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The Gulf of Guayaquil is one of the most productive sites on the South American coast, where estuaries play a fundamental role in nutrient dynamics and the development of the area's characteristic biodiversity. The objective of the study was to use satellite information to analyze the trophic level of a point of the internal estuary of the Gulf of Guayaquil, in the Bocana de Balao channel, applying trophic level's index, such as the Karydis index (1983) and The Organization for Economic Cooperation and Development index (OCDE,1982), to establish the seasonal variations of trophic index of nutrients to preserve the relationships with the El Niño and La Niña períods. Subsequently, to obtain the seasonal trend of the trophic index of the nutrients analyzed. The point is located in the internal estuary of the Gulf of Guayaquil analyzing time series of the main nutrients such as NO3, PO4 and SiO4. These data were obtained from the COPERNICUS maritime space server during the 2010 and 2020 study period. The results revealed an oligomesotrophic state for the study point, where SiO4 is at a mesotrophic level while the IK of PO4 and NO3 are present in an oligotrophic, comparable to the trophic state of chlorophyll, according to the OECD index, during the 11-year period and regardless of climatic seasons. Correlations were also identified between IK and ONI during the rainy season of 2015 and 2016, which aligns with the warm events associated with the El Niño phenomenon in those years. On the other hand, the time series of the Karydis indices exhibited variations with different slopes according to the climatic seasons, with the predominant tendency being the permanence in an oligomesotrophic state, despite the fact that it is known of the constant nutrient's contribution of anthropogenic origin, so it is suggested to incorporate biological variables into the study. [ABSTRACT FROM AUTHOR]

In most caves, the main source of organic matter is provided by bats, through guano, which is influenced by their type of diet. A wide variety of organisms live in it, such as bacteria, fungi, mites, springtails, and other arthropods, many of them adapted to the cave environment, especially several families of mites with different eating habits are frequent in the guano and each of them has a role in the nutrient cycling that takes place within the caves. As part of a research project on argasid ticks in caves in Mexico, during 2010-2016, bat guano collections were carried out in 15 caves in seven states of the country. Herein, the records of 90 Acari taxa are presented, included in four orders, 52 families, 27 genera and 11 species determined to date, associated with guano from caves in central and southern Mexico with a diverse geological origin. Different groups of mites carry out particular roles in the food web within caves, due to their diverse feeding habits. The information presented provides data to understand the diversity of guanobia mites and their role within the caves. [ABSTRACT FROM AUTHOR]

Soil is an ecosystem with a carbon pool that suports biological diversity. In this review, it is presented how significant is the symbiosis between the plant root and the macro and microorganisms of the soil, as well as the benefits it generates to achieve an ecological balance and maintain low populations of plant pathogens in food production. For instance, earthworms, collembola, mealybugs and oribatid mites greatly influence the functioning of the soil system, as they build and maintain soil structure and actively participate in nutrient cycling through mineralization and humification processes, in addition to consuming pathogens. On the other hand, microorganisms such as mycorrhizal fungi, which benefit by absorbing the nutrients of the plant and help it absorb minerals from the soil, provide protection to roots against phytopathogens. Mycorrhizal fungi induce changes in the plant and then the plant responds by producing exudates from the roots that reduce or repel plant pathogens. Another example is the Trichoderma fungus, known as a biocontrol agent for producing secondary metabolites with antimicrobial activity against plant pathogens. Biological control agents and their secondary metabolites are potential approaches currently being used to reduce or replace agrochemicals. Finally, integrated crop management promotes competition and balance essential to maintaining soil health and ensuring food production. [ABSTRACT FROM AUTHOR]

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Zooplankton is one of the most important trophic components for the functioning of aquatic ecosystems, these organisms are the food base of fish and contribute to the cycling of nutrients. The challenge of this study was to find temporal variations of taxonomic composition, structure, and diversity of zooplankton and their relationship with environmental variables in the Ciénaga de Paredes from 2013 to 2014. We worked with zooplankton samples deposited in the Natural History Museum UIS and the community structure was evaluated, using Hill's effective numbers and analysis of variance to determine significant differences between floodplain periods. Non-metric Multidimensional Scaling showing low stress (0.073). Transparency, deep, and conductivity showed significant differences during the floodplain periods. Rotifers were the most representative group, these organisms could be favored by the tolerance of the fluctuations in the water column. Keratella americana and Lecane proiecta were the most abundant species throughout the study period. There are cosmopolitan species characteristic of eutrophic systems, with a high load of nutrients and organic matter, as is observed in the Ciénaga de Paredes. The specific diversity decreased compared to a previous study in this area, which may suggest changes in the characteristics that could affect the functioning of the ecosystem. Fifteen new records are reported for the department of Santander. [ABSTRACT FROM AUTHOR]

Copyright of Agronomía & Ambiente is the property of Universidad de Buenos Aires. Facultad de Agronomia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Biotecnología is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of organic amendments improves the quality and increases the fertility of the soils due to their adsorption properties, stimulates nutrient cycling and can be used to reduce the availability of heavy metals. The main objective of the research was to evaluate the effect of biochar (BC) derived from pig manure on the availability of Pb in a contaminated and limed agricultural soil. A randomized experimental design was applied, the pig manure was dried at room temperature (23 °C) and pyrolyzed at 500 °C for 2 h. Doses of 5%, 10% and 20% of BC were applied to the Pb soils contaminated (165.7 mg/kg), that were arranged in 2 kg pots except for the control sample, and Lactuca sativa was subsequently grown cultivated to evaluate the Pb availability. The results indicated an improvement in soil quality at higher BC dose, increase of 0.34 pH units, decrease of Pb extracted by EDTA (27% to 62% of decrease), and non-significant Pb content in leachates (< 1 mg Pb/L) and no detection in plant roots (< 0.01 mg/kg), except for the control plant (0.7 mg Pb/kg) in the original soil. A logarithmic relational model between BC dose and Pb adsorbed in the soil was obtained (R² = 0.9938, p < 0.05) showing that the decrease of Pb availability in the soil increased for higher BC doses, which represents an eco-friendly remediation alternative. It is recommended to investigate the interaction relationships between the soil quality parameters and to establish functional models of bioaccumulation and extractable metal of the amended soil. [ABSTRACT FROM AUTHOR]

Dung beetles are excellent indicators of ecosystem ecological integrity, accomplishing an essential role in nutrient cycling process that includes fertilization and soil aeration. Nevertheless, very little is known about the influence of season variation on the assemblage composition and ecological function of dung beetles from high Andean zones. We aimed to investigate the seasonal effect on the diversity and ecological function of dung beetles in terms of biomass. We sampled two pasture patches of the "Reserva Biológica Encenillo", located in Cundinamarca-Colombia, using ten pitfall traps baited with feces placed 50 m apart for 24 hours. This sample design was replicated during each season (dry, transition, and rain). A significant seasonal variation was documented, demonstrating an important association with the rainy season. Significant differences were found for the biomass between species and seasons. The species with the highest biomass was Homocopris achamas. It is evident that high Andean pastures assemblages have low diversity, due to the strong human disturbance, the pressures associated with the altitude, and the evolutionary dynamics of these regions. The marked seasonality of the registered species and the close association with the rainy season are consistent with the pattern established for the Neotropical region. Likewise, a strong seasonal variation of the biomass is evident, which could have a significant impact on the ecological functionality and the ecosystem services in this habitat. In future studies, it is necessary to quantify the functional contribution of the species and their seasonal variation to contribute to their conservation. [ABSTRACT FROM AUTHOR]

Copyright of Gestión y Ambiente is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction-- The edaphic mesofauna intervenes in the decomposition processes of organic matter, constituting an important characteristic of soil quality. Objective-- Characterize the soil mesofauna in six municipalities of Norte de Santander (Colombia). Methodology-- The present study was developed in 15 farms of the municipalities; Arboledas, Convencion, La Playa, La Esperanza, Ocaña and Mutiscua in the department of Norte de Santander where 18 agroecological models would be established (3 / municipality). The abundance and diversity of the mesofauna were characterized before establishing the crops, comparing the situation of the main groups by municipalities. Results-- In Arboledas the highest abundance of mesofauna was observed, with the presence of six classes, with detritive habits Crustacea, Collembola, Anelida, Symphyla and Arachnia: Oribatida, while in Esperanza and Mutiscua there were four classes; Insecta, Collembola, Symphyla and Arachnida and in the rest, the last three, which gives a measure of the processes of decomposition of organic matter and recycling of nutrients in these farms. Conclusions-- In five municipalities, the highest abundance of mesofauna corresponded to the Collembola class, while Insecta was more abundant in Esperanza and ranked second in Mutiscua, Symplyla was second in Convencion, and La Playa and Arachnida in Ocaña and Arboledas. The specific richness varied from 5.0 for Convencion and Ocaña to 28 for Arboledas and the diversity of species from 0.91 in Convencion to 3.54 in Arboledas, a municipality that was statistically separated from the rest, leaving Mutiscua and Esperanza intermediate with respect to the rest. [ABSTRACT FROM AUTHOR]

Copyright of Gestión y Ambiente is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Boletín Científico Centro de Museos de Historia Natural is the property of Universidad de Caldas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bess beetles are important components on tropical forest dead wood nutrient cycling, since they act as direct consumers and ease the consumption by another organism (indirect). Studies of bess beetle ecology are scarce and have focused on communities responses to environmental changes on alimentary resources. We characterized the bess beetles guild composition in an elevation gradient, according to their differential use of resources (microhabitat) and morphological traits quantification (geometric and lineal), as a potential tool to improve our understanding on resource use and functional ecology of beetles. Three guilds (underbark, sapwood-heartwood and generalists feeders), five species and 198 familiar groups were recognized; their richness decreased as elevation increased. Changes in linear morphometric measures were influenced by elevation; morphogeometrical measures were not associated with the elevation gradient, only grouping at guild level were observed. Morphological markers analysis (morphometric) provided information to guild delimitation. Body and metatibiae shape contributed with the best information to guild grouping. Quantification of those structural markers proved the relationship between resource repartition, because they are involved in movement on wood galleries and wood consumption, this fact allowed to propose specific functional roles. The identified patterns have contributed on the understanding of functional processes in Passalidae communities and their role in ecosystem function. [ABSTRACT FROM AUTHOR]

The article reports that coral bleaching is not a new phenomenon and has been observed for over 150 years. Eugen von Ransonnet, an Austrian explorer, documented coral bleaching in lithographs made in 1862 during the period known as the "Little Ice Age." Additionally, it is mentioned that whales play an important role in nutrient recycling in marine ecosystems, consuming large amounts of krill. Finally, the importance of increasing the size of marine protected areas for the conservation of gray reef sharks is highlighted. [Extracted from the article]

Tropical forest restoration strategies have the potential to accelerate the recovery of the nutrient cycles in degraded lands. Litter production and its decomposition represent the main transfer of organic material and nutrients into the soil substrate. We evaluated litter production, accumulation on the forest floor, and its decomposition under three restoration strategies: plantation (entire area planted with trees), island (trees planted in patches of three different sizes) and control (natural regeneration) plots. We also compared restoration strategies to young secondary forest (7-9yr). Restoration treatments were established in 50x50m plots in June 2004 at six sites in Southern Costa Rica. Planted tree species included two native timber species (Terminalia amazonia and Vochysia guatemalensis) interplanted with two N fixers (Erythrina poeppigiana and Inga edulis). Litter was collected every 15 days between September 2008 and August 2009 in 12 0.25m² litter traps distributed within each plot; litter that accumulated on the soil surface was collected at four locations (0.25m² quadrats) within each plot in February and May 2009. Total litter production in plantation (6.3Mg/ha) and secondary forest (7.3Mg/ha) did not differ, but were greater than in islands (3.5Mg/ha) and control (1.4Mg/ha). Plantation had greatest accumulation of litter on the soil surface (10.6Mg/ha) as compared to the other treatments (SF=7.2; I=6.7; C=4.9). Secondary forest was the only treatment with a greater annual production of litter than litter accumulation on the soil surface. Carbon storage in litter was similar between plantation and secondary forest, and significantly greater than the other treatments. No differences were found for carbon concentration and storage in the soil among treatments. There was also high variability in the production and accumulation of litter and carbon among sites. Active restoration treatments accelerated the production of litter and carbon storage in comparison to areas under natural recovery. However, the nutrient cycle has not necessarily been restored under these conditions, as high litter accumulation on the soil surface indicates a low decomposition rate, which slows nutrient return to the soil. Rev. Biol. Trop. 59 (3): 1323-1336. Epub 2011 September 01. [ABSTRACT FROM AUTHOR]

The wider use of malting barley with high yield potential will necessarily increase soil nutrient requirements, the resulting nutritional deficiency placing constraints on production. The Diagnosis and Recommendation Integrated System (DRIS) approach uses leaf nutrient relationships to rank the importance of different nutrients in limiting crop yield. The objectives of the present study were to: a) evaluate the sensitivity of the DRIS methodology in detecting responses to nitrogen (N) fertilizer; b) establish the ranking of the main macronutrient requirements; and c) determine whether N application improves the nutrient balance in plants. Malting barley plants were taken from fertilizer experiments carried out in 1999 and 2000 and sampled at the tillering and heading stages. At tillering, N was found to be the most deficient nutrient in the control and fertilized plots and S in cases where N was more abundant (fertilized with 30 or 60 kg N ha-1). The Nutritional Balance Index (IBN) and N:S ratio show a slight nutritional imbalance at this stage. At the heading stage the plants showed significant N deficiency, followed in many cases by S deficiency, directly affecting yield parameters. No P and K deficiencies were registered in the soils. In 1999, yields were low and showed fertilization response except in Alberti, where nitrate availability and yields were high. In 2000, higher water availability gave rise to higher yields with marked deficiencies in N owing to the shortage of N availably at sowing. S alternated with N in the order of requirements and IBN values decreased with increasing N availability. There was an 87% and 68% correlation between this index and the yields of the control and fertilized plots, respectively. The DRIS approach proved a good indicator of nutritional balance and of plant response to N fertilization. [ABSTRACT FROM AUTHOR]

La hojarasca constituye la vía de entrada principal de los nutrientes en el suelo y es uno de los puntos clave del reciclado de la materia orgánica y de los nutrientes. Varios autores han estudiado con detalle la dinámica de la descomposición de la hojarasca de las plantas leñosas, tanto en climas templados como en el mediterráneo. Sin embargo, hay pocos estudios sobre la dinámica de la descomposición de la hojarasca en los pastizales a pesar de su importancia en la producción primaria y secundaria, sobre todo en los sistemas donde los nutrientes disponibles para la vegetación escasean, como ocurre en los ecosistemas de pastizales. Por ello en el presente artículo se abordan dichos procesos, así como el efecto del clima, la vegetación, el suelo y la fauna descomponedora, como factores principales que determinan el proceso de descomposición de la hojarasca en los pastizales. Además se brindan los resultados más relevantes relacionados con el empleo de los sistemas silvopastoriles como alternativa viable para lograr la sostenibilidad ecológica y productiva de los pastizales tropicales, con mayor énfasis en el papel que estos desempeñan en el reciclaje de los nutrientes. [ABSTRACT FROM AUTHOR]