Harmful Algal Blooms (HABs) are of global concern, as their presence is often associated with socio-economic and environmental issues including impacts on public health, aquaculture and fisheries. Therefore, monitoring the occurrence and succession of HABs is fundamental for managing coastal regions around the world. Yet, due to the lack of adequate in situmeasurements, the detection of HABs in coastal marine ecosystems remains challenging. Sensors on-board satellite platforms have sampled the Earth synoptically for decades, offering an alternative, cost-effective approach to routinely detect and monitor phytoplankton. The Red Sea, a large marine ecosystem characterised by extensive coral reefs, high levels of biodiversity and endemism, and a growing aquaculture industry, is one such region where knowledge of HABs is limited. Here, using high-resolution satellite remote sensing observations (1km, MODIS-Aqua) and a second-order derivative approach, in conjunction with available in situ datasets, we investigate for the first time the capability of a remote sensing model to detect and monitor HABs in the Red Sea. The model is able to successfully detect and generate maps of HABs associated with different phytoplankton functional types, matching concurrent in situdata remarkably well. We also acknowledge the limitations of using a remote-sensing based approach and show that regardless of a HAB’s spatial coverage, the model is only capable of detecting the presence of a HAB when the Chl-a concentrations exceed a minimum value of ~ 1 mg m-3. Despite the difficulties in detecting HABs at lower concentrations, and identifying species toxicity levels (only possible through in situ measurements), the proposed method has the potential to map the reported spatial distribution of several HAB species over the last two decades. Such information is essential for the regional economy (i.e., aquaculture, fisheries & tourism), and will support the management and sustainability of the Red Sea’s coastal economic zone.
The following titles are freely-available, or include a link to a preprint or postprint.
The concept of multi-use of the sea has gained popularity in recent years as a result of ocean space (coastal areas and regions with relatively small sea space in particular) becoming increasingly crowded due to the development of the maritime economy. Competing claims for space can be a source of conflict, however this may also lead to mutual benefits for different users when sustainable combinations are sought. Despite increasing European-wide efforts, on-the-ground knowledge and practice of multi-use are still limited. Therefore, with the aim of investigating opportunities for multi-use development in the European seas, 10 case studies were selected, involving different site-specific contexts. This study analyses the characteristics and development potential for ocean multi-use, integrating results from desk analysis and stakeholder perceptions from different sectors in each of the case study locations. Similarities and differences between various combinations of sea uses are also identified. The results show a high heterogeneity of multi-use opportunities between case studies, with a range of combinations identified. The investigated combinations of maritime uses share an overall balance between factors promoting (drivers) and hindering (barriers) multi-use development. Based on stakeholder opinions, expected benefits (added values) of multi-use implementation outweigh potential negative impacts. Management actions are also proposed to further exploit multi-use potential at a local, regional (sub-national) and national levels.
There is a growing interest in how the management of ‘blue carbon’ sequestered by coastal wetlands can influence global greenhouse gas (GHG) budgets. A promising intervention is through restoring tidal exchange to impounded coastal wetlands for reduced methane (CH4) emissions. We monitored an impounded wetland’s GHG flux (CO2 and CH4) prior to and following tidal reinstatement. We found that biogeochemical responses varied across an elevation gradient. The low elevation zone experienced a greater increase in water level and an associated greater marine transition in the sediment microbial community (16 S rRNA) than the high elevation zone. The low elevation zone’s GHG emissions had a reduced sustained global warming potential of 264 g m−2 yr−1 CO2-e over 100 years, and it increased to 351 g m−2 yr−1 with the removal of extreme rain events. However, emission benefits were achieved through a reduction in CO2 emissions, not CH4emissions. Overall, the wetland shifted from a prior CH4 sink (−0.07 to −1.74 g C m−2 yr−1) to a variable sink or source depending on the elevation site and rainfall. This highlights the need to consider a wetland’s initial GHG emissions, elevation and future rainfall trends when assessing the efficacy of tidal reinstatement for GHG emission control.
We performed an environmental risk assessment for microplastics (<5 mm) in the marine environment by estimating the order of magnitude of the past, present and future concentrations based on global plastic production data. In 2100, from 9.6 to 48.8 particles m−3 are predicted to float around in the ocean, which is a 50-fold increase compared to the present-day concentrations. From a meta-analysis with effect data available in literature, we derived a safe concentration of 6650 buoyant particles m−3 below which adverse effects are not likely to occur. Our risk assessment (excluding the potential role of microplastics as chemical vectors) suggests that on average, no direct effects of free-floating microplastics in the marine environment are to be expected up to the year 2100. Yet, even today, the safe concentration can be exceeded in sites that are heavily polluted with buoyant microplastics. In the marine benthic compartment between 32 and 144 particles kg−1 dry sediment are predicted to be present in the beach deposition zone. Despite the scarcity of effect data, we expect adverse ecological effects along the coast as of the second half of the 21st century. From then ambient concentrations will start to outrange the safe concentration of sedimented microplastics (i.e. 540 particles kg−1sediment). Additional ecotoxicological research in which marine species are chronically exposed to realistic environmental microplastic concentration series are urgently needed to verify our findings.
With the recent ratification of the International Convention for the Control and Management of Ships' Ballast Water and Sediments, 2004, it will soon be necessary to assess ships for compliance with ballast water discharge standards. Sampling skids that allow the efficient collection of ballast water samples in a compact space have been developed for this purpose. We ran 22 trials on board the RV Meteor from June 4–15, 2015 to evaluate the performance of three ballast water sampling devices (traditional plankton net, Triton sampling skid, SGS sampling skid) for three organism size classes: ≥ 50 μm, ≥ 10 μm to < 50 μm, and < 10 μm. Natural sea water was run through the ballast water system and untreated samples were collected using paired sampling devices. Collected samples were analyzed in parallel by multiple analysts using several different analytic methods to quantify organism concentrations. To determine whether there were differences in the number of viable organisms collected across sampling devices, results were standardized and statistically treated to filter out other sources of variability, resulting in an outcome variable representing the mean difference in measurements that can be attributed to sampling devices. These results were tested for significance using pairwise Tukey contrasts. Differences in organism concentrations were found in 50% of comparisons between sampling skids and the plankton net for ≥ 50 μm, and ≥ 10 μm to < 50 μm size classes, with net samples containing either higher or lower densities. There were no differences for < 10 μm organisms. Future work will be required to explicitly examine the potential effects of flow velocity, sampling duration, sampled volume, and organism concentrations on sampling device performance.
To prevent new ballast water-mediated introductions of aquatic nonindigenous species (NIS), many ships will soon use approved Ballast Water Management Systems (BWMS) to meet discharge standards for the maximum number of viable organisms in ballast water. Type approval testing of BWMS is typically conducted during warmer seasons when plankton concentrations are highest, despite the fact that ships operate globally year-round. Low temperatures encountered in polar and cool temperate climates, particularly during the winter season, may impact treatment efficacy through changes in plankton community composition, biological metabolic rates or chemical reaction rates. Filtration + UV irradiance is one of the most common ballast water treatment methods, but its effectiveness at low temperatures has not been assessed. The objective in this study was to examine the efficacy of filtration + UV-C irradiation treatment at low temperatures for removal or inactivation of phytoplankton and zooplankton populations during simulated ballast water treatment. Organisms from two size classes (≥ 10 to < 50 μm and ≥ 50 μm) were identified and enumerated using microscope and culture techniques. The response of organisms in both size categories to UV-C irradiation was evident across a range of temperatures (18 °C, 12 °C and 2 °C) as a significant decrease in concentration between controls and treated samples. Results indicate that filtration + UV-C irradiation will be effective at low temperatures, with few viable organisms ≥ 10 to < 50 μm recorded even 21 days following UV exposure (significantly lower than in the control treatment).
Marine spatial planning (MSP) processes seek to better manage ocean spaces by balancing ecological, social and economic objectives using public and participatory processes. To meet this challenge, MSP approaches and tools have evolved globally, from local to national scales. At two International Marine Conservation Congresses (2016 and 2018), MSP practitioners and researchers from diverse geographic, technical and socio-economic contexts met to share advances in practical approaches and spatial tools to achieve multi-objective MSP. Here we share the lessons learned and commonalities that emerged from studies conducted in Belize, Canada, South Africa, Seychelles, the United Kingdom and the United States on a number of topics related to advancing MSP. We identify seven important themes that we believe are broadly relevant to any multi-objective MSP process: (1) indigenous and local knowledge should inform planning goals and objectives; (2) transparent and evidence-based approaches can reduce user conflict; (3) simple ecosystem service models and scenarios can facilitate multi-objective planning; (4) trade-off analyses can help balance diverse objectives; (5) ecosystem services may assist planning for high value-data poor Blue Economy sectors; (6) game theoretic decision rules can help to deliver fair, equitable and win–win spatial allocation solutions; and (7) strategic mapping products can facilitate decision making amongst stakeholders from different sectors. Some of these themes are evident in MSP processes that have been completed in the previous decade, but the fast-evolving field of MSP is addressing increasingly more complex objectives, and practitioners need to respond with practical approaches and spatial tools that can address this complexity.
Manta ray watching tourism has become a popular tourist attraction over the past two decades, with a number of destinations offering different encounter experiences for tourists. This type of attraction has drawn worldwide attention because it can offer significant contributions to the local economy through snorkelling and diving services. Since its early development, a number of scientists have conducted research on the impacts of manta ray watching tourism, and have reported different findings regarding its sustainability. Based on published scientific articles, this study provides a literature review of manta ray watching tourism and examines the sustainability of its operation. This paper also highlights manta ray tourism hotspots in Indonesia including Nusa Penida, Komodo, and Raja Ampat as the study locations. Interviews with ten key persons including government officials, tourism operators, community, and non-governmental organization were conducted to collect and identify their perceptions. This study demonstrates different impacts of economy, ecology, and socialcultural aspects. Furthermore, different study areas apply different management approach in managing their tourist in terms of manta ray watching tourism operation. In conclusion, good governance, regulations/law enforcement, and collaborative management are significant factors to achieve sustainable manta ray watching tourism.
The objective of this study was to identify the main environmental covariates related to the abundance of 17 cetacean species/groups in the western North Atlantic Ocean based on generalized additive models, to establish a current habitat suitability baseline, and to estimate abundance that incorporates habitat characteristics. Habitat models were developed from dedicated sighting survey data collected by NOAA- Northeast and Southeast Fisheries Science Centers during July 2010 to August 2013. A group of 7 static physiographic characteristics and 9 dynamic environmental covariates were included in the models. For the small cetacean models, the explained deviance ranged from 16% to 69%. For the large whale models, the explained deviance ranged from 32% to 52.5%. Latitude, sea surface temperature, bottom temperature, primary productivity and distance to the coast were the most common covariates included and their individual contribution to the deviance explained ranged from 5.9% to 18.5%. The habitat-density models were used to produce seasonal average abundance estimates and habitat suitability maps that provided a good correspondence with observed sighting locations and historical sightings for each species in the study area. Thus, these models, maps and abundance estimates established a current habitat characterization of cetacean species in these waters and have the potential to be used to support management decisions and conservation measures in a marine spatial planning context.
Indonesia has more than 600s offshore oil and gas platforms spread in its territorial waters and of that amount, about 50 % were built around 1980s. Since the first generation platform was built almost half a century ago, decommissioning the offshore structures is something that has never been done before in Indonesia. The assets are now approaching their end of production and touching a point of minimum economic viability. Therefore, the dismantling of those structures is unavoidable issues in the near future. However, this process is not easy and presents many challenges, eg. status of assets, costs, etc. The current regulations have not been able to get the operators to dismantle and write off their assets so that many of them are left abandoned and endanger for the sea traffic for instance. There is a trend that these abandoned and idle offshore structures have now become "a fashionable donation" project from oil companies to coastal state to be re-used as artificial reefs or also known as Rigs-to-Reef (R2R). This study is attempting to improve the visibility of R2R as a potential decommissioning solution in Indonesia that provide good benefits not only for the environment but also for the coastal community while at the same time offer effective and efficient way out for oil and gas companies. The feasibility study of platform placement was done in the provincial marine conservation areas (Kawasan Konservasi Perairan Daerah, KKPD) in Bontang, East Kalimantan.
In recent years, coral reef degradation has been increasing. Management and conservation efforts have tended to focus only on the physical condition of the coral reefs with less attention to biological and oceanographic aspects, in particular genetics and hydrodynamics. Genetic data can illustrate the connectivity between and within populations of an organism, making it is possible to determine source and sink populations or sites. Studies of physical water movements can also illustrate the likely patterns of movement or predict the mobility of coral planulae. Both of these approaches can help to strengthen Marine Protected Area (MPA) design, especially at the formation stage, in particular MPAs focused on coral reef ecosystems. Together, these two approaches can provide data on biological networks in a region and help delineate stocks. The implications of such studies can help to identify conservation priorities and improve the effectiveness of management processes in Indonesia, and can certainly enable the refinement of general approaches to help produce management plans tailored to local and regional conditions and processes. This brief review aims to review the constraints that occur in the management process, including barriers to and potential benefits of integrating molecular and hydrodynamic data into the management and conservation process, as illustrated through a critical review of MPA implementation in the waters around Sulawesi Island.
The amphipod Hirondellea gigas inhabits the deepest regions of the oceans in extreme high-pressure conditions. However, the mechanisms by which this amphipod adapts to its high-pressure environment remain unknown. In this study, we investigated the elemental content of the exoskeleton of H. gigas specimens captured from the deepest points of the Mariana Trench. The H. gigas exoskeleton contained aluminum, as well as a major amount of calcium carbonate. Unlike other (accumulated) metals, aluminum was distributed on the surface of the exoskeleton. To investigate how H. gigas obtains aluminum, we conducted a metabolome analysis and found that gluconic acid/gluconolactone was capable of extracting metals from the sediment under the habitat conditions of H. gigas. The extracted aluminum ions are transformed into the gel state of aluminum hydroxide in alkaline seawater, and this gel covers the body to protect the amphipod. This aluminum gel is a good material for adaptation to such high-pressure environments.
The pelagic ecosystems of the Western Antarctic Peninsula are dynamic and changing rapidly in the face of sustained warming. There is already evidence that warming may be impacting the food web. Antarctic krill, Euphausia superba, is an ice-associated species that is both an important prey item and the target of the only commercial fishery operating in the region. The goal of this study is to develop a dynamic trophic model for the region that includes the impact of the sea-ice regime on krill and krill predators. Such a model may be helpful to fisheries managers as they develop new management strategies in the face of continued sea-ice loss. A mass balanced food-web model (Ecopath) and time dynamic simulations (Ecosim) were created. The Ecopath model includes eight currently monitored species as single species to facilitate its future development into a model that could be used for marine protected area planning in the region. The Ecosim model is calibrated for the years 1996–2012. The successful calibration represents an improvement over existing Ecopath models for the region. Simulations indicate that the role of sea ice is both central and complex. The simulations are only able to recreate observed biomass trends for the monitored species when metrics describing the sea-ice regime are used to force key predator-prey interactions, and to drive the biomasses of Antarctic krill and the fish species Gobionotothen gibberifrons. This model is ready to be used for exploring results from sea-ice scenarios or to be developed into a spatial model that informs discussions regarding the design of marine protected areas in the region.
Applying a proteomic approach for biomonitoring marine environments offers a useful tool for identifying organisms’ stress responses, with benthic filter-feeders being ideal candidates for this practice. Here, we investigated the proteomic profile of two solitary ascidians (Chordata, Ascidiacea): Microcosmus exasperatus, collected from five sites along the Mediterranean coast of Israel; and Polycarpa mytiligera collected from four sites along the Red Sea coast. 193 and 13 proteins in M. exasperatus and P. mytiligera, respectively, demonstrated a significant differential expression. Significant differences were found between the proteomes from the northern and the southern sites along both the Mediterranean and the Red Sea coasts. Some of the significant proteins had previously been shown to be affected by environmental stressors, and thus have the potential to be further developed as biomarkers. Obtaining a proteomic profile of field-collected ascidians provides a useful tool for the early-detection of a stress response in ascidians worldwide.
Ship traffic in Northwestern European seas is intense and continuing to increase, posing a threat to vulnerable seabird species as a result of disturbance. However, information on species-specific effects of ship traffic on seabirds at sea is limited, and tools are needed to prioritize species and areas to support the integration of conservation needs in Marine Spatial Planning. In this study, we investigated the responses of 26 characteristic seabird species in the German North and Baltic Seas to experimental ship disturbance using large datasets collected as part of the seabirds at Sea counts. We developed a Disturbance Vulnerability Index (DVI) for ship traffic combining indicators for species’ shyness, escape costs, and compensatory potential, and analyzed the relationships among shyness, escape costs, and vulnerability. The DVI was calculated using the following eight indicators: escape distance, proportion of escaping birds, proportion of birds swimming prior to disturbance, wing loading, habitat use flexibility, biogeographic population size, adult survival rate, European threat and conservation status. Species-specific disturbance responses differed considerably, with common scoters (Melanitta nigra) and red-throated loons (Gavia stellata) showing the longest escape distances and highest proportions of escaping individuals. Red-throated loon, black guillemot (Cepphus grylle), Arctic loon (Gavia arctica), velvet scoter (Melanitta fusca), and red-breasted merganser (Mergus serrator) had the highest DVI values, and gulls and terns had the lowest. Contrary to theoretical considerations, shyness correlated positively with escape costs, with the shyest species also being the most vulnerable among the species studied. The strong reactions of several species to disturbance by ships suggest the need for areas with little or no disturbance in some marine protected areas, to act as a refuge for vulnerable species. This DVI can be used in combination with distribution data to identify the areas most vulnerable to disturbance.
Improved understanding of human-nature interactions is crucial to conservation science and practice, but collecting relevant data remains challenging. Recently, social media have become an increasingly important source of information on human-nature interactions. However, the use of advanced methods for analysing social media is still limited, and social media data are not used to their full potential. In this article, we present available sources of social media data and approaches to mining and analysing these data for conservation science. Specifically, we (i) describe what kind of relevant information can be retrieved from social media platforms, (ii) provide a detailed overview of advanced methods for spatio-temporal, content and network analyses, (iii) exemplify the potential of these approaches for real-world conservation challenges, and (iv) discuss the limitations of social media data analysis in conservation science. Combined with other data sources and carefully considering the biases and ethical issues, social media data can provide a complementary and cost-efficient information source for addressing the grand challenges of biodiversity conservation in the Anthropocene epoch.
Plastics is all the rage, and mitigating marine litter is topping the agenda for nations pushing issues such as ocean acidification, or even climate change, away from the public consciousness. We are personally directly affected by plastics and charismatic megafauna is dying from it, and it is something that appears to be doable. So, who cares about the issue of ocean acidification anymore? We all should. The challenge is dual in the fact that is both invisible to the naked eye and therefore not felt like a pressing issue to the public, thereby not reaching the top of the agenda of policy makers; but also that it is framed in the climate change narrative of fear - whereby it instills in a fight-or-flight response in the public, resulting in their avoidance of the issue because they feel they are unable to take action that have results. In this article, we argue that the effective global environmental governance of ocean acidification, though critical to address, mitigate against and adapt to, is hindered by the both this lack of perception of urgency in the general public, fueled by a lack of media coverage, as well as a fight-or-flight response resulting from fear. We compare this to the more media friendly and plastics problem that is tangible and manageable. We report on a media plots of plastics and ocean acidification coverage over time and argue that the issue needs to be detangled from climate change and framed as its own issue to reach the agenda at a global level, making it manageable to assess and even care about for policy makers and the public alike?
Coastal areas in the eastern sub-region of Thailand, a popular destination in Southeast Asia, are facing rapid tourism-related urbanization and associated consequences of environment and climate change (CC). Thus, this study aims to analyze the relationships between tourism, coastal areas, the environment, and CC in the context of tourism urbanization; and recommend strategies for enhancing the governance of coastal areas. Three popular destinations were selected as study areas, Koh Chang, Pattaya, and Koh Mak. Group discussions, questionnaire surveys, interviews, and observation were used for primary data collection together with secondary data. The results show that the development of these destinations has been incompatible with the coastal environment and CC patterns. Rapid urbanization from tourism development is the main driver of environmental changes and makes the areas vulnerable to CC-related risks. While water scarcity and pollution are found the most critical environmental issues of the destinations, coastal areas are negatively affected in terms of increased air and water pollution and resource degradation. They have also been exposed to different CC-related problems while the risks of accumulative impacts of both environment and CC have not been adequately recognized or addressed. Although some measures have provided synergies of improved environment and increased climate resilience, possible conflicts and gaps were also found. Public infrastructure integration and optimization to enhance coastal areas’ environment and climate resilience are suggested.
Timing of reproduction may be of crucial importance for fitness, particularly in environments that vary seasonally in food availability or predation risk. However, for animals with spatially separated feeding and breeding habitats, optimal reproductive timing may differ between parents and their offspring, leading to parent-offspring conflict. We assume that offspring have highest survival and fitness if they are spawned around a fixed date, and use state-dependent life-history theory to explore whether variation in conditions affecting only parents (food availability and survival) may influence optimal timing of reproduction. We apply the model to Pacific herring (Clupea palasii) in Puget Sound, USA, where 20 subpopulations spawn at different times of the year. Our model suggests that relatively small differences in adult food availability can lead to altered prioritization in the trade-off between maternal fecundity and what from the offspring’s perspective is the best time to be spawned. Our model also shows that observed among-population variability in reproductive timing may result from adults using different feeding grounds with divergent food dynamics, or from individual variation in condition caused by stochasticity at a single feeding ground. Identifying drivers of reproductive timing may improve predictions of recruitment, population dynamics, and responses to environmental change.
Decades of billfish tagging studies have been hindered by below-par conventional tag recovery rates and high rates of premature satellite pop-up tag shedding. With hopes of obtaining long-term tracking data, we performed the world’s first archival tagging study on an istiophorid, surgically implanting 99 archival tags into the peritoneal cavity of striped marlin (Kajikia audax) off the coast of Baja California, Mexico. Marlin were also tagged externally with a conventional tag before release. Ten archival tags (10.1%) were recovered with days at liberty (DAL) ranging from 400 to 2795. Nine recoveries were from Mexican waters, whereas one marlin was recaptured off Ecuador. In total, 100% of the light stalks on the archival tags failed, with nine failing within the first 3 months of deployment; because the light data are used to estimate the geographic position of the tagged fish, tracking data were compromised. The absence of conventional tags on all recaptured marlin indicates that studies of marlin using conventional tags have been hindered by tag shedding rather than tagging-associated mortality or underreporting. Our high recapture rate and long DAL suggest istiophorid science could be greatly advanced by archival tagging if new tag designs or methods can eliminate tag failure.