TY - GEN A1 - Porada, Philipp A1 - Tamm, Alexandra A1 - Raggio, Jose A1 - Yafang, Cheng A1 - Kleidon, Axel A1 - Pöschl, Ulrich A1 - Weber, Bettina T1 - Global NO and HONO emissions of biological soil crusts estimated by a process-based non-vascular vegetation model T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - The reactive trace gases nitric oxide (NO) and nitrous acid (HONO) are crucial for chemical processes in the atmosphere, including the formation of ozone and OH radicals, oxidation of pollutants, and atmospheric self-cleaning. Recently, empirical studies have shown that biological soil crusts are able to emit large amounts of NO and HONO, and they may therefore play an important role in the global budget of these trace gases. However, the upscaling of local estimates to the global scale is subject to large uncertainties, due to unknown spatial distribution of crust types and their dynamic metabolic activity. Here, we perform an alternative estimate of global NO and HONO emissions by biological soil crusts, using a process-based modelling approach to these organisms, combined with global data sets of climate and land cover. We thereby consider that NO and HONO are emitted in strongly different proportions, depending on the type of crust and their dynamic activity, and we provide a first estimate of the global distribution of four different crust types. Based on this, we estimate global total values of 1.04 Tg yr⁻¹ NO–N and 0.69 Tg yr⁻¹ HONO–N released by biological soil crusts. This corresponds to around 20% of global emissions of these trace gases from natural ecosystems. Due to the low number of observations on NO and HONO emissions suitable to validate the model, our estimates are still relatively uncertain. However, they are consistent with the amount estimated by the empirical approach, which confirms that biological soil crusts are likely to have a strong impact on global atmospheric chemistry via emissions of NO and HONO. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 746 KW - net primary productivity KW - hilly loes plateau KW - mojave desert KW - spatial-distribution KW - nitrous-oxide KW - succulent karoo KW - inner-mongolia KW - carbon KW - lichens KW - bryophytes Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-435682 SN - 1866-8372 IS - 746 SP - 2003 EP - 2031 ER - TY - JOUR A1 - Porada, Philipp A1 - Tamm, Alexandra A1 - Raggio, Jose A1 - Yafang, Cheng A1 - Kleidon, Axel A1 - Pöschl, Ulrich A1 - Weber, Bettina T1 - Global NO and HONO emissions of biological soil crusts estimated by a process-based non-vascular vegetation model JF - Biogeosciences N2 - The reactive trace gases nitric oxide (NO) and nitrous acid (HONO) are crucial for chemical processes in the atmosphere, including the formation of ozone and OH radicals, oxidation of pollutants, and atmospheric self-cleaning. Recently, empirical studies have shown that biological soil crusts are able to emit large amounts of NO and HONO, and they may therefore play an important role in the global budget of these trace gases. However, the upscaling of local estimates to the global scale is subject to large uncertainties, due to unknown spatial distribution of crust types and their dynamic metabolic activity. Here, we perform an alternative estimate of global NO and HONO emissions by biological soil crusts, using a process-based modelling approach to these organisms, combined with global data sets of climate and land cover. We thereby consider that NO and HONO are emitted in strongly different proportions, depending on the type of crust and their dynamic activity, and we provide a first estimate of the global distribution of four different crust types. Based on this, we estimate global total values of 1.04 Tg yr⁻¹ NO–N and 0.69 Tg yr⁻¹ HONO–N released by biological soil crusts. This corresponds to around 20% of global emissions of these trace gases from natural ecosystems. Due to the low number of observations on NO and HONO emissions suitable to validate the model, our estimates are still relatively uncertain. However, they are consistent with the amount estimated by the empirical approach, which confirms that biological soil crusts are likely to have a strong impact on global atmospheric chemistry via emissions of NO and HONO. KW - net primary productivity KW - hilly loes plateau KW - mojave desert KW - spatial-distribution KW - nitrous-oxide KW - succulent karoo KW - inner-mongolia KW - carbon KW - lichens KW - bryophytes Y1 - 2019 U6 - https://doi.org/10.5194/bg-16-2003-2019 SN - 1726-4170 SN - 1726-4189 VL - 16 SP - 2003 EP - 2031 PB - Copernicus Publ. CY - Göttingen ER - TY - JOUR A1 - Müller, Jörg A1 - Heinze, Johannes A1 - Joshi, Jasmin Radha A1 - Boch, Steffen A1 - Klaus, Valentin H. A1 - Fischer, Markus A1 - Prati, Daniel T1 - Influence of experimental soil disturbances on the diversity of plants in agricultural grasslands JF - Journal of plant ecology N2 - Disturbance is supposed to play an important role for biodiversity and ecosystem stability as described by the intermediate disturbance hypothesis (IDH), which predicts highest species richness at intermediate levels of disturbances. In this study, we tested the effects of artificial soil disturbances on diversity of annual and perennial vascular plants and bryophytes in a field experiment in 86 agricultural grasslands differing in land use in two regions of Germany. On each grassland, we implemented four treatments: three treatments differing in application time of soil disturbances and one control. One year after experimental disturbance, we recorded vegetation and measured biomass productivity and bare ground. We analysed the disturbance response taking effects of region and land-use-accompanied disturbance regimes into account. Region and land-use type strongly determined plant species richness. Experimental disturbances had small positive effects on the species richness of annuals, but none on perennials or bryophytes. Bare ground was positively related to species richness of bryophytes. However, exceeding the creation of 12% bare ground further disturbance had a detrimental effect on bryophyte species richness, which corresponds to the IDH. As biomass productivity was unaffected by disturbance our results indicate that the disturbance effect on species richness of annuals was not due to decreased overall productivity, but rather due to short-term lowered inter- and intraspecific competition at the newly created microsites. Generally, our results highlight the importance of soil disturbances for species richness of annual plants and bryophytes in agricultural grasslands. However, most grasslands were disturbed naturally or by land-use practices and our additional experimental soil disturbances only had a small short-term effect. Overall, total plant diversity in grasslands seemed to be more limited by the availability of propagules rather than by suitable microsites for germination. Thus, nature conservation efforts to increase grassland diversity should focus on overcoming propagule limitation, for instance by additional sowing of seeds, while the creation of additional open patches by disturbance might only be appropriate where natural disturbances are scarce. KW - annuals KW - bryophytes KW - colonization KW - intermediate disturbance hypothesis KW - microsites Y1 - 2014 U6 - https://doi.org/10.1093/jpe/rtt062 SN - 1752-9921 SN - 1752-993X VL - 7 IS - 6 SP - 509 EP - 517 PB - Oxford Univ. Press CY - Oxford ER - TY - THES A1 - Kiss, Andrea T1 - Moss-associated bacterial and archaeal communities of northern peatlands: key taxa, environmental drivers and potential functions T1 - Moos-assoziierte bakterielle und archaelle Gemeinschaften nördlicher Moore: Schlüsselspezies, beeinflussende Umweltfaktoren und potentielle Funktionen N2 - Moss-microbe associations are often characterised by syntrophic interactions between the microorganisms and their hosts, but the structure of the microbial consortia and their role in peatland development remain unknown. In order to study microbial communities of dominant peatland mosses, Sphagnum and brown mosses, and the respective environmental drivers, four study sites representing different successional stages of natural northern peatlands were chosen on a large geographical scale: two brown moss-dominated, circumneutral peatlands from the Arctic and two Sphagnum-dominated, acidic peat bogs from subarctic and temperate zones. The family Acetobacteraceae represented the dominant bacterial taxon of Sphagnum mosses from various geographical origins and displayed an integral part of the moss core community. This core community was shared among all investigated bryophytes and consisted of few but highly abundant prokaryotes, of which many appear as endophytes of Sphagnum mosses. Moreover, brown mosses and Sphagnum mosses represent habitats for archaea which were not studied in association with peatland mosses so far. Euryarchaeota that are capable of methane production (methanogens) displayed the majority of the moss-associated archaeal communities. Moss-associated methanogenesis was detected for the first time, but it was mostly negligible under laboratory conditions. Contrarily, substantial moss-associated methane oxidation was measured on both, brown mosses and Sphagnum mosses, supporting that methanotrophic bacteria as part of the moss microbiome may contribute to the reduction of methane emissions from pristine and rewetted peatlands of the northern hemisphere. Among the investigated abiotic and biotic environmental parameters, the peatland type and the host moss taxon were identified to have a major impact on the structure of moss-associated bacterial communities, contrarily to archaeal communities whose structures were similar among the investigated bryophytes. For the first time it was shown that different bog development stages harbour distinct bacterial communities, while at the same time a small core community is shared among all investigated bryophytes independent of geography and peatland type. The present thesis displays the first large-scale, systematic assessment of bacterial and archaeal communities associated both with brown mosses and Sphagnum mosses. It suggests that some host-specific moss taxa have the potential to play a key role in host moss establishment and peatland development. N2 - Während die Beziehungen zwischen Moosen und den mit ihnen assoziierten Mikroorganismen oft durch syntrophische Wechselwirkungen charakterisiert sind, ist die Struktur der Moos-assoziierten mikrobiellen Gemeinschaften sowie deren Rolle bei der Entstehung von Mooren weitgehend unbekannt. Die vorliegende Arbeit befasst sich mit mikrobiellen Gemeinschaften, die mit Moosen nördlicher, naturnaher Moore assoziiert sind, sowie mit den Umweltfaktoren, die sie beeinflussen. Entlang eines groß angelegten geographischen Gradienten, der von der Hocharktis bis zur gemäßigten Klimazone reicht, wurden vier naturbelassene Moore als Probenstandorte ausgesucht, die stellvertretend für verschiedene Stadien der Moorentwicklung stehen: zwei Braunmoos-dominierte Niedermoore mit nahezu neutralem pH-Wert sowie zwei Sphagnum-dominierte Torfmoore mit saurem pH-Wert. Die Ergebnisse der vorliegenden Arbeit machen deutlich, dass die zu den Bakterien zählenden Acetobacteraceae das vorherrschende mikrobielle Taxon der Sphagnum-Moose gleich welchen geographischen Ursprungs darstellen und insbesondere innerhalb des Wirtsmoosgewebes dominieren. Gleichzeitig gehörten die Acetobacteraceae zum wesentlichen Bestandteil der mikrobiellen Kerngemeinschaft aller untersuchten Moose, die sich aus einigen wenigen Arten, dafür zahlreich vorkommenden Prokaryoten zusammensetzt. Die vorliegende Arbeit zeigt zudem erstmals, dass sowohl Braunmoose als auch Torfmoose ein Habitat für Archaeen darstellen. Die Mehrheit der Moos-assoziierten Archaeen gehörte dabei zu den methanbildenden Gruppen, wenngleich die metabolischen Aktivitätsraten unter Laborbedingungen meistens kaum messbar waren. Im Gegensatz hierzu konnte die Bakterien-vermittelte Methanoxidation sowohl an Braunmoosen als auch an Sphagnum-Moosen gemessen werden. Dies zeigt eindrucksvoll, dass Moos-assoziierte Bakterien potenziell zur Minderung von Methanemissionen aus nördlichen, aber auch wiedervernässten Mooren beitragen können. Ein weiteres wichtiges Resultat der vorliegenden Arbeit ist die Bedeutung des Moortyps (Niedermoor oder Torfmoor), aber auch der Wirtsmoosart selbst für die Struktur der Moos-assoziierten Bakteriengemeinschaften, während die archaeellen Gemeinschaftsstrukturen weder vom Moortyp noch von der Wirtsmoosart beeinflusst wurden und sich insgesamt deutlich ähnlicher waren als die der Bakterien. Darüber hinaus konnte erstmalig gezeigt werden, dass sich die bakteriellen Gemeinschaften innerhalb der unterschiedlichen Moorsukzessionsstadien zwar ganz erheblich voneinander unterscheiden, ein kleiner Teil der Bakterien dennoch Kerngemeinschaften bilden, die mit allen untersuchten Moosarten assoziiert waren. Bei der hier präsentierten Arbeit handelt es sich um die erste systematische Studie, die sich auf einer großen geographischen Skala mit den bakteriellen und archaeellen Gemeinschaften von Braunmoosen und Torfmoosen aus naturbelassenen nördlichen Mooren befasst. Die vorliegenden Ergebnisse machen deutlich, dass die untersuchten Moose ein ganz spezifisches mikrobielles Konsortium beherbergen, welches mutmaßlich eine Schlüsselrolle bei der Etablierung der Wirtspflanzen am Anfang der Moorentwicklung spielt und darüber hinaus das Potential hat, die charakteristischen Eigenschaften von Mooren sowie deren weitere Entwicklung zu prägen. KW - moss-microbe-interactions KW - moss-associated bacteria KW - moss-associated archaea KW - northern peatlands KW - peatland core microbiome KW - Acetobacteraceae KW - moss-associated methanotrophy KW - moss-associated methanogenesis KW - Sphagnum KW - Amblystegiaceae KW - endophytes KW - brown mosses KW - epiphytes KW - peatland development KW - bryophytes KW - host-specificity KW - large-scale study KW - methanotrophic bacteria KW - methanogenic archaea KW - Essigsäurebakterien KW - Amblystegiaceae KW - Torfmoose KW - Braunmoose KW - Bryophyten KW - Endophyten KW - Epiphyten KW - Wirtsspezifität KW - geographische Großstudie KW - methanproduzierende Archaeen KW - methanoxidierende Bakterien KW - Moos-assoziierte Methanproduktion KW - Moos-assoziierte Methanoxidation KW - Moos-Mikroben-Interaktion KW - nördliche Moore KW - mikrobielle Moor-Kerngemeinschaft KW - Moorsukzession Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-630641 ER - TY - JOUR A1 - Hargis, Hailey A1 - Gotsch, Sybil G. A1 - Porada, Philipp A1 - Moore, Georgianne W. A1 - Ferguson, Briana A1 - Van Stan, John T. T1 - Arboreal epiphytes in the soil-atmosphere interface BT - how often are the biggest "buckets" in the canopy empty? JF - Geosciences N2 - Arboreal epiphytes (plants residing in forest canopies) are present across all major climate zones and play important roles in forest biogeochemistry. The substantial water storage capacity per unit area of the epiphyte "bucket" is a key attribute underlying their capability to influence forest hydrological processes and their related mass and energy flows. It is commonly assumed that the epiphyte bucket remains saturated, or near-saturated, most of the time; thus, epiphytes (particularly vascular epiphytes) can store little precipitation, limiting their impact on the forest canopy water budget. We present evidence that contradicts this common assumption from (i) an examination of past research; (ii) new datasets on vascular epiphyte and epi-soil water relations at a tropical montane cloud forest (Monteverde, Costa Rica); and (iii) a global evaluation of non-vascular epiphyte saturation state using a process-based vegetation model, LiBry. All analyses found that the external and internal water storage capacity of epiphyte communities is highly dynamic and frequently available to intercept precipitation. Globally, non-vascular epiphytes spend <20% of their time near saturation and regionally, including the humid tropics, model results found that non-vascular epiphytes spend similar to 1/3 of their time in the dry state (0-10% of water storage capacity). Even data from Costa Rican cloud forest sites found the epiphyte community was saturated only 1/3 of the time and that internal leaf water storage was temporally dynamic enough to aid in precipitation interception. Analysis of the epi-soils associated with epiphytes further revealed the extent to which the epiphyte bucket emptied-as even the canopy soils were often <50% saturated (29-53% of all days observed). Results clearly show that the epiphyte bucket is more dynamic than currently assumed, meriting further research on epiphyte roles in precipitation interception, redistribution to the surface and chemical composition of "net" precipitation waters reaching the surface. KW - precipitation KW - interception KW - bromeliad KW - vascular epiphyte KW - non-vascular epiphyte KW - lichens KW - bryophytes KW - water storage capacity Y1 - 2019 U6 - https://doi.org/10.3390/geosciences9080342 SN - 2076-3263 VL - 9 IS - 8 PB - MDPI CY - Basel ER - TY - GEN A1 - Hargis, Hailey A1 - Gotsch, Sybil G. A1 - Porada, Philipp A1 - Moore, Georgianne W. A1 - Ferguson, Briana A1 - Van Stan II, John T. T1 - Arboreal epiphytes in the soil-atmosphere interface BT - how often are the biggest “buckets” in the canopy empty? T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Arboreal epiphytes (plants residing in forest canopies) are present across all major climate zones and play important roles in forest biogeochemistry. The substantial water storage capacity per unit area of the epiphyte “bucket” is a key attribute underlying their capability to influence forest hydrological processes and their related mass and energy flows. It is commonly assumed that the epiphyte bucket remains saturated, or near-saturated, most of the time; thus, epiphytes (particularly vascular epiphytes) can store little precipitation, limiting their impact on the forest canopy water budget. We present evidence that contradicts this common assumption from (i) an examination of past research; (ii) new datasets on vascular epiphyte and epi-soil water relations at a tropical montane cloud forest (Monteverde, Costa Rica); and (iii) a global evaluation of non-vascular epiphyte saturation state using a process-based vegetation model, LiBry. All analyses found that the external and internal water storage capacity of epiphyte communities is highly dynamic and frequently available to intercept precipitation. Globally, non-vascular epiphytes spend <20% of their time near saturation and regionally, including the humid tropics, model results found that non-vascular epiphytes spend ~1/3 of their time in the dry state (0–10% of water storage capacity). Even data from Costa Rican cloud forest sites found the epiphyte community was saturated only 1/3 of the time and that internal leaf water storage was temporally dynamic enough to aid in precipitation interception. Analysis of the epi-soils associated with epiphytes further revealed the extent to which the epiphyte bucket emptied—as even the canopy soils were often <50% saturated (29–53% of all days observed). Results clearly show that the epiphyte bucket is more dynamic than currently assumed, meriting further research on epiphyte roles in precipitation interception, redistribution to the surface and chemical composition of “net” precipitation waters reaching the surface. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 928 KW - precipitation KW - interception KW - bromeliad KW - vascular epiphyte KW - non-vascular epiphyte KW - lichens KW - bryophytes KW - water storage capacity Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-441993 SN - 1866-8372 IS - 928 ER -