Contribution of shredder macroinvertebrates and aquatic hyphomycetes to litter decomposition in remote insular streams

Dissertação de Mestrado, Biodiversidade e Biotecnologia, 31 de janeiro de 2019, Universidade dos Açores.É bem conhecido que os trituradores desempenham um papel crucial no processamento de matéria orgânica. Nos sistemas oceânicos dulçaquícolas, onde os ribeiros são caracterizados por uma baixa densidade e riqueza de trituradores, os microrganismos (hifomicetes aquáticos) parecem ser os principais decompositores da folhada. No entanto, o que aconteceria se a densidade de trituradores fosse maior? Contribuiriam ativamente para a decomposição da folhada? Aqui tentamos responder a estas questões avaliando os efeitos dos trituradores e hifomicetes aquáticos na decomposição da folhada em ribeiros insulares. Três espécies de folhas com características físicas e químicas distintas, Alnus glutinosa, Clethra arborea e Cryptomeria japonica, foram colocadas em sacos de rede com malha grossa e fina para permitir e evitar a entrada de macroinvertebrados, respectivamente, e incubadas em seis ribeiros ao longo de um gradiente de Limnephilus atlanticus (Trichoptera) na ilha de São Miguel. Na presença de trituradores, a perda de massa foliar foi maior nos sacos de malha grossa. No entanto, nenhuma diferença significativa foi encontrada na perca de massa entre os tipos de sacos em ribeiros sem L. atlanticus. A decomposição da folhada na presença de trituradores foi significativamente mais rápida para A. glutinosa do que C. arborea e C. japonica. Os resultados mostram que, quando L. atlanticus está presente em densidades altas, pode ter um papel significativo no processamento de matéria orgânica, enquanto que a decomposição da folhada é principalmente mediada por microorganismos quando a densidade de L. atlanticus é baixa, ou estão ausentes, mesmo na presença de outros trituradores. Além disso, a decomposição depende da qualidade da folhada, sendo as folhas com alta concentração de nutrientes e baixa concentração de compostos secundários preferidas pelos trituradores e hifomicetes aquáticos.ABSTRACT: It is well known that shredders play a crucial role in organic matter processing. In oceanic freshwater systems were streams are characterized by low shredder density and richness, microbes seem to be the main litter decomposers. However, what would happen if the densities of shredders were greater? Would they contribute actively to litter decomposition? Here we try to answer these questions by evaluating the effects of shredders and aquatic hyphomycetes on litter decomposition in insular streams. Three leaf species differing in physical and chemical characteristics, Alnus glutinosa, Clethra arborea and Cryptomeria japonica, were enclosed in bags of coarse and fine mesh to allow and avoid macroinvertebrate access to the litter, respectively, and incubated in six streams along a gradient of Limnephilus atlanticus (Trichoptera) density in São Miguel island. In the presence of shredders, leaf mass loss was higher in coarse mesh bags. However, no difference in litter mass loss was found between bag types in streams with no L. atlanticus, despite the presence of other shredder taxa. Litter decomposition in the presence of shredder was significantly faster for A. glutinosa than C. arborea and C. japonica. These results suggest that when L. atlanticus are present at relatively high densities they may have a significant role on organic matter processing, while microbes mainly drive litter decomposition when L. atlanticus density is low, or they are absent. Moreover, litter decomposition depend on litter quality, with leaves with high nutrient concentration and low concentration of secondary compounds being more preferred by shredder and aquatic hyphomycetes

Experimental investigations of the homogeneity coefficient of root crops crushed particles

У загальній структурі виробництва продукції тваринництва до 50…70% усіх витрат припадає на дольову частку приготування різнопланових соковитих кормів з коренеплодів. Шнекові транспортери широко застосовуються в аграрній сфері виробництва для переміщення, змішування, дозування продуктів тощо. Удосконалення існуючих конструкцій шнекових транспортерів і обгрунтування їх раціональних параметрів і режимів роботи є актуальним науковим завданням. Метою дослідження є підвищення (розширення) функціональних можливостей технологічних операцій шнекових транспортерів шляхом розробки комбінованих робочих органів, які забезпечують одночасне подрібнення та переміщення коренеплодів у процесі їх підготовки та переробки на соковиті корми. Основними задачами дослідження, які забезпечують реалізацію сформульованої мети, є обгрунтування параметрів комбінованого робочого органу шнекового транспортера-подрібнювача, який застосовується у технологічних лініях переробки коренеплодів. За результатами проведених експериментальних досліджень отримано рівняння регресії коефіцієнта однорідності подрібнених частин коренеплодів комбінованим шнековим транспортером-подрібнювачем, яке характеризує характер зміни параметра оптимізації залежно від кількості установлених Г-подібни х ножів-подрібнювачів на одному спіральному витку шнека, частоти обертання шнека та робочої довжини шнека. На основі аналізу побудованих поверхонь відгуку та їх двомірних перерізів зміни коефіцієнта однорідності подрібнення коренеплодів шнековим транспортером-подрібнювачем встановлено, що основний масив апроксимованих значень коефіцієнта однорідності подрібнення коренеплодів знаходиться від 36 до 85%. Результати досліджень є подальшим кроком із розроблення методології обгрунтування параметрів робочих органів і режимів роботи шнекових механізмів.In the general structure of livestock products manufacturing up to 50 ... 70% of all costs are accounted for the share of preparation of various juicy forages from root crops. Screw conveyors are widely used in the agrarian production sector for moving, mixing, dosing products, etc. Improvement of the existing structures of screw conveyors and substantiation of their rational parameters and operating modes are important scientific tasks. The objective of the investigation is to increase (expand) the functional abilities of technological operations of screw conveyors by developing the combination of operating elements that ensure the simultaneous shredding and movement of roots in the process of their preparation and processing on juicy feed. The main objectives of the research, which ensure the implementation of the stated goal, is to prove the parameters of the combined working body screw conveyor-shredder, which is used in the processing lines of roots. The research results are the further steps in developing the methodology for justifying the parameters of operatiing bodies and modes of screw mechanisms operation

Effect of riverbed morphology, stream order and season on the structural and functional attributes of caddisfly assemblages (Insecta: Trichoptera)

We tested the individual and joint effects of stream order, riverbed morphology (i.e. pool-riffle sequence), and season on the structural (i.e. species composition, density and richness) and functional (i.e. percent ratio of shredders, collectors, scrapers, and predators) properties of caddisfly assemblages in a closely natural headwater system (Börzsöny Mts., North Hungary). Each factor, both individually and in interaction had a significant effect on caddisfly assemblages as shown by MANOVA analyses. To clarify the effects of stream order, riverbed morphology and season on caddisflies, assemblage properties were also separately studied by ANOVAs. Percent ratio of shredders and collectors were strongly affected by all factors, whereas other attributes were not always sensitive to stream order, season and riverbed morphology. In contrast, species compositions of the reaches differing in stream order and riverbed morphology were significantly different. Our findings on the contrasting differences in shredder composition between riffles and pools may suggest that not only riparian vegetation, but also instream habitat features could shape the accumulation and retention of particulate organic matter (in streams with pool-riffle heterogeneity)

Chapter 9: Aquatic Macroinvertebrates, Section A: Aquatic Macroinvertebrates (Exclusive of Mosquitoes)

Final Report. Excerpt (Chapter 9, Section A) from The Des Plaines River Wetlands Demonstration Project, Volume II, Baseline Survey, edited by Donald L. Hey and Nancy S. PhilippiReport issued on: October 1985INHS Technical Report prepared for Wetlands Research, Inc

Comparative studies on the structure of an upland African stream ecosystem

Upland stream systems have been extensively investigated in Europe, North America and Australasia and many of the central ideas concerning their function are based on these systems. One central paradigm, the river continuum concept is ultimately derived from those North American streams whose catchments remain forested with native vegetation. Streams of the tropics may or may not fit the model. They have been little studied. The Amani Nature Reserve in the East Usambara Mountains of north-eastern Tanzania offers an opportunity to bring these naturally forested systems to the attention of the ecological community. This article describes a comparison made between two lengths of the River Dodwe in this area. The work was carried out by a group of postgraduate students from eighteen European and African countries with advice from five staff members, as part of a course organised by the Tropical Biology Association. Rigorous efforts were made to standardise techniques, in a situation where equipment and laboratory facilities were very basic, through a management structure and deliberate allocation of work to specialists in each area.The article offers a summary of invertebrate communities found in the stream and its biomass. Crabs seem to be the key organism in both sections of the streams

Leaf Processing in a Slough of an Ozark Stream

Processing of sugar maple (Acer saccharum), black oak (Quercus velutina), and American sycamore (Platanus occidentalis) was investigated in a slough of the Illinois River, Benton County, Arkansas, using 5-gram packs in wire baskets. Oak and sycamore showed similar degradation rates, while maple was processed much faster. All processing rates were strongly retarded during a period of siltation. Chironomid larvae were the dominant organisms associated with the packs and their numbers were depressed by the silt influx. Shredders were notably few in number as compared with studies from the northwestern United States

Preliminary estimates of mass-loss rates, changes in stable isotope composition, and invertebrate colonisation of evergreen and deciduous leaves in a Waikato, New Zealand, stream.

Rates of mass loss are important in the choice of tree species used in riparian rehabilitation because leaves that break down fast should contribute to stream food-webs more rapidly than leaves that break down more slowly. To examine comparative mass-loss rates of some native evergreen and introduced deciduous trees in a New Zealand stream, fallen leaves were incubated in bags with 2 x 3 mm mesh openings. The native trees were mahoe (Melicytus ramiflorus), kahikatea (Dacrycarpus dacrydioides), silver beech (Nothofagus menziesii), rewarewa (Knightia excelsa), tawa (Beilschmiedia tawa), and the introduced trees were silver birch (Betula pendula) and alder (Alnus glutinosa). The leaf bags were left in the Mangaotama Stream for 28 days from mid April to mid May 1995 when mean water temperature was 14.5deg.C, giving a total of 406 degree days. Rates of mass loss followed the sequence: mahoe > silver birch > alder > kahikatea > silver beech > rewarewa > tawa. Mean mass-loss rate for mahoe, assuming a negative exponential model, was 0.0507 k day-1 (0.00350 k (degree day)-1), and for tawa was 0.0036 k day-1 (0.00025 k (degree day)-1). C:N ratio decreased on average from 45:1 to 35:1, and d15N increased between 0.7 and 3.0[[perthousand]] (1.8 +/- 0.41[[perthousand]], mean +/-1 standard error), excluding kahikatea. Changes in d13C were smaller and not consistent in direction. Biomass of invertebrates was greatest in bags that had lost 25-45% of their initial leaf biomass

Bioassessment of the West Fork of the White River, Northwest Arkansas

The West Fork-White River has been and continues to be an important water resource for northwest Arkansas. It is used recreationally for fishing and swimming, agriculturally as a source of water for livestock and irrigation of crops, it is mined for gravel, used as a receiving stream for municipal wastewater effluent, and contributes to Beaver Lake which provides water for treatment and distribution to most of northwest Arkansas. While these uses have benefited a large segment of the Arkansas population, they have also contributed to the decline in environmental quality of the river. To facilitate the development of appropriate management protocols and assess restoration potential, we provided a biological assessment of the West ForkWhite River to complement studies of its physical and chemical properties. This holistic evaluation can be used presently, and to track changes in the environmental quality of the river in the future

Puyehue Cordón -Caulle: post-eruption analysis of changes in stream benthic fauna of Patagonia

Las erupciones volcánicas son los fenómenos naturales con las consecuencias más variadas y complejas, y tienen efectos importantes en ambientes tanto terrestres como acuáticos. El 4 de junio de 2011, el complejo volcánico Puyehue Cordón-Caulle (2.236 msnm, 40 º 32 'S, 72 º 2' W, Chile) entró en erupción, eyectando el primer día 950 millones de toneladas de cenizas hacia la atmósfera. Debido al predominio de vientos del oeste, 24 millones de hectáreas de la Patagonia Argentina fueron cubiertas gradualmente de ceniza. Para explorar cómo se vieron afectados por la caída de ceniza arroyos del noroeste de Patagonia y los posibles procesos de recuperación de la calidad del agua y de las comunidades de macroinvertebrados bentónicos se seleccionaron tres arroyos. Los arroyos seleccionados correspondieron a tres niveles de depositación de ceniza (i.e. máximo, intermedio y mínimo). En cada arroyo se seleccionaron dos sitios de muestreo, donde se midieron: pH, conductividad, sólidos totales disueltos (STD) y turbidez (NTU) y se tomaron muestras de macroinvertebrados durante los veranos de 2012 y 2013. Luego de la erupción volcánica se observaron cambios ambientales relacionados con la cantidad de ceniza eyectada y depositada en las áreas más cercanas al volcán. Cambios en la calidad del agua debido a la caída de ceniza se vieron reflejados en bajos valores de densidad, índices EPT (Ephemeroptera, Plecoptera y Trichoptera) y BMPS (Índice de Monitoreo Biótico de Arroyos de Patagonia), principalmente en los arroyos más cercanos al volcán. Luego de dieciocho meses, las densidades, composición de taxones y estructuras de tramas tróficas de los arroyos estudiados no fueron comparables con las de otros arroyos previamente estudiados en la región. El análisis exploratorio sugirió que el mayor impacto fue consecuencia de la deposición de ceniza en términos de cantidad y proporciones de tamaño de partícula.Volcanic eruptions are natural phenomena with the most diverse and varied consequences, and have important effects on both terrestrial and aquatic environments. On June 4th, 2011 the volcanic Puyehue Cordón-Caulle complex (2.236 masl, 40º 32´ S-72º 2´ W, Chile) erupted explosively ejecting on the first day, 950 million metric tons of ashes into the atmosphere. Due to predominant westerly winds, 24 million hectares of Argentinian Patagonia were covered by the ashfall. We studied three streams in northwestern Patagonia in order to explore the ash fall impact and possible recovery processes in water quality and macroinvertebrate communities. We selected three streams representing maximum, intermediate and minimum ash deposition levels. For each stream, we selected two sampling sites to measure pH, conductivity, total dissolved solids (TDS), turbidity (NTU) and to take three macroinvertebrate samples during summer 2012 and 2013. After the eruption of the Puyehue-Cordón Caulle complex, substantial environmental changes were observed in association with the large amount of ash ejected by the volcano and deposited on the nearest areas. Low benthic fauna densities, as well as low values of Ephemeroptera, Plecoptera and Trichoptera (EPT) and Biotic Monitoring Patagonian Streams (BMPS) indexes, reflected changes in water quality due to ash fall, mainly in the two streams closer to the volcano. After eighteen months, the streams had not reached the density, taxa composition and structure of trophic webs comparable to other streams previously studied in the region. The exploratory analysis suggests that the main impact was a consequence of ash fall in terms of the amount and particle size proportions.Fil: Lallement, Mailén Elizabeth. Universidad Nacional del Comahue; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Juárez, Santiago Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Macchi, Patricio Jorge. Universidad Nacional del Comahue; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vigliano, Pablo Horacio. Universidad Nacional del Comahue; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Longitudinal patterns in an Arkansas River Valley stream: an Application of the River Continuum Concept

The River Continuum Concept (RCC) provides the framework for studying how lotic ecosystems vary from headwater streams to large rivers. The RCC was developed in streams in eastern deciduous forests of North America, but watershed characteristics and land uses differ across ecoregions, presenting unique opportunities to study how predictions of the RCC may differ across regions. Additionally, RCC predictions may vary due to the influence of fishes, but few studies have used fish taxa as a metric for evaluating predictions of the RCC. Our goal was to determine if RCC predictions for stream orders 1 through 5 were supported by primary producer, macroinvertebrate, and fish communities in Cadron Creek of the Arkansas River Valley. We sampled chlorophyll a, macroinvertebrates, and fishes at five stream reaches across a gradient of watershed size. Contrary to RCC predictions, chlorophyll a did not increase in concentration with catchment size. As the RCC predicts, fish and macroinvertebrate diversity increased with catchment size. Shredding and collecting macroinvertebrate taxa supported RCC predictions, respectively decreasing and increasing in composition as catchment area increased. Herbivorous and predaceous fish did not follow RCC predictions; however, surface-water column feeding fish were abundant at all sites as predicted. We hypothesize some predictions of the RCC were not supported in headwater reaches of this system due to regional differences in watershed characteristics and altered resource availability due to land use surrounding sampling sites