Description: Microbial degradation of organic carbon in marine sediments is a key driver of global element cycles on multiple time scales. However, it is not known to what depth microorganisms alter organic carbon in marine sediments or how microbial rates of organic carbon processing change with depth, and thus time since burial, on a global scale. To better understand the connection between the dynamic carbon cycle and life’s limits in the deep subsurface, we have combined a number of global data sets with a reaction transport model (RTM) describing first, organic carbon degradation in marine sediments deposited throughout the Quaternary Period and second, a bioenergetic model for microbial activity. The RTM is applied globally, recognizing three distinct depositional environments – continental shelf, margin and abyssal zones. The results include the masses of particulate organic carbon, POC, stored in three sediment-depth layers: bioturbated Holocene (1.7 × 10^17 g C), non-bioturbated Holocene (2.6 × 10^18 g C) and Pleistocene (1.4 × 1020 g C) sediments. The global depth-integrated rates of POC degradation have been determined to be 6.8 × 10^13, 1.2 × 10^14 and 1.2 × 10^14 g C yr-1 for the same three layers, respectively. A number of maps depicting the distribution of POC, as well as the fraction that has been degraded have also been generated. Using POC degradation as a proxy for microbial catabolic activity, total heterotrophic processing of POC throughout the Quaternary is estimated to be between 10^-11 – 10^-6 g C cm-3 yr-1, depending on the time since deposition and location. Bioenergetic modeling reveals that laboratory-determined microbial maintenance powers are poor predictors of sediment biomass concentration, but that cell concentrations in marine sediments can be accurately predicted by combining bioenergetic models with the rates of POC degradation determined in this study. Our model can be used to quantitatively describe both the carbon cycle and microbial activity on a global scale for marine sediments less than 2.59 million years old.

Description: Over two million leisure boats use the coastal areas of the Baltic Sea for recreational purposes. The majority of these boats are painted with toxic antifouling paints that release biocides into the coastal ecosystems and negatively impact non-targeted species. Regulations concerning the use of antifouling paints differ dramatically between countries bordering the Baltic Sea and most of them lack the support of biological data. In the present study, we collected data on biofouling in 17 marinas along the Baltic Sea coast during three consecutive boating seasons (May–October 2014, 2015 and 2016). In this context, we compared different monitoring strategies and developed a fouling index (FI) to characterise marinas according to the recorded biofouling abundance and type (defined according to the hardness and strength of attachment to the substrate). Lower FI values, i.e. softer and/or less abundant biofouling, were consistently observed in marinas in the northern Baltic Sea. The decrease in FI from the south-western to the northern Baltic Sea was partially explained by the concomitant decrease in salinity. Nevertheless, most of the observed changes in biofouling seemed to be determined by local factors and inter-annual variability, which emphasizes the necessity for systematic monitoring of biofouling by end-users and/or authorities for the effective implementation of non-toxic antifouling alternatives in marinas. Based on the obtained results, we discuss how monitoring programs and other related measures can be used to support adaptive management strategies towards more sustainable antifouling practices in the Baltic Sea.

Description: Highlights • Archaeal community composition reflects locally specific environmental challenges • Biogeochemical properties do not predict archaeal community structure • Environmental history controls subseafloor archaeal populations Summary We explore archaeal distributions in sedimentary subseafloor habitats of Guaymas Basin and the adjacent Sonora Margin, located in the Gulf of California, México. Sampling locations include (1) control sediments without hydrothermal or seep influence, (2) Sonora Margin sediments underlying oxygen minimum zone water, (3) compacted, highly reduced sediments from a pressure ridge with numerous seeps at the base of the Sonora Margin, and (4) sediments impacted by hydrothermal circulation at the off-axis Ringvent site. Generally, archaeal communities largely comprise Bathyarchaeal lineages, members of the Hadesarchaea, MBG-D, TMEG, and ANME-1 groups. Variations in archaeal community composition reflect locally specific environmental challenges. Background sediments are divided into surface and subsurface niches. Overall, the environmental setting and history of a particular site, not isolated biogeochemical properties out of context, control the subseafloor archaeal communities in Guaymas Basin and Sonora Margin sediments.

Description: Coastal ecosystems provide a broad range of ecosystem services, which can be used to justify habitat conservation. The cultural ecosystem services of coastal ecosystems are generally underappreciated, and this is particularly the case when quantifying their scientific value. We created a tiered set of indicators to quantify scientific value spatially, and tested them using the case study of the island nation of Singapore. We conducted a systematic review of research papers, book chapters, conference reports and academic theses produced across 10 coastal ecosystems in Singapore, including mangroves, seagrasses, coral reefs, beaches and artificial coastal structures. At least 656 articles have been produced on Singapore’s coastal zone, with 2201 unique observations, showing that scientific value is spatially variable along Singapore’s coastline. Novel indicators such as the Site Impact Factor are able to differentiate scientific value between sites. This method has shed light on an under-recognised, but important cultural ecosystem service, and is applicable to other spatially-bounded coastal, marine and terrestrial landscapes.

Description: Highlights • Nd isotope records from the South Atlantic and Southern Ocean. • New Early Cretaceous general circulation model. • Opening history of gateways on the Falkland Plateau. • Gateway opening controlled organic carbon burial. Organic carbon burial is an important driver of carbon cycle and climate dynamics on geological and shorter time scales. Ocean basins emerging during the Early Cretaceous break-up of Gondwana were primary sites of organic carbon burial, implying that their tectonic and oceanographic evolution may have affected trends and perturbations in global climate via changes in local organic carbon burial. Assessing the role of individual ocean basins in the global carbon-climate context requires a sound understanding of the processes that induced large-scale changes in carbon burial and the timing of these changes. Here we reconstruct the oceanographic evolution, and its links to organic carbon burial, in the Barremian to Albian South Atlantic and Southern Ocean basins, which may have acted as carbon sinks of global importance. Our reconstruction is based on combined seawater neodymium isotope and sedimentological records obtained from multiple deep sea drill sites and a new general circulation model. Deep water circulation within and between those basins was primarily controlled by the opening of the shallow Falkland Plateau Gateway (between ∼118 Ma and ∼113 Ma) and the deep Georgia Basin Gateway (by ∼110 Ma), for which we provide new age constraints based on biostratigraphic and carbon isotope data. The opening of these gateways was accompanied by local to basin-wide decreases in organic carbon burial, suggesting that ocean circulation affected the oxygenation state via changes in deep water ventilation. Although our data do not provide quantitative information on the impact of changes in regional organic carbon burial on the global carbon cycle, the synchronicity between the reduction of organic carbon burial in the South Atlantic basin and global warming during the Early Albian points to a strong causal relationship.

Description: Highlights: • 1st global long-term fishery biomass trends evaluation of 1300 exploited marine populations. • Decline in average fishery biomass observed across oceans and climate zones. • Systemic wide-spread overfishing of the world's coastal and continental shelf water. Abstract: This contribution presents time series of the ‘fishery biomass’ of fish populations, defined as the weight (whole-body, wet weight) of the in-water part of a fishable population, i.e., that part of a population (also called ‘stock’) that is exposed to a certain fishing gear. Detailed data of this type are only available for a limited number of species that are targets of the fisheries in the waters of economically developed regions, such as Europe, the USA, Canada or Australia. However, similar fishery biomass assessments are generally lacking for developing countries, even for many of their most heavily fished species. Here, an estimation of the long-term fishery biomass trends of 1320 fish and invertebrate populations for 483 species exploited by fisheries in the 232 coastal Marine Ecoregions (MEs) around the world was undertaken. Fishery biomass trends were derived using the Bayesian CMSY stock assessment method applied to the global fisheries catch database for 1950–2014 as reconstructed by the Sea Around Us for every maritime fishing country in the world. Overall, the results suggest a consistent decline in the fishery biomass of exploited populations, in virtually all climatic zones and ocean basins in the world. The only zone with currently higher fishery biomass than in 1950 is the northern Pacific polar-boreal zone, likely due to environmental changes that occurred in the region positively affecting fish populations, combined with prudent management of the fisheries. For populations in MEs that are known to have highly questionable catch statistics, the results suggested smaller declines in fishery biomass than likely occurred in reality, implying that these results do not exaggerate declining trends in fishery biomass. This study used informative Bayesian priors to improve the trend analyses in areas where systematic stock assessments were conducted. The use of these independent assessments reduced the uncertainty associated with the findings of this study.

Description: Wastewater treatment plants (WWTPs) are a focal point for the removal of microplastic (MP) particles before they are discharged into aquatic environments. WWTPs are capable of removing substantial quantities of larger MP particles but are inefficient in removing particles with any one dimension of less than 100 mu m, with influents and effluents tending to have similar quantities of these smaller particles. As a single WWTP may release 〉100 billion MP particles annually, collectively WWTPs are significant contributors to the problem of MP pollution of global surface waters. Currently, there are no policies or regulations requiring the removal of MPs during wastewater treatment, but as concern about MP pollution grows, the potential for wastewater technologies to capture particles before they reach surface waters has begun to attract attention. There are promising technologies in various stages of development that may improve the removal of MP particles from wastewater. Better incentivization could speed up the research, development and adoption of innovative practices. This paper describes the current state of knowledge regarding MPs, wastewater and relevant policies that could influence the development and deployment of new technologies within WWTPs. We review existing technologies for capturing very small MP particles and examine new developments that may have the potential to overcome the shortcomings of existing methods. The types of collaborations needed to encourage and incentivize innovation within the wastewater sector are also discussed, specifically strong partnerships among scientific and engineering researchers, industry stakeholders, and policy decision makers.

Description: Since 2016, the European Union (EU) has required Member States to prevent, control and eradicate selected invasive alien species (IAS) designated as Species of Union Concern. To improve these conservation efforts, online information systems are used to convey IAS information to the wider public, often as a means to bolster community-based environmental monitoring. Despite this, both the conformity and quality of information presented amongst online databases remain poorly understood. Here, we assess the harmonisation and educational potential of four major IAS databases (i.e., conformity of information and information quality, respectively): CABI, EASIN, GISD and NOBANIS. All databases were interrogated for information concerning 49 IAS of Union Concern. For each species, information presented within the evaluated databases was scored in relation to several key topics: morphological identification; EU distribution; detrimental impacts; control options; and the use of source material citations. Overall, scores differed significantly among databases and thus lacked harmonisation, whereby CABI ranked significantly highest based on the combined scores for all topics. In addition, CABI ranked highest for the individual topics of species identification, impacts, control options, and for the use of citations. EASIN ranked highest for species distribution data. NOBANIS consistently ranked as the lowest scoring database across all topics. For each topic, the highest scoring databases achieved scores indicative of detailed or highly detailed information, which suggests a high educational potential for the information portrayed. Nevertheless, the extent of harmonisation and quality of information presented amongst online databases should be improved. This is especially pertinent if online databases are to contribute to public participatory monitoring initiatives for IAS detection.

Description: Environmental concerns and insecticide resistance threaten the sustained efficacy of mosquito control approaches which remain reliant on synthetic chemicals. Plant-based extracts may be an environmentally sustainable and effective alternative to contemporary mosquito control approaches; however, the efficacies of many possible plant-based extracts remain untested. The present study examines the effects of extracts from three floating and three submerged aquatic plants on larval mosquito Culex pipiens mortality, and development to pupal and adult stages. Physical impacts of floating plant species on mosquito mortality and development are also examined. Extracts of Lagarosiphon major and Lemna minuta were toxic, causing significantly increased mosquito mortality compared to plant-free controls. Effects of Azolla filiculoides, Crassula helmsii, Elodea canadensis and Lemna minor were statistically unclear, yet in some cases tended to increase pupal and larval numbers at high extract concentrations. Surface coverage of all floating Lemna species drove significant mosquito mortality through mechanical processes which likely impeded surface respiration by larval mosquitoes. In particular, high-density mats of L. minuta consistently caused total larval mortality. The present study thus suggests that targeted use of specific aquatic plants could assist in mosquito control protocols. However, as the chemical composition of botanic material will differ across spatial and temporal gradients, even for a singular species, localised assessment of the efficacy of plant-based extracts from within areas experiencing problematic mosquito control is required. The application of aquatic plants that are both toxic to larvae and are effective physical control agents presents an economic and effective method of mosquito control.

Description: Highlights • Holocene cold-water coral mound formation started non-synchronous in Belgica province. • Coral mounds and slope sediments record changes in intermediate water mass dynamics. • Increased turbulent bottom currents steered slope erosion and mound formation. • Internal waves at the ENAW-MOW boundary enhance energy supply and particle flux. • Transition zone between the ENAW-MOW shifted 250 m upslope during the last deglacial. Abstract Turbulent bottom currents significantly influence the formation of cold-water coral mounds and sedimentation processes on continental slopes. Combining records from coral mounds and adjacent slope sediments therefore provide an unprecedented palaeo-archive to understand past variations of intermediate water-mass dynamics. Here, we present coral ages from coral mounds of the Belgica province (Porcupine Seabight, NE Atlantic), which indicate a non-synchronous Holocene re-activation in mound formation suggested by a temporal offset of ∼2.7 kyr between the deep (start: ∼11.3 ka BP at 950 m depth) and shallow (start: ∼8.6 ka BP at 700 m depth) mounds. A similar depth-dependent pattern is revealed in the slope sediments close to these mounds that become progressively younger from 22.1 ka BP at 990 m to 12.2 ka BP at 740 m depth (based on core-top ages). We suggest that the observed changes are the consequence of enhanced bottom-water hydrodynamics, caused by internal waves associated to the re-invigoration of the Mediterranean Outflow Water (MOW) and the development of a transition zone (TZ) between the MOW and the overlying Eastern North Atlantic Water (ENAW), which established during the last deglacial. These highly energetic conditions induced erosion adjacent to the Belgica mounds and supported the re-initiation of mound formation by increasing food and sediment fluxes. The striking depth-dependent patterns are likely linked to a shift of the ENAW-MOW-TZ, moving the level of maximum energy ∼250 m upslope since the onset of the last deglaciation.