristics and seascape-scale variables on the abundance of fish in a seagrass-dominated seascape in the Bazaruto Archipelago, Mozambique, particularly examining patterns of nursery- vs. resident species as well as mobile- vs. sedentary species. We found that fish distribution patterns in this seagrass-dominated seascape were dependent on species’ life history characteristics; nursery taxa showed lower abundance in seagrass meadows further from adult reef habitats, while resident species within seagrass meadows occurred in higher abundances far from reefs. For taxa utilizing both mangroves and seagrass meadows as nursery habitat, proximity to mangroves was an important factor. Fish abundances were generally influenced by variables at the seascape scale (km), while sedentary species were predominantly influenced by area variables, and smaller seascapes (<500 m in radius) better explained distribution patterns. The influence of marine protected areas was taxon-specific, with the strongest effects of protection on resident species. Our results indicate that protection efforts in seagrass-dominated seascapes can have varying impacts on fish distribution, depending on the life history of the species present, and the geographical placement of the reserve within the seascape. Further, we suggest that simple species attributes can be utilised to describe generalized abundance patterns of fish in seagrass seascapes.
- On the properties evolution of eco-material dedicated to manufacturing artificial reef via 3D printing: Long-term interactions of cementitious materials in the marine environmentPublication . Boukhelf, Fouad; Sebaibi, Nassim; Boutouil, Mohamed; Yoris-Nobile, Adrian I.; Blanco-Fernandez, Elena; Castro-Fresno, Daniel; Real-Gutierrez, Carlos; Herbert, Roger J.H.; Greenhill, Sam; Reis, Bianca; Franco, João N.; Borges, Maria Teresa; Pinto, Isabel Sousa; van der Linden, Pieter; Babé Gómez, Oscar; Meyer, Hugo Sainz; Almada, Emanuel; Stafford, Richard; Danet, Valentin; Lobo-Arteaga, Jorge; Tuaty Guerra, Miriam; Hall, Alice E.This paper deals with the evolution monitoring of biomass colonization and mechanical properties of 3D printed eco-materials/mortars immersed in the sea. Measurements of tensile strength, compressive strength, and Young’s modulus were determined on samples deployed along the Atlantic coast of Europe, in France, United Kingdom, Spain, and Portugal. The samples were manufactured using 3D printing, where six mix designs with a low environmental impact binder were used. These mortars were based on geopolymer and cementitious binders (Cement CEM III), in which sand is replaced by three types of recycled sand, including glass, seashell, and limestone by 30%, 50%, and 100% respectively. The colonization of concrete samples by micro/macro-organisms and their durability were also evaluated after 1, 3, 6, 12, and 24 months of immersion. The results showed that both biomass colonization and mechanical properties were better with CEM III compared to geopolymer-based compositions. Therefore, the mixed design optimized according to mechanical properties show that the use of CEM III should be preferred over these geopolymer binders in 3D printed concrete for artificial reef applications.
- Snapshot of macroalgae and fish assemblages in temperate reefs in the Southern European Atlantic ecoregionPublication . Franco, Joao N.; Arenas, Francisco; Sousa-Pinto, Isabel; Santos, Carmen B. de losMost of the biodiversity studies in the South European Atlantic Shelf ecoregion are limited to shallow subtidal or intertidal habitats, while deeper reef habitats, also of relevant ecological importance, are particularly understudied. Macroalgal communities, associated fauna, and sea surface temperature were studied in deep reefs (25–30 m) at two locations in this ecoregion: Parcel, North of Portugal (41º N), and Tarifa, Southern Spain (35º N). Specifically, algal assemblages were assessed using biomass collection and associated ichthyofauna was assessed using visual census techniques using scuba. Seawater surface temperature was higher (>3º C) in the southern region—Tarifa, compared to the northern region—Parcel. Our survey revealed 18 fish species and 23 algae species. The highest abundance of cold-water species (both macroalgae and fish species) was recorded in Parcel and warm-water species were dominant in Tarifa. In light of climate global trends, both regions might experience biodiversity shifts towards tropicalization. Current knowledge on their biodiversity is imperative to further evaluate potential shifts.
- Range-edge populations of seaweeds show niche unfilling and poor adaptation to increased temperaturesPublication . Hernández, Sandra; García, Ana G.; Arenas, Francisco; Escribano, M. Pilar; Jueterbock, Alexander; De Clerck, Olivier; Maggs, Christine; Franco, Joao N.; Martínez, Brezo D.C.Aim: Global warming is affecting the distribution of species worldwide, but the level of adaptation of edge populations to warmer temperatures remains an open question. Here, we assess the thermal tolerance of populations of two habitat-forming seaweeds along their latitudinal range, using thermal niche unfilling to assess their resilience to global warming. Location: European Atlantic coastline. Taxon: Ascophyllum nodosum (Linnaeus) Le Jolis (Phaeophyceae) and Chondrus crispus Stackhouse (Rhodophyta). Methods: We studied the ecotypic variation in upper survival temperatures (USTs) by measuring survival and growth of adults representing populations under a gradient of seawater temperature (12–30°C). Comparing the USTs with maximum seawater temperatures obtained from satellites, we investigated safety margins and niche unfilling states, both in recent history and under future climate scenarios. Results: USTs (≈24°C) did not differ significantly between populations, except for higher values (27.9°C) for the northernmost populations (cold edge) of A. nodosum. Populations of both species had thermal safety margins over the last few decades (from 1982 to 2021). However, projections based on USTs showed that in several years these margins have been eliminated and will completely disappear in the Bay of Biscay under RCP4.5 and RCP6.0 2090–2100 IPCC scenarios for C. crispus and under RCP8.5 for both species, threatening the populations there. Main Conclusions: Southern marginal populations were not better adapted to global warming than populations elsewhere. Both seaweed species tolerated higher temperatures than the ambient maxima, suggesting a thermal niche unfilling state with thermal safety margins in their recent history. However, those are being depleted by ongoing climate change and this trend is predicted to increase. Marine heat waves are important threats to these habitat-forming species, transiently reducing or even eliminating safety margins in the hottest parts of the European Atlantic coastline, contributing to explaining the distributional gap there.
- Dynamics and fate of blue carbon in a mangrove–seagrass seascape: influence of landscape configuration and land-use changePublication . Dahl, Martin; Ismail, Rashid O.; Arias-Ortiz, Ariane; Deyanova, Diana; Franco, Joao N.; Hammar, Linus; Hoamby, Arielle I.; Linderholm, Hans W.; Lyimo, Liberatus D.; Perry, Diana; Rasmusson, Lina M.; Ridgway, Samantha N.; Gispert, Gloria Salgado; D’Agata, Stéphanie; Glass, Leah; Mahafina, Jamal Angelot; Ramahery, Volanirina; Masque, Pere; Björk, Mats; Gullström, Martin; Asplund, Maria E.Context: Seagrass meadows act as efficient natural carbon sinks by sequestering atmospheric CO2 and through trapping of allochthonous organic material, thereby preserving organic carbon (Corg) in their sediments. Less understood is the influence of landscape configuration and transformation (land-use change) on carbon sequestration dynamics in coastal seascapes across the land–sea interface. Objectives: We explored the influence of landscape configuration and degradation of adjacent mangroves on the dynamics and fate of Corg in seagrass habitats. Methods: Through predictive modelling, we assessed sedimentary Corg content, stocks and source composition in multiple seascapes (km-wide buffer zones) dominated by different seagrass communities in northwest Madagascar. The study area encompassed seagrass meadows adjacent to intact and deforested mangroves. Results: The sedimentary Corg content was influenced by a combination of landscape metrics and inherent habitat plant- and sediment-properties. We found a strong land-to-sea gradient, likely driven by hydrodynamic forces, generating distinct patterns in sedimentary Corg levels in seagrass seascapes. There was higher Corg content and a mangrove signal in seagrass surface sediments closer to the deforested mangrove area, possibly due to an escalated export of Corg from deforested mangrove soils. Seascapes comprising large continuous seagrass meadows had higher sedimentary Corg levels in comparison to more diverse and patchy seascapes. Conclusion: Our results emphasize the benefit to consider the influence of seascape configuration and connectivity to accurately assess Corg content in coastal habitats. Understanding spatial patterns of variability and what is driving the observed patterns is useful for identifying carbon sink hotspots and develop management prioritizations.
- Kelp carbon sink potential decreases with warming due to accelerating decompositionPublication . Filbee-Dexter, Karen; Feehan, Colette J.; Smale, Dan A.; Krumhansi, Kira A.; Augustine, Skye; De Bettignies, Florian; Burrows, Michael T.; Byrnes, Jarrett E.K.; Campbell, Jillian; Davoult, Dominique; Dunton, Kenneth H.; Franco, Joao N.; Garrido, Ignacio; Grace, Sean P.; Hancke, Kasper; Johnson, Ladd E.; Konar, Brenda; Moore, Pippa J.; Norderhaug, Kjell Magnus; O'Dell, Alasdair; Pedersen, Morten F.; Salomon, Anne K.; Sousa-Pinto, Isabel; Tiegs, Scott; Yiu, Dara; Wernberg, ThomasCycling of organic carbon in the ocean has the potential to mitigate or exacerbate global climate change, but major questions remain about the environmental controls on organic carbon flux in the coastal zone. Here, we used a field experiment distributed across 28° of latitude, and the entire range of 2 dominant kelp species in the northern hemisphere, to measure decomposition rates of kelp detritus on the seafloor in relation to local environmental factors. Detritus decomposition in both species were strongly related to ocean temperature and initial carbon content, with higher rates of biomass loss at lower latitudes with warmer temperatures. Our experiment showed slow overall decomposition and turnover of kelp detritus and modeling of coastal residence times at our study sites revealed that a significant portion of this production can remain intact long enough to reach deep marine sinks. The results suggest that decomposition of these kelp species could accelerate with ocean warming and that low-latitude kelp forests could experience the greatest increase in remineralization with a 9% to 42% reduced potential for transport to long-term ocean sinks under short-term (RCP4.5) and long-term (RCP8.5) warming scenarios. However, slow decomposition at high latitudes, where kelp abundance is predicted to expand, indicates potential for increasing kelp-carbon sinks in cooler (northern) regions. Our findings reveal an important latitudinal gradient in coastal ecosystem function that provides an improved capacity to predict the implications of ocean warming on carbon cycling. Broad-scale patterns in organic carbon decomposition revealed here can be used to identify hotspots of carbon sequestration potential and resolve relationships between carbon cycling processes and ocean climate at a global scale.
- High seasonal variability in sediment carbon stocks of cold‐temperate seagrass meadowsPublication . Dahl, Martin; Asplund, Maria E.; Deyanova, Diana; Franco, Joao N.; Koliji, Alan; Infantes, Eduardo; Perry, Diana; Björk, Mats; Gullström, MartinSeagrass meadows have a high ability to capture and store atmospheric CO2 in the plant biomass and underlying sediment and thereby function as efficient carbon sinks. The seagrass Zostera marina is a common species in the temperate Northern Hemisphere, a region with strong seasonal variations in climate. How seasonality affects carbon storage capacity in seagrass meadows is largely unknown, and therefore, in this study, we aimed to assess variations in sedimentary total organic carbon (TOC) content over a 1‐year cycle in seagrass meadows on the Swedish west coast. The TOC was measured in two Z. marina sites, one wave exposed and one sheltered, and at two depths (1.5 and 4 m) within each site, every second month from August 2015 to June 2016. We found a strong seasonal variation in carbon density, with a peak in early summer (June), and that the TOC was negatively correlated to the net community production of the meadows, presumably related to organic matter degradation. There was seasonal variation in TOC content at all sediment sections, indicating that the carbon content down to 30 cm is unstable on a seasonal scale and therefore likely not a long‐term carbon sink. The yearly mean carbon stocks were substantially higher in the sheltered meadow (3,965 and 3,465 g m−2) compared to the exposed one (2,712 and 1,054 g m−2) with similar seasonal variation. Due to the large intra‐annual variability in TOC content, seasonal variation should be considered in carbon stock assessments and management for cold‐temperate seagrass meadows.
- Leveraging the blue economy to transform marine forest restorationPublication . Filbee-Dexter, Karen; Wernberg, Thomas; Barreiro, Rodolfo; Coleman, Melinda A.; Bettignies, Thibaut de; Feehan, Colette J.; Franco, Joao N.; Hasler, Berit; Louro, Ines; Norderhaug, Kjell M.; Staehr, Perter A. U.; Tuya, Fernando; Verbeek, JanThe UN Decade of Ecosystem Restoration is a response to the urgent need to substantially accelerate and upscale ecological restoration to secure Earth’s sustainable future. Globally, restoration commitments have focused overwhelmingly on terrestrial forests. In contrast, despite a strong value proposition, efforts to restore seaweed forests lag far behind other major ecosystems and continue to be dominated by small-scale, short-term academic experiments. However, seaweed forest restoration can match the scale of damage and threat if moved from academia into the hands of community groups, industry, and restoration practitioners. Connecting two rapidly growing sectors in the Blue Economy—seaweed cultivation and the restoration industry—can transform marine forest restoration into a commercial-scale enterprise that can make a significant contribution to global restoration efforts.
- Rapid tropicalization evidence of subtidal seaweed assemblages along a coastal transitional zonePublication . Azevedo, Jonas de; Franco, Joao N.; Vale, Cândida G.; Lemos, Marco F.L.; Arenas, FranciscoAnthropogenic climate change, particularly seawater warming, is expected to drive quick shifts in marine species distribution transforming coastal communities. These shifts in distribution will be particularly noticeable in biogeographical transition zones. The continental Portuguese coast stretches from north to south along 900 km. Despite this short spatial scale, the strong physical gradient intensified by the Iberian upwelling creates a transition zone where seaweed species from boreal and Lusitanian-Mediterranean origin coexist. On the northern coast, kelp marine forests thrive in the cold, nutrient-rich oceanic waters. In the south, communities resemble Mediterranean-type seaweed assemblages and are dominated by turfs. Recent evidence suggests that in these coastal areas, marine intertidal species are shifting their distribution edges as a result of rising seawater temperatures. Taking advantage of previous abundance data collected in 2012 from subtidal seaweed communities, a new sampling program was carried out in the same regions in 2018 to assess recent changes. The results confirmed the latitudinal gradient in macroalgal assemblages. More importantly we found significant structural and functional changes in a short period of six years, with regional increases of abundance of warm-affinity species, small seaweeds like turfs. Species richness, diversity, and biomass increase, all accompanied by an increase of community temperature index (CTI). Our findings suggest that subtidal seaweed communities in this transitional area have undergone major changes within a few years. Evidence of “fast tropicalization” of the subtidal communities of the Portuguese coast are strong indication of the effects of anthropic climate change over coastal assemblages.