Effects of acidification on the biogeochemistry of unvegetated and seagrass marine sediments.

Many studies addressed ocean acidification (OA) effects on marine life, whereas its effects on sedimentary organic matter (OM) have received less attention. We investigated differences in OM features in sediments from unvegetated and seagrass (Posidonia oceanica) beds in a shallow hydrothermal area (Aeolian Archipelago, Mediterranean Sea), under natural (8.1-8.0) and acidified (7.8-7.9) conditions. We show that a pH difference of -0.3 units have minor effects on OM features in unvegetated sediments, but relevant consequences within acidified seagrass meadows, where OM quantity and nutritional quality are lower than those under natural pH conditions. Effects of acidified conditions on OM biogeochemistry vary between unvegetated and seagrass sediments, with lower C degradation rates and longer C turnover time in the former than in the latter. We conclude that OA, although with effects not consistent between unvegetated and vegetated sediments, can affect OM quantity, composition, and degradation, thus having possible far-reaching consequences for benthic trophic webs.

Local businesses' consumption and perception of Single-Use Plastics: A preliminary assessment for conservation and mitigation plans in the Egadi Islands Marine Protected Area.

Modern society depends on plastic, especially through single-use plastic products (SUPs), which can affect ecological systems after use. Local policymakers can strategically adopt measures against SUPs pollution by setting effective local governance. This work was designed to evaluate SUPs consumption inside the Marine Protected Area of the Egadi Islands. A questionnaire mixed approach to understanding stakeholders' consumption, attitudes and perceptions about the uses and impacts of SUPs in the third sector was used. Results show a significant seasonal consumption of SUPs and uncertainty in the behaviour to discard them. These provide valuable insights to fill research gaps in estimating the use of SUPs and consumers' perceptions. The main aim of this work has been to understand the critical issues regarding the use of SUPs, considering the target area's patterns, in support of designing action plans for changing behaviour and the mitigation of critical issues in favour of environmental conservation.

Larval connectivity of the invasive blue crabs Callinectes sapidus and Portunus segnis in the Mediterranean Sea: A step toward improved cross border management.

The two invasive blue crabs, Callinectes sapidus and Portunus segnis have spread rapidly in the Mediterranean and no data exists on the connectivity of populations. Determining the source and recruitment areas is crucial to prioritize where population control measures should be put into immediate action. We simulated the dispersal of blue crab larvae using a Lagrangian model coupled at high resolution to estimate the potential connectivity of blue crab populations over a 3-year period. Our results reveal that the main areas at risk are the Spanish, French, Italian Tyrrhenian and Sardinian coasts for Callinectes sapidus with high populations connectivity. Tunisia and Egypt represent high auto recruitment zones for Portunus segnis restricted to the central and western basins. This study provides an overview of the connectivity between populations and will help define priority areas that require the urgent implementation of management measures.

Evenness, biodiversity, and ecosystem function of intertidal communities along the Italian coasts: Experimental short-term response to ambient and extreme air temperatures.

Biodiversity can promote ecosystem functioning in both terrestrial and marine environments, emphasizing the necessity of biodiversity conservation in order to preserve critical ecosystem functions and associated services. However, the role of biodiversity in buffering ecosystem functioning under extreme events caused by climate change remains a major scientific issue, especially for intertidal systems experiencing stressors from both terrestrial and marine drivers. We performed a regional-scale field experiment along the Italian coast to investigate the response of unmanipulated intertidal communities (by using a natural biodiversity gradient) to low tide aerial exposure to both ambient and short-term extreme temperatures. We specifically investigated the relationship between Biodiversity and Ecosystem Functioning (BEF) using different biodiversity indexes (species richness, functional diversity and evenness) and the response of the intertidal communities' ecosystem functioning (community respiration rates). Furthermore, we investigated which other environmental variables could influence the BEF relationship. We show that evenness explained a greater variation in intertidal community ecosystem functioning under both temperature conditions. Species richness (the most often used diversity metric in BEF research) was unrelated to ecosystem functioning, while functional diversity was significantly related to respiration under ambient but not extreme temperatures. We highlight the importance of the short-term thermal history of the communities (measured as body temperature) in the BEF relationship as it was consistently identified as the best predictor or response under both temperature conditions. However, Chlorophyll a in seawater and variation in sea surface temperature also contributed to the BEF relationship under ambient but not under extreme conditions, showing that short-duration climate-driven events can overcome local physiological adaptations. Our findings support the importance of the BEF relationship in intertidal communities, implying that systems with more diverse and homogeneous communities may be able to mitigate the effects of extreme temperatures.

Impact of COVID-19 on Croatian mariculture: Findings from the first national surveys.

An overview of the negative effects of the COVID-19 pandemic on the mariculture industry of the republic of Croatia is provided. An initial online survey was circulated early after the onset of the pandemic and a follow-up field survey was performed a year into the pandemic. The surveyed companies varied in size (micro to medium enterprises), location (north, central and southern coast) and cultured organism (European flat oyster, Mediterranean mussel, European sea bass, Gilthead sea bream and/or Bluefin tuna) and were asked questions on the subject of economic and job losses, aquaculture supply chain processes and implemented or proposed measures for mitigation of negative effects. Results from the online survey showed higher economic loss than job loss, but companies reported increased job loss in the period leading to the field survey. Most companies reported reductions in sales and avenues of procurement, which, in addition to direct stressors, indirectly affected business processes. Micro enterprises fared well due to their part-time nature, low capital investments and running costs, while small to medium enterprises were under the most pressure. Large enterprises were barely affected as they had secure local and/or international distribution chains and dominated the market. Producers most affected were those that relied on the HoReCa market for product placement and/or had difficulty coping with existing stressors. Bivalve producers generally experienced a higher drop in sales than finfish farms and companies with specialized production were not able to adapt to market changes to the degree that more versatile businesses seemed capable of.

Biological traits approaches in benthic marine ecology: Dead ends and new paths.

Biological traits analysis (BTA) links community structure to both ecological functions and response to environmental drivers through species' attributes. In consequence, it has become a popular approach in marine benthic studies. However, BTA will reach a dead end if the scientific community does not acknowledge its current shortcomings and limitations: (a) uncertainties related to data origins and a lack of standardized reporting of trait information; (b) knowledge gaps on the role of multiple interacting traits on driving the organisms' responses to environmental variability; (c) knowledge gaps regarding the mechanistic links between traits and functions; (d) a weak focus on the spatial and temporal variability that is inherent to the trait expression of species; and, last but not least, (e) the large reliance on expert knowledge due to an enormous knowledge gap on the basic ecology of many benthic species. BTA will only reach its full potential if the scientific community is able to standardize and unify the reporting and storage of traits data and reconsider the importance of baseline observational and experimental studies to fill knowledge gaps on the mechanistic links between biological traits, functions, and environmental variability. This challenge could be assisted by embracing new technological advances in marine monitoring, such as underwater camera technology and artificial intelligence, and making use of advanced statistical approaches that consider the interactive nature and spatio-temporal variability of biological systems. The scientific community has to abandon some dead ends and explore new paths that will improve our understanding of individual species, traits, and the functioning of benthic ecosystems.

Mediterranean rocky reefs in the Anthropocene: Present status and future concerns.

Global change is striking harder and faster in the Mediterranean Sea than elsewhere, where high levels of human pressure and proneness to climate change interact in modifying the structure and disrupting regulative mechanisms of marine ecosystems. Rocky reefs are particularly exposed to such environmental changes with ongoing trends of degradation being impressive. Due to the variety of habitat types and associated marine biodiversity, rocky reefs are critical for the functioning of marine ecosystems, and their decline could profoundly affect the provision of essential goods and services which human populations in coastal areas rely upon. Here, we provide an up-to-date overview of the status of rocky reefs, trends in human-driven changes undermining their integrity, and current and upcoming management and conservation strategies, attempting a projection on what could be the future of this essential component of Mediterranean marine ecosystems.

The buffer effect of canopy-forming algae on vermetid reefs' functioning: A multiple stressor case study.

Biodiversity plays a key role for our planet by buffering ongoing and future changes in environmental conditions. We tested if canopy-forming algae enhancing biodiversity (CEB) in a Mediterranean intertidal reef ecological community could alleviate the effect of stressors (heat waves and pollution from sewage) on community metabolic rates (as expressed by oxygen consumption) used as a proxy of community functioning. CEB exerted a buffering effect related to the properties of stressor: physical-pulsing (heat wave) and chronic-trophic (sewage). After a simulated heat wave, CEB was effective in buffering the impacts of detrimental temperatures on the functioning of the community. In reefs exposed to chronic sewage effluents, benefits derived from CEB were less evident, which is likely due to the stressor's contextual action. The results support the hypothesis that ecological responses depend on stressor typology acting at local level and provide insights for improving management measures to mitigate anthropogenic disturbance.

Non-indigenous species in Mediterranean ports: A knowledge baseline.

Port areas have been considered bioinvasion hotspots due to the concentration of several invasion vectors. However, the actual distribution of non-indigenous species (NIS) in Mediterranean ports is still poorly understood. Here we conducted a literature review with the aim to provide a knowledge baseline about NIS distribution in Mediterranean ports. NIS distribution in Mediterranean ports showed a high degree of heterogeneity in terms of studies across the whole basin, with a limited knowledge on both specific taxa and geographical areas, as well as a generally low proportion of investigated ports. The low rate of specific studies designed to monitor these particular environments may represent the main source of knowledge gaps. Mediterranean ports host NIS from all regions of the world, playing a key role in marine bioglobalization. Our synthesis represents the first baseline addressing the presence of NIS in Mediterranean ports, which may be useful to define plans of NIS management and strategies focusing on a network of recognised focal hotspots.

Seascape connectivity of European anchovy in the Central Mediterranean Sea revealed by weighted Lagrangian backtracking and bio-energetic modelling.

Ecological connectivity is one of the most important processes that shape marine populations and ecosystems, determining their distribution, persistence, and productivity. Here we use the synergy of Lagrangian back-trajectories, otolith-derived ages of larvae, and satellite-based chlorophyll-a to identify spawning areas of European anchovy from ichthyoplanktonic data, collected in the Strait of Sicily (Central Mediterranean Sea), i.e., the crucial channel in between the European and African continents. We obtain new evidence of ecosystem connectivity between North Africa and recruitment regions off the southern European coasts. We assess this result by using bio-energetic modeling, which predicts species-specific responses to environmental changes by producing quantitative information on functional traits. Our work gives support to a collaborative and harmonized use of Geographical Sub-Areas, currently identified by the General Fisheries Commission for the Mediterranean. It also confirms the need to incorporate climate and environmental variability effects into future marine resources management plans, strategies, and directives.

Predicting shifting sustainability trade-offs in marine finfish aquaculture under climate change.

Defining sustainability goals is a crucial but difficult task because it often involves the quantification of multiple interrelated and sometimes conflicting components. This complexity may be exacerbated by climate change, which will increase environmental vulnerability in aquaculture and potentially compromise the ability to meet the needs of a growing human population. Here, we developed an approach to inform sustainable aquaculture by quantifying spatio-temporal shifts in critical trade-offs between environmental costs and benefits using the time to reach the commercial size as a possible proxy of economic implications of aquaculture under climate change. Our results indicate that optimizing aquaculture practices by minimizing impact (this study considers as impact a benthic carbon deposition ≥ 1 g C m-2  day-1 ) will become increasingly difficult under climate change. Moreover, an increasing temperature will produce a poleward shift in sustainability trade-offs. These findings suggest that future sustainable management strategies and plans will need to account for the effects of climate change across scales. Overall, our results highlight the importance of integrating environmental factors in order to sustainably manage critical natural resources under shifting climatic conditions.

Monitoring of persistent organic pollutants in the polar regions: knowledge gaps & gluts through evidence mapping.

Persistent organic pollutants (POPs) are widespread compounds that accumulating in polar regions canalise through trophic webs. Although several dozens of studies have been carried out in the last decades, the information is generally scattered across a large number of literature sources. This does not allow an efficient synthesis and constraints our understanding on how address future monitoring plans and environmental conservation strategies on the Polar Regions with respect to POPs. Thus, here, we present the outcome of a systematic map (SM) to scope, screen and chart evidences from literature dealing with POPs in Polar regions. The SMs strive to produce rigorous guidelines and have recently been proposed as useful and effective tools to summarise growing bodies of research that seek to reduce bias and increase reliability, particularly in the case of high priority and controversial topics. Our SM was based on 125 polar studies, focussing on the most studied target species among those listed in the International Union for Conservation of Nature's Red List (IUCN Red List). To facilitate analysis of evidence, the studies were classified into Accumulation Monitoring (accounting for POP monitoring through sub-organismal, functional and population levels) and Food Web Monitoring approaches (accounting for contaminants monitoring through food webs). Our SM allowed us to assess and visualise, a set of both knowledge gaps and gluts and lastly a list was provided to address future research on POPs in Polar Regions.

Ecological assessment of a heavily human-stressed area in the Gulf of Milazzo, Central Mediterranean Sea: an integrated study of biological, physical and chemical indicators.

Marine environmental disturbance can be assessed directly from physical and chemical parameters, or indirectly by the study of indicator species. In this study, an integrated approach to monitor the Gulf of Milazzo, labeled as a highly contaminated site, is presented. A total of 83 samples were collected from hard and soft bottoms in 2010. In sum, 2739 specimens belonging to 246 taxa, two first records for the Tyrrhenian Sea (Micronephthys stammeri and Nicomache lumbricalis) and three nonindigenous species (Brachidontes pharaonis, Crassostrea gigas and Notomastus aberans) were recorded. Biodiversity and biotic indices and their relationship with sediment parameters and the level of pollutants were assessed to describe faunal assemblage and evaluate environmental quality. Pearson tests evidenced significant negative correlation between polychlorinated biphenyls (PCBs) and specific richness (p<0.10). A comparison of the standard and recorded biotic values showed that M-AMBI seems to be the index more representative of ecological quality status (EcoQ) in the Gulf of Milazzo. No evident signs were highlighted on the complex.