Global trade, food production and ecosystem support : Making the interactions visible

Modern food production is a complex, globalized system in which what we eat and how it is produced are increasingly disconnected. This thesis examines some of the ways in which global trade has changed the mix of inputs to food and feed, and how this affects food security and our perceptions of sustainability. One useful indicator of the ecological impact of trade in food and feed products is the Appropriated Ecosystem Areas (ArEAs), which estimates the terrestrial and aquatic areas needed to produce all the inputs to particular products. The method is introduced in Paper I and used to calculate and track changes in imported subsidies to Swedish agriculture over the period 1962-1994. In 1994, Swedish consumers needed agricultural areas outside their national borders to satisfy more than a third of their food consumption needs. The method is then applied to Swedish meat production in Paper II to show that the term “Made in Sweden” is often a misnomer. In 1999, almost 80% of manufactured feed for Swedish pigs, cattle and chickens was dependent on imported inputs, mainly from Europe, Southeast Asia and South America. Paper III examines ecosystem subsidies to intensive aquaculture in two nations: shrimp production in Thailand and salmon production in Norway. In both countries, aquaculture was shown to rely increasingly on imported subsidies. The rapid expansion of aquaculture turned these countries from fishmeal net exporters to fishmeal net importers, increasingly using inputs from the Southeastern Pacific Ocean. As the examined agricultural and aquacultural production systems became globalized, levels of dependence on other nations’ ecosystems, the number of external supply sources, and the distance to these sources steadily increased. Dependence on other nations is not problematic, as long as we are able to acknowledge these links and sustainably manage resources both at home and abroad. However, ecosystem subsidies are seldom recognized or made explicit in national policy or economic accounts. Economic systems are generally not designed to receive feedbacks when the status of remote ecosystems changes, much less to respond in an ecologically sensitive manner. Papers IV and V discuss the problem of “masking” of the true environmental costs of production for trade. One of our conclusions is that, while the ArEAs approach is a useful tool for illuminating environmentally-based subsidies in the policy arena, it does not reflect all of the costs. Current agricultural and aquacultural production methods have generated substantial increases in production levels, but if policy continues to support the focus on yield and production increases alone, taking the work of ecosystems for granted, vulnerability can result. Thus, a challenge is to develop a set of complementary tools that can be used in economic accounting at national and international scales that address ecosystem support and performance. We conclude that future resilience in food production systems will require more explicit links between consumers and the work of supporting ecosystems, locally and in other regions of the world, and that food security planning will require active management of the capacity of all involved ecosystems to sustain food production.

Los SIG aplicados a la organización de la información marina. Experiencias en el proyecto MEDINA (Marine Ecosystem Dynamics and Indicators for North Africa)

[ES] Los Sistemas de Información Geográfica (SIG) juegan un papel primordial en cualquier proyecto que use de algún modo datos georreferenciados. El proyecto FP7 MEDINA (Marine ecosystem dynamics and indicators for north Africa) no es una excepción, donde trabajamos con indicadores provenientes de diferentes países e instituciones. Una de las labores que se ha llevado a cabo es la armonización de dicha información y la puesta en común mediante las posibilidades que ofrecen los SIG y herramientas afines. Hablaremos de la capacidad de los SIG, especialmente en sus soluciones libres, para poder organizar, gestionar y analizar la información geográfica.

Trasformazione di un ambiente fisico in Cyber-Physical Ecosystem

Obiettivo di questo lavoro di tesi è il perfezionamento di un sistema di Health Smart Home, ovvero un ambiente fisico (ad esempio un'abitazione) che incorpora una rete di comunicazione in grado di connettere apparecchi elettronici e servizi controllabili da remoto, con l'obiettivo di facilitare la vita ad anziani, malati o disabili nelle loro case. Questo lavoro di tesi mostrerà come è stato possibile realizzare tale sistema partendo dalle teorie e dalle tecnologie sviluppate per il Web Semantico, al fine di trasformare l'ambiente fisico in un Cyber Physical (Eco)System perfettamente funzionante.

Harmful algae and their potential impacts on the coastal ecosystem: growth and toxin production dynamics

The main goal of the present thesis was to study some harmful algal species which cause blooms in Italian coastal waters, leading to consequences for human health, coastal ecosystem, fishery and tourism. In particular, in the first part of this thesis the toxicity of Adriatic strains of the raphidophyte Fibrocapsa japonica was investigated. Despite several hypotheses have been proposed for the toxic mechanism of the raphidophytes, especially for the species Chattonella antiqua and C. marina, which have been studied more extensively, just a few studies on the toxic effects of these species for different organisms were reported. Moreover, a careful reading of the literature evidenced as any ichthyotoxic events reported worldwide can be linked to F. japonica blooms. Although recently several studies were performed on F. japonica strains from the USA, Japan, Australia, New Zealand, the Netherlands, Germany, and France in order to characterize their growth and toxicity features, the work reported in this thesis results one of the first investigation on the toxic effects of F. japonica for different organisms, such as bacteria, crustaceans and fish. Mortality effects, together with haemolysis of fish erythrocytes, probably due to the relatively high amount of PUFAs produced by this species, were observed. Mortality for fish, however, was reported only at a high cell density and after a long exposition period (9-10 days); moreover a significant increase of H2O2 obtained in the tanks where sea basses were exposed to F. japonica was also relevant. This result may justify the absence of ichthyotoxic events in the Italian coasts, despite F. japonica blooms detected in these areas were characterized by high cell densities. This work reports also a first complete characterization of the fatty acids produced and extracellularly released by the Adriatic F. japonica, and results were also compared with the fatty acid profile of other strains. The absence of known brevetoxins in F. japonica algal extracts was also highlighted, leading to the hypothesis that the toxicity of F. japonica may be due to a synergic effect of PUFAs and ROS. Another microalgae that was studied in this thesis is the benthic dinoflagellate Ostreopsis cf. ovata. This species was investigated with the aim to investigate the effect of environmental parameters on its growth and toxicity. O. cf. ovata, in fact, shows different blooming periods along the Italian coasts and even the reported toxic effects are variable. The results of this work confirmed the high variability in the growth dynamic and toxin content of several Italian strains which were isolated in recent years along the Adriatic and Tyrrhenian Seas. Moreover, the effects of temperature and salinity on the behaviour of the different isolates are in good agreement with the results obtained from field surveys, which evidence as the environmental parameters are important factors modulating O. cf. ovata proliferation. Another relevant result that was highlighted is the anomaly in the production of palytoxin-like compounds reported by one of the studied isolate, in particular the one isolated in 2008 in Ancona (Adriatic Sea). Only this strain reported the absence of two (ovatoxin-b and –c) of the five ovatoxins so far known in the toxin profile and a different relative abundance of the other toxins. The last aspect that was studied in this thesis regards the toxin biosythesis. In fact, toxins produced (palytoxin-like compounds) or supposed to be produced (brevetoxin-like compounds) by O. cf. ovata and F. japonica, respectively, are polyketides, which are highly oxygenated compounds synthesized by complex enzymes known as polyketide synthase (PKS) enzymes. These enzymes are multi-domain complexes that structurally and functionally resemble the fatty acid synthases (FASs). This work reports the first study of PKS proteins in the dinoflagellates O. cf. ovata, C. monotis and in the raphidophyte F. japonica. For the first time some PKSs were identified in these species, confirming the presence of PKS proteins predicted by the in silico translation of the transcripts found in K. brevis also in other species. The identification of O. cf. ovata PKSs and the localization of the palytoxin-like compounds produced by this dinoflagellate in a similar location (chloroplast) as that observed for other dinoflagellate and cyanobacterial toxins provides some indication that these proteins may be involved in polyketide biosynthesis. However, their potential function as fatty acid synthases cannot be ruled out, as plant fatty acid synthesis also occurs within chloroplasts. This last hypothesis is also supported by the fact that in all the investigated species, and in particular in F. japonica, PKS proteins were present. Therefore, these results provide an important contribution to the study of the polyketides and of the involvement of PKS proteins in the toxin biosynthesis.

Biogenic emission of halocarbons

Within this doctoral thesis, biogenic emissions of several globally relevant halocarbons (methyl chloride, methyl bromide, methyl iodide, dibromomethane, chloroform and bromoform) have been investigated in different environments. An airborne study was focused on the tropical rainforest ecosystem, while shipborne measurements investigated naturally occurring oceanic plankton blooms. Laboratory experiments using dried plant material were made to elucidate abiotic production mechanisms occurring in organic matter. Airborne measurements over the tropical rainforest of Suriname and French Guyana (3 - 6 °N, 51 - 59 °W) revealed net fluxes of 9.5 (± 3.8 2σ) µg m-2 h-1 methyl chloride and 0.35 (± 0.15 2σ) µg m-2 h-1 chloroform emitted in the long dry season (October) 2005. An extrapolation of these numbers to all tropical forests helped to narrow down the range of the recently discovered and poorly quantified methyl chloride source from tropical ecosystems. The value for methyl chloride obtained (1.5 (± 0.6 2σ) Tg yr-1) affirms that the contribution of the tropical forest ecosystem is the major source in the global budget of methyl chloride. The extrapolated global net chloroform flux from tropical forests (56 (± 23 2σ) Gg yr-1) is of minor importance (5 - 10 %) compared to the global sources. A source of methyl bromide from this region could not be verified. The abiotic formation of methyl chloride and methyl bromide from dead plant material was tested in a laboratory study. The release from plant tissue representative of grassland, deciduous forest, agricultural areas and coastal salt marshes (hay, ash, tomato and saltwort) has been monitored. Incubations at different temperatures (25 - 50 °C) revealed significant emissions even at ambient temperature, and that the emissions increased exponentially with temperature. The strength of the emission was found to be additionally dependent on the availability of halide and the methoxyl group within the plant tissue. However, high water content in the plant material was found to inhibit methyl halide emissions. The abiotic nature of the reaction yielding methyl halides was confirmed by its high activation energy calculated via Arrhenius plots. Shipborne measurements of the atmospheric mixing ratios of methyl chloride, methyl bromide, methyl iodide, dibromomethane and bromoform have been conducted along a South Atlantic transect from the 27.01. - 05.02.2007 to characterize halocarbon emissions from a large-scale natural algae bloom encountered off the coast of Argentina. Mixing ratios of methyl chloride and methyl bromide were not significantly affected by the occurrence of the phytoplankton bloom. Emissions of methyl iodide, dibromomethane and bromoform showed pronounced mixing ratio variations, triggered by phytoplankton abundance. Methyl iodide was strongly correlated with dimethyl sulfide throughout the sampled region. A new technique combining satellite derived biomass marker (chlorophyll a) data with back trajectory analysis was successfully used to attribute variations in mixing ratios to air masses, which recently passed over areas of enhanced biological production.

Quantifying and modeling ecosystem services provided by urban greening in cities of the Southern Alps, N Italy

Population growth in urban areas is a world-wide phenomenon. According to a recent United Nations report, over half of the world now lives in cities. Numerous health and environmental issues arise from this unprecedented urbanization. Recent studies have demonstrated the effectiveness of urban green spaces and the role they play in improving both the aesthetics and the quality of life of its residents. In particular, urban green spaces provide ecosystem services such as: urban air quality improvement by removing pollutants that can cause serious health problems, carbon storage, carbon sequestration and climate regulation through shading and evapotranspiration. Furthermore, epidemiological studies with controlled age, sex, marital and socio-economic status, have provided evidence of a positive relationship between green space and the life expectancy of senior citizens. However, there is little information on the role of public green spaces in mid-sized cities in northern Italy. To address this need, a study was conducted to assess the ecosystem services of urban green spaces in the city of Bolzano, South Tyrol, Italy. In particular, we quantified the cooling effect of urban trees and the hourly amount of pollution removed by the urban forest. The information was gathered using field data collected through local hourly air pollution readings, tree inventory and simulation models. During the study we quantified pollution removal for ozone, nitrogen dioxide, carbon monoxide and particulate matter (<10 microns). We estimated the above ground carbon stored and annually sequestered by the urban forest. Results have been compared to transportation CO2 emissions to determine the CO2 offset potential of urban streetscapes. Furthermore, we assessed commonly used methods for estimating carbon stored and sequestered by urban trees in the city of Bolzano. We also quantified ecosystem disservices such as hourly urban forest volatile organic compound emissions.

Soil biogenic emissions of nitric oxide from arid and semi-arid ecosystems

The biogenic production of NO in the soil accounts for between 10% and 40% of the global total. A large degree of the uncertainty in the estimation of the biogenic emissions stems from a shortage of measurements in arid regions, which comprise 40% of the earth’s land surface area. This study examined the emission of NO from three ecosystems in southern Africa which cover an aridity gradient from semi-arid savannas in South Africa to the hyper-arid Namib Desert in Namibia. A laboratory method was used to determine the release of NO as a function of the soil moisture and the soil temperature. Various methods were used to up-scale the net potential NO emissions determined in the laboratory to the vegetation patch, landscape or regional level. The importance of landscape, vegetation and climatic characteristics is emphasized. The first study occurred in a semi-arid savanna region in South Africa, where soils were sampled from 4 landscape positions in the Kruger National Park. The maximum NO emission occurred at soil moisture contents of 10%-20% water filled pore space (WFPS). The highest net potential NO emissions came from the low lying landscape positions, which have the largest nitrogen (N) stocks and the largest input of N. Net potential NO fluxes obtained in the laboratory were converted in field fluxes for the period 2003-2005, for the four landscape positions, using soil moisture and temperature data obtained in situ at the Kruger National Park Flux Tower Site. The NO emissions ranged from 1.5-8.5 kg ha-1 a-1. The field fluxes were up-scaled to a regional basis using geographic information system (GIS) based techniques, this indicated that the highest NO emissions occurred from the Midslope positions due to their large geographical extent in the research area. Total emissions ranged from 20x103 kg in 2004 to 34x103 kg in 2003 for the 56000 ha Skukuza land type. The second study occurred in an arid savanna ecosystem in the Kalahari, Botswana. In this study I collected soils from four differing vegetation patch types including: Pan, Annual Grassland, Perennial Grassland and Bush Encroached patches. The maximum net potential NO fluxes ranged from 0.27 ng m-2 s-1 in the Pan patches to 2.95 ng m-2 s-1 in the Perennial Grassland patches. The net potential NO emissions were up-scaled for the year December 2005-November 2006. This was done using 1) the net potential NO emissions determined in the laboratory, 2) the vegetation patch distribution obtained from LANDSAT NDVI measurements 3) estimated soil moisture contents obtained from ENVISAT ASAR measurements and 4) soil surface temperature measurements using MODIS 8 day land surface temperature measurements. This up-scaling procedure gave NO fluxes which ranged from 1.8 g ha-1 month-1 in the winter months (June and July) to 323 g ha-1 month-1 in the summer months (January-March). Differences occurred between the vegetation patches where the highest NO fluxes occurred in the Perennial Grassland patches and the lowest in the Pan patches. Over the course of the year the mean up-scaled NO emission for the studied region was 0.54 kg ha-1 a-1 and accounts for a loss of approximately 7.4% of the estimated N input to the region. The third study occurred in the hyper-arid Namib Desert in Namibia. Soils were sampled from three ecosystems; Dunes, Gravel Plains and the Riparian zone of the Kuiseb River. The net potential NO flux measured in the laboratory was used to estimate the NO flux for the Namib Desert for 2006 using modelled soil moisture and temperature data from the European Centre for Medium Range Weather Forecasts (ECMWF) operational model on a 36km x 35km spatial resolution. The maximum net potential NO production occurred at low soil moisture contents (<10%WFPS) and the optimal temperature was 25°C in the Dune and Riparian ecosystems and 35°C in the Gravel Plain Ecosystems. The maximum net potential NO fluxes ranged from 3.0 ng m-2 s-1 in the Riparian ecosystem to 6.2 ng m-2 s-1 in the Gravel Plains ecosystem. Up-scaling the net potential NO flux gave NO fluxes of up to 0.062 kg ha-1 a-1 in the Dune ecosystem and 0.544 kg h-1 a-1 in the Gravel Plain ecosystem. From these studies it is shown that NO is emitted ubiquitously from terrestrial ecosystems, as such the NO emission potential from deserts and scrublands should be taken into account in the global NO models. The emission of NO is influenced by various factors such as landscape, vegetation and climate. This study looks at the potential emissions from certain arid and semi-arid environments in southern Africa and other parts of the world and discusses some of the important factors controlling the emission of NO from the soil.

Soil organic carbon dynamics under perennial energy crops

The European renewable energy directive 2009/28/EC (E.C. 2009) provides a legislative framework for reducing GHG emissions by 20%, while achieving a 20% share of energy from renewable sources by 2020. Perennial energy crops could significantly contribute to limit GHG emissions through replacing equivalent fossil fuels and by sequestering a considerable amount of carbon into the soil through the large amounts of belowground biomass produced. The objective of this study is to evaluate the effects of land use change that perennial energy crops have on croplands (switchgrass) and marginal grasslands (miscanthus). For that purpose above and belowground biomass, SOC variation and Net Ecosystem Exchange were evaluated after five years of growth. At aboveground level both crops produced high biomass under cropland conditions as well as under marginal soils. At belowground level they also produced large amounts of biomass, but no significant influences on SOC in the upper layer (0-30 cm) were found. This is probably because of the "priming effect" that caused fast carbon substitution. In switchgrass only it was found a significant SOC increase in deeper layers (30-60 cm), while in the whole soil profile (0-60 cm) SOC increased from 42 to 51 ha-1. However, the short experimental periods (for both switchgrass and miscanthus), in which land use change was evaluated, do not permit to determine the real capacity of perennial energy crops to accumulate SOC. In conclusion the large amounts of belowground biomass enhanced the SOC dynamic through the priming effect resulting in increased SOC in cropland but not in marginal grassland.

Summer drought reduces total and litter-derived soil CO2 effluxes in temperate grassland - clues from a 13C litter addition experiment

Current climate change models predict significant changes in rainfall patterns across Europe. To explore the effect of drought on soil CO2 efflux (FSoil) and on the contribution of litter to FSoil we used rain shelters to simulate a summer drought (May to July 2007) in an intensively managed grassland in Switzerland by reducing annual precipitation by around 30% similar to the hot and dry year 2003 in Central Europe. We added 13C-depleted as well as unlabelled grass/clover litter to quantify the litter-derived CO2 efflux (FLitter). Soil CO2 efflux and the 13C/12C isotope ratio (δ13C) of the respired CO2 after litter addition were measured during the growing season 2007. Drought significantly decreased FSoil in our litter addition experiment by 59% and FLitter by 81% during the drought period itself (May to July), indicating that drought had a stronger effect on the CO2 release from litter than on the belowground-derived CO2 efflux (FBG, i.e. soil organic matter (SOM) and root respiration). Despite large bursts in respired CO2 induced by the rewetting after prolonged drought, drought also reduced FSoil and FLitter during the entire 13C measurement period (April to October) by 26% and 37%, respectively. Overall, our findings show that drought decreased FSoil and altered its seasonality and its sources. Thus, the C balance of temperate grassland soils respond sensitively to changes in precipitation, a factor that needs to be considered in regional models predicting the impact of climate change on ecosystems C balance.

Abandoned Coal Mine Drainage and Its Remediation: Impacts on Stream Ecosystem Structure and Function

The effects of abandoned mine drainage (AMD) on streams and responses to remediation efforts were studied using three streams (AMD-impacted, remediated, reference) in both the anthracite and the bituminous coal mining regions of Pennsylvania (USA). Response variables included ecosystem function as well as water chemistry and macroinvertebrate community composition. The bituminous AMD stream was extremely acidic with high dissolved metals concentrations, a prolific mid-summer growth of the filamentous alga, Mougeotia, and .10-fold more chlorophyll than the reference stream. The anthracite AMD stream had a higher pH, substrata coated with iron hydroxide(s), and negligible chlorophyll. Macroinvertebrate communities in the AMD streams were different from the reference streams, the remediated streams, and each other. Relative to the reference stream, the AMD stream(s) had (1) greater gross primary productivity (GPP) in the bituminous region and undetectable GPP in the anthracite region, (2) greater ecosystem respiration in both regions, (3) greatly reduced ammonium uptake and nitrification in both regions, (4) lower nitrate uptake in the bituminous (but not the anthracite) region, (5) more rapid phosphorus removal from the water column in both regions, (6) activities of phosphorus-acquiring, nitrogenacquiring, and hydrolytic-carbon-acquiring enzymes that indicated extreme phosphorus limitation in both regions, and (7) slower oak and maple leaf decomposition in the bituminous region and slower oak decomposition in the anthracite region. Remediation brought chlorophyll concentrations and GPP nearer to values for respective reference streams, depressed ecosystem respiration, restored ammonium uptake, and partially restored nitrification in the bituminous (but not the anthracite) region, reduced nitrate uptake to an undetectable level, restored phosphorus uptake to near normal rates, and brought enzyme activities more in line with the reference stream in the bituminous (but not the anthracite) region. Denitrification was not detected in any stream. Water chemistry and macroinvertebrate community structure analyses capture the impact of AMD at the local reach scale, but functional measures revealed that AMD has ramifications that can cascade to downstream reaches and perhaps to receiving estuaries.