Earthworms are iteroparous organisms with indeterminate growth, i.e. they continue to increase in size throughout their life and after completion of sexual development. Terrestrial oligochaetes vary greatly in size. Depending on the species, adult earthworms can reach between 10 mm and 3 m in length and between <1 mm and >25 mm in width, with most being of length 5-15 cm. Among the more than 7000 species described to date, very few (~20) reach lengths greater than 1 m. The longest earthworm on record is Amynthas mekongianus, which is found in the mud banks of the Mekong River in Southeast Asia and which reaches almost 3 m in length. It is about the same size as Megascolides australis, the ‘Giant Gippsland Earthworm’. These atypically giant earthworm species remain a scientific curiosity in terms of their biology, but they cannot be considered cases of gigantism. Gigantism occurs when organisms are much larger than normal or exhibit excessive growth. Earthworms obtain energy from the organic matter on which they feed, and their growth mainly depends on the quality of the resource and on the species, as well as on food availability, environmental factors, which can directly or indirectly affect growth by modifying food availability, and other factors such as competition. This is particularly evident in earthworms, which display indeterminate growth and large species-dependent variations in size. The biology, life cycle and growth and reproduction rates of Eisenia fetida (Savigny 1826) and Eisenia andrei (Bouché 1972), the earthworm species most commonly used in vermicomposting and vermiculture, have been widely reported. Here we present details of the enormous growth of individual specimens of Eisenia andrei and Dendrobaena hortensis reared under particular culture conditions and fed a special diet. Individuals almost 20 times the average weight of individuals of the species have been obtained. Possible explanations for this interesting phenomenon are discussed.

Despite widespread industrial use, the environmental safety of Hydroquinone (HQ), a benzene compound from plants used in processes like cosmetics, remains uncertain. This study evaluated the ecotoxicological impact of HQ on soil and river environments, utilizing non-target indicator organisms from diverse trophic levels: Daphnia magna, Vibrio fischeri, Allium cepa, and Eisenia fetida. For a more environmentally realistic assessment, microbial communities from a river and un-treated soil underwent 16S rRNA gene sequencing, with growth and changes in community-level physiological profiling assessed using Biolog EcoPlate™ assays. The water indicator D. magna exhibited the highest sensitivity to HQ (EC50 = 0.142 µg/mL), followed by V. fischeri (EC50 = 1.446 µg/mL), and A. cepa (LC50 = 7.631 µg/mL), while E. fetida showed the highest resistance (EC50 = 234 mg/Kg). Remarkably, microbial communities mitigated HQ impact in both aquatic and terrestrial environments. River microorganisms displayed minimal inhibition, except for a significant re-duction in polymer metabolism at the highest concentration (100 µg/mL). Soil communities demonstrated resilience up to 100 µg/mL, beyond which there was a significant decrease in population growth and the capacity to metabolize carbohydrates and polymers. Despite microbial mitigation, HQ remains highly toxic to various trophic levels, emphasizing the necessity for en-vironmental regulations.

Earthworm invasions often reduce biodiversity and affect the ability of ecosystems to perform ecosystem functions. Over the past few decades, European lumbricide 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 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, 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.

Earthworms and soil microorganisms contribute to soil health, quality and fertility, but their importance in agricultural soils is often underestimated. This study aims at examining whether and to what extent the presence of earthworms [Eisenia fetida (Savigny, 1826)] affected the a) soil bacterial community composition, b) litter decomposition, and c) plant growth (Brassica oleracea L., broccoli; Vicia faba L., faba bean). We performed a mesocosm experiment in which plants were grown outdoors for four months with or without earthworms. Soil bacterial community structure was evaluated by a 16S rRNA-based metabarcoding approach. Litter decomposition rates were determined by using the tea bag index (TBI) and litter bags (olive residues). Earthworm number almost doubled throughout the experimental period. Independently of the plant species, earthworm presence had a significant impact on the structure of soil bacterial communities, in terms of enhanced α- and β-diversity (especially that of Proteobacteria, Bacteroidota, Myxococcota, and Verrucomicrobia) and increased 16S rRNA gene abundance (+89% in broccoli and +223% in faba bean). Microbial decomposition (TBI) was enhanced in the treatments with earthworms, and showed a significantly higher decomposition rate constant (kTBI) and a lower stabilization factor (STBI), whereas decomposition in the litter bags (dlitter) increased by about 6% in broccoli and 5% in faba bean. Earthworms significantly enhanced root growth (in terms of total length and fresh weight) of both the plant species. Our results show the strong influence of earthworms and crop identity in shaping soil bacterial communities, litter decomposition and plant growth. These findings could be used for developing nature-based solutions that ensure the long-term biological sustainability of soil agro- and natural ecosystems.

Hypercholesterolemia is a major risk for the development of cardiovascular diseases (CVDs), the main cause of mortality worldwide, and it is characterized by high levels of circulating cholesterol. The drugs currently available for hypercholesterolemia control have several side effects, so it is necessary to develop new effective and safer therapies. Seaweeds serve as sources of several bio-active compounds with claimed beneficial effects. Eisenia bicyclis (Aramé) and Porphyra tenera (Nori) are edible seaweeds which were previously recognized as rich in bioactive compounds. In the present study, we aim to evaluate the anti-hypercholesterolemia effect of these two seaweeds ex-tracts and their health potential. Both extracts, but more efficiently Aramé extract demonstrated to have liver 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) inhibitory activity and to reduce approximately 30 % cholesterol permeation through human Caco-2 cells simulating the intestinal lining, targets for hypercholesterolemia treatments. An untargeted metabolomic assay on human intestinal Caco-2 and liver Hep-G2 cells lines exposed to Aramé and Nori extracts revealed changes in the cell’s metabolism as indicators of the extract’s health beneficial effects. The metabolic pathways affected by exposure to both extracts were associated to lipid metabolism, such as phospholipids, and fatty acid metabolism, pathways of amino acid, cofactors and vitamins and cellular respiration metabolism. More profound for Aramé treated cells, but also seen for Nori ex-posed cells, the metabolites modifications were associated with the protection against CVDs and other diseases and, to the improvement of cells oxidative stress tolerance. The results obtained for the anti-hypercholesterolemia properties, in addition to the revelation of the positive impact on cells metabolism, are an important contribution for further evaluation of these seaweeds extracts as functional foods or for CVDs prevention.