J. Fredrik Lindgren

PAH effects on meio- and microbial benthic communities strongly depend on bioavailability

The effects of anthropogenic pollutants in dissimilar habitats can vary depending on differences in bioavailability. The factors determining bioavailability are not yet fully understood. This study was performed to evaluate whether analysis of total PAH concentrations in sediments is a satisfactory measurement to indicate environmental effects or if bioavailability is needed to be taken into account. We have here performed a 60-day experiment, where nominal PAH concentrations of 1,300 μg/kg sediment were added to three different marine sediments. Meiofaunal and microbial communities were analyzed for alterations in community response at 30 and 60 days. Results showed that bioavailability of PAHs varied between the three different sediments. Nonetheless, the petroleum addition gave rise to significant negative effects on all three sediments at both time points. The two direct measurements of toxicity on the microbial community, potential nitrification and denitrification, displayed a lower effect of the PAH addition in the muddy sediment at both time points, compared to the other two sediment types. No effects were seen in the analysis of meiofaunal community structure. Measurements of PAH bioavailability in the three sediment types concurred with the results from the microbial community, revealing a lower bioavailability in the muddy sediment compared to the other two sediment types, 34% compared to sandy and 18% compared to organic at day 0. At day 60 it was 61% lower compared to sandy and 20% lower compared to organic. The negative effects of the PAH addition on the microbial nitrogen cycle were in six out of eight cases best correlated to the amount of alkylated bioavailable PAH in the sediments, and thus microbial nitrogen cycle is a possible good indicator for assessing PAH-induced stress. The results presented here have implications for risk analysis studies of petroleum-contaminated marine sediments; consequently, sediment characteristics and its effects on bioavailability are important to include. In addition, these results add to the understanding that bioavailability measurements of PAHs are a more correct assessment compared to measurements of total PAH concentrations, and need to be included when estimating effects of PAHs in marine benthic communities.

Meiofaunal and bacterial community response to diesel additions in a microcosm study

Effects of low PAH-containing diesel were studied in a 60-day microcosm experiment at PAH concentrations 130, 1300 and 13,000μg/kg sediment. Nutrient fluxes, potential nitrification and meiofaunal community composition were analysed at three time points. Changed ∑NOx-fluxes indicated reduced sediment nitrification in Medium and High with time, in agreement with lowered potential nitrification rates in all treatments. Reduction in silicate and phosphate fluxes over time suggested severe effects on activity of meiofauna. Reduced activity increased the anoxic sediment layer, which could have contributed to the changed ∑NOx-fluxes. There were significant differences in meiofaunal community composition after 30 and 60days in Medium and High. Changes were due to increasing numbers of harpacticoids and the foraminiferan group Rotaliina, as well as decreasing numbers of Nematodes and the foraminiferan group Reophax. In spite of the low PAH-level, small additions of this diesel can still have pronounced effects on meiofaunal and bacterial communities.

Low concentrations of PAHs induce tolerance in nitrifying bacteria

The ability of marine microbes to develop tolerance to polycyclic aromatic hydrocarbons (PAHs) was examined in a 90-day experiment. PAH levels in sediment were increased 0.3 and 1.6 times compared to the control sediment. Day 30, 60 and 90 the microbes were re-exposed to PAHs in a short-term toxicity test to detect tolerance, where nitrification and denitrification were used as endpoints. In addition, molecular analysis of the microbial communities was performed to detect possible differences in proportions of nitrifying bacteria compared to total bacterial abundance (amoA/rpoB-ratio) between treatments and control. We here show PAH-induced tolerance in nitrifying microbial communities after 60 and 90 days of pre-exposure, as potential nitrification EC10-values were significantly higher in the low treatment (L) after 60 days and in both treatments after 90 days compared to control. Tolerance development in denitrification was not detected. Furthermore, the developed tolerance resulted in reduced nitrification efficiency, compared to control. It was also shown that the induced tolerance produced dissimilar amoA/rpoB-ratio between treatments and control, indicating that development of tolerance changed the community composition and that the development time depended on initial exposure. The results from this study have implications for future studies or environmental monitoring programs of long-term oil and PAH-contaminated sites. The possibility for development of tolerance needs to be taken into account and potential nitrification can be used for evaluation of marine microbial health. Furthermore, changed proportions of nitrifying microbes can alter the capacity of ammonium oxidizing in benthic marine sediments.

Infrastructure, Marine Spatial Planning and Shipwrecks

In association to the shipping industry there is a broad infrastructure that is connected with multiple activities, e.g., transportation, building and recycling. This infrastructure services the industry, for example ports, and its connected transport network, fairways and canals. The infrastructure activities also entail various environmental issues, such as land use, air emissions, noise, erosion and increased water turbidity. From an environmental perspective, ships have different impacts during the various phases of their lifetimes. Building ships is a highly energy demanding process, and various environmental issues are connected to ship yards. Moreover, when ships are scrapped, the workers typically work under very crude conditions, and often no environmental concern is exercised. To facilitate the effective use of ocean near-shore areas and avoid conflicts among stakeholders, marine spatial planning (MSP) can be applied. Marine spatial planning is a process that views a system and its potential usages from both spatial and temporal perspectives and can facilitate the implementation of ecosystem-based management plans, avoiding conflicts and creating opportunities between various actors in the area. This concept is now being introduced in many countries. Shipwrecks represent a hidden problem that must be addressed. Several thousand shipwrecks litter the ocean floor, containing massive amounts of oil and other toxic chemicals.

The Natural Environment and Human Impacts

To comprehend the implications of the various environmental issues that man is inducing on the Earth (with a focus on the shipping industry), an understanding of the Earths major systems is necessary. The natural environment, which consists of air, water, land and living organisms, is a dynamic system in which material and energy are exchanged within and between the individual components. The system is divided into four spheres (atmosphere, hydrosphere, geosphere, and biosphere), and fluxes of energy and material are exchanged amongst these spheres. The spheres also largely govern the fate of various environmental problems originating from the shipping industry. Therefore, background information related to these spheres is provided, and their major properties and implications are explained. Regarding the atmosphere, radiation and energy budgets are explained in conjunction with the weather and climate. Concerning the hydrosphere, oceanography is introduced together with marine ecology. Addressing the geosphere, the elements in the Earths crust and mineral commodities are discussed. Regarding the biosphere, energy is transferred through food chains; the differences between life in water and life on land are examined. Energy flows through and is stored in these spheres; this stored energy is essential to the natural environment and human society. The different primary energy sources are described and divided into non-renewable and renewable sources. Finally, an introduction to human impacts on the natural environment and to major environmental issues is provided.

Induced tolerance in situ to chronically PAH exposed ammonium oxidizers

Sediment was sampled in the vicinity of a long-term source of Polycyclic Aromatic Hydrocarbons (PAHs) to evaluate whether tolerance can be induced in situ. Total PAH concentrations as well as the bioavailable PAHs were measured, and for nine PAHs the pore water concentration could be calculated. An induced tolerance in the ammonium oxidizing community was detected at the site with highest PAH concentration and tolerance was strongest, although not significantly, correlated to bioavailable alkylated PAHs. In addition, the tolerant microbial community showed a significant lower baseline capability for nitrification with an on average 35% reduction compared to the other sites. Meiofaunal community structure differed between all sites, and the difference was significantly correlated to bioavailable alkylated PAHs and PAH31 concentrations. The results suggest that in order to judge magnitude of long-term effects, the bioavailable fraction is to be preferred, and when possible as estimation of the freely dissolved concentration.

Improving Environmental Performance in Shipping

This book addresses the environmental issues related to shipping and the natural environment, including descriptions of and proposed solutions to the issues. Currently, challenges exist that must be addressed if shipping is to become sustainable and fulfil the zero vision of no harmful emissions to the environment. In this chapter, we evaluate the steps that have been taken (if any) to limit the various environmental issues and discuss possible steps to be taken to improve environmental performance. Furthermore, future challenges must also be addressed, e.g., the current trend of increasing ship operations in the Arctic. In general, three factors could be addressed in order to reach environmentally sustainable shipping: regulations, technical solutions, and increased environmental awareness.

Discharges to the Sea

In this chapter, various environmental issues from the shipping industry which ends up in the oceans are described. Oil pollution, wastewater, antifouling paint, ballast water and litter are all described in detail. Various sources of oil pollution exist, ranging from large accidents to small continuous leakages from, e.g., propeller shaft bearings. The behaviour of oil when it enters the sea can differ, ultimately affecting the environment. Wastewater from ships is divided into sewage and grey water, and different regulations can affect their characteristics. Fouling on ship hulls affects the drag on the ship, which increases fuel consumption when maintaining a constant speed. The various antifouling paints used today to combat fouling are described herein, and a review of the environmental implications of using these paints is provided. Ballast water contains organisms that can become invasive if released into a new geographical area. Invasive species can entail costs on the order of millions of euros. Finally, litter is discussed in this chapter. Litter is deposited in the ocean via several sources and can affect organisms over long periods of time. Plastic causes the largest litter-related problem because it does not biodegrade; such material only becomes smaller, ultimately reaching a microplastic state. Henee, litter can affect organisms in different ways.

Measures to Reduce Discharges and Emissions

Discharges and emissions from shipping can be reduced through different technical measures, many of which apply similar principles, e.g., filtration or absorption. Ballast water treatment systems can be used to limit the spread of invasive species. Selective catalytic reduction units and exhaust gas recirculation can be used to reduce nitrogen oxide emissions, and scrubbers and diesel particulate filters can be used to reduce sulphur dioxide and particle emissions . The restoration or remediation of natural environments may also be required after large oil spills. Possible remediation methods include booms, mechanical techniques and dispersant chemicals. These and several additional technical measures to reduce discharges and emissions are described in this chapter, including measures to reduce the impact of the infrastructure related to the shipping industry.