Zeitschriftenartikel: „Macroalgal forest“

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Jung, Somi, Than Van Chau, Minju Kim und Won-Bae Na. „Artificial Seaweed Reefs That Support the Establishment of Submerged Aquatic Vegetation Beds and Facilitate Ocean Macroalgal Afforestation: A Review“. Journal of Marine Science and Engineering 10, Nr. 9 (24.08.2022): 1184. http://dx.doi.org/10.3390/jmse10091184.

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Macroalgae are invaluable constituents of marine forest environments and important sources of material for human needs. However, they are currently at risk of severe decline due to global warming and negative anthropogenic factors. Restoration efforts focus on beds where macroalgae previously existed, as well as the creation of new marine forests. Some artificial seaweed reefs (ASRs) have succeeded but others have failed; the contributions of ASRs to marine forest formation have been not fully determined. Here, we review ASRs, the benefits of macroalgal forests, threats to macroalgae, restoration, and marine forest formation to explore the current status of ASRs. The published literature indicates that ASRs have played critical roles in marine forest formation; notably, they support the establishment of submerged aquatic vegetation beds that allow ocean macroalgal afforestation. ASRs have evolved in terms of complexity and the materials used; they can sustainably mitigate marine deforestation. However, continuous reviews of ASR performance are essential, and performance improvements are always possible.

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Pita, Pablo, Diana Fernández-Márquez und Juan Freire. „Spatiotemporal variation in the structure of reef fish and macroalgal assemblages in a north-east Atlantic kelp forest ecosystem: implications for the management of temperate rocky reefs“. Marine and Freshwater Research 69, Nr. 4 (2018): 525. http://dx.doi.org/10.1071/mf17193.

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Temperate rocky reefs and kelp forest ecosystems have been severely affected by overfishing, pollution and habitat destruction, and climate change is a major driver of kelp decline in many regions. Although necessary for management, ecological interactions between kelp and fish remain largely unknown in the north-east Atlantic. In the present study, underwater visual censuses (UVC) and univariate and multivariate multiple regression models were used to analyse the spatiotemporal variations in the abundance and habitat use of the rocky reef fish and macroalgae assemblages of Galicia (north-west Spain). The underwater seascape was dominated by large rocks and kelp forests of Laminaria hyperborea, L. ochroleuca and Saccorhiza polyschides. Fish assemblages were ruled by gadids, labrids and sparids. The most frequent fish species were Labrus bergylta (counted in 90% of UVC) and Pollachius pollachius (in 100% of UVC), whereas the most abundant were Boops boops (mean±s.d., 556.4±39.7 individuals ha–1) and L. bergylta (432.10±440.05 individuals ha–1). Fish and macroalgal assemblages showed different spatial preferences and responded strongly to seasonality, wave exposure and depth. To a lesser degree, fish and macroalgal assemblages showed preferences for habitat structure. Moreover, because the findings of the present study indicate that L. bergylta is a good indicator species of the health of rocky reef and kelp forests ecosystems, monitoring of this fish can be helpful for management and conservation actions.

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O’Riain, MJ, CS Armitage, T. Kutti, V. Husa, MD Skogen, T. Bekkby, MA Carvajalino-Fernández et al. „Large-scale salmon farming in Norway impacts the epiphytic community of Laminaria hyperborea“. Aquaculture Environment Interactions 13 (25.03.2021): 81–100. http://dx.doi.org/10.3354/aei00392.

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Large-scale finfish farms are increasingly located in dispersive hard-bottom environments where Laminaria hyperborea forests dominate; however, the interactions between farm effluents and kelp forests are poorly understood. Effects of 2 levels of salmonid fish-farming effluents (high and low) on L. hyperborea epiphytic communities were studied by sampling canopy plants from 12 sites in 2 high-energy dispersive environments. Specifically, we assessed if farm effluents stimulated fast-growing epiphytic algae and faunal species on L. hyperborea stipes—as this can impact the kelp forest community composition—and/or an increased lamina epiphytic growth, which could negatively impact the kelp itself. We found that bryozoan biomass on the stipes was significantly higher at high-effluent farm sites compared to low-effluent farm and reference sites, resulting in a significantly different epiphytic community. Macroalgal biomass also increased with increasing effluent levels, including opportunistic Ectocarpus spp., resulting in a less heterogeneous macroalgae community at high-effluent farm sites. This habitat heterogeneity was further reduced by the high bryozoan biomass at the high-effluent sites. Such changes in the epiphyte community could have implications for the faunal community that relies on the epiphytes for food and refuge. On the kelp lamina, no clear response to farm effluents was found.

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García, Abel Furlan, Marília Bueno und Fosca Pedini Pereira Leite. „The Bostrychietum community of pneumatophores in Araçá Bay: an analysis of the diversity of macrofauna“. Journal of the Marine Biological Association of the United Kingdom 96, Nr. 8 (09.12.2015): 1617–24. http://dx.doi.org/10.1017/s0025315415001964.

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A mangrove forest can harbour several macroalgal assemblages growing on pneumatophores, roots, stems and other hard substrates. These algae belong to various genera, most typically Bostrychia, and form a community called the Bostrychietum. This study describes the fauna associated with the Bostrychietum and the effect of emersion time on the community. Seasonal samples were collected from pneumatophores on an island in Araçá Bay in 2012, in two areas, one on the border of the island and one inland. Each pneumatophore was considered a sample. The border samples, with a shorter emersion time, contained a richer algal flora associated with pneumatophores, and fauna with species of varied dietary habits. The inland samples, with a longer emersion time, contained only two algal genera and fauna species comprised mostly of omnivorous amphipods and desiccation-resistant detritivorous species. Macrofauna diversity and richness varied over time and were lower in spring. Therefore, the emersion time of the Bostrychietum and the period of the year affect the community structure, for both the macroalgae and the associated fauna.

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Stewart, Nathan L., und Brenda Konar. „Kelp Forests versus Urchin Barrens: Alternate Stable States and Their Effect on Sea Otter Prey Quality in the Aleutian Islands“. Journal of Marine Biology 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/492308.

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Macroalgal and urchin barren communities are alternately stable and persist in the Aleutians due to sea otter presence and absence. In the early 1990s a rapid otter population decline released urchins from predation and caused a shift to the urchin-dominated state. Despite increases in urchin abundance, otter numbers continued to decline. Although debated, prey quality changes have been implicated in current otter population status. This study examined otter prey abundance, size, biomass, and potential energy density in remnant kelp forest and urchin-dominated communities to determine if alternate stable states affect prey quality. Findings suggest that although urchin barrens provide more abundant urchin prey, individual urchins are smaller and provide lower biomass and potential energy density compared to kelp forests. Shifts to urchin barrens do affect prey quality but changes are likely compensated by increased prey densities and are insufficient in explaining current otter population status in the Aleutians.

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Pinna, S., L. Piazzi, G. Ceccherelli, A. Castelli, G. Costa, M. Curini-Galletti, P. Gianguzza et al. „Macroalgal forest vs sea urchin barren: Patterns of macro-zoobenthic diversity in a large-scale Mediterranean study“. Marine Environmental Research 159 (Juli 2020): 104955. http://dx.doi.org/10.1016/j.marenvres.2020.104955.

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Schram, Julie B., Margaret O. Amsler, Aaron W. E. Galloway, Charles D. Amsler und James B. McClintock. „Fatty acid trophic transfer of Antarctic algae to a sympatric amphipod consumer“. Antarctic Science 31, Nr. 6 (22.10.2019): 315–16. http://dx.doi.org/10.1017/s0954102019000397.

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The shallow benthos along the western Antarctic Peninsula supports brown macroalgal forests with dense amphipod assemblages, commonly including Gondogeneia antarctica (Amsler et al. 2014). Gondogeneia antarctica and most other amphipods are chemically deterred from consuming the macroalgae (Amsler et al. 2014). They primarily consume diatoms, other microalgae, filamentous macroalgae and a few undefended macroalgal species, including Palmaria decipiens (Aumack et al. 2017). Although unpalatable when alive, G. antarctica and other amphipods will consume the chemically defended brown algae Himantothallus grandifolius and Desmarestia anceps within a few weeks of death (Amsler et al. 2014).

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Freeman, Debbie J., und Robert G. Creese. „Predation as a driver of gastropod distribution in north-eastern New Zealand kelp forests“. Marine and Freshwater Research 62, Nr. 5 (2011): 471. http://dx.doi.org/10.1071/mf10259.

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Gastropods play an important ecological role in kelp forests; however, this role is dependent on where exactly in such communities these animals are located. We assessed the spatial and temporal patterns in the utilisation of available reef and macroalgal substrates by three gastropods in a north-eastern New Zealand kelp (Ecklonia radiata (C. Agardh) J. Agardh, 1848) forest, focusing on predation as a factor influencing these patterns. Although kelp provided a large habitable surface area for gastropods, much of this area was under-utilised. During the day, gastropods on E. radiata were largely confined to the primary laminae. At night, gastropods on the reef migrated into the algal canopy where they occupied regions of the kelp that were not occupied during the day. Over a 36-day period, 93% of the gastropods tethered to the reef were consumed by predators, whereas none tethered in the algal canopy was consumed. We consider that night-time vertical migration and dispersion through the algal canopy may be primarily a response to predation by diurnally feeding fish and nocturnal benthic predators such as lobsters. Our research highlights the importance of considering diel changes in epifaunal distribution and abundance when assessing their ecological role.

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Hong, Seokwoo, Junsu Kim, Young Wook Ko, Kwon Mo Yang, Daniela Macias und Jeong Ha Kim. „Effects of sea urchin and herbivorous gastropod removal, coupled with transplantation, on seaweed forest restoration“. Botanica Marina 64, Nr. 5 (01.10.2021): 427–38. http://dx.doi.org/10.1515/bot-2021-0043.

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Abstract This study aims to investigate the relative effects of urchin removal, non-urchin gastropod herbivores removal, and transplantation on macroalgal forest restoration using an additive manipulation design. A field experiment was conducted in subtidal urchin barren rocks in the eastern coast of South Korea from August 2017 to June 2020 with three experimental treatments: no urchins (NU), NU plus no herbivorous gastropods (NH), NH plus Ecklonia bicyclis transplant (NHT). Six months after experiment initiation, seaweed abundance rapidly increased in all three experimental treatments. The highest peak was found in the spring season of the first year (2018). The year-to-year variations became smaller throughout the survey period. The results of comparing NU and control site indicated that urchin removal had an exclusive effect on algal recovery while additional removal of herbivorous gastropods did not affect algal recovery quantitatively. With the successful establishment of E. bicyclis, the community assemblages of the three treatments became more distinct in the subsequent years, showing diverse dominance in NU, red algal dominance in NH, and dominance of E. bicyclis canopy and understory groups in NHT. This study provides evidence that urchin removal on its own from barren grounds can lead to rapid restoration of seaweed forest in subtidal habitats.

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Heiser, Sabrina, Charles D. Amsler, James B. McClintock, Andrew J. Shilling und Bill J. Baker. „Every Rule Has an Exception: a Cheater in the Community-Wide Mutualism in Antarctic Seaweed Forests“. Integrative and Comparative Biology 60, Nr. 6 (04.06.2020): 1358–68. http://dx.doi.org/10.1093/icb/icaa058.

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Synopsis Dense macroalgal forests on the Western Antarctic Peninsula serve important ecological roles both in terms of considerable biomass for primary production as well as in being ecosystem engineers. Their function within the Antarctic ecosystem has been described as a crucial member of a community-wide mutualism which benefits macroalgal species and dense assemblages of associated amphipod grazers. However, there is a cheater within the system that can feed on one of the most highly chemically defended macroalgal hosts. The amphipod Paradexamine fissicauda has been found to readily consume the finely branched red macroalga Plocamium cartilagineum. This amphipod grazer not only feeds on its host, but also appears to sequester its host’s chemical defenses for its own utilization. This review summarizes what we know about both of these exceptions to the community-wide mutualism.

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Vergés, Adriana, Peter D. Steinberg, Mark E. Hay, Alistair G. B. Poore, Alexandra H. Campbell, Enric Ballesteros, Kenneth L. Heck et al. „The tropicalization of temperate marine ecosystems: climate-mediated changes in herbivory and community phase shifts“. Proceedings of the Royal Society B: Biological Sciences 281, Nr. 1789 (22.08.2014): 20140846. http://dx.doi.org/10.1098/rspb.2014.0846.

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Climate-driven changes in biotic interactions can profoundly alter ecological communities, particularly when they impact foundation species. In marine systems, changes in herbivory and the consequent loss of dominant habitat forming species can result in dramatic community phase shifts, such as from coral to macroalgal dominance when tropical fish herbivory decreases, and from algal forests to ‘barrens’ when temperate urchin grazing increases. Here, we propose a novel phase-shift away from macroalgal dominance caused by tropical herbivores extending their range into temperate regions. We argue that this phase shift is facilitated by poleward-flowing boundary currents that are creating ocean warming hotspots around the globe, enabling the range expansion of tropical species and increasing their grazing rates in temperate areas. Overgrazing of temperate macroalgae by tropical herbivorous fishes has already occurred in Japan and the Mediterranean. Emerging evidence suggests similar phenomena are occurring in other temperate regions, with increasing occurrence of tropical fishes on temperate reefs.

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Yiu, B. A., D. J. Booth, A. M. Fowler und D. A. Feary. „Macroalgal resource use differences across age and size classes in the dominant temperate herbivorous fish Aplodactylus lophodon (Aplodactylidae)“. Marine and Freshwater Research 70, Nr. 4 (2019): 531. http://dx.doi.org/10.1071/mf18086.

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Herbivorous fishes comprise a substantial proportion of temperate fish communities, although there is little understanding of their trophic resource use and whether this changes throughout post-settlement ontogeny. With increasing loss of macroalgal forests, understanding how temperate fishes use macroalgae will be vital in predicting future effects on temperate fish biodiversity. The Australian rock cale (Aplodactylus lophodon) is one of the most abundant herbivorous fish inhabiting shallow temperate south-eastern Australian reefs. We examined gastrointestinal contents throughout ontogeny and demonstrated that this species maintains a herbivorous diet through all life stages. Differences in algal taxa consumed were apparent through ontogeny, with the juvenile diet dominated by filamentous red and green algae and the adult diet dominated by brown and calcareous red algae. Relative gut length increased through ontogeny, potentially facilitating dietary transition to less digestible algae, but no concurrent increase in jaw power was observed. The results highlight the diversity of trophic resource use in a temperate marine herbivore, but the near-complete dominance of dietary algae throughout ontogeny indicates the reliance on primary producers across all life stages. Given the importance of fucoid resources in the adult diet, any loss of macroalgal forests within south-eastern Australia may affect foraging success and persistence.

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Gumansalangi, Frysye, Jose L. P. Calle, Marta Barea-Sepúlveda, Manikharda, Miguel Palma, Lideman, Mohamad Rafi, Andriati Ningrum und Widiastuti Setyaningsih. „A Rapid Method for Authentication of Macroalgae Based on Vis-NIR Spectroscopy Data Combined with Chemometrics Approach“. Water 15, Nr. 1 (28.12.2022): 100. http://dx.doi.org/10.3390/w15010100.

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Macroalgae are an essential basic ingredient for many industries from which numerous derived products with great economic value are manufactured. Each macroalga has a unique composition that might provide specific physical and chemical information that can be used as markers for authentication. Their compositions may differ depending on different factors, including geographical regions. Unsupervised exploratory techniques, namely principal component analysis (PCA) and hierarchical cluster analysis (HCA), and nonparametric supervised methods including support vector machines (SVMs) and random forests (RFs), were applied to the Vis-NIR spectroscopic data to standardize the quality of macroalgae based on three regional zones in Indonesia (Western, Central, Eastern). A total of 35 macroalgae samples from six islands in Indonesia were analyzed. The PCA and HCA results present a tendency for the samples to be distributed and clustered according to the type of their species. Meanwhile, the SVM successfully classified samples based on their regional zones, and when combined with five-fold cross-validation, acquired an accuracy of 82%. The RF model algorithm obtained an accuracy of 100%, 80%, and 82% for the training, test, and five-fold cross-validation, respectively.

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Pascoaloto, Domitila, und Sérgio Roberto Bulcão Bringel. „MACROALGAS E QUALIDADE DA ÁGUA NA BACIA DO ALTO RIO NEGRO - MUNICÍPIO DE SÃO GABRIEL DA CACHOEIRA (AM).“ Caminhos de Geografia 11, Nr. 36 (02.01.2011): 318–30. http://dx.doi.org/10.14393/rcg113616219.

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Neste estudo foram investigadas as comunidades de macroalgas e qualidade da água do rio Negro no município de São Gabriel da Cachoeira, desde a entrada do rio Negro no Brasil, na comunidade Cucuí (hemisfério norte) até o rio Marié (hemisfério sul), entre setembro/2007 e maio/2009. As águas dos locais apresentaram pH ácido (< 5,5), condutividade elétrica baixa (< 13 μS/cm) e foram bem oxigenadas (> 6,0 mgO2/L). As entidades ecológicas de macroalgas observadas pertenceram aos gêneros Batrachospermum Roth (Batrachospermaceae, Rhodophyta); Microspora Thuret (Microsporaceae, Chorophyta), Oedogonium Link ex Hirn (Oedogoniaceae, Chorophyta); Oscillatoria Vaucher ex Gomont (Oscillatoriaceae, Cyanophyta); Phormidium Kützing ex Gomont (Phormidiaceae, Cyanophyta); Spirogyra Link (Zygnemaceae, Chlorophyta); Tabellaria Ehrenberge ex Kützing (Fragilariophyceae, Bacillariophyta). Na sede da cidade, a macroalga mais freqüente (50% dos registros) foi Spirogyra spp.. Gametófitos estéreis de Batrachospermum spp. foram observados em três sítios amostrais em setembro/2007, período de águas mais baixas; em agosto/2008, período de águas altas, foram observados, em fragmentos rochosos na orla da sede do município, filamentos férteis de Batrachospermum sp. em estágio juvenil, o que impediu a identificação da espécie. A fase “Chantransia” de Batrachospermum spp. esteve presente na orla da cidade em todos os períodos investigados.

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Islam, Md Ariful, Mst Zannatun Mauya, S. M. Rafiquzzaman, Md Rashedul Islam und Lawrence M. Liao. „First Report of the Red Algal Genus Chondria C. Agardh (Rhodomelaceae, Rhodophyta) for the Marine Flora of Bangladesh“. Diversity 11, Nr. 6 (20.06.2019): 95. http://dx.doi.org/10.3390/d11060095.

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Epiphytic algae in mangrove forests contribute to high productivity in these unique mangrove ecosystems. A general survey of mangrove-associated macroalgae was conducted during February–March (dry season) and November–December (wet season) in the Sundarbans Mangrove Forest, Bangladesh. Different macroalgae were collected from mangrove pneumatophores, roots, and branches of trees. During this survey, a small and inconspicuous species of Chondria was encountered from the upper-middle of the intertidal zone in the Malancha River (22°5′11.37″ N and 89°13′12.37″ E). External–internal anatomical traits were examined and the sample was identified as Chondria intertexta Silva, a new record for the algal flora of Bangladesh. Furthermore, its geographical distribution and some other ecological notes are also discussed.

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Dobkowski, Katie. „The role of kelp crabs as consumers in bull kelp forests—evidence from laboratory feeding trials and field enclosures“. PeerJ 5 (25.05.2017): e3372. http://dx.doi.org/10.7717/peerj.3372.

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The Northern kelp crab (Pugettia producta) and the graceful kelp crab (Pugettia gracilis) are common primary consumers in bull kelp beds near the San Juan Islands (Salish Sea, NE Pacific). In this system, urchins (often considered the most voracious herbivores exerting top-down control on kelp beds) tend to remain sedentary because of the high availability of detrital macroalgae, but the extent to which kelp crabs consume kelp (and other food options) is largely unknown. I conducted four types of laboratory feeding experiments to evaluate kelp crab feeding patterns: (1) feeding electivity between bull kelp (Nereocystis luetkeana) and seven species of co-occurring local macroalgae; (2) feeding electivity on aged vs. fresh bull kelp; (3) feeding preference between N. luetkeana and small snails (Lacuna sp.); and (4) scaling of feeding rate with body size in P. producta and P. gracilis. In choice experiments, P. producta consumed greater mass of N. luetkeana than of other macroalgal species offered and elected to eat fresh bull kelp over aged. However, P. producta also consumed snails (Lacuna sp.), indicating more generalized feeding than previously suspected. Feeding rates for P. producta exceeded the expected 3∕4 scaling rule of metabolic rates, indicating that larger P. producta may have a disproportionately large impact on bull kelp. A subtidal field experiment, designed to assess the influence of consumers on juvenile bull kelp net tissue gain, found that only fully enclosed (protected) bull kelp increased in wet mass and blade length. Herbivory by kelp crabs, among other consumers, is likely to play a previously unrecognized role in mediating the growth and survival of this annual kelp species within the Salish Sea.

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Tamburello, Laura, Antonia Chiarore, Erika Fabbrizzi, Alberto Colletti, Giulio Franzitta, Daniele Grech, Fabio Rindi, Lucia Rizzo, Beatrice Savinelli und Simonetta Fraschetti. „Can we preserve and restore overlooked macroalgal forests?“ Science of The Total Environment 806 (Februar 2022): 150855. http://dx.doi.org/10.1016/j.scitotenv.2021.150855.

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Chemello, Silvia, Geraldina Signa, Antonio Mazzola, Tania Ribeiro Pereira, Isabel Sousa Pinto und Salvatrice Vizzini. „Limited Stress Response to Transplantation in the Mediterranean Macroalga Ericaria amentacea, a Key Species for Marine Forest Restoration“. International Journal of Environmental Research and Public Health 19, Nr. 19 (27.09.2022): 12253. http://dx.doi.org/10.3390/ijerph191912253.

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In the Mediterranean Sea, brown macroalgae represent the dominant species in intertidal and subtidal habitats. Despite conservation efforts, these canopy-forming species showed a dramatic decline, highlighting the urge for active intervention to regenerate self-sustaining populations. For this reason, the restoration of macroalgae forests through transplantation has been recognized as a promising approach. However, the potential stress caused by the handling of thalli has never been assessed. Here, we used a manipulative approach to assess the transplant-induced stress in the Mediterranean Ericaria amentacea, through the analysis of biochemical proxies, i.e., phenolic compounds, lipids, and fatty acids in both transplanted and natural macroalgae over time. The results showed that seasonal environmental variability had an important effect on the biochemical composition of macroalgae, suggesting the occurrence of acclimation responses to summer increased temperature and light irradiance. Transplant-induced stress appears to have only amplified the biochemical response, probably due to increased sensitivity of the macroalgae already subjected to mechanical and osmotic stress (e.g., handling, wounding, desiccation). The ability of E. amentacea to cope with both environmental and transplant-induced stress highlights the high plasticity of the species studied, as well as the suitability of transplantation of adult thalli to restore E. amentacea beds.

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Cornwall, Christopher E., Christopher D. Hepburn, Christina M. McGraw, Kim I. Currie, Conrad A. Pilditch, Keith A. Hunter, Philip W. Boyd und Catriona L. Hurd. „Diurnal fluctuations in seawater pH influence the response of a calcifying macroalga to ocean acidification“. Proceedings of the Royal Society B: Biological Sciences 280, Nr. 1772 (07.12.2013): 20132201. http://dx.doi.org/10.1098/rspb.2013.2201.

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Coastal ecosystems that are characterized by kelp forests encounter daily pH fluctuations, driven by photosynthesis and respiration, which are larger than pH changes owing to ocean acidification (OA) projected for surface ocean waters by 2100. We investigated whether mimicry of biologically mediated diurnal shifts in pH—based for the first time on pH time-series measurements within a kelp forest—would offset or amplify the negative effects of OA on calcifiers. In a 40-day laboratory experiment, the calcifying coralline macroalga, Arthrocardia corymbos a, was exposed to two mean pH treatments (8.05 or 7.65). For each mean, two experimental pH manipulations were applied. In one treatment, pH was held constant. In the second treatment, pH was manipulated around the mean (as a step-function), 0.4 pH units higher during daylight and 0.4 units lower during darkness to approximate diurnal fluctuations in a kelp forest. In all cases, growth rates were lower at a reduced mean pH, and fluctuations in pH acted additively to further reduce growth. Photosynthesis, recruitment and elemental composition did not change with pH, but δ 13 C increased at lower mean pH. Including environmental heterogeneity in experimental design will assist with a more accurate assessment of the responses of calcifiers to OA.

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Mc Clintic, Amy S., Dale A. Casamatta und Morgan L. Vis. „A survey of algae from montane cloud forest and alpine streams in Bolivia: Macroalgae and associated microalgae“. Nova Hedwigia 76, Nr. 3-4 (01.05.2003): 363–79. http://dx.doi.org/10.1127/0029-5035/2003/0076-0363.

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Rossi, Sergio. „HOW CARBON IMMOBILIZATION FROM RESTORED MARINE FORESTS MAY HELP CLIMATE CHANGE MITIGATION PLANS?“ Arquivos de Ciências do Mar 55, Especial (18.03.2022): 202–18. http://dx.doi.org/10.32360/acmar.v55iespecial.78542.

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The ocean transformation due to the direct or indirect human influence is a fact. One of the most affected ecosystems are the benthic ones, where bottom trawling, urban/agricultural development and climate change (among other things) deeply transform the bottom communities. Among these threatened communities, the marine forest is the most extended. The marine forest is composed of benthic macroalgae, phanerogams and suspension feeders (sponges, corals, gorgonians, etc.) which conform three-dimensional living structures. Coral reefs, seaweeds, sponge grounds, seagrasses, oyster banks, cold water corals are some examples of this vast set of ecosystems dispersed all over the world. During the last two decades, the concept of Blue Carbon has been consolidated, describing the stocked carbon in vegetated coastal and marine habitats such as mangroves, salt marshes, seagrasses and seaweeds. There are also world-wide numbers about how much carbon is retained in the terrestrial forests, crops and soils. These systems act as carbon immobilizers from which we have proxies. Can we design and apply an ambitious shallow and deep marine forest restoration plan to help climate change mitigation? The aim of thispaper is developing a simplified realistic calculation of the role as carbon immobilizers of a restored marine forests in one area as a case study, setting up a huge restoration plan to help mitigating climate change, enhancing carbon retention. A shallow (10-30 meters depth) restoration plan of the marine animal forests with new technologies based on symbiotic artificial reefs, enhancing the role as carbon immobilizers and creating a protocol to help the climate change mitigation, is explained, using realistic numbers to calculate the real impact of such regenerative plan. Is time to have a much more applied and holistic view of what is in the ocean’s floors in terms of habitat composition, complexity and biomass stocks, implementing new methods and technologies that are already in our hands. It is also time to give a chance to the oceans in helping in the climate change mitigation plans applying brave new restoration approaches that may change our relation with the sea. Keywords: marine restoration, marine animal forests, artificial reefs, transplantation,forest ecology.

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Gaylord, Brian, Daniel C. Reed, Libe Washburn und Peter T. Raimondi. „Physical–biological coupling in spore dispersal of kelp forest macroalgae“. Journal of Marine Systems 49, Nr. 1-4 (August 2004): 19–39. http://dx.doi.org/10.1016/j.jmarsys.2003.05.003.

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Pinho, Daniela, Iacopo Bertocci, Francisco Arenas, João N. Franco, David Jacinto, João J. Castro, Raquel Vieira, Isabel Sousa-Pinto, Thomas Wernberg und Fernando Tuya. „Spatial and temporal variation of kelp forests and associated macroalgal assemblages along the Portuguese coast“. Marine and Freshwater Research 67, Nr. 1 (2016): 113. http://dx.doi.org/10.1071/mf14318.

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Kelp communities are in decline in many regions. Detecting and addressing population declines require knowledge of patterns of spatial and temporal variation in the distribution and abundance of kelps and their associated organisms. We quantified kelp and associated macroalgal assemblages three times over a period of 2 years, at three regions along a natural gradient in temperature and nutrient availability across the Portuguese coast. Kelps were mostly found at the northern cool region (Viana do Castelo), which was also clearly separated from the two more southerly regions (Peniche, Sines) in terms of algal assemblage structure. This pattern was consistent, although varying in intensity, through time, providing support for this general spatial configuration. The overall richness of taxa increased towards lower latitudes. These findings indicated that kelp beds in southern Europe are currently restricted to northern Portugal, though supporting less diverse macroalgal assemblages compared with those located in central and southern Portugal.

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Beckley, BA, und MS Edwards. „Mechanisms leading to recruitment inhibition of giant kelp Macrocystis pyrifera by an understory alga“. Marine Ecology Progress Series 657 (07.01.2021): 59–71. http://dx.doi.org/10.3354/meps13550.

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The forest-forming giant kelp Macrocystis pyrifera and the communities it supports have been decreasing across their native ranges in many parts of the world. The sudden removal of giant kelp canopies by storms increases space and light for the colonization by understory macroalgae, such as Desmarestia herbacea, which can inhibit M. pyrifera recovery and alter local community composition. Understanding the mechanisms by which algae such as D. herbacea interact with M. pyrifera can provide insight into patterns of kelp forest recovery following these disturbances and can aid in predicting future community structure. This study experimentally tested the independent and combined effects of two likely competitive mechanisms by which D. herbacea might inhibit recovery of M. pyrifera in the Point Loma kelp forest in San Diego, California (USA). Specifically, we conducted field experiments to study the individual and combined effects of shade and scour by D. herbacea on the survival of M. pyrifera microscopic life stages, and the recruitment, survival, and growth of its young sporophytes. Our results show that scour had the strongest negative effect on the survival of M. pyrifera microscopic life stages and recruitment, but shade and scour both adversely affected survival and growth of these sporophytes as they grew larger. Canopy-removing storms are increasing in frequency and intensity, and this change could facilitate the rise of understory species, like D. herbacea, which might alter community succession and recovery of kelp forests.

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Pascoaloto, Domitila, Terezinha de Jesus Gonçalves, Maria do Socorro Rocha da Silva, Vanessa Karem Carvalho Lins, Mário Andrei de Oliveira Conrado und Maria da Conceição Negrão Alves. „ESTUDO DA DINÂMICA DE MACROALGAS EM FLUTUANTES DE DUAS COMUNIDADES RIBEIRINHAS NA BACIA DO TARUMÃ-MIRIM (ÁREA RURAL DE MANAUS/AM) POR ALUNOS DO ENSINO FUNDAMENTAL“. Caminhos de Geografia 11, Nr. 33 (22.03.2010): 66–75. http://dx.doi.org/10.14393/rcg113315877.

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O presente estudo faz parte de um projeto voltado para Educação ambiental na bacia do Tarumã-Mirim. Em abril/2008 seis alunos do ensino fundamental acompanharam, por quinze dias, a presença de macroalgas em três flutuantes da comunidade Nossa Senhora de Fátima, a flutuação do nível do igarapé nesses flutuantes e a distância entre a sede da comunidade o porto principal. Também foi feito o levantamento das macroalgas na comunidade Nossa Senhora do Livramento. Macroalgas estiveram presentes em todos os locais, em ambas as comunidades. A distância entre a sede da comunidade e o flutuante principal variou 1,4 metros; a variação do nível de água no igarapé foi de 0,33 a 0,92 metros. As características químicas da água foram semelhantes (ácidas e pouco mineralizadas). Os alunos verificaram que a presença das macroalgas esteve mais relacionada com as características físicas dos locais (substrato estável e incidência de luz solar).

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Fragkopoulou, Eliza, Ester A. Serrão, Olivier De Clerck, Mark J. Costello, Miguel B. Araújo, Carlos M. Duarte, Dorte Krause‐Jensen und Jorge Assis. „Global biodiversity patterns of marine forests of brown macroalgae“. Global Ecology and Biogeography 31, Nr. 4 (17.01.2022): 636–48. http://dx.doi.org/10.1111/geb.13450.

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Krause-Jensen, D., C. M. Duarte, I. E. Hendriks, L. Meire, M. E. Blicher, N. Marbà und M. K. Sejr. „Macroalgae contribute to nested mosaics of pH variability in a sub-Arctic fjord“. Biogeosciences Discussions 12, Nr. 6 (27.03.2015): 4907–45. http://dx.doi.org/10.5194/bgd-12-4907-2015.

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Abstract. The Arctic Ocean is considered the most vulnerable ecosystem to ocean acidification (OA) and large-scale assessments of pH and the saturation state for aragonite (Ωarag) indicate that it is already close to corrosive states (Ωarag < 1). In high-latitude coastal waters the regulation of pH and Ωarag is far more complex than offshore because increased biological activity and input of glacial meltwater affect pH. As most calcifiers occupy coastal habitats, the assessment of risks from OA to these vulnerable organisms cannot be derived from extrapolation of current and forecasted offshore conditions, but requires an understanding of the regimes of pH and Ωarag in their coastal habitats. To increase knowledge of the natural variability of pH in the Arctic coastal zone and specifically to test the influence of benthic vegetated habitats, we quantified pH-variability in a Greenland fjord in a nested scale approach. A sensor array logging pH, O2, PAR, temperature and salinity was applied on spatial scales ranging from km-scale across the horizontal extension of the fjord, over 100 m scale vertically in the fjord, 10–100 m scale between subtidal habitats with and without kelp forests and between vegetated tidal pools and adjacent vegetated shores, to cm-m scale within kelp forests and mm-scale across boundary layers of macrophyte tissue. In addition, we assessed the temporal variability in pH on diurnal and seasonal scales. Based on pH-measurements combined with relationships between salinity, total alkalinity and dissolved inorganic carbon we also estimated variability of Ωarag. Results show variability in pH and Ωarag of up to 0.2–0.3 units at several scales, i.e. along the horizontal and vertical extension of the fjord, between seasons and on a diel basis in benthic habitats and within 1 m3 of kelp forest. Vegetated intertidal pools exhibited extreme diel pH variability of > 1.5 units and macrophyte boundary layers a pH-range of up to 0.8 units. Overall, Ωarag was favorable to calcification, and pelagic and benthic metabolism was an important driver of pH and Ωarag producing mosaics of variability from low levels in the dark to peak levels at high irradiance. We suggest that productive coastal environments may form niches of high pH in a future acidified Arctic Ocean.

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Krause-Jensen, D., C. M. Duarte, I. E. Hendriks, L. Meire, M. E. Blicher, N. Marbà und M. K. Sejr. „Macroalgae contribute to nested mosaics of pH variability in a subarctic fjord“. Biogeosciences 12, Nr. 16 (19.08.2015): 4895–911. http://dx.doi.org/10.5194/bg-12-4895-2015.

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Abstract. The Arctic Ocean is considered the most vulnerable ecosystem to ocean acidification, and large-scale assessments of pH and the saturation state for aragonite (Ωarag) have led to the notion that the Arctic Ocean is already close to a corrosive state. In high-latitude coastal waters the regulation of pH and Ωarag is, however, far more complex than offshore because increased biological activity and input of glacial meltwater affect pH. Effects of ocean acidification on calcifiers and non-calcifying phototrophs occupying coastal habitats cannot be derived from extrapolation of current and forecasted offshore conditions, but they require an understanding of the regimes of pH and Ωarag in their coastal habitats. To increase knowledge of the natural variability in pH in the Arctic coastal zone and specifically to test the influence of benthic vegetated habitats, we quantified pH variability in a Greenland fjord in a nested-scale approach. A sensor array logging pH, O2, PAR, temperature and salinity was applied on spatial scales ranging from kilometre scale across the horizontal extension of the fjord; to 100 m scale vertically in the fjord, 10–100 m scale between subtidal habitats with and without kelp forests and between vegetated tidal pools and adjacent vegetated shores; and to centimetre to metre scale within kelp forests and millimetre scale across diffusive boundary layers of macrophyte tissue. In addition, we assessed the temporal variability in pH on diurnal and seasonal scales. Based on pH measurements combined with point samples of total alkalinity, dissolved inorganic carbon and relationships to salinity, we also estimated variability in Ωarag. Results show variability in pH and Ωarag of up to 0.2–0.3 units at several scales, i.e. along the horizontal and vertical extension of the fjord, between seasons and on a diel basis in benthic habitats and within 1 m3 of kelp forest. Vegetated intertidal pools exhibited extreme diel pH variability of > 1.5 units and macrophyte diffusive boundary layers a pH range of up to 0.8 units. Overall, pelagic and benthic metabolism was an important driver of pH and Ωarag producing mosaics of variability from low levels in the dark to peak levels at high irradiance generally appearing favourable for calcification. We suggest that productive coastal environments may form niches of high pH in a future acidified Arctic Ocean.

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Sheath, Robert G., Paul B. Hamilton, Julie A. Hambrook und Kathleen M. Cole. „Stream macroalgae of the eastern boreal forest region of North America“. Canadian Journal of Botany 67, Nr. 12 (01.12.1989): 3553–62. http://dx.doi.org/10.1139/b89-437.

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Fifty-one stream segments were sampled in northwestern Newfoundland, central Labrador, and west-central Quebec during June and July 1987. There was a great range in stream size, current velocity, pH, and ion content. The eastern boreal forest was found to be one of the most diverse regions in North America for stream macroalgae, having a flora of 67 species. The major divisions in terms of species numbers were the Chlorophyta (43%), Cyanophyta (21%), Chrysophyta (19%), and Rhodophyta (16%). Mats were the most widespread form (51% of the species), followed by filaments (27%), colonies (13%), tissues (5%), and palmelloid forms (3%). Species number was positively correlated with water temperature and total cover and negatively correlated with pH. The most widespread species was Batrachospermum moniliforme, which occurred in 31% of the stream segments examined. Distribution was patchy, with total cover varying from < 1 to ca. 60% of the stream bottom. Species numbers per segment ranged from 1 to 11. The most closely associated species were Microspora pachyderma, Mougeotia sp., and Batrachospermum keratophytum. The known distribution range of the rare rhodophyte Boldia erythrosiphon was extended north by ca. 1000 km.

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Schmidt, Susanne, William C. Dennison, Gordon J. Moss und George R. Stewart. „Nitrogen ecophysiology of Heron Island, a subtropical coral cay of the Great Barrier Reef, Australia“. Functional Plant Biology 31, Nr. 5 (2004): 517. http://dx.doi.org/10.1071/fp04024.

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Coral cays form part of the Australian Great Barrier Reef. Coral cays with high densities of seabirds are areas of extreme nitrogen (N) enrichment with deposition rates of up to 1000 kg N ha–1 y–1. The ways in which N sources are utilised by coral cay plants, N is distributed within the cay, and whether or not seabird-derived N moves from cay to surrounding marine environments were investigated. We used N metabolite analysis, 15N labelling and 15N natural abundance (δ15N) techniques. Deposited guano-derived uric acid is hydrolysed to ammonium (NH4+) and gaseous ammonia (NH3). Ammonium undergoes nitrification, and nitrate (NO3–) and NH4+ were the main forms of soluble N in the soil. Plants from seabird rookeries have a high capacity to take up and assimilate NH4+, are able to metabolise uric acid, but have low rates of NO3– uptake and assimilation. We concluded that NH4+ is the principal source of N for plants growing at seabird rookeries, and that the presence of NH4+ in soil and gaseous NH3 in the atmosphere inhibits assimilation of NO3–, although NO3– is taken up and stored. Seabird guano, Pisonia forest soil and vegetation were similarly enriched in 15N suggesting that the isotopic enrichment of guano (δ15N 9.9‰) carries through the forest ecosystem. Soil and plants from woodland and beach environments had lower δ15N (average 6.5‰) indicating a lower contribution of bird-derived N to the N nutrition of plants at these sites. The aquifer under the cay receives seabird-derived N leached from the cay and has high concentrations of 15N-enriched NO3– (δ15N�7.9‰). Macroalgae from reefs with and without seabirds had similar δ15N values of 2.0–3.9‰ suggesting that reef macroalgae do not utilise 15N-enriched seabird-derived N as a main source of N. At a site beyond the Heron Reef Crest, macroalgae had elevated δ15N of 5.2‰, possibly indicating that there are locations where macroalgae access isotopically enriched aquifer-derived N. Nitrogen relations of Heron Island vegetation are compared with other reef islands and a conceptual model is presented.

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Orlando-Bonaca, Martina, Domen Trkov, Katja Klun und Valentina Pitacco. „Diversity of Molluscan Assemblage in Relation to Biotic and Abiotic Variables in Brown Algal Forests“. Plants 11, Nr. 16 (16.08.2022): 2131. http://dx.doi.org/10.3390/plants11162131.

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Canopy-forming macroalgae, mainly those belonging to the order Fucales, form the so-called brown algal forests, which are among the most productive assemblages in shallow coastal zones. Their vertical, branching canopies increase nearshore primary production, provide nursery areas for juvenile fish, and sustain understory assemblages of smaller algae and both sessile and vagile fauna. The majority of benthic invertebrates inhabiting these forests have larval stages that spend some time floating freely or swimming in the plankton. Therefore, canopy-forming macroalgae play an important role as species collectors related to larval supply and hydrodynamic processes. During the past several decades, brown algal forests have significantly reduced their extension and coverage in the Mediterranean basin, due to multiple interacting natural and anthropogenic pressures, with negative consequences also for the related fauna. The aim of this research was to examine how differences in macrophyte abundance and structure, as well as environmental variables, affect the associated molluscan communities in the shallow northern Adriatic Sea. Sampling sites with well-developed vegetation cover dominated by different canopy-forming species were selected in the shallow infralittoral belt of the northern Adriatic Sea in the spring–summer period of the years 2019 and 2020. Our results confirm the importance of algal forests for molluscan assemblage, with a total of 68 taxa of molluscs found associated with macrophytes. Gastropods showed the highest richness and abundance, followed by bivalves. Mollusc richness and diversity (in terms of biotic indices) were not related with the degree of development of canopy-forming species (in terms of total cover and total volume), nor with the ecological status of benthic macroalgae at different depths. On the contrary, the variability in molluscan taxa abundances was explained by some environmental variables, such as temperature, pH, light, and nitrates concentration.

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Smale, Dan A., Graham Epstein, Esther Hughes, Andrew O. M. Mogg und Pippa J. Moore. „Patterns and drivers of understory macroalgal assemblage structure within subtidal kelp forests“. Biodiversity and Conservation 29, Nr. 14 (21.10.2020): 4173–92. http://dx.doi.org/10.1007/s10531-020-02070-x.

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Fabbrizzi, Erika, Sylvaine Giakoumi, Francesco De Leo, Laura Tamburello, Antonia Chiarore, Alberto Colletti, Marianna Coppola et al. „The challenge of setting restoration targets for macroalgal forests under climate changes“. Journal of Environmental Management 326 (Januar 2023): 116834. http://dx.doi.org/10.1016/j.jenvman.2022.116834.

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Pascoaloto, Domitila, Antônia Gomes Neta Pinto und Eliana Emiko Araújo Takano. „CARACTERÍSTICAS FÍSICAS E COMUNIDADES DE MACROALGAS EM UM IGARAPÉ DE TERRA FIRME NA RESERVA FLORESTAL ADOLPHO DUCKE (MANAUS/AM)“. Caminhos de Geografia 9, Nr. 25 (17.03.2008): 108–14. http://dx.doi.org/10.14393/rcg92515688.

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Este estudo foi realizado em três segmentos do igarapé Barro, em novembro de 2005, como parte de um projeto em educação ambiental voltado para alunos do ensino médio, com o objetivo de destacar a importância das variáveis físicas na composição das espécies de macroalgas. O segmento "campoâ€? foi um local natural, sombreado; o "laguinhoâ€?, uma área represada, pouco sombreado; o "igarapézinhoâ€?, novamente um segmento natural, sombreado. A velocidade média superficial variou de zero a 43,48 cm.s-1. No "campoâ€? não foram observadas macroalgas; no "laguinhoâ€? foram encontradas quatro; no "igarapézinhoâ€?, duas. Não foram observadas diferenças na química da água. No "campoâ€? o substrato predominante foi areia; no "laguinhoâ€?, raízes; no "igarapézinhoâ€?, areia. Estudos anteriores, no "campoâ€?, revelaram a presença de grandes quantidades de uma rodofícea; como não foram identificadas alterações nas características da água, mas foram observadas alterações na profundidade do canal e na quantidade de troncos e galhos caídos, confirmou-se a hipótese de que as características físicas do local são os fatores determinantes na configuração das comunidades de macroalgas desse igarapé.

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Ihua, Maureen W., Jamie A. FitzGerald, Freddy Guihéneuf, Stephen A. Jackson, Marcus J. Claesson, Dagmar B. Stengel und Alan D. W. Dobson. „Diversity of bacteria populations associated with different thallus regions of the brown alga Laminaria digitata“. PLOS ONE 15, Nr. 11 (25.11.2020): e0242675. http://dx.doi.org/10.1371/journal.pone.0242675.

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Stipitate kelp species such as Laminaria digitata dominate most cold-water subtidal rocky shores and form underwater forests which are among the most productive coastal systems worldwide. Laminaria also sustains rich bacterial communities which offer a variety of biotechnological applications. However, to date, in-depth studies on the diversity and uniqueness of bacterial communities associated with this macroalgal species, their ecological role and their interactions with the alga are under-represented. To address this, the epibacterial populations associated with different thallus regions (holdfast, stipe, meristem, blade) of this brown seaweed were investigated using high-throughput Illumina sequencing of the 16S rRNA genes. The results show that epibacterial communities of the brown seaweed are significantly different and specific to the thallus region, with the shared bacterial population comprising of only 1.1% of the total amplicon sequence variants. The diverse holdfast and blade tissues formed distinct clusters while the meristem and stipe regions are more closely related. The data obtained further supports the hypothesis that macroalgal bacterial communities are shaped by morphological niches and display specificity.

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Amani, Meisam, Candace Macdonald, Abbas Salehi, Sahel Mahdavi und Mardi Gullage. „Marine Habitat Mapping Using Bathymetric LiDAR Data: A Case Study from Bonne Bay, Newfoundland“. Water 14, Nr. 23 (23.11.2022): 3809. http://dx.doi.org/10.3390/w14233809.

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Marine habitats provide various benefits to the environment and humans. In this regard, an accurate marine habitat map is an important component of effective marine management. Newfoundland’s coastal area is covered by different marine habitats, which should be correctly mapped using advanced technologies, such as remote sensing methods. In this study, bathymetric Light Detection and Ranging (LiDAR) data were applied to accurately discriminate different habitat types in Bonne Bay, Newfoundland. To this end, the LiDAR intensity image was employed along with an object-based Random Forest (RF) algorithm. Two types of habitat classifications were produced: a two-class map (i.e., Vegetation and Non-Vegetation) and a five-class map (i.e., Eelgrass, Macroalgae, Rockweed, Fine Sediment, and Gravel/Cobble). It was observed that the accuracies of the produced habitat maps were reasonable considering the existing challenges, such as the error of the LiDAR data and lacking enough in situ samples for some of the classes such as macroalgae. The overall classification accuracies for the two-class and five-class maps were 87% and 80%, respectively, indicating the high capability of the developed machine learning model for future marine habitat mapping studies. The results also showed that Eelgrass, Fine Sediment, Gravel/Cobble, Macroalgae, and Rockweed cover 22.4% (3.66 km2), 51.4% (8.39 km2), 13.5% (2.21 km2), 6.9% (1.12 km2), and 5.8% (0.95 km2) of the study area, respectively.

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Aikanathan, Sarala, und A. Sasekumar. „The community structure of macroalgae in a low shore mangrove forest in Selangor, Malaysia“. Hydrobiologia 285, Nr. 1-3 (Juni 1994): 131–37. http://dx.doi.org/10.1007/bf00005661.

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Maggi, E., E. Puccinelli und L. Benedetti-Cecchi. „Ecological feedback mechanisms and variable disturbance regimes: the uncertain future of Mediterranean macroalgal forests“. Marine Environmental Research 140 (September 2018): 342–57. http://dx.doi.org/10.1016/j.marenvres.2018.07.002.

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Duarte, Carlos M. „Reviews and syntheses: Hidden forests, the role of vegetated coastal habitats in the ocean carbon budget“. Biogeosciences 14, Nr. 2 (23.01.2017): 301–10. http://dx.doi.org/10.5194/bg-14-301-2017.

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Abstract. Vegetated coastal habitats, including seagrass and macroalgal beds, mangrove forests and salt marshes, form highly productive ecosystems, but their contribution to the global carbon budget remains overlooked, and these forests remain hidden in representations of the global carbon budget. Despite being confined to a narrow belt around the shoreline of the world's oceans, where they cover less than 7 million km2, vegetated coastal habitats support about 1 to 10 % of the global marine net primary production and generate a large organic carbon surplus of about 40 % of their net primary production (NPP), which is either buried in sediments within these habitats or exported away. Large, 10-fold uncertainties in the area covered by vegetated coastal habitats, along with variability about carbon flux estimates, result in a 10-fold bracket around the estimates of their contribution to organic carbon sequestration in sediments and the deep sea from 73 to 866 Tg C yr−1, representing between 3 % and 1∕3 of oceanic CO2 uptake. Up to 1∕2 of this carbon sequestration occurs in sink reservoirs (sediments or the deep sea) beyond these habitats. The organic carbon exported that does not reach depositional sites subsidizes the metabolism of heterotrophic organisms. In addition to a significant contribution to organic carbon production and sequestration, vegetated coastal habitats contribute as much to carbonate accumulation as coral reefs do. While globally relevant, the magnitude of global carbon fluxes supported by salt-marsh, mangrove, seagrass and macroalgal habitats is declining due to rapid habitat loss, contributing to loss of CO2 sequestration, storage capacity and carbon subsidies. Incorporating the carbon fluxes' vegetated coastal habitats' support into depictions of the carbon budget of the global ocean and its perturbations will improve current representations of the carbon budget of the global ocean.

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Ginting, D. N. B., P. Wicaksono und N. M. Farda. „MAPPING BENTHIC HABITAT FROM WORLDVIEW-3 IMAGE USING RANDOM FOREST CASE STUDY: NUSA LEMBONGAN, BALI, INDONESIA“. International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVIII-4/W6-2022 (06.02.2023): 123–29. http://dx.doi.org/10.5194/isprs-archives-xlviii-4-w6-2022-123-2023.

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Abstract. Benthic habitats are coastal ecosystems that provide many benefits and play an important role in the diversity of nature. The maps are developed using random forest method on the Worldview-3 image. Optically shallow water around Nusa Lembongan was selected as the study area. Sunglint and water column correction were applied to surface reflectance data to produce deglint, depth invariant index, and deglint-depth invariant index band for random forest classification. In addition, tuning parameters, including the number of trees and the function to determine the number of randomly selected, are used in the classification. The benthic habitats classification scheme was constructed based on the variations of in situ data, which consisted of coral reefs, seagrass, macroalgae, and substrate. The confusion matrix was used to analyze the accuracy, and the McNemar test to evaluate the level of statistical significance between different processing scenarios. The best benthic habitats map is determined based on the accuracy and spatial distribution of the object. Meanwhile, the random forest algorithm produced 62.72% – 73.00% overall accuracy and these accuracy variations were not statistically significant. According to the findings, surface reflectance data with the parameter setting comprising 500 trees and square root function yielded the best random forest scenario for mapping benthic ecosystems.

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Setiawan, Kuncoro Teguh, Nana Suwargana, Devica Natalia Br. Ginting, Masita Dwi Mandini Manessa, Nanin Anggraini, Syifa Wismayati Adawiah, Atriyon Julzarika, Surahman Surahman, Syamsu Rosid und Agustinus Harsono Supardjo. „BATHYMETRY EXTRACTION FROM SPOT 7 SATELLITE IMAGERY USING RANDOM FOREST METHODS“. International Journal of Remote Sensing and Earth Sciences (IJReSES) 16, Nr. 1 (23.10.2019): 23. http://dx.doi.org/10.30536/j.ijreses.2019.v16.a3085.

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The scope of this research is the application of the random forest method to SPOT 7 data to produce bathymetry information for shallow waters in Indonesia. The study aimed to analyze the effect of base objects in shallow marine habitats on estimating bathymetry from SPOT 7 satellite imagery. SPOT 7 satellite imagery of the shallow sea waters of Gili Matra, West Nusa Tenggara Province was used in this research. The estimation of bathymetry was carried out using two in-situ depth-data modifications, in the form of a random forest algorithm used both without and with benthic habitats (coral reefs, seagrass, macroalgae, and substrates). For bathymetry estimation from SPOT 7 data, the first modification (without benthic habitats) resulted in a 90.2% coefficient of determination (R2) and 1.57 RMSE, while the second modification (with benthic habitats) resulted in an 85.3% coefficient of determination (R2) and 2.48 RMSE. This research showed that the first modification achieved slightly better results than the second modification; thus, the benthic habitat did not significantly influence bathymetry estimation from SPOT 7 imagery.

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Desmond, Matthew J., Liina Pajusalu, Daniel W. Pritchard, Tiffany A. Stephens und Christopher D. Hepburn. „Whole community estimates of macroalgal pigment concentration within two southern New Zealand kelp forests 1“. Journal of Phycology 55, Nr. 4 (24.06.2019): 936–47. http://dx.doi.org/10.1111/jpy.12884.

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Melis, R., G. Ceccherelli, L. Piazzi und M. Rustici. „Macroalgal forests and sea urchin barrens: Structural complexity loss, fisheries exploitation and catastrophic regime shifts“. Ecological Complexity 37 (Januar 2019): 32–37. http://dx.doi.org/10.1016/j.ecocom.2018.12.005.

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Pascoaloto, Domitila, Maria do Socorro Rocha da Silva, Antônia Gomes Neta Pinto, Terezinha de Jesus Gonçalves, Vanessa Karem Carvalho Lins, Juliana Freitas Lins, Roberta Kelly Batalha da Silva und Eliana Emiko Araújo Takano. „MACROALGAS E QUALIDADE DA ÁGUA EM TRÊS COMUNIDADES RIBEIRINHAS NA BACIA DO TARUMÃ-MIRIM, MANAUS (AM)“. Caminhos de Geografia 10, Nr. 29 (15.03.2009): 135–43. http://dx.doi.org/10.14393/rcg102916021.

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Este estudo foi desenvolvido como subsídio para explicar a alunos do ensino fundamental a importância do meio físico para organismos aquáticos. Foram investigadas as macroalgas e a qualidade da água do rio Tarumã-Mirim, próximo às comunidades Nossa Senhora de Fátima, Nossa Senhora do Livramento e São Sebastião. O estudo foi realizado entre setembro/2006 e maio/2007. As características físico-químicas da água nos três locais foram condizentes com as esperadas para rios de água preta: ácidas, com valores baixos de turbidez e condutividade, embora em alguns locais, com maior incidência de pessoas, principalmente nos finais de semana, o pH tenha sido superior a 5,0. A existência dos balneários ou das comunidades não afetou significativamente a qualidade da água dos rios, oposto do que foi observado anteriormente na parte urbana da bacia do Tarumã-Açu, onde as águas de quase todos os igarapés já estão contaminadas por esgotos domésticos e pelo "churumeâ€? do aterro sanitário. Macroalgas estiveram em Nossa Senhora de Fátima e do Livramento, onde houve substrato disponível. As espécies encontradas também não indicam contaminação das águas.

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Rognstad, Rhiannon, Andrew Rassweiler, Daniel Reed, Li Kui und Robert Miller. „Species Archetype Models of Kelp Forest Communities Reveal Diverse Responses to Environmental Gradients“. Oceanography 34, Nr. 2 (01.06.2021): 92–101. http://dx.doi.org/10.5670/oceanog.2021.217.

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Assessing ecosystem integrity by monitoring populations and communities is an important management tool, but is often limited by the immense variety of species and the rarity of many of them. Grouping species by their responses to variation in the environment is one approach to choosing species to serve as effective indicators of community change. Moreover, identifying species that are characterized by similar archetypical responses to the environment increases the power to predict their occurrence and simplifies management of diverse species assemblages by focusing on a much smaller number of archetypes. To this end, we used the species archetype model (SAM) to fit generalized linear models of environmental covariates to species distribution data in order to identify environmentally correlated groups of kelp forest species in the Santa Barbara Channel region. Eighty-two species of macroalgae, invertebrates, and fish monitored in kelp forests across the channel were grouped into one of 10 archetypes based on their similar responses to environmental parameters, with water temperature emerging as one of the strongest drivers of archetype differences. Predictive maps of the distribution of species archetypes identified sites where multiple archetypes are common, indicating high diversity, as well as sites where rare species are more likely to occur. Potential indicator species were identified for each archetype. New monitoring efforts across the growing Marine Biodiversity Observation Network could use modeling approaches like SAM to guide their designs, optimizing the cost-to-benefit ratio of monitoring whole communities.

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Capdevila, Pol, Cristina Linares, Eneko Aspillaga, Joan Lluís Riera und Bernat Hereu. „Effective dispersal and density-dependence in mesophotic macroalgal forests: Insights from the Mediterranean species Cystoseira zosteroides“. PLOS ONE 13, Nr. 1 (12.01.2018): e0191346. http://dx.doi.org/10.1371/journal.pone.0191346.

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Włodarska-Kowalczuk, Maria, Piotr Kukliński, Marta Ronowicz, Joanna Legeżyńska und Sławomira Gromisz. „Assessing species richness of macrofauna associated with macroalgae in Arctic kelp forests (Hornsund, Svalbard)“. Polar Biology 32, Nr. 6 (25.02.2009): 897–905. http://dx.doi.org/10.1007/s00300-009-0590-9.

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Schlenger, Adam J., Rodrigo Beas-Luna und Richard F. Ambrose. „Forecasting ocean acidification impacts on kelp forest ecosystems“. PLOS ONE 16, Nr. 4 (22.04.2021): e0236218. http://dx.doi.org/10.1371/journal.pone.0236218.

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Ocean acidification is one the biggest threats to marine ecosystems worldwide, but its ecosystem wide responses are still poorly understood. This study integrates field and experimental data into a mass balance food web model of a temperate coastal ecosystem to determine the impacts of specific OA forcing mechanisms as well as how they interact with one another. Specifically, we forced a food web model of a kelp forest ecosystem near its southern distribution limit in the California large marine ecosystem to a 0.5 pH drop over the course of 50 years. This study utilizes a modeling approach to determine the impacts of specific OA forcing mechanisms as well as how they interact. Isolating OA impacts on growth (Production), mortality (Other Mortality), and predation interactions (Vulnerability) or combining all three mechanisms together leads to a variety of ecosystem responses, with some taxa increasing in abundance and other decreasing. Results suggest that carbonate mineralizing groups such as coralline algae, abalone, snails, and lobsters display the largest decreases in biomass while macroalgae, urchins, and some larger fish species display the largest increases. Low trophic level groups such as giant kelp and brown algae increase in biomass by 16% and 71%, respectively. Due to the diverse way in which OA stress manifests at both individual and population levels, ecosystem-level effects can vary and display nonlinear patterns. Combined OA forcing leads to initial increases in ecosystem and commercial biomasses followed by a decrease in commercial biomass below initial values over time, while ecosystem biomass remains high. Both biodiversity and average trophic level decrease over time. These projections indicate that the kelp forest community would maintain high productivity with a 0.5 drop in pH, but with a substantially different community structure characterized by lower biodiversity and relatively greater dominance by lower trophic level organisms.

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Cannarozzi, Laura, Stanislao Bevilacqua, Giuseppina Alongi, Valentina Asnaghi, Mariachiara Chiantore, Annachiara Pagnotta, Chiara Paoli, Ilaria Rigo, Paolo Vassallo und Annalisa Falace. „Assessing the Effect of Full Protection on the Biomass of Ericaria amentacea and Understory Assemblages: Evidence from Two Mediterranean Marine Protected Areas“. Diversity 15, Nr. 1 (10.01.2023): 89. http://dx.doi.org/10.3390/d15010089.

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Cystoseira sensu lato marine forests, which are among the most productive and diverse systems in rocky intertidal and subtidal habitats of the Mediterranean Sea, are experiencing a widespread decline throughout the basin due to increasing human pressures. Yet it is still unclear whether Marine Protected Areas (MPAs) may represent effective tools for conservation of these important habitat formers and their associated assemblages. Here, we compared the biomass of intertidal stands of Ericaria amentacea (C. Agardh) Molinari and Guiry and their understory assemblages between the no-take zone and control sites in two Mediterranean MPAs. We did not find evidence supporting a significant effect of full protection in increasing the biomass of E. amentacea stands and associated assemblages, except for macroalgae of the understory in one of the investigated MPAs, raising concerns on the potential effectiveness of MPAs in mitigating human impacts on these marine forests. Such findings call for major efforts to implement long-term monitoring programs of protected Cystoseira s.l. forests in order to inform an adaptive management of conservation measures within MPAs and eventually to set active interventions of restoration.

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KLETOU, DEMETRIS, IOANNIS SAVVA, KONSTANTINOS TSIAMIS und JASON M. HALL-SPENCER. „Opportunistic seaweeds replace Cystoseira forests on an industrialised coast in Cyprus“. Mediterranean Marine Science 19, Nr. 3 (16.07.2018): 598. http://dx.doi.org/10.12681/mms.16891.

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Seaweeds are affected by humans worldwide, although no studies have assessed this in Cyprus. The Water Framework Directive requires ecological assessments of European coastal waters with biological indicators. We investigated macroalgal community metrics in the upper subtidal across ca 10 km of shoreline, encompassing undeveloped areas with limited human access as well as the most industrialised and impacted coast of Cyprus (Vasiliko Bay). Quadrats (20 x 20cm) were used to survey the algal communities in summer 2012 and spring 2013. Of the 51 taxa, we recorded, Cladophora nigrescens and Laurencia caduciramulosa (a non-native species) are new records for Cyprus. Brown algae of the genus Cystoseira, e.g., Cystoseira barbatula, formed dense forests covering rocky substrata on shorelines with limited human access. Cystoseira decreased in abundance around bathing waters and was very rare in heavily industrialised parts of the bay. In impacted areas, fleshy and filamentous opportunistic species such as opportunistic Ulva and Chaetomorpha species with lower biomass than perennial species, proliferated in spring. The Ecological Evaluation Index (EEI-c) we used was a robust biotic index reflecting anthropogenic stress. Without improved management, the Marine Strategy Framework Directive targets may not be met on some coastlines of Cyprus since seaweed forests are in decline and are further threatened by imminent development.

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