Species composition plays a key role in ecosystem functioning. Theoretical, experimental and field studies show positive effects of biodiversity on ecosystem processes. However, this link can differ between taxonomic and functional diversity components and also across trophic levels. These relationships have been hardly studied in planktonic communities of coastal upwelling systems. Using a 28-year time series of phytoplankton and zooplankton assemblages, we examined the effects of phytoplankton diversity on resource use efficiency (RUE, ratio of biomass to limiting resource) at the two trophic levels in the Galician upwelling system (NW Iberian peninsula). By fitting generalized least square models, we show that phytoplankton diversity was the best predictor for RUE across planktonic trophic levels. This link varied depending on the biodiversity component considered: while the effect of phytoplankton richness on RUE was positive for phytoplankton RUE and negative for zooplankton RUE, phytoplankton evenness effect was negative for phytoplankton RUE and positive for zooplankton RUE. Overall, taxonomic diversity had higher explanatory power than functional diversity, and variability in phytoplankton and zooplankton RUE decreased with increasing phytoplankton taxonomic diversity. Phytoplankton used resources more efficiently in warmer waters and at greater upwelling intensity, although these effects were not as strong as those for biodiversity. These results suggest that phytoplankton species numbers in highly dynamic upwelling systems are important for maintaining the planktonic biomass production leading us to hypothesize the relevance of complementarity effects. However, we further postulate that a selection effect may operate also because assemblages with low evenness were dominated by diatoms with specific functional traits increasing their ability to exploit resources more efficiently.
The design and development of an offshore port terminal is a complex task that involves distinctive design and decision challenges. In this paper, we propose the implementation of a floating, modular, platform that can act as an additional terminal of a port, with the aim of expanding its current container handling capacity. To this end, we introduce a generic methodology to tackle three aspects of an offshore terminal: terminal layout design, strategic logistics optimization, and operational process coordination. The terminal layout design includes the modular arrangements, handling on and between platform modules by the associated equipment. To select the final layout design concept, we evaluate different alternatives on criteria such as layout complexity, scalability, and the number of moves associated with the modular nature of the platform. Subsequently, the selected concept is given as input to a strategic logistics optimization approach that introduces a mixed-integer linear programming model. The proposed model minimizes the capital, operational, and maintenance costs of the floating modular terminal, i.e., number and size of modules, number and type of equipment, as well as capacities. In parallel, we develop a simulation of the floating terminal’s hinterland connections, where the number and type of required vessels are specified for relevant destinations and transport configurations. At the operational level, we focus on the coordination of handling equipment on the offshore platform by employing a tailored simulation/optimization approach. Our methodology is demonstrated on a case study that considers accommodating the growth of a port in the Hamburg-Le Havre range via the use of a modular, floating, transport, and logistics hub.
In the Gulf of Mexico, the bulk of published studies for sea turtles have focused on northern (United States) waters where economic resources are centered, with fewer studies in the southern portion of the basin, resulting in significant knowledge gaps in these underrepresented areas. Similarly, publications on adult sea turtles are dominated by research on females that come ashore to nest and can be readily studied (e.g., through the collection of biological samples and the application of satellite-telemetry devices), whereas information on adult male sea turtles is scarce. The goal of this paper is to begin filling these knowledge gaps by synthesizing available data on adult male sea turtles in the southern Gulf of Mexico. We used satellite-telemetry, boat- and drone-based surveys, and stranding records combined with ocean circulation modeling to better understand the spatial distribution of male loggerhead (Caretta caretta), green (Chelonia mydas), hawksbill (Eretmochelys imbricata), and Kemp’s ridley (Lepidochelys kempii) sea turtles in the southern Gulf of Mexico. These spatially explicit analyses will provide context for opportunistically collected data on male sea turtles and better contribute to the management and restoration of sea turtle populations that use the Gulf of Mexico. Moreover, this synthesis can serve as a launching point for directed studies on male sea turtles in this region.
Chemical changes in the diffusive boundary layer (DBL) generated by photosynthesising macroalgae are expected to play an important role in modulating the effects of ocean acidification (OA), but little is known about the effects on early life stages of marine invertebrates in modified DBLs. Larvae that settle to macroalgal surfaces and remain within the DBL will experience pH conditions markedly different from the bulk seawater. We investigated the interactive effects of seawater pH and DBL thickness on settlement and early post-settlement growth of the sea urchin Pseudechinus huttoni, testing whether coralline-algal DBLs act as an environmental buffer to OA. DBL thickness and pH levels (estimated from well-established relationships with oxygen concentration) above the crustose coralline algal surfaces varied with light availability (with photosynthesis increasing pH to as high as pH 9.0 and respiration reducing pH to as low as pH 7.4 under light and dark conditions, respectively), independent of bulk seawater pH (7.5, 7.7, and 8.1). Settlement success of P. huttoni increased over time for all treatments, irrespective of estimated pH in the DBL. Juvenile test growth was similar in all DBL manipulations, showing resilience to variable and low seawater pH. Spine development, however, displayed greater variance with spine growth being negatively affected by reduced seawater pH in the DBL only in the dark treatments. Scanning electron microscopy revealed no observable differences in structural integrity or morphology of the sea urchin spines among pH treatments. Our results suggest that early juvenile stages of P. huttoni are well adapted to variable pH regimes in the DBL of macroalgae across a range of bulk seawater pH treatments.
Biological fitness relies on processes acting at various levels of organization, all of which can be modified by environmental change. Application of synthesis frameworks, such as the Adverse Outcome Pathway (AOP), can enhance our understanding of the responses to stressors identified in studies at each level, as well as the links among them. However, the use of such frameworks is often limited by a lack of data. In order to identify contexts with sufficient understanding to apply the AOP framework, we conducted a meta-analysis of studies considering ocean acidification effects on calcifying mollusks. Our meta-analysis identified that most studies considered the adult life history stage, bivalve taxonomic group, individual-level changes, and growth- and metabolism-related responses. Given the characteristics of the published literature, we constructed an AOP for the effects of ocean acidification on calcification in an adult bivalve, specifically the Pacific oyster (Magallana gigas). By structuring results within the AOP framework, we identify that, at present, the supported pathways by which ocean acidification affects oyster calcification are via the downregulation of cavortin and arginine kinase transcription. Such changes at the molecular level can prompt changes in cellular and organ responses, including altered enzyme activities, lipid peroxidation, and regulation of acid–base status, which have impacts on organism level metabolic rate and, therefore, calcification. Altered calcification may then impact organism mortality and population sizes. We propose that when developed and incorporated in future studies, the AOP framework could be used to investigate sources of complexity including varying susceptibility within and among species, feedback mechanisms, exposure duration and magnitude, and species interactions. Such applications of the AOP framework will allow more effective reflections of the consequences of environmental change, such as ocean acidification, on all levels of biological organization.
The growth of phytoplankton at high latitudes was generally thought to begin in open waters of the marginal ice zone once the highly reflective sea ice retreats in spring, solar elevation increases, and surface waters become stratified by the addition of sea-ice melt water. In fact, virtually all recent large-scale estimates of primary production in the Arctic Ocean (AO) assume that phytoplankton production in the water column under sea ice is negligible. However, over the past two decades, an emerging literature showing significant under-ice phytoplankton production on a pan-Arctic scale has challenged our paradigms of Arctic phytoplankton ecology and phenology. This evidence, which builds on previous, but scarce reports, requires the Arctic scientific community to change its perception of traditional AO phenology and urgently revise it. In particular, it is essential to better comprehend, on small and large scales, the changing and variable icescapes, the under-ice light field and biogeochemical cycles during the transition from sea-ice covered to ice-free Arctic waters. Here, we provide a baseline of our current knowledge of under-ice blooms (UIBs), by defining their ecology and their environmental setting, but also their regional peculiarities (in terms of occurrence, magnitude, and assemblages), which is shaped by a complex AO. To this end, a multidisciplinary approach, i.e., combining expeditions and modern autonomous technologies, satellite, and modeling analyses, has been used to provide an overview of this pan-Arctic phenological feature, which will become increasingly important in future marine Arctic biogeochemical cycles.
Shipping is the most pervasive source of anthropogenic underwater continuous noise and local intermittent noise. This study focused on the separation of anthropogenic intermittent noise from dynamic background noise in the Gulf of Finland using an adaptive threshold level (ATL) technique. The intermittent noise was validated with Automatic Identification System (AIS) data and the background noise with selected environmental factors. Separated components were characterized and compared with a sound exposure level (SEL) in three 1/3 octave bands. Intermittent noise can be separated with ATL in the Baltic Sea, and vessel traffic identified as the primary source. Background noise varies spatially and is partially explained by environmental factors. Intermittent noise has strong persisting influence on the acoustic environment near shipping lanes, elevating the SEL in each of the 1/3 octave bands: by 20–30 dB in the 63 Hz band, by 13–22 dB in the 125 Hz band and by 5–8 dB in the 2000 Hz band. We conclude that strong intermittent noise is characteristic to the underwater acoustic environment in the study area with heavy shipping traffic. By combining ATL with data from AIS, intermittent noise peaks in underwater hydrophone recordings can be associated with passages of individual vessels.
Developing a typology of heterogeneous fishing practices through the use of métier analysis is a useful step in understanding the dynamics of fishing fleets and enabling effective implementation of management outcomes. We develop a non-hierarchical clustering framework to quantitatively categorize individual fishing events to a particular métier based on corresponding catch composition, gear configuration, and spatial and temporal references. Our clustering framework has several innovations over predecessors including: (i) introducing alternative methods for encoding and transforming fisheries data; (ii) variable (feature) selection methods; (iii) complementary metrics and methods for internal métier validation; and (iv) use of a network science method to model and analyze fishing practices. To demonstrate applicability, we apply this framework to the Australian Eastern Tuna and Billfish Fishery (ETBF), a multispecies pelagic longline fishery with a diversity of fishing practices. We identified a total of seven stable métiers within the ETBF. While each métier was characterized by a predominant target species, they were differentiated more by seasonal and temporal references (e.g., time of set, month, latitude) than gear configuration (e.g., hooks per basket) or target species. By collapsing a large amount of high-dimensional operational data into a relatively uniform and limited number of components, decision-makers can more easily evaluate the likely consequences of management and design policies that target a particular métier.
Relating the Sustainable Development Goal (SDG) 14 for Ocean and Life Below Water to the 16 remaining SDGs in the UN 2030 sustainable development agenda. A holistic approach that embraces sustainable Ocean stewardship informed by best available science, data and services to support society and the economy is required to create the ‘Future We Want’. The UN Decade of Ocean Science for Sustainable Development is an essential foundation to achieve this objective.
Polychlorinated biphenyls (PCBs) tend to accumulate in adipose tissue and induce toxicity due to their high lipophilicity and persistence. Tuna play an important role in the ocean food web and human diet. PCBs can damage the growth of tuna directly and have some adverse effects on human indirectly. This review aims to provide geographic variations, bioaccumulation factors and the toxic effects of PCBs in tuna. PCB levels found were varied significantly among the different regions and it showed a trend of offshore greater than pelagic, with the northern hemisphere higher than the southern hemisphere. The highest PCB concentration of tuna was in FAO area 37. Nearly all of the specimens presented similar domain configuration, while their concentrations varied significantly. PCB congeners and concentrations in tuna were affected by a vast of factors, such as geographical distribution, tissue types, trophic level and growth stage, gender, tuna species and physical and chemical properties of PCBs. They can damage reproductive, neurologic and development systems. This review gives a systematic insight into PCBs in tuna and highlights the more attention should be paid to the long-term changes of PCBs in tuna and oceans. There is also a need to strengthen the assessment of PCB impacts on tuna ecology.
• The implementation of evidence in policymaking requires a guideline referenced by scientists and political makers.
• Five perspectives cover the points that should be considered in the process of producing and using evidence.
• Institutionalization via the science-policy interaction prescribes a way of evaluating the process of producing and using evidence.
• Reference framework promotes evidence-based policymaking and its implementation.
• Case study on mercury pollution proves how the framework provides specific guidance that can promote evidence-based policy and practice.
This study presents wave measurements in the Marginal Ice Zone (MIZ) obtained from ship mounted sensors. The system combines altimeter readings from the ship bow with ship motion correction data to provide estimated single point ocean surface elevation. Significant wave height and mean wave period, as well as one-dimensional wave spectra are derived from the combined measurements. The results are compared with integrated parameters from two spectral wave models over a period of eight days in the open ocean, and with spectra and integrated parameters derived from motion detecting instruments placed on ice floes inside the MIZ. Mean absolute errors of the integrated parameters are in the range 13.4-29.9% when comparing with the spectral wave models and 1.0-9.6% when comparing with valid motion detecting instruments. The spatial wave damping coefficient is estimated by looking at the change in spectral wave amplitude found at discrete frequency values as the ship was moving along the longitudinal direction of the MIZ within time intervals where the wave field is found to be approximately constant in time. As expected from theory, high frequency waves are effectively dampened by the presence of sea ice. The observed wave attenuation rates compare favourably with a two-layer dissipation model. Our methodology can be regarded as a simple and reliable way to collect more waves-in-ice data as it can be easily added to any ship participating to ice expeditions, at little extra cost.
Despite increasing threats to Tonga’s coral reefs from stressors that are both local (e.g. overfishing and pollution) and global (e.g. climate change), there is yet to be a systematic assessment of the status of the country’s coral reef ecosystem and reef fish fishery stocks. Here, we provide a national ecological assessment of Tonga’s coral reefs and reef fish fishery using ecological survey data from 375 sites throughout Tonga’s three main island groups (Ha’apai, Tongatapu and Vava’u), represented by seven key metrics of reef health and fish resource status. Boosted regression tree analysis was used to assess and describe the relative importance of 11 socio-environmental variables associated with these key metrics of reef condition. Mean live coral cover across Tonga was 18%, and showed a strong increase from north to south correlated with declining sea surface temperature, as well as with increasing distance from each provincial capital. Tongatapu, the southernmost island group, had 2.5 times greater coral cover than the northernmost group, Vava’u (24.9% and 10.4% respectively). Reef fish species richness and density were comparable throughout Tongatapu and the middle island group, Ha’apai (~35 species/transect and ~2500 fish/km2), but were significantly lower in Vava’u (~24 species/transect and ~1700 fish/km2). Spatial patterns in the reef fish assemblage were primarily influenced by habitat-associated variables (slope, structural complexity, and hard coral cover). The biomass of target reef fish was greatest in Ha’apai (~820 kg/ha) and lowest in Vava’u (~340 kg/ha), and was negatively associated with higher human influence and fishing activity. Overall mean reef fish biomass values suggest that Tonga’s reef fish fishery can be classified as moderately to heavily exploited, with 64% of sites having less than 500 kg/ha. This study provides critical baseline ecological information for Tonga’s coral reefs that will: (1) facilitate ongoing management and research; and (2) enable accurate reporting on conservation targets locally and internationally.
The escalating rate at which coral communities are declining globally requires urgent intervention and new approaches to reef management to reduce and halt further coral loss. For reef systems with limited natural larval supply, the introduction of large numbers of competent coral larvae directly to natural reef substrata provides a potentially useful approach to replenish adult coral populations. While few experiments have tested this approach, only one experiment has demonstrated its long-term success to date. Given the differences in life-history traits among corals, and different sensitivities of larvae to abiotic and biotic factors, coupled with the dynamic nature of post-settlement survivorship and recruitment processes, trials of the larval enhancement technique with larvae of different coral species are needed to test the broader applicability and viability of this approach. Accordingly, in this paper we examine the applicability of the larval enhancement technique to restore a population of Acropora loripes in the Bolinao-Anda Reef Complex, Pangasinan, northwestern Philippines. Larvae were cultured ex situ following spawning of collected A. loripes colonies in June 2014. Competent larvae were transported to degraded reef areas and approximately 300,000 larvae were introduced in each of three 6 × 4 m plots directly on the reef. Fine mesh enclosures retained the larvae inside each treatment plot for five days. Three adjacent 6 × 4 m plots that served as controls were also covered with mesh enclosures, but no larvae were introduced. Each plot contained ten 10 × 10 cm conditioned settlement tiles cut from dead tabulate Acropora that were used to quantify initial larval settlement. After allowing larval settlement for five days, mean settlement on tiles from the larval enhancement plots that were monitored under stereomicroscopes was significantly higher (27.8 ± 6.7 spat per tile) than in control plots, in which not a single recruit was recorded. Post-settlement survivorship and growth of spat and coral recruits on tiles and reef substrata inside the experimental plots were monitored periodically for 35 months. After 35 months, the mean size of each of the remaining 47 A. loripes coral colonies surviving on the reef substrata was 438.1 ± 5.4 cm3, with a mean diameter of 7.9 ± 0.6 cm. The average production cost for each of the surviving A. loripes colonies at 35 months was USD 35.20. These colonies are expected to spawn and contribute to the natural larval pool when they become reproductively mature, thereby enhancing natural coral recovery in the area. This study demonstrates that mass coral larval enhancement can be successfully used for restoring populations of coral species with different life-history traits, and the techniques can rapidly increase larval recruitment rates on degraded reef areas, hence catalysing the regeneration of declining coral populations.
Water quality standards are essential for regulation of contaminants in marine environment. Seawater quality criteria (SWQC) for arsenic (As), cadmium (Cd) and lead (Pb) have not been developed for India. The aim of this study is to derive the SWQC for the metals based on Species Sensitivity Distribution (SSD). Eight species of sensitive marine organisms belonging to five phyla were assessed for their sensitivity to toxicity of As, Cd and Pb. Median effective concentrations (EC50) and Median Lethal Concentrations (LC50) were derived from the acute toxicity bio-assays. No Observed Effect Concentrations (NOEC), Lowest Observed Effect Concentrations (LOEC) and chronic values were derived from chronic toxicity bio-assays. Diatoms were more sensitive to As with 96 h EC50 of 0.1 mg/l and copepods were more sensitive to Cd and Pb with 96 h EC50 of 0.019 mg/l and 0.05 mg/l respectively. Estimated NOECs ranged from 4.87 to 21.55 µg/l of As, 1.0 to 120 µg/l of Cd and 5.67 to 91.67 µg/l of Pb. Similarly, chronic values (µg/l) were in the range of 6.71–26.1, 1.38–170, and 7.67–91.67 of As, Cd and Pb respectively. The Criterion Maximum Concentration (CMC), Criterion Continuous Concentration (CCC) and Predicted No Effect Concentration (PNEC) values were prescribed as SWQC. The CMC (µg/l) of 19, 1.7 and 17 for As, Cd, and Pb were derived respectively for acute exposure during accidental marine outfalls. The CCC (µg/l) for As was 4.6, 1.1 for Cd and 5.9 for Pb are recommended as SWQC for protection of 95% of marine organisms. PNEC (µg/l) of 3.8 for As, 0.92 for Cd and 4.3 for Pb are suggested for highly disturbed ecosystems, shell fishing and mariculture uses of water bodies. These values are recommended as a baseline for site specific water quality criteria for the coastal waters of the country.
To evaluate the current microplastics (MPs) contamination on the NW coast of Portugal, opportunistic samples from coastal areas with different levels of anthropogenic impacts were analyzed. Water samples were collected from a coastal marine protected area, an urban estuary, a submarine wreck, and a recreational marina. An optimized protocol for the quantification of MPs, followed by visual identification and FTIR spectroscopy analysis was used to characterize MPs (polymer, type, size, color). MPs were found in all the case studies. A total of 2456 MPs particles were identified and classified as fibers (39%), film (39%), and fragments (22%). Up to 54% of MPs had a size range between 1 and 3 mm. Transparent was the dominant color (56%), followed by white (19%). Polyethylene and polypropylene were the main MPs polymers detected. Higher MPs concentration were found in areas associated with high intense fishing and shipping activities. This study showed that different types of MPs were present in all the aquatic environments surveyed, mainly in areas with more anthropogenic activities, emphasizing the need for measures to properly manage plastic litter and mitigate marine plastic pollution.
To generate innovative solutions for marine sustainability challenges, scientists, policymakers, and funders are increasingly calling for interdisciplinary research that transcends disciplinary boundaries. However, challenges associated with doing interdisciplinary research persist and undermine progress toward tackling the complex challenges faced by marine social-ecological systems. One barrier for engaging in effective interdisciplinary research is a lack of understanding about the institutional capacities that support interdisciplinary knowledge production. Based on in-depth qualitative interviews with members of the Centre for Marine Socioecology in Australia, we identify five principles that underpin effective interdisciplinary research organizations. The principles are: (1) support female leadership; (2) forge partnerships outside of academia; (3) develop impact-based performance metrics; (4) focus on long-term funding; and (5) cultivate a visible brand. Going forward, these principles could be used to inform organizational design that transforms institutional barriers into enablers of innovative interdisciplinary research for more sustainable, desirable, and equitable futures.
CircularSeas European Project, as part of the European Union Circular Economy , aims at promoting the Green Economy by encouraging the development of green products, parts and components by Maritime Industries. The strategy is a combination of Circular Economy principles, with the use of ocean plastic waste for developing new greener materials, and the uptake of advanced manufacturing technology, 3D printing, flexible enough to adapt to the manufacturing conditions for new eco-innovative small and medium parts and components. The paper presents the ongoing research in the project about strategies to introduce Circular Economy in the maritime sector from plastic wastes. This first prospective phase is focused on a series of interviews with each node stakeholders. The paper presents the survey results, together with the challenges to be faced for the implementation of Circular Economy in that specific scenario, despite the -apriori- short term low-profit disadvantages.
Today, many science communicators are using social media to share scientific information with citizens, but, as research has shown, fostering conversational exchanges remains a challenge. This largely qualitative study investigated the communication strategies applied by individual scientists and environmental non-governmental organizations on Twitter and Instagram to determine whether particular social media practices encourage two-way conversations between science communicators and citizens. Data from Twitter and Instagram posts, interviews with the communicators, and a survey of audience members were triangulated to identify emergent communication strategies and the resulting engagement; provide insight into why particular practices are employed by communicators; and explain why audiences choose to participate in social media conversations with communicators. The results demonstrate that the application of interpersonal communication strategies encourage conversational engagement, in terms of the number of comments and unique individuals involved in conversations. In particular, using selfies (images and videos), non-scientific content, first person pronoun-rich captions, and responding to comments result in the formation of communicator-audience relationships, encouraging two-way conversations on social media. Furthermore, the results indicate that Instagram more readily supports the implementation of interpersonal communication strategies than Twitter, making Instagram the preferred platform for promoting conversational exchanges. These findings can be applicable to diverse communicators, subjects, audiences, and environments (online and offline) in initiatives to promote awareness and understanding of science.
Marine protected areas (MPAs) are valuable tools for marine conservation that aim to limit human impacts on marine systems and protect valuable species or habitats. However, as species distributions shift due to ocean warming, acidification, and oxygen depletion from climate change, the areas originally designated under MPAs may bear little resemblance to their past state. Different approaches have been suggested for coping with species on the move in conservation. Here, we test the effectiveness of different MPA designs, including dynamic, network, and different directional orientations on protecting shifting species under climate change through ecosystem modeling in a theoretical ecosystem. Our findings suggest that dynamic MPAs may benefit some species (e.g., whiting and anchovy) and fishing fleets, and these benefits can inform the design or adaptation of MPAs worldwide. In addition, we find that it is important to design MPAs with specific goals and to account for the effects of released fishing pressure and species interactions in MPA design.