North Sea Archaeologies traces the way people engaged with the North Sea from the end of the last ice age, around 10,000 BC, to the close of the Middle Ages, about AD 1500, drawing upon archaeological research from many countries, including the UK, Netherlands, Germany, Denmark, Sweden, Norway, Belgium, and France. It addresses topics which include the first interactions of people with the emerging North Sea, the origin and development of fishing, the creation of coastal landscapes, the importance of islands and archipelagos, the development of seafaring ships and their use by early seafarers and pirates, and the treatment of boats and ships at the end of their useful lives. The study offers a ‘maritime turn’ in Archaeology through the investigation of aspects of human behaviour that have been, to various extents, disregarded, overlooked, or ignored in archaeological studies of the land. The study concludes that the relationship between humans and the sea challenges the frequently invoked dichotomy between pre-modernity and modernity, since many ancient beliefs, superstitions, and practices linked to seafaring and engagement with the sea are still widespread in the modern era.

Constructed wetlands are considered an inefficient technology for long-term phosphorus (P) removal. The P retention effectiveness of subsurface wetlands can be improved by using appropriate substrates. The objectives of this study were to: (i) use sorption isotherms to estimate the P sorption capacity of the two materials, masonry sand and light weight expanded shale; (ii) describe dissolved P removal in small (2.7 m3) subsurface flow wetlands; (iii) quantify the forms of P retained by the substrates in the pilot cells; and (iv) use resulting data to assess the technical and economic feasibility of the most promising system to remove P. The P sorption capacity of masonry sand and expanded shale, as determined with Langmuir isotherms, was 60 mg/kg and 971 mg/kg respectively. In the pilot cells receiving secondarily treated wastewater, cells containing expanded shale retained a greater proportion of the incoming P (50.8 percent) than cells containing masonry sand (14.5 percent). After a year of operation, samples were analyzed for total P (TP) and total inorganic P (TIP). Subsamples were fractionated into labile-P, Fe+Al-bound P, humic-P, Ca+Mg-bound P, and residual-P. Means and standard deviations of TP retained by the expanded shale and masonry sand were 349 + 169 and 11.9 + 18.6 mg/kg respectively. The largest forms of P retained by the expanded shale pilot cells were Fe+Al- bound P (108 mg/kg), followed by labile-P (46.7 mg/kg) and humic-P (39.8). Increases in the P forms of masonry sand were greatest in labile-P (7.5 mg/kg). The cost of an expanded shale wetland is within the range of costs conventional technologies for P removal. Accurate cost comparisons are dependent upon expansion capacity of the system under consideration. Materials with a high P sorption capacity also have potential for enhancing P removal in other constructed wetland applications such as stormwater wetlands and wetlands for treating agricultural runoff.

Nutrient availability, water depth, competition, and soil management effects on cattail (Typha latifolia) growth in wetland systems were examined. Soluble reactive phosphorous (SRP), nitrate-nitrogen (NO3-N), and ammonia-nitrogen (NH3-N) removals were tested at a constructed wetland receiving municipal wastewater effluent. Over all, no significant differences in nutrients occurred between diverse planted and cattail areas. T. latifolia seeds, under the canopy of Eleochoris macrostachya, had low seed germination. Established stands of emergent vegetation can prevent cattail colonization and spread. Germination of T. latifolia at various water depths was tested, and depth impacts on cattail seedling growth and survival were ascertained using various moist soil management techniques in three ponds. Water levels at 0cm and >40cm can adversely impact cattail establishment.

In this study we determined the magnitude of plant mediated CH4 emission (flux) in two vegetation types of Carex ramenskii. The objectives of this paper were to quantify the proportion of CH4 emissions from plant mediated flux and the total flux (plant and soil). This information is needed in order to understand how grazing affects plant mediated CH4 flux. In addition, we differentiated between two vegetation morphs, grazed and ungrazed, and determined the plant mediated CH4 flux for vegetation type.  This study was conducted at a field site on the Tutakoke River (61 15’N, 165 30’W) which is located in the coastal region of the Yukon-Kuskokwim Delta. Three replicate plots of the two vegetation morphs of Carex ramenskii were established. Methane flux was measured with a total flux chamber (plant and soil) and a single leaf chamber using a Picarro Cavity Ring-Down Spectroscopy Analyzer (Model G2308, Picarro Inc., Santa Clara, California). Plant density for the two plant types was determined. Temperature measurements were taken and correlated with gas flux. This study found that total net CH4 emissions from Carex ssp. were the same in both vegetation types. This similarity could indicate that plant mediated flux through vegetation is not affected by grazing in the sense that grazing is neither facilitating nor inhibiting plant mediated CH4 flux. The magnitude of plant mediated flux was still greater in the ungrazed meadow type, indicating on both greater facilitation of CH4 flux, and below ground oxygen transport enabling higher rates of CH4 consumption.

Submitted in complete fulfillment for the degree of Doctor of Philosophy (Biotechnology) in the Department of Biotechnology and Food Technology, Durban University of Technology, Durban, South Africa, 2016. / Many households in developing countries are still without proper sanitation systems. The problems are even more prevalent in rural communities where there are no septic systems in place for the treatment of wastewater. This has resulted in the urgent need for the development and implementation of innovative wastewater treatment systems that are inexpensive, environmental friendly and are able to reduce contaminants to levels that pose no harm to the communities. Constructed rhizofiltration systems have been explored for this purpose. They have been used for many decades in many countries with varying degrees of success at the primary, secondary and tertiary levels of wastewater treatment. Poor optimization of this technology has been due to limited information available about the roles played by the whole system as well as by each component involved in the treatment technology. The current work elucidates the role played by macrophytes and microbial biofilms in the removal of nutrients in the rhizofiltration system. Factors affecting waste removal as well as environmental friendliness of the system were also investigated. The rhizofiltration system was constructed in Durban and was divided into planted (planted with Phragmites australis and Kyllinga nemoralis) and unplanted (reference) section. Dissolved oxygen (DO), pH, water temperature, total dissolved solids (TDS), electrical conductivity (EC) and salinity were monitored. The removal efficiency of nutrients was measured using spectrophotometric methods by measuring the concentration of ammonia, nitrate, nitrite, phosphate and orthophosphate in the wastewater pre- and post-treatment. The total organic carbon, chemical oxygen demand (COD), total Kehldjahl nitrogen, biological oxygen demand (BOD), ammonia, nitrate and the flow rate of wastewater into the system from the settling tank were used for the estimation of carbon dioxide, methane and nitrous oxide emitted from the rhizofilter using the 2009 EPA formulae. Both the planted and reference sections of the system removed nutrients with varying efficiencies. The reduction of nutrients in the rhizofilter was found to be seasonal, with most nutrients removed during the warm seasons. The system also retained more nutrients when wastewater containing low levels of nutrients was used. The unpaired t-test was used to determine the differences between nutrient removals between planted and reference sections. Higher reduction efficiencies of nutrients were obtained in the planted section. Up to 65% nitrite and 99% nitrate were removed while up to 86% total phosphorus was removed in a form of orthophosphate (86%). Removal of total nitrogen was shown to increase under high temperature conditions, while the same conditions decreased the total phosphorus removal. High temperatures also increased the performance of the system. The reduction of nutrients in the system corresponded to reduction of the chemical oxygen demand which also positively correlated to the dissolved oxygen concentration. Considering the discharge limits for all nutrients, the discharges in the effluent of the planted section were within the allowable limits as per South Africa’s Department of Water affairs and Forestry in 2012 but not in 2013. The results obtained in 2013 were due to increased nutrient loading introduced into the system. Diverse microbial communities occurred in the treatment system, with more diversity in the planted section. These organisms were supported by macrophytes in the planted section, and were responsible for nitrogen and phosphorus transformation. This explains why total nitrogen and phosphorus reduction was higher in the planted compared to the reference section. Both the planted and the reference sections of the rhizofiltration system produced the greenhouse gases. When the two sections were compared, the planted section produced more gases. Gases emitted by both sections were lower when compared to emission from sludge treatment reed beds and other conventional systems of wastewater treatments. These findings indicated that constructed rhizofiltration is a cleaner form of waste treatment, producing significantly less greenhouse gases and affecting less of a climate change. Findings of this work have revealed that rhizofiltration technology can be used as a low-cost alternative technology for the treatment of wastewater, using the combination of macrophytes and microbial biofilms. Macrophytes accumulated nitrogen and phosphorus as well as supported diverse microorganisms that metabolized and reduced nutrients in the rhizofiltration unit. / D

Mikroplast, här definierat som plastobjekt mindre än 5 mm, befaras kunna göra stor skada på vattenlevande djur. Fram tills idag har studier av mikroplastreduktion främst utförts i kommunala avloppsreningsverk där mycket av plasten avskiljs. De stora spillvattenflödena gör ändå reningsverken till betydande utsläppspunkter av mikroplast till sjöar och hav. Information har hittills till stor del saknats om mikroplastförekomst i dagvatten, vilket ofta släpps ut orenat och i större volymer än spillvatten. Förekomst av mikroplast >20 µm (>0,02 mm) har undersökts för tre tätorters dagvatten samt för två avloppsreningsverks utloppsvatten. Avskiljning av mikroplast har undersökts för två spillvattenvåtmarker och två dagvattendammar. Båda anläggningstyper är relativt billiga och effektiva när det gäller reduktion av tungmetaller och övergödande näringsämnen. Örsundsbro våtmark och våtmark Alhagen tar båda emot behandlat spillvatten från kommunala avloppsreningsverk. I våtmark Alhagen finns även ett inlopp för dagvatten från Nynäshamn. Till dagvattenanläggningen Korsängens vattenpark leds en stor del av Enköpings dagvatten, medan Tibbledammen tar emot det dagvatten som kommer från Kungsängen i Upplands-Bro kommun. Vatten från anläggningarnas inlopp och utlopp, samt från två punkter inuti våtmark Alhagen har pumpats genom 20 µm-filter och 300 µm-filter. Provtagningen har kompletterats med insamling av mindre vattenvolymer som har filtrerats på laboratorium. Kvantifiering av mikroplast har gjorts med hjälp av stereomikroskop och vanligt förekommande objekts material har undersökts genom FTIR-spektroskopi. I våtmark Alhagens inkommande spillvatten var mikroplastkoncentrationen 4 objekt/liter, vilket liknar de koncentrationer andra svenska studier uppmätt i behandlat spillvatten. I inkommande vatten till Örsundsbro våtmark var koncentrationen över 950 objekt/liter, långt över vad andra svenska studier uppmätt i helt obehandlat spillvatten. I dagvatteninloppen var mikroplastinnehållet 5,4–10 objekt/liter, vilket indikerar på att mikroplatsutsläpp via dagvatten kan befaras vara minst lika stora som via spillvatten. I alla anläggningars inkommande vatten, förutom i våtmark Alhagens dagvatteninlopp, uppmättes höga koncentrationer av rödfärgade partiklar. Partiklarna kan vara av plast eller av annat okänt material och är till utseendet relativt lika de som andra studier påträffat i svenska kustvatten. Svarta partiklar påträffades i alla inflöden och ofta i mer än 100 gånger högre halter än de för mikroplast och röda partiklar, förutom i våtmark Alhagens spillvatteninlopp där de röda partiklarna var något fler. Partiklarna tros kunna vara däck- och vägrester eller förbränningspartiklar. Alla anläggningar visade på en tydlig avskiljning, ofta 90-100 %, för mikroplast, svarta och röda partiklar >20 µm. Till följd av resultatet samt anläggningarnas variation i ålder, storlek och utformning bör dagvattendammar och anlagda våtmarker generellt kunna förväntas fungera som effektiva barriärer mot spridning av mikroplast, svarta partiklar och röda partiklar. / Microplastics (MPs), here defined as plastic objects smaller than 5 mm, are suspected to cause great harm to fish when released into lakes and oceans. Studies of MP retention have until recently mainly been done for sewage treatment plants (STPs), where much of the plastics are shown to be retained in the sludge. However, due to large water flows in STPs, they can be seen as significant points for the spreading of MPs to recipient waters. Today there isn’t much information to be found about MP contents in stormwater. Stormwater is often released untreated and depending on climate it can be released in greater volumes than sewage water from urban areas. The occurrence of MPs >20 µm (>0.02 mm) has been studied in two STP effluents, and in stormwater from three urban catchments. The retention of MPs has been studied for two stormwater ponds, and for two free water surface wetlands constructed for tertiary treatment of sewage. Wetland Alhagen and Örsundsbro wetland both receive the effluents of secondary STPs. In wetland Alhagen there is also a stormwater inlet from the town of Nynäshamn. To the stormwater pond Korsängens vattenpark, stormwater is lead from the town of Enköping, while the stormwater pond Tibbledammen receives stormwater from Kungsängen in Upplands-Bro municipality. Influents and effluents from the facilities, as well as water from two points within wetland Alhagen was pumped through 20 µm and 300 µm filters. In addition, water from every sampling point was collected in minor volumes for later filtration carried out in a laboratory. Quantification was done with microscopy and a number of objects were analyzed with FTIR spectroscopy for material determination. In wetland Alhagen, the sewage inlet contained 4 MPs/liter, which is similar to results for STP effluents in other Swedish studies. In Örsundsbro wetland, the incoming water contained more than 950 MPs/liter, far greater than what other studies have shown for untreated sewage. The MP concentrations in the three stormwater inlets were between 5.4-10 MPs/liter. This indicates that untreated stormwater could be seen as a pathway for MPs at least as big as treated sewage. In almost all inlets, characteristic red particles were found in great numbers and in sizes of 20-300 µm. Analysis of some of the red particles indicated that they contained plastic while others were of unknown materials. The particles had a similar appearance to red particles commonly found in Swedish coastal waters. Black particles, a kind of microscopic particles that may originate in tyre wear (i.e. MPs) or combustion, was also found in large quantities. Except for in the main influents of wetland Alhagen, where the number of red particles was slightly higher, the black particles were always found in far greater numbers than both regular MPs and red particles (often >100x greater). The retention of MPs, black particles and red particles >20 µm was high in all the facilities, often around 90-100 percent. Based on these results and the variation of size, design and year of construction, stormwater ponds and constructed free water surface wetlands can be seen as effective barriers against the spreading of MPs.

A study was undertaken to explore relationships between wetland characteristics which make them efficient water purifiers versus their ability to serve as wildlife habitat. The effects of designing constructed wetlands for improved habitat on water treatment efficiencies were quantified. Results indicate that some sacrifice in treatment efficiency is required and that the degree of efficiency reduction is dependant upon pollutant loading rates. However, sacrifice in efficiency is much smaller than increase in habitat quality, and can be offset by increasing wetland area. A practical, theoretical application was then attempted.

Long-term perspectives on the evolution of river deltas have provided useful knowledge capable of responding to pending questions related to the ongoing climate and environmental changes. Increasing utilization pressure on delta environments has necessitated increased attention to protect the socio-economic and ecological values. As a result, multiple local initiatives have been designed, aimed at mitigating environmental deterioration and implementing adaptive measures, but many such initiatives have shown limited success. This thesis uses a case study of Save River delta in Mozambique to explore the relation between geomorphological evolution and socio-ecological system dynamics in delta environments. In addition, key environmental variables that concern the society today are highlighted and discussed in a management perspective. The results of the study show the development of Save River delta from the mid-Holocene to the present. The geomorphological settings of the delta suggest a faulted coastline over which subsequent deposition of fluvial sediments has formed a protruding delta front. Between c. 3000 and 1300 years ago, fine-grained sediments accumulated on top of the delta-front in the proximal part of the delta. This type of material was deposited under intertidal conditions and supported the formation of mangrove habitat. The geographical distribution of the mangrove deposit was driven by successive stages of back-barrier swamp formation and sea-level change as the delta evolved. From c. 1300 years ago, the river delta started to receive fluvial sediments from pulses of floods forming an alluvial floodplain. These sediments have accumulated mainly on the fine-grained mangrove wetland deposit. All the geomorphological features have evolved in a shoreward-shifting pattern over time. Centennial to decadal changes observed in the delta have followed a predictable geomorphological pattern, which is also part of the millennial evolution. The mangrove system, the base for the socio-economic system, is consequently strongly affected by the geomorphological development of the area. An increasing sensitivity of socio-ecological systems to environmental stressors, e.g. floods, cyclones and erosion, has motivated multiple initiatives to work towards a sustainable management of delta environments. This thesis highlights the need for interplay between geomorphology and ecology, considering both long- and short-term dynamics of delta environments. Hitherto, management initiatives have been concentrated on fragmented interventions of controlling water flow, which have disrupted the natural dynamics by obstructing the sedimentation-erosion cycle. To change this trend, coastal planners need to consider the significance of natural processes, e.g. cyclones, floods, erosion and accretion, for the long-term ecological and social sustainability of delta environments. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 2. Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.</p>

Phragmites australis is a perennial grass presently invading many intertidal and freshwater wetlands throughout much of the Atlantic Coast of North America. The spread of Phragmites into coastal wetlands is in part determined by available freshwater and nutrients, especially nitrogen, within the watershed where Phragmites populations occur. The Eastern Shore of Virginia is an intensive agricultural area, and watershed landcover may play a major role in Phragmites invasion. Forty-five Phragmites patches were sampled in eight VA Eastern Shore mainland watersheds and on a barrier island. Regardless of watershed landcover characteristics, there was little variation in Phragmites australis patch characteristics along the oceanside of the entire Eastern Shore of Virginia. Phragmites is a generalist with broad environmental tolerances. Thus, successful management and eradication plans may have broad scale application for this invasive grass.

In wetland soils, hydrology is considered to be one of the primary factors shaping wetland function and microbial community structure, but plant-soil interactions are also important mechanisms affecting microbial nutrient transformations. The research presented here considered the interactive effect to describe how hydrology and the presence of plants alter the soil profile, the development of the bacterial community, and their associated functions. To achieve this goal, plots were established in three hydrologically-distinct regimes (Wet, Intermediate, and Dry) within a non-tidal freshwater wetland along the James River (Charles City County, Virginia). Inside each main plot, ten subplots were cleared of all aboveground plant material; five plots were left to re-grow (“Vegetated” reference), while the remaining five were weeded each week to maintain bare soil (“Clipped” treatment subplots). Manipulations were started at the beginning of the growing season, and sampling continued until the following winter. Every eight weeks, soil cores (30 cm) were collected and analyzed for a variety of soil properties (e.g., pH, OM, C:N, redox, vegetation and root biomass), microbial community structure (16S-rDNA-based T-RFLP),bacterial abundance (Acridine Orange Direct Count), and soil function (Extracellular Enzyme Activity (EEA)). A mixed-effects repeated measures analysis of variance (ANOVA) was used to better understand how each variable responded within each hydrological regime and treatment. Principal component analysis (PCA) and Partial Mantel tests were used to elucidate how saturation and vegetation influence the microbial community structure and soil enzyme function. Bacterial community properties and soil functions followed differences in soil saturation and associated physicochemical parameters (i.e., pH and redox). Correlations with wetland vegetation were primarily related to seasonal changes in plant community composition and biomass, and differences between experimental treatments were small. Evidence suggests the present plant species and the amount of above- and belowground biomass plays a more selective role shaping bacterial communities and soil function. Due to the short-term of this study and tight soil correlations, it is difficult to determine if observed differences are a product of the plant community or soil saturation, but it is clear that each is important. Based on the literature, plant effects were smaller in this wetland than might be expected. This experiment took place in a recently exposed lake basin, so plant-soil-microbe interaction may not be well established. As the wetland matures, relative importance of vegetation is expected to increase and impact bacterial composition and function. Collectively, these results demonstrate that wetlands are not a product of one separate variable, but result from various factors interlinked to shape microbial communities and soil functions.