Litter Composition Research Articles

Warming‐induced functional shifts in the decomposer community interact with plant community compositional shifts to impact litter decomposition

Abstract Climate warming is altering plant and soil microbial communities, with important implications for ecosystem processes like litter decomposition. As warming alters plant community composition, the quality of litter will change. Further, shifts in microbial community activity and/or composition will alter microbial function. However, it is not yet completely understood how these shifts will interact to drive decomposition. We explored how changes in plant and microbial communities interact to influence litter decomposition using a 15‐year‐old grassland warming experiment. Previous studies within this system have shown that warming shifted the microbial community in ways that accelerate litter decomposition while simultaneously shifting the plant community in ways that may slow decomposition. Specifically, warming increased abundance of Sorghastrum nutans, while decreasing abundance of the previously dominant Schizachyrium scoparium. Using a series of lab‐based microcosm experiments, we examined the rate at which eight common grasses and, separately, varying abundances of S. nutans and S. scoparium decomposed. Using litter and soil from the warming experiment, we then incubated soils from warmed or control plots with different abundances of S. nutans and S. scoparium in a reciprocal design. We found S. nutans to be the slowest‐decomposing grass in our system. Further, decomposition slowed as S. nutans increased and S. scoparium decreased. When examining the interaction of plant and microbial communities, decomposition was generally greater early in our experiment as the relative abundance of S. scoparium increased. However, soil microbial community origin and litter composition interacted significantly. Specifically, decomposition increased with greater relative abundance of S. scoparium on soils derived from control plots, while litter composition did not shape rates of decomposition on soils from warmed plots. The influence of litter species on decomposition waned in the later stages of the experiment when decomposition was driven by microbial community origin. These results suggest that warming‐induced changes in microbial community function may interact with changes in plant litter composition to mitigate the impacts of warming on rates of decomposition. This emphasizes the importance of considering concurrent warming‐induced changes in both plant and microbial communities on ecosystem processes like decomposition. Read the free Plain Language Summary for this article on the Journal blog.

Oceanographic and anthropogenic variables driving marine litter distribution in Mediterranean protected areas: Extensive field data supported by forecasting modelling

Marine litter concentration in the Mediterranean Sea is strongly influenced both by anthropogenic pressures and hydrodynamic factors that locally characterise the basin. Within the Plastic Busters MPAs (Marine Protected Areas) Interreg Mediterranean Project, a comprehensive assessment of floating macro- and microlitter in the Pelagos Sanctuary and the Tuscan Archipelago National Park was performed. An innovative multilevel experimental design has been planned ad-hoc according to a litter provisional distribution model, harmonising and implementing the current sampling methodologies. The simultaneous presence of floating macro- and microlitter items and the potential influences of environmental and anthropogenic factors affecting litter distribution have been evaluated to identify hotspot accumulation areas representing a major hazard for marine species. A total of 273 monitoring transects of floating macrolitter and 141 manta trawl samples were collected in the study areas to evaluate the abundance and composition of marine litter. High mean concentrations of floating macrolitter (399 items/km2) and microplastics (259,490 items/km2) have been found in the facing waters of the Gulf of La Spezia and Tuscan Archipelago National Park as well in the Genova canyon and Janua seamount area. Accordingly, strong litter inputs were identified to originate from the mainland and accumulate in coastal waters within 10–15 nautical miles. Harbours and riverine outfalls contribute significantly to plastic pollution representing the main sources of contamination as well as areas with warmer waters and weak oceanographic features that could facilitate its accumulation. The results achieved may indicate a potentially threatening trend of litter accumulation that may pose a serious risk to the Pelagos Sanctuary biodiversity and provide further indications for dealing with plastic pollution in protected areas, facilitating future management recommendations and mitigation actions in these fragile marines and coastal environments.

Hydrological Properties of Litter in Different Vegetation Types: Implications for Ecosystem Functioning

This study investigated the hydrological properties of litter in different vegetation cover types, including Eucalyptus sp. plantation, Agroforestry, and Restoration Forest. The research focused on evaluating litter accumulation, composition, water holding capacity, and effective water retention. The results revealed variations in litter accumulation among the stands, and especially Eucalyptus sp., which had a higher proportion of branches compared to leaves. The water holding capacity of the litter differed among the stands. Agroforest and Restoration Forest showed higher litter water capacities than Eucalyptus sp. The composition and decomposition stage of the litter fractions influenced their water retention capabilities, with leaves exhibiting superior water retention. In contrast, branches had lower water absorption due to their hydrophobic nature. Despite these differences, the effective water retention, which indicates the ability of litter to intercept precipitation, was similar among the stands. The findings highlight the importance of considering litter composition and species-specific characteristics in understanding the hydrological functions of litter. This knowledge contributes to effective conservation and management strategies for sustainable land use practices and water resource management. Further research is recommended to expand the study’s scope to include a wider range of forest types and natural field conditions, providing a more comprehensive understanding of litter hydrological functions and their implications for ecosystem processes.

Impact of forest fire on the mercury stable isotope composition in litter and soil in the Amazon

Mercury (Hg) emissions from forest fires, especially tropical forests such as the Amazonian forest, were shown to contribute significantly to the atmospheric mercury budget, but new methods are still necessary to improve the traceability and to reduce the great uncertainties related to this emission source. Recent studies have shown that the combustion process can result in Hg stable isotope fractionation that allows tracking coal combustion Hg emissions, as influenced by different factors such as combustion temperature. The main goal of the present study was, therefore, to investigate for the first time the potential of Hg stable isotopes to trace forest fire Hg emissions and pathways. More specifically, small-scale and a large scale prescribed forest fire experiments were conducted in the Brazilian Amazonian forest to study the impact of fire severity on Hg isotopic composition of litter, soil, and ash samples and associated Hg isotope fractionation pathways. In the small-scale experiment, no difference was found in the mercury isotopic composition of the samples collected before and after burning. In contrast, the larger-scale experiment resulted in significant mass dependent fractionation (MDF δ202Hg) in soils and ash suggesting that higher combustion temperature influence Hg isotopic fractionation with the emission of lighter Hg isotopes to the atmosphere and enrichment with heavier Hg in ashes. As for coal combustion, mass independent fractionation was not observed. To our knowledge, these results are the first to highlight the potential of forest fires to cause Hg isotopic fractionation, depending on the fire severity. The results also allowed to establish an isotopic fingerprint for tropical forest fire Hg emissions that corresponds to a mixture of litter and soil Hg isotopic composition (resulting atmospheric δ202Hg, Δ200Hg and Δ199Hg were −1.79 ± 0.24‰, −0.05 ± 0.04‰ and −0.45 ± 0.12‰, respectively).

Compensatory growth and piglets weight variability within the litter as breeding criteria for ukrainian meat pig breed performance

Aim. To determine the factors, affecting compensatory growth and performance of the Ukrainian meat (UM) pig breed. To analyze the impact of selection traits on the live weight of pigs during different age periods, using several growth and development indices. To determine compensatory growth by two groups of piglets (based on their individual weight, which was above the average mean piglet weight in the litter (M+) or with a weight which was below average mean piglet weight in the litter (M–), in relation to the average daily gain, ADG), in order to use these factors in a specific breeding program. Methods. Uniform microclimate conditions to rear experimental piglets were maintained using Eletor SC-12 (Poland) equipment. When selecting animals for research groups, physiological conditions were determined (by direct observation), age (according to primary zootechnical records), and live weight weighing on electronic scales (Axis (Ukraine) with a measurement accuracy of 0.02 Kg. The basis of our research was the live weight of pigs of Ukrainian meat breed, n = 381 animals. First two groups of piglets were formed (M+; M–) n = 143(М+); n = 158(М–); based on their individual weight, which was above the average mean piglet weight in the litter (M+) or with a weight which was below average mean piglet weight in the litter (M–). Furthermore, two groups were later formed based on presence or absence of compensatory growth (M++, M+–, M–+ and M– –) n = 66(M++), n = 77(M+–), n = 68(M–+) and n = 90 (M– –). Results. The group M++ at the stage of rearing, at the age of 2–6 months, exhibited superior average daily gains by 22.2 % (P < 0.001) during the period from 2 to 4 months and by 8.8 % (P < 0.01) during the period from 4 to 6 months as compared to the other groups. An ANOVA analysis showed that the changes in weight gain of compensatory growth from 60 to 120 days affects the live weight of pigs at the age of 3–8 months (P < 0.001). The variability of piglet mean live weight in a litter at 60 days influenced the live weight of pigs at the age of 3–7 months (P < 0.001) and at the age of 8 months (P < 0.05), while the interaction between these two factors affects the live weight of piglets at the age of 3–5 months (P < 0.001) and 6 months (P < 0.05). Conclusions. New data have been obtained regarding the impact of piglet weight above or below the average mean piglet weight in the litter and the degree of compensatory growth in Ukrainian meat breed pigs on their average daily gains. Animals from group M–+ at 60 days of age, in the presence of compensatory growth, still outperformed their counterparts from group M+– at 60 days of age by 22.2 % (P < 0.001) during the period from 2 to 4 months and by 8.8 % (P < 0.01) during the period from 4 to 6 months, when not exhibiting compensatory growth. The influence of the aforementioned factors was also determined on the growth rate from 2 to 6 months, with the growth rate index in the M++ group being 1.81 times higher than in the M+– group and 1.54 times higher than in the M–+ group. The highest impact of litter composition on the average daily gain (ADG) in weight was observed at the age of 2–4 months (20.5 %; P = 4.2*10–12). Group compositions towards weight above piglet average weight in the litter and compensatory growth (M++) have been shown to be useful as selection and breeding criteria for the Ukrainian meat pig breed and are possibly so for other pig breeds, which will be investigated in future.

Composition of marine litter from fishing activities: a preliminary study at the fish landing base of Pantai Labu North Sumatera

Pantai Labu Fish Landing Base (PPI) is a type D fishing port that’s located in Paluh Sibaji Village, Pantai Labu District, Deli Serdang Regency. The existence of garbage in the sea is important to know because the generation of garbage in the sea can have a negative effect in several sectors, one of which is in carrying out fishing activities. The purpose of this study was to determine the composition of marine litter from fishing activities by fishing units at Pantai Labu Fish Landing Base. This research was conducted in January 2022 in Paluh Sibaji Village, Pantai Labu District, North Sumatra. Data collection method used purposive sampling. The results showed that the composition of inorganic waste generated from fishing activities consisted of plastic, metal, paper and cardboard. Types of waste made from plastic materials consist of plastic bags, food wrappers, plastic bottles, bottle caps, plastic cups, cigarette packs, foamed plastic, and monofilament fishing line.

Monitoring the composition, sources and spatial distribution of seafloor litter in the Adriatic Sea (Mediterranean Sea) through Fishing for Litter initiatives.

Although the seafloor is an important sink for marine litter, its less accessible environment makes seafloor litter the least studied component. Nevertheless, detailed monitoring of its composition and spatial distribution is urgently needed to develop appropriate mitigation strategies in areas exposed to multiple anthropogenic pressures, such as the Adriatic Sea. Commercial fisheries such as bottom trawls can serve as an opportunistic platform for collecting data on seafloor litter and help researchers in addressing the lack of data through Fishing for Litter initiatives. In this study, the crews of twelve trawlers from two Italian Adriatic ports collected seafloor litter as part of their Fishing for Litter initiatives. In addition to the classical scheme, the collected litter was sorted on board into different bags, and speed, duration and geographical coordinates of each haul were recorded to allow an assessment of both densities and spatial distribution. More than 600 kg of litter was removed from the seafloor by the fishers in approximately 1 month and characterised by the researchers on the docks. Most of the found items were made of synthetic polymers and related to packaging, fisheries and aquaculture activities. Abandoned, lost or discarded fishing gear and mussel nets were identified as of particular concern in the maritime compartment of Chioggia and Civitanova Marche, respectively. Three hotspots for marine litter were identified: near the Venice lagoon, in the centre of the northern basin and at greater depth in the central Adriatic. This study provides a detailed picture of the spatial distribution and composition of seafloor litter in the areas studied and highlights the importance of increased cooperation between fishermen and scientists to improve the identification of hotspots and sources while removing marine litter from the seafloor and raising awareness of the problem.

Abundance, composition and sources of benthic marine litter trawled-up in the fishing grounds on the Moroccan Mediterranean coast

This study aims to investigate the abundance, composition and sources of marine litter captured with fishing net during a fisheries survey in the Al Hoceima region, in the Moroccan Mediterranean. A total of 50 hauls were conducted and 2664 items of litter were collected. Plastic (57.15%) was the most frequent type of litter, and consisted mainly of bottles, crisps packets and plastic bags. The abundance values range between 0 and 1887 items/km2. Comparing our findings with other regions of the Mediterranean, Moroccan waters displayed a higher impact, probably due to high human population density and also poor waste management. Higher amounts of litter were reported in coastal areas, especially offshore coastal cities and at river mouths. The abundance of marine litter varies by region, season and depth. The litter abundance was significantly greater at 24–50 m (957 items/km2) compared to 50–100 m (405 items/km2) and >100 m (297 items/km2) depth classes. This study also indicates that the Al Hoceima Marine Protected Area is a hotspot for marine litter that can threaten the biological richness of this region. Our observation also showed that fishermen are poorly managing the litter caught in the nets. In all the trips, the fishermen did not keep the waste caught in the nets but threw it back into the water after sorting. This study highlights the need for educational programs for fishermen to develop good environmental practices that will help protect the marine environment.

Mixed-Species Plantation of Pinus massoniana Lamb. and Quercus variabilis Bl. and High Soil Nutrient Increase Litter Decomposition Rate

Changes in land use and forest planting have led to substantial changes in soil fertility and leaf litter input. The effects of mixed planting on the leaf litter decomposition rate in contrasting soil nutrient conditions are poorly understood. To elucidate the effects of litter composition and soil fertility on litter decomposition, we conducted a field litterbag-decomposition experiment with single (Pinus massoniana Lamb. or Quercus variabilis Bl.) and mixed (P. massoniana and Q. variabilis) litter treatments on soils of three nutrient levels (high, medium, and low). During the 3-year decomposition, at each decomposition stage and soil nutrient level, the mass-loss rate (MLR) was higher in mixed-litter than in the two single-litter treatments, with the exception of Q. variabilis, which recorded a higher MLR at 724 d in medium and high soil substrates. Between the two single-litter treatments, the MLR of Q. variabilis litter was higher than that of the P. massoniana litter; the MLR of the component litter of P. massoniana and Q. variabilis was higher than that of the corresponding two single-litter treatments. The k values over the 3-year-experiment period increased with the soil nutrient level for all litter treatments, as did microbial biomass carbon and nitrogen content. These findings suggest that mixed planting and high level of soil nutrient can accelerate litter decomposition.

Spatio-temporal variability in the abundance and composition of beach litter and microplastics along the Baltic Sea coast of Schleswig-Holstein, Germany

Abundance and composition of beach litter and microplastics (20–5000 μm, excluding fibres) were assessed in spring and autumn 2018 at various beaches along the Baltic Sea coast of Schleswig-Holstein, Northern Germany. The beach litter survey followed the OSPAR guidelines, while microplastics were extracted from sediment samples using density separation and were then identified with Raman μ-spectroscopy. We observed seasonality in the abundance and composition, but not in the mass of beach litter. The median microplastic abundance was 2 particles per 500 g of dry sediment in spring as well as in autumn, while six different synthetic polymers (PE, PP, PS, PET, PVC, POM) were detected. We found no correlation between the abundances of beach litter and microplastics. Our data represent the first systematic co-assessment of macro- and micro beach litter along the Baltic Sea coast of Schleswig-Holstein.

Распределение радиоактивного и стабильного цезия в почвах и растениях лесных экосистем

The paper presents the results of determining the content of radioactive (137Cs) and stable (133Cs) isotopes of cesium in soil and plant samples (lichens, mosses, bark, wood) collected in a medium-aged pine forest on the territory of the Polesye State Radiation-Ecological Reserve, as well as the results of the experiment to assess the vertical precipitation of 137Cs on horizontal plates. The ratios of concentrations of 137Cs to 133Cs have been calculated, which can be used to quantify the level of equilibrium between 137Cs and 133Cs in the forest ecosystems. Based on the assumption that the physicochemical properties of 133Cs and 137Cs are similar, the analysis of 133Cs and comparison of its ratios with 137Cs can be useful for understanding the long-term behavior of the radionuclide and its equilibrium distribution in forest ecosystems. As a result of the conducted research, it was established that the precipitation activity of 137Cs in the composition of tree litter is higher in comparison with the atmospheric precipitation of the radionuclide on horizontal plates. In the autumn season, there is a decrease in the average daily values of 137Cs activity observed in the samples of radioactive fallout from the atmosphere and an increase in the tree litter samples. At the same time, more than half of the total activity of the radionuclide is retained by the tree litter. The vertical distribution of the 137Cs exchange form in the forest soil’s mineral layers was compared to that of 133Cs. The total content of 137Cs in the soil profile decreases with depth. The content of the 137Cs exchange form in the soil profile has an uneven distribution, and the concentration of the stable isotope’s exchange form increases with depth. The 137Cs to 133Cs ratios in the soil profile decrease with a soil depth from the horizon of 0-5 cm to the horizon of 15-20 cm, which indicates a nonequilibrium ratio of these isotopes. It is shown that the content of 137Cs and 133Cs in lichens, mosses, bark and wood varies depending on the type of a sample and the part of a plant. The highest activity values of 137Cs were determined in lichens and mosses. Under conditions of co-growth, mosses are characterized by a higher concentration of 133Cs when compared to lichens. A good correlation was noted between the content of 137Cs and 133Cs for all types of the plant samples. This result suggests the conclusion that these plants absorb 137Cs similarly to 133Cs.

Influence of Improved Microclimate Conditions on Growth and Physiological Performance of Two Japanese Quail Lines

Microclimate parameters (ammonia, ambient temperature, heat index, and relative humidity) surrounding birds affect the production and health status of poultry. Therefore, this study aimed to evaluate the impact of adding natural zeolite to the litter of Japanese quail on improving microclimate parameters and its reflection in growth performance, blood gases, and blood biochemical parameters. A total of 1152 chicks were obtained from the same hatch at the 20th selection generation. Chicks were allocated into two groups based on the litter composition: Group 1: wheat straw as litter (untreated group); Group 2: 80% wheat straw + 20% zeolite (treated group). Each group consisted of 576 chicks: 410 selected line chicks and 166 control line chicks. Significant and favorable effects of the treatment on microclimate parameters during tested periods were found to favor the treated group. Either the treated group or the selected line had significantly better growth performance than the untreated group and control line. Zeolite-treated quails had significantly desirable blood gases and lower blood acidity and serum total iron binding capacity compared to the untreated group. Thus, adding natural zeolite to the litter enhanced the microclimate parameters that improved growth performance, blood gases, and blood biochemical parameters and reduced ammonia emission.

Understanding the factors affecting the quantity and composition of street litter: Implication for management practices

Some urban areas have more litter than others. Understanding the reason for this is important not only for dealing with urban littering but also for marine water quality because approximately 80% of the world's marine litter originates on land. This study aimed to better understand the quality and quantity of litter on sidewalks along with the sampling site's socio-economic attributes to better discern why some areas have more/different litter than others and what, if any, are the implications for a more tailored waste management strategy. We surveyed twice each of the 35 sites we selected from the Lower Passaic River watershed and the related Harbor Estuary within New Jersey, U.S.A. A total of 28,431 litter items were recorded with a total mass and volume of 245.8 kg and 4.7 m3, respectively. Floatable items accounted for 66% of all objects collected. Cigarette butts were the most numerous among all items (28%) and represented 43% of the total floatable items, the remaining 57% being represented by potentially recyclable items such as plastic, rubber, and Styrofoam. Stepwise linear regression was used to explore the relationship between the litter collected and various predictors. Among others, the results suggest the importance of strategically placing collection bins around properties with relatively lower assessed values, outdoor smoking areas, close to schools, and places where people predominantly walk to their destination. Possible management strategies include prohibiting single use plastic bags, limiting foam food ware, public education, and outreach.

From source to sink: A comparative study of streamside and beach litter in the Black Sea

The increasing amount of marine litter pollution and its impact on the marine environment raises global concern. This study aims to reveal the effect of streams on marine litter density and composition. A total of ten stations on the southeastern Black Sea and six stations on the Manahoz stream were seasonally surveyed. The litter density ranged between 0.838 ± 0.33 and 4.01 ± 0.55 items/m2 in the beach stations, and 0.93 ± 0.27 2.40 ± 2.18 items/m2 in the streamside stations. No significant difference was determined among the seasons for both beach and streamside (Kruskal-Wallis test, p > 0.05). On the other hand, the litter density was also similar in beach and streamside stations in the same season. The litter composition consisted of > 75% plastic. Principal component analysis and PERMANOVA determined no significant difference in litter composition among beach and streamside stations. The litter items mostly consisted of single-use items. Among them, plastic beverage containers were the most abundant litter subcategory during the study (ranging between 18.79% and 34.50%). The subcategory composition exhibited a significant difference among beach and streamside stations (ANOSIM, p < 0.05), which was mainly explained by plastic pieces, beverage containers, and foams according to SIMPER analysis. Personal protection equipment that was not reported before the COVID-19 pandemic emerged. The results of our study can be used for marine litter modeling studies and legislation for restriction or ban of most abundant single-use litter items.

Всхожесть семян хвойных интродуцентов в условиях Центрального Казахстана при различной стратификации и внесении в субстрат хвойного опада

This study observes the issues of the possible usage of wastes from timber industry in the sprouting of seeds of coniferous plants in the arid climate of Central Kazakhstan. Such treatment of coniferous seeds is easily implementable and cost-effective, compared to the other methods. However, the complex chemical composition of needle litter in the soil substrate has the multifactorial and controversial effects on such indicators as germination energy, seed germination capacity and rest energy. In addition, the article discusses the use of long-term natural seed stratification as an alternative method of planting seeds in forest nurseries. The other studies have shown that natural stratification has a more significant effect on the indicators of seed rest energy and germination energy. However, it should be said that these parameters mostly correlate with the generic assignment of the objects. Thus, representatives of the genera Picea and Abies have more significant rates of germination during spring stratification. Whereas, representatives of the genera Pinus and Pseudotsuga – with natural stratification. This may be the result of their ecological and biological adaptation. The conditions of Central Kazakhstan are characterized by a sharply continental climate, which includes not only a sharp climate change, but also a rather low snow cover and low temperatures. Under these conditions, the seeds of the genera Pinus and Pseudotsuga may have higher adaptive abilities, which may become a further subject of research. At the same time, it was determined that despite the rather convincing data obtained during autumn stratification, the highest results of seed germination in most experimental species were noted during spring stratification, including variation with the use of needle litter. Again, it is not entirely advisable to introduce the use of this method based only on the indicators of seed germination in arid conditions of Central Kazakhstan, since the favorable period for seed germination in this area is unstable from year to year. Thus, based on the results of the study, it was concluded that the most suitable method for germinating seeds of conifers, with some exceptions, is natural stratification. The use of needle litter affects insignificantly the rates of seed germination, and in some cases even suppresses this process.

First Short-Term Study of the Relationship between Native and Invasive Earthworms in the Zone of Soil Freezing in Western Siberia—Experiments in Mesocosms

Earthworm invasions often reduce biodiversity and affect the ability of ecosystems to perform ecosystem functions. Over the past few decades, European lumbricid species have spread widely in natural habitats in Western Siberia, without completely displacing the native species. The aim of the present experiment is to study the survival, reproductive potential, vertical distribution, abundance, and biomass of Aporrectodea caliginosa and Lumbricus rubellus invasive species for the region and the native species Eisenia nordenskioldi and their influence on each other. For this purpose, winter and vegetation experiments were conducted in mesocosms simulating the real situation of invasions in the same communities on the same types of soils with the same amount and composition of litter. The authors found that the native species was significantly inferior to A. caliginosa in reproduction rate, number of offspring, and final biomass, but had an advantage over L. rubellus. The native species was positively influenced by the presence of A. caliginosa. In the experiment, there was a significant rejuvenation of the populations of the studied species, as well as an increase in abundance and relative mass under interaction conditions compared to mono variants. The native species had advantages over the invasive species in terms of winter survival. The natural volume of litter used in the experiment was insufficient for L. rubellus. According to the results of the experiment, it can be assumed that the spread of L. rubellus will continue to be limited to non-freezing biotopes rich in organic matter. A. caliginosa will spread in natural communities and agrocenoses of Western Siberia.

Chemical and Microbial Characterization of Fermented Forest Litters Used as Biofertilizers

The excessive use of chemicals in intensive agriculture has had a negative impact on soil diversity and fertility. A strategy for developing sustainable agriculture could rely on the use of microbial-based fertilizers, known as biofertilizers. An alternative to marketed products could be offered to small farmers if they could produce their own biofertilizers using forest litters, which harbor one of the highest microbial diversities. The aim of this study is to characterize microbial communities of Fermented Forest Litters (FFL), assuming that the fermentation process will change both their abundance and diversity. We investigated two types of differing in the chemical composition of the initial litters used and the climatic context of the forest where they are originated from. The abundance and diversity of bacterial and fungal communities were assessed using quantitative PCR and molecular genotyping techniques. The litter chemical compositions were compared before and after fermentation using Infrared spectrometry. Results obtained showed that fermentation increased the abundance of bacteria but decreased that of fungi. Low pH and change in organic matter composition observed after fermentation also significantly reduced the α-diversity of both bacterial and fungal communities. The higher proportion of aliphatic molecules and lower C/N of the FFLs compared to initial litters indicate that FFLs should be rapidly decomposed once added into the soil. This preliminary study suggests that the agronomic interest of FFLs used as biofertilizers is probably more related to the contribution of nutrients easily assimilated by plants than to the diversity of microorganisms that compose it. Further studies must be conducted with sequencing techniques to identify precisely the microbial species likely to be beneficial to plant growth.

BIOMASS AND NUTRIENTS IN THE FOREST-FLOOR LITTER OF SECOND-GROWTH BRAZILIAN ATLANTIC FORESTS

This study aimed to evaluate the biomass and chemical composition of the forest floor litter in three remnants of Submontane Dense Ombrophilous Forest located in the Guaricica Natural Reserve in the municipality of Antonina, state of Paraná, Brazil. The areas selected for this study are at different stages of secondary succession, here named initial stage (INI), intermediate stage (INT), and advanced stage (ADV). The litter was collected in different seasons of the year (summer and winter of 2013 and 2014) and sorted into fractions: whole leaves (WL), leaves under some stage of decomposition (DL), miscellaneous litter (ML), and branches (B). After sorting, the litter was oven-dried, weighed, and had the contents of C, N, P, K, Ca, and Mg measured. After that, the accumulated amount of each nutrient in the different litter fractions was estimated. Accumulation of biomass in the INI was lower than that in the ADV. The DL fraction showed the highest level of biomass accumulation among all fractions. The average concentration of macronutrients in the litter showed the following sequence: C&gt;N&gt;Ca&gt;Mg&gt;K&gt;P. The C/N ratio was higher in the INI and INT compared with that in the ADV. Higher levels of macronutrients were frequently observed in the ADV. Inputs of C and of most nutrients increased from the INI to the ADV, except for Ca, whose input varied little throughout the different successional stages.

First baseline assessment of seafloor litter on Italian coralligenous assemblages (Mediterranean Sea) in accordance with the European Marine Strategy Framework Directive

A monitoring programme for coralligenous assemblages was carried out in Italy for implementation of the Marine Strategy Framework Directive (MSFD), aiming to characterise the coralligenous' environmental status and litter distribution. A standardised monitoring protocol, based on ROV-imaging, has been applied; this paper analyses the data obtained during the first MSFD cycle (2015–2019). Ninety-five areas were monitored at depths ranging between 14 and 199 m in the three subregions bordering Italy. Overall, 4316 macrolitter items were recorded. The median litter density was 2 items 100 m−2 (range: 0–120 items 100 m−2), but significant subregional differences emerged in litter quantities and composition. Fishery-related litter (mainly lines and ropes) was the most common type (86 %), affecting vulnerable coralligenous reefs. A first baseline is proposed for assessing achievement toward Good Environmental Status and evaluation of the efficacy of the Italian MSFD measures aiming to eliminate the negative effects of marine litter on vulnerable reefs.

Additional N Input May Alter the Species-Specific Blue Carbon Cycling Differently in Mangroves

Aquaculture is one of the fastest-growing economic activities in the world that results in a high amount of nitrogen-rich wastewater discharge into mangroves and affects the plant tissue’s decomposition. However, a comprehensive analysis of above- and belowground litter affected by the nitrogen (N) input is rare. This study investigated the responses of above- and belowground litter decomposition to the different levels of N input in decomposition rates, chemical components, and the release of chemical compounds. Exogenous N input had stimulating, retarding, or even no effect on plants’ litter decomposition and nutrient release in mangroves. The above- and belowground litter decompositions had different responses to anthropogenic N addition and varied among different mangrove species. The mechanism of the impacts of anthropogenic nitrogen input varies depending on species identity, litter composition, and additional N level. These results show that N enrichment in mangroves can be beneficial and detrimental to ecosystem function. For the native mangrove species, Kandelia obovata and Avicennia marina , the belowground tissues that had a direct correlation with carbon accumulation were significantly influenced by the additional N input. The worldwide problem of offshore aquaculture effluent discharge is a potential risk to the ecological function of mangroves in carbon storage.