Editorial: New plastic pollution types and novel sources of microplastic pollution in marine systems

Plastic pollution has been extensively studied over the past decades. For instance, it is well known that animals get entangled in discarded plastic (Afonso and Fidelis, 2023) and consume microplastics (plastic particles < 5 mm) while foraging (Ehlers et al., 2021). Examples of microplastic sources comprise everyday single-use items such as plastic packaging material (Tziourrou et al., 2021), lost or discarded plastic fishing gear (Wu et al., 2023), and tire wear (Goßmann et al., 2021). However, novel microplastic sources, such as weathering polymer-based paints, have only recently been identified (Figure 1A). Even though paints are used in various applications on a regular basis, this source has been largely neglected in the past (Gaylarde et al., 2021)

Exploring visual methods for monitoring marine non-indigenous species colonizing artificial structures in the Madeira archipelago (NE Atlantic)

The introduction of non-indigenous species (NIS) poses a significant threat to biodiversity in coastal communities globally, with maritime traffic serving as a primary vector for introducing these species into new habitats. Managing potential new marine invasions begins in harbours and marinas, where artificial structures are the first step towards establishing new habitats. In this study, we aimed to examine and compare the performance of three methods: Plate, Photo quadrate, and a new Video approach, using image analysis for monitoring fouling communities in artificial structures, with a specific focus on NIS in marinas. Additionally, we evaluated attributes for each method, including cost, area, deployment/sampling time, and logistics, to determine the most reliable, efficient, and affordable method with respect to species richness (S) and cover (N). The video (VID) method performed similarly to the plate (PLA) method in species identification and outperformed the photo (PHO) method. The VID method represents a novel and faster approach for monitoring NIS in artificial structures, offering several advantages. It allows data gathering that can be performed by non-taxonomic experts, facilitating rapid detection and intervention in managing marine invasions in port environments. By assessing the effectiveness of these methods, we sought to contribute to developing improved strategies and faster approaches for monitoring and mitigating the impact of NIS in coastal communities

Non-Indigenous Species on Artificial Coastal Environments: Experimental Comparison between Aquaculture Farms and Recreational Marinas

Globally, there is growing concern regarding the effects of the increasing anthropogenic pressures in marine communities. Artificial structures such as marinas and aquaculture facilities serve as invasion hotspots; hence, monitoring fouling communities on these structures can be valuable for detecting new invasions. In the current study, 24 settlement PVC plates were deployed for three months to compare the recruitment ability of these two artificial environments along the south coast of the offshore island of Madeira (NE Atlantic). The results showed higher variations in the species richness between regions (SW vs. SE) than between artificial habitats (sea-cages vs. marinas), although the community composition differed. Cnidaria and Bryozoa were the most representative groups in the aquaculture systems, while Bryozoa and Chordata were in the marinas. A sum of 18 NIS was recorded for the study, accounting for between 21.88% and 54.84% of the total number of species in the aquaculture facilities and marinas, respectively. The higher NIS percentage from the marinas was even more explicit in the SE coast, where Cradoscrupocellaria bertholletii, Parasmittina alba, and Botrylloides niger distinctly dominated fouling populations. The results suggest that at least some particular NIS previously reported in the studied marinas successfully colonized sea-cages. Future assessments need to address the potential role of aquaculture facilities as drivers for the secondary spread of NIS. Additionally, two new records are considered for Madeira: Eudendrium capillare and Ericthonius punctatus.Versión del edito

Management of non-indigenous species in Macaronesia: Misconceptions and alerts to decision-makers

Human-induced pressures have led to substantial changes in marine ecosystems worldwide, with the introduction of non-indigenous species (NIS) emerging as a significant threat to ecological, economic, and social aspects. The Macaronesian islands, comprising the Azores, Madeira, Canary Islands, and Cabo Verde archipelagos, are regions where the regional economy is dependent on marine resources (e.g., marine traffic, ecotourism and fisheries). Despite their importance, concerted efforts to manage marine biological invasions in Macaronesia have been scarce. In this context, the current study aims to contribute to the much-needed debate on biosecurity measures in this unique insular ecosystem to prevent and mitigate the impact of NIS. By adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria, this work validated and analyzed 260 documents providing insights into the management of NIS in Macaronesia until 2022. These documents revealed the presence of 29 Invasive Alien Species (IAS), most of which are misconceptions regarding this terminology. Most studies focused on the stages of early detection, rapid response, and eradication across the archipelagos. Cabo Verde had comparatively fewer studies. The most common techniques include monitoring/sampling, literature reviews, and taxonomic reviews. NIS introduction pathways were mainly attributed to transport (stowaway) and unaided migration, with ship fouling, ballast water, rafting, ocean currents, and tropicalization being also identified as significant contributors. This systematic review highlights the current efforts to establish robust biosecurity protocols in Macaronesia and emphasizes the urgent need to safeguard the region's ecological, economic, and social well-being.11 página

Marine fouling communities from artificial and natural habitats: comparison of resistance to chemical and physical disturbances

Assessing the resistance of fouling communities to anthropogenic disturbances is an important goal for the development of effective management and control strategies. In this context, we conducted a manipulative experiment on natural and artificial habitats to examine fouling communities that developed outside and inside a marina on Madeira Island (NE Atlantic Ocean) following the application of two types of stressors frequently observed in coastal habitats, namely chemical and physical disturbances. The tested fouling communities, dominated by native and non- indigenous species respectively, were in general strongly affected by the chemical but not by the physical disturbance applied, and a higher resistance to disturbance was observed in the communities outside the marina. This suggests higher capacities for communities richer in native species to tolerate anthropogenic disturbances, while non-indigenous species did not play a key role. Further research can assess the resilience of natural and artificial fouling communities when exposed to disturbances

The collapse of marine forests: drastic reduction in populations of the family Sargassaceae in Madeira Island (NE Atlantic)

Species of the genera Cystoseira, Ericaria, Gongolaria, and Sargassum (family Sargassaceae) are key components of the Mediterranean-Atlantic marine forests, essential for biodiversity and ecosystem functioning. Populations of these foundational species are particularly vulnerable to anthropogenic impacts, likely to be intensified under future scenarios of climate change. The decline and even disappearance of these species have been reported in different areas of the world. At Madeira Island (NE Atlantic), populations of Gongolaria abies-marina, Ericaria selaginoides, Sargassum vulgare, and Sargassum filipendula, the most ecologically relevant species in Macaronesian marine forests, have been suffering a drastic decline during the last decades, especially on the southern coast of the island, where anthropogenic pressure is higher than on the north coast. The lack of sufficient temporal coverage on qualitative and quantitative studies of Sargassaceae communities in Madeira poses a challenge to establish a specific period for this decline. Consulting qualitative studies and historical records, we have set for the first time a timeline that shows an evident decrease in Sargassaceae populations in the last 20 years on Madeira Island. Following this timeline, we pinpoint the start of this decline in the first decade of the 2000s. This can be particularly confirmed for places like Funchal and Reis Magos, with significantly higher historical records. Currently, most benthic communities on shallow subtidal rocky reefs along the south coast are dominated by sea urchins and crustose coralline algae, the so-called sea urchin barrens. However, in some cases, they are entirely covered by a layer of sediment. We discuss the possible factors contributing to these drastic changes, bringing Madeira’s marine forests to a dramatic decline. As many animal species rely on marine forests, the decline of Sargassaceae populations represents an invaluable ecological loss for the coastal ecosystem of the island.M1420-09-5369-FSE-000002, CEECINST/00098/2018, MAC2/1.1a/347, MAC2/4.6d/249, UIDB/04292/2020info:eu-repo/semantics/publishedVersio

The role of biofilms developed under different anthropogenic pressure on recruitment of macro-invertebrates

Microbial biofilms can be key mediators for settlement of macrofoulers. The present study examines the coupled effects of microbial biofilms and local environmental conditions on the composition, structure and functioning of macrofouling assemblages. Settlement of invertebrates over a gradient of human-impacted sites was investigated on local biofilms and on biofilms developed in marine protected areas (MPAs). Special attention was given to the presence of non-indigenous species (NIS), a global problem that can cause important impacts on local assemblages. In general, the formation of macrofouling assemblages was influenced by the identity of the biofilm. However, these relationships varied across levels of anthropogenic pressure, possibly influenced by environmental conditions and the propagule pressure locally available. While the NIS Watersipora subatra seemed to be inhibited by the biofilm developed in the MPA, Diplosoma cf. listerianum seemed to be attracted by biofilm developed in the MPA only under mid anthropogenic pressure. The obtained information is critical for marine environmental management, urgently needed for the establishment of prevention and control mechanisms to minimize the settlement of NIS and mitigate their threats.Xunta de Galicia | Ref. I2C-BXunta de Galicia | Ref. FEDER ED431D 2017/20Xunta de Galicia | Ref. ED431C 2017/46Agência Regional para o Desenvolvimento da Investigação Tecnologia e Inovação (ARDITI) | Ref. M1420-09-5369-FSE-000001European Regional Development Fund | Ref. M1420-01-0145-FEDER-000001Fundação para a Ciência e Tecnologia | Ref. UIDB/04292/2020Fundação para a Ciência e a Tecnologia | Ref. CEECINST/00098/201

Disease Outbreak in a Keystone Grazer Population Brings Hope to the Recovery of Macroalgal Forests in a Barren Dominated Island

Macroalgal forests play a key role in shallow temperate rocky reefs worldwide, supporting communities with high productivity and providing several ecosystem services. Sea urchin grazing has been increasingly influencing spatial and temporal variation in algae distributions and it has become the main cause for the loss of these habitats in many coastal areas, causing a phase shift from macroalgae habitats to barren grounds. The low productive barrens often establish as alternative stable states and only a major reduction in sea urchin density can trigger the recovery of macroalgal forests. The present study aims to assess if the 2018 disease outbreak, responsible for a strong reduction in the sea urchin Diadema africanum densities in Madeira Island, was able to trigger a reverse shift from barren grounds into macroalgae-dominated state. By assessing the diversity and abundance of benthic sessile organisms, macroinvertebrates and fishes before, during and after that particular mass mortality event, we evaluate changes in benthic assemblages and relate them to variations in grazer and herbivore densities. Our results revealed a clear shift from barren state to a macroalgae habitat, with barrens characterized by bare substrate, sessile invertebrate and Crustose Coralline Algae (CCA) disappearing after the mortality event. Overall variations in benthic assemblages was best explained by four taxa (among grazers and herbivores species). However, it was the 2018 demise of D. africanum and its density reduction that most contributed to the reverse shift from a long stable barren state to a richer benthic assemblage with higher abundance of macroalgae. Despite this recent increase in macroalgae dominated habitats, their stability and persistence in Madeira Island is fragile, since it was triggered by an unpredictable disease outbreak and depends on how D. africanum populations will recover. With no control mechanisms, local urchin populations can easily reach the tipping point needed to promote a new shift into barren states. New conservation measures and active restoration are likely required to maintain and promote the local stability of macroalgal forests

A worrying arrival: the first record of brown macroalga Rugulopteryx okamurae in Madeira Island and its invasive risk

The brown macroalgae Rugulopteryx okamurae is described as one of the most severe and threatening invasive marine macroalgae in European waters. This study reports the first record of R. okamurae in the Madeira archipelago, which represents a new southern distribution limit of this species in NE Atlantic European waters. Morphological and molecular characters were used to confirm the species' identity, and its potential invasion risk in Madeiran waters was screened using the standard risk assessment tool AS-ISK. Results show that R. okamurae has a medium-high risk of becoming invasive in Madeira Island under present and future climate scenarios. The greater risk of impact involves suppressing local species growth and the modification and degradation of local habitats, including trophic cascade effects. However, environmental and commercial impacts could also occur in case of an explosion of the invasive populations. This new introduction in Madeira coastal waters emphasises the need for regular monitoring of R. okamurae, particularly to assess population dynamics to avoid establishing and further expansions. Finally, we recommend the evaluation of the possible derived impacts affecting rocky coastal communities and adopting the necessary mitigation measures and policies