The objectives of my research were twofold: 1) to evaluate new technologies (camera traps and a new type of GPS collar) for studying large mammals in tropical forests, and 2) to study the ecology of the lowland tapir (Tapirus terrestris) in the Peruvian Amazon. Camera traps proved to be an efficient tool for mammal inventories in tropical forests. They recorded 24 out of 28 terrestrial medium and large sized mammal species with a survey effort of 2340 camera days. Camera traps were also able to reveal important information on habitat use, activity patterns and the use of mineral licks for five Amazonian ungulate species. There was a high spatial overlap between all the species with the grey brocket deer being the only species that was restricted to terra firme forest. White-lipped peccaries, tapirs and red brocket deer frequently used mineral licks, whereas collared peccaries and grey brocket deer were hardly ever observed at licks. A new type of GPS collar (TrackTag) tested in this study performed well under the dense canopy of a tropical forest. Position success rates of 87% for stationary collars and 48% for collars placed on tapirs were comparable to data obtained with GPS collars in temperate forests. The mean location error for stationary collars inside the forest was 28.9 m and the 95% error was 76.8 m. GPS collars placed on six tapirs for seven to 182 days showed home range sizes of 102 to 386 hectares. Tapirs were mainly nocturnal and areas used for foraging during the night differed from resting sites used during the day. Tapirs could walk up to 10 km to visit a mineral lick. Visits were irregular at intervals of a few days up to 36 days. The analysis of 135 tapir dung samples showed that tapirs ingest seeds of over 120 plant species. Seeds were found throughout the year but monthly species diversity was related to fruit availability. The size distribution of ingested seeds was related to availability. Most seeds were less then 10 mm wide, but seeds up to 25 mm were found. Both camera traps and TrackTag GPS collars greatly increased the possibilities for studying large rainforest mammals. The two technologies collect complementary information and each one is suited for a different set of questions.

Abstract The research was conducted as a part of the phase III of the KEEP(Kuroshio Edge Exchange Processes)program. Two strings of sediment traps were deployed simultaneously: one near the outlet of North Mien-Hua Canyon (T15), and the other at the south rim of the South Okinawa Trough (T16). The purposes are to collect settling particulates at various depths for the studies of temporal and spatial variations of the particulate flux, 210Pb activity, 210Pb flux and size distribution. The particulate fluxes showed synchronous variations among the traps deployed at different depths of the same site. In general, the particulate flux in the marginal sea areas increases with depth but the maximum values may be at the mid-depth rather than at the deepest trap and remain so for the entire mooring period as observed at T15 and T16. Unusually high particulate fluxes could occur within the same period, probably reflecting an episodic event, such as typhoon or rain storm. 210Pb activity measured from different depths at T15 and T16 increases generally with depth along with the increase of the particulate flux toward the bottom. The temporal variation of 210Pb activity is generally smaller than that of the particulate flux in terms of relative amplitude. At the outlet of the canyon, T15, the temporal mean particulate flux of each trap ranged from 0.16 to 3.3 g/m2/d(a factor of ~ 20), while the mean 210Pb activity of each trap varied from about 98 to 168 dpm/g. At T16 located at the south rim of the South Okinawa Trough, the temporal mean particulate flux ranged from 0.06 to 5.7 g/m2/d(a factor of ~ 100), while the mean 210Pb activity varied from 82 to 192 dpm/g. The particulate 210Pb flux was smaller at T15 than at T16 because T15 has smaller particulate flux. The trapped particulates in the canyon(T1-T3) are mostly silt and sand, while the particulates collected from the Okinawa Trough(T15, T16) are mainly silt and clay. The 210Pb activity of the former is much lower than that of the latter, indicating the enrichment of 210Pb on the fine particulates. As the fine-grained particulates away from landmass have longer residence time in the ambient water, they can scavenge 210Pb more effectively.

I compared the strength of bottom- up and top-down effects on insect herbivores along a natural salinity gradient in salt marsh communities in West - Central, Florida. I used a 2x2 factorial design with plots divided into four different treatments: 1) fertilizer applied to increase plant quality 2) sticky traps added to remove natural enemies (parasitoids) 3) fertilizer applied and sticky traps added and 4) control plots. These plots were placed on 7 different sites containing the salt marsh plant Borrichia frutescens along a natural stress salinity gradient. In each plot I determined the abundance of the sap sucker Pissonotus quadripustulatus, the gall maker Asphondylia borrichiae, spiders and the number of chewed leaves and bored stems. I also recorded leaf area, plant density, plant height and foliar nitrogen. Plants in fertilized plots exhibited increased height, density and leaf area.

This study explored the effects of seasonal variability on the geochemistry of sinking pthesiss and on the nitrogen cycle of the Cariaco Basin. Pthesis fluxes were measured at the base of the euphotic zone (the depth of 1% of photosynthetically active radiation - PAR) with drifting sediment traps during months of upwelling and non-upwelling regimes from March 2007 to November 2009. Flux estimates were analyzed in the context of seasonal variations in sea surface temperature, primary productivity, and chlorophyll a concentrations using data generated by the CARIACO Time-series Program as well as satellite data. Additionally, nine years (1996-2000 and 2004-2007) of nutrients, phytoplankton taxonomy and δ15N of sinking pthesis data within the twilight zone (225 m) from the CARIACO Time-series Program were examined. Results showed that the flux of organic matter responded to changes in surface chlorophyll a but not to primary production. Sinking organic matter decreased by an order of magnitude from the base of the euphotic zone to the oxic-anoxic interface; most of the organic matter produced in surface waters was remineralized before leaving the upper 50-100 m. Lithogenic material often represented a large fraction of the flux. Isotopic analyses showed that 13C/12C ratios of sinking organic carbon were enriched (~-19‰) during the upwelling period and depleted during relaxation (~-23‰). This reflects seasonal changes in inorganic carbon utilization by phytoplankton and suggests that the δ13C of organic carbon in Cariaco sediments can be used as a proxy for carbon fixation by primary producers. The δ15N of the settling flux was influenced by the strength of the upwelling and the presence of the nitrogen fixer Trichodesmium thiebautii in the basin in different seasons; the 15N/14N ratio of sinking nitrogen reflects both imported and local nitrogen fixation signals. This result argues against previous interpretations of the δ15N from the basin's sedimentary record, which suggested that the nitrogen isotopic composition of flux is influenced by denitrification at the oxic-anoxic interface. Dissolved gas samples from the Cariaco eastern and western sub-basins from September 2008 (non-upwelling) and March 2009 (upwelling) were studied to assess the production of biogenic nitrogen gas through mass spectrometric N2/Ar ratiometry. Excess nitrogen gas indicated that upwelling affects the intensity of denitrification at the oxic-anoxic interface. In four of the six stations the concentration of biogenic nitrogen gas at the oxic-anoxic interface was 2.7-6.1 µM N higher during the upwelling period than during the relaxation season (p< 0.001), implying that denitrification in the basin was stimulated by the vertical flux of organic matter and/or the ventilation of the oxic-anoxic interface by oxygenated and nutrient-rich intermediate Caribbean waters.

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Οι έντονες εναλλαγές σχετικά ακραίων συνθηκών και η συνεξέλιξη των μεσογειακών οικοσυστημάτων με τη φωτιά αποτελούν τα βασικά στοιχεία που προσδίδουν τη μεγάλη ετερογένεια που χαρακτηρίζει τα οικοσυστήματα αυτά. Τα δάση χαλεπίου πεύκης έχουν αναπτύξει προσαρμογές για σύντομη αποκατάσταση έπειτα από πυρκαγιά. Η συνήθης διαδοχή περιλαμβάνει την εμφάνιση αρχικά ποώδους βλάστησης (που σε περίπτωση έντονης υποβάθμισης μπορεί να γίνεται φρύγανα), κατόπιν θαμνώδους (μακκίας) βλάστησης σε διάφορα στάδια ανάπτυξης, και εντέλει νέου πευκοδάσους. Το μωσαϊκό πρότυπο στη βλάστηση, το οποίο δημιουργείται από τη δράση παραγόντων όχλησης, είναι δυνατό να έχει σημαντικές συνέπειες στη δυναμική των πληθυσμών των ζώων. Με τη χρήση παγίδων παρεμβολής, μελετήθηκαν οι βιοκοινότητες των εδαφικών αρθροπόδων σε μια τέτοια σύγχρονη εμφάνιση των σταδίων διαδοχής στις παρυφές της Πάρνηθας. Τα χερσόβια Ισόποδα μελετήθηκαν σε επίπεδο είδους, ενώ οι λοιπές ζωικές ομάδες μακροαρθροπόδων, με την εξαίρεση των Αραχνών και των Κολεοπτέρων, μελετήθηκαν σε επίπεδο τάξης. Συμπερασματικά, τα αρθρόποδα σε επίπεδο τάξης και τα Ισόποδα σε επίπεδο είδους, μπορούν να εμφανίζουν το μέγιστο της δραστηριότητάς τους είτε το καλοκαίρι είτε την άνοιξη ή/και το φθινόπωρο. Επιπλέον, η παρατηρούμενη διαφοροποίηση στη σύνθεση της κοινότητας των εδαφικών αρθροπόδων (τόσο σε επίπεδο τάξης όσο και σε επίπεδο είδους για τα Ισόποδα) είναι σύμφωνη με τα στάδια διαδοχής της βλάστησης (CA, PCA). Η βιοκοινότητα των φρυγάνων εμφανίζει σαφή διαφοροποίηση και μεγαλύτερη ποικιλότητα από τις υπόλοιπες βιοκοινότητες, ενώ τα Ισόποδα εμφανίζονται ιδιαίτερα άφθονα στα φρύγανα. Μεταξύ των κοινοτήτων εδαφικών αρθροπόδων στους έξι βιοτόπους (στάδια διαδοχής), παρατηρούνται αλλαγές στη σχετική αφθονία των τάξεων των αρθροπόδων και των ειδών Ισοπόδων, ενώ παρατηρούνται ακόμη και αλλαγές κυριαρχίας μεταξύ τάξεων αρθροπόδων και ειδών Ισοπόδων. Το πρότυπο αυτό, ενδεχομένως οφείλεται στην προσαρμογή των εδαφικών αρθροπόδων στις οχλήσεις, οι οποίες είναι χαρακτηριστικές των μεσογειακών οικοσυστημάτων. / Climatic extremes and coevolution with fire make the Mediterranean-Type Ecosystems to appear highly heterogeneous. Aleppo pine forests have developed adaptations for rapid restoration after fire. A typical successional sequence includes herbaceous formations (turned into phrygana in case of severe deterioration) followed by sclerophyllous shrubland (maquis) in various stages of progressive succession to forest. Mosaic patterns in vegetation generated by disturbance are likely to have a profound effect on the population dynamics of animals. The communities of soil arthropods in a mosaic of sites in different succesional stages on the slopes of mountain Parnitha, were studied using pitfall traps. Terrestrial isopods were analysed at species level, whereas the rest of the macroarthropods, with the exception of Araneae and Coleoptera, were analysed at ordinal level. In conclusion, macroathropods at ordinal level and Isopoda at species level have activity peaks either in summer or in spring and/or autumn. In addition, the observed differences between edaphic macroarthropod communities (even at ordinal level as well as species level for Isopoda) are consistent with the successional stages (CA, PCA). The macroarthropod community in phrygana shows marked differentiation and highest diversity in comparison with the communities in the rest successional stages. The abundance of Isopoda is remarkably high in phrygana. Differences in relative abundance and distribution of dominance among the orders of macroarthropods and species of Isopoda were found between communities of different successional stages. It is likely that the observed pattern is a result of the adaptation of soil arthropods over evolutionary time to the characteristic disturbance regimes of the Mediterranean-Type Ecosystems.

Neutrophils are one of the main effector cells of innate immunity and were shown to kill bacteria by phagocytosis more than 100 years ago. Neutrophils are also capable of antimicrobial activity by producing extracellular structures named neutrophil extracellular traps (NETs). This thesis is an investigation of porcine neutrophils and their ability to produce NETs, as well as the antimicrobial ability of secretions from activated porcine neutrophils in combating a variety of common porcine pathogens. Porcine neutrophils were found to produce NET-like structures, and secretions from activated neutrophils were found to possess variable bactericidal activity against common pathogens of swine. Antimicrobial proteins dependent on elastase activity were shown to be partially responsible for the bactericidal activities of activated neutrophils. Several antimicrobial proteins and peptides were identified via proteomic techniques. This work allows for better understanding of innate immunity in swine, and identification of potential targets for addressing porcine health. / Ontario Ministry of Agriculture Food & Rural Affairs, Ontario Pork, Natural Sciences and Engineering Research Council of Canada

Neutrophils play an important, yet poorly understood role, in complement mediated pathologies. Here we identified that neutrophils contain key components from the complement alternative pathway: properdin (CFP), complement component 3 (C3), complement factor B (CFB), and complement factor H (CFH). Activation of neutrophils resulted in secretion of these complement components. When neutrophils are further activated to form neutrophil extracellular traps (NETs), CFP is deposited onto the surfaces of the NETs. In addition, CFP is able to bind to Pseudomonas aeruginosa, an opportunistic bacterium which can activate neutrophils to form NETs. Furthermore, NETs activate complement and increase formation of the terminal complement complex. The activation of complement on NETs can be initiated through multiple pathways, however, activation of the alternative pathway is dependent on CFP. This mechanism, potentially required for effective host defense, may also contribute to complement activation and disease.

No description available.

Neutrophils play an important, yet poorly understood role, in complement mediated pathologies. Here we identified that neutrophils contain key components from the complement alternative pathway: properdin (CFP), complement component 3 (C3), complement factor B (CFB), and complement factor H (CFH). Activation of neutrophils resulted in secretion of these complement components. When neutrophils are further activated to form neutrophil extracellular traps (NETs), CFP is deposited onto the surfaces of the NETs. In addition, CFP is able to bind to Pseudomonas aeruginosa, an opportunistic bacterium which can activate neutrophils to form NETs. Furthermore, NETs activate complement and increase formation of the terminal complement complex. The activation of complement on NETs can be initiated through multiple pathways, however, activation of the alternative pathway is dependent on CFP. This mechanism, potentially required for effective host defense, may also contribute to complement activation and disease.