Ecological functions of earthworms in soil
Andriuzzi, W.S. - \ 2015
Wageningen University. Promotor(en): Lijbert Brussaard; T. Bolger, co-promotor(en): O. Schmidt. - Wageningen : Wageningen University - ISBN 9789462574175 - 154
aardwormen - oligochaeta - bodemfauna - bodembiologie - bodemecologie - ecosystemen - bodemstructuur - earthworms - oligochaeta - soil fauna - soil biology - soil ecology - ecosystems - soil structure
Ecological functions of earthworms in soil
Walter S. Andriuzzi
Earthworms are known to play an important role in soil structure and fertility, but there are still big knowledge gaps on the functional ecology of distinct earthworm species, on their own and in interaction with other species. This thesis investigated how earthworms affect soil biochemical and biophysical functioning, and other organisms such as plants and smaller soil organisms.
Two field experiments with stable isotope tracers were performed to investigate how anecic earthworms (which feed on organic matter at the soil surface and dig deep burrows) transfer carbon and nitrogen from fresh plant litter into soil, and how this in turn affects soil organic matter composition, protists and nematodes. Another field experiment tested whether the anecic earthworm Lumbricus terrestris can counteract negative effects of intense rainfall on soil and plants (ryegrass). A greenhouse experiment was carried out to study how co-occurring earthworm species – two anecic and one endogeic (smaller, soil-feeding) – affect transfer of nitrogen from dung to soil and plants, nitrogen retention in soil, and plant growth. For the latter experiment, a method to produce herbivore (rabbit) dung triple-labelled with carbon, nitrogen and sulphur stable isotopes was developed.
Overall, the findings highlight important functions of earthworms in carbon and nitrogen cycling, soil biophysical structure maintenance due to burrow formation, and resulting biotic interactions. A novel finding was that the sphere of influence of anecic earthworms in soil (the ‘drilosphere’) is a much larger biochemical and biological hotspot than hitherto assumed. Rapid movement of carbon and nitrogen from surface to soil thanks to anecic earthworm activity resulted in spatial heterogeneity in soil carbon content, organic matter composition, and density of smaller eukaryotes (e.g. bacterial-feeding protists). Evidence was found that distinct earthworm anecic species may have dissimilar effects on soil biochemistry and plant growth, and that both anecic and endogeic earthworms may feed on surface organic matter (dung). This shows that the validity of earthworm ecological groups depends on the function under study, and suggests that, for some research questions, species identity should not be neglected; other approaches to quantify ecological differences between species (e.g. functional traits) are appraised. Finally, L. terrestris was found to ameliorate the disturbance of intense rain on plants, giving evidence to the idea that some components of soil biodiversity may contribute to ecosystem stability in the face of disturbance.
Effects of silver nanoparticles (NM-300K) on Lumbricus rubellus earthworms and particle characerization in relevant test matrices including soil
Ploeg, M.J.C. van der; Handy, R.D. ; Waalewijn-Kool, P. ; Berg, J.H.J. van den; Herrera Rivera, Z.E. ; Bovenschen, J. ; Molleman, B. ; Baveco, J.M. ; Tromp, P. ; Peters, R.J.B. ; Koopmans, G.F. ; Rietjens, I. ; Brink, N.W. van den - \ 2014
Environmental Toxicology and Chemistry 33 (2014)4. - ISSN 0730-7268 - p. 743 - 752.
in-vitro - size - invertebrates - oligochaeta - dissolution - responses - toxicity - exposure - behavior - impacts
The impact of silver nanoparticles (AgNP; at 0¿mg Ag/kg, 1.5¿mg Ag/kg, 15.4¿mg Ag/kg, and 154¿mg Ag/kg soil) and silver nitrate (AgNO3; 15.4¿mg Ag/kg soil) on earthworms, Lumbricus rubellus, was assessed. A 4-wk exposure to the highest AgNP treatment reduced growth and reproduction compared with the control. Silver nitrate (AgNO3) exposure also impaired reproduction, but not as much as the highest AgNP treatment. Long-term exposure to the highest AgNP treatment caused complete juvenile mortality. All AgNP treatments induced tissue pathology. Population modeling demonstrated reduced population growth rates for the AgNP and AgNO3 treatments, and no population growth at the highest AgNP treatment because of juvenile mortality. Analysis of AgNP treated soil samples revealed that single AgNP and AgNP clusters were present in the soil, and that the total Ag in soil porewater remained high throughout the long-term experiment. In addition, immune cells (coelomocytes) of earthworms showed sensitivity to both AgNP and AgNO3 in vitro. Overall, the present study indicates that AgNP exposure may affect earthworm populations and that the exposure may be prolonged because of the release of a dissolved Ag fraction to soil porewater.
Earthworms and the soil greenhouse gas balance
Lubbers, I.M. - \ 2014
Wageningen University. Promotor(en): Lijbert Brussaard, co-promotor(en): Jan-Willem van Groenigen. - Wageningen : Wageningen University - ISBN 9789461739315 - 222
aardwormen - oligochaeta - broeikasgassen - bodem - koolstofvastlegging in de bodem - koolstofvastlegging - emissie - bodembiologie - earthworms - oligochaeta - greenhouse gases - soil - soil carbon sequestration - carbon sequestration - emission - soil biology
Earthworms play an essential part in determining the greenhouse gas (GHG) balance of soils worldwide. Their activity affects both biotic and abiotic soil properties, which in turn influence soil GHG emissions, carbon (C) sequestration and plant growth. Yet, the balance of earthworms stimulating C sequestration on the one hand and increasing GHG emissions on the other has not been investigated. Indeed, much is still unclear about how earthworms interact with agricultural land use and soil management practices, making predictions on their effects in agro-ecosystems difficult. In this thesis, I aimed to determine to what extent GHG mitigation by soil C sequestration as affected by earthworms is offset by earthworm-induced GHG emissions from agro-ecosystems under different types of management. To reach this aim, I combined mesocosm and field studies, as well as meta-analytic methods to quantitatively synthesize the literature.
Using meta-analysis, I showed that, on average, earthworm activity leads to a 24% increase in aboveground biomass, a 33% increase in carbon dioxide (CO2) emissions and a 42% increase in nitrous oxide (N2O) emissions. The magnitude of these effects depends on soil factors (e.g., soil organic matter content), experimental factors (e.g., crop residue addition or fertilizer type and rate) and earthworm factors (e.g., earthworm ecological category and -density).
Conducting both a mesocosm and a field study, I showed that earthworm activity results in increased N2O emissions from fertilized grasslands. Under field conditions I found an increase in earthworm-induced N2O emissions in autumn but not in spring, suggesting that earthworm effects in the field depend on soil physicochemical parameters influenced by meteorological and seasonal dynamics.
In a unique two-year experiment with a simulated no-tillage (NT) system and a simulated conventional tillage (CT) system, I found that earthworm presence increases GHG emissions in an NT system to the same level as in a CT system. This suggests that the GHG mitigation potential of NT agro-ecosystems is limited. When considering the C budget in the simulated NT system, I demonstrated that over the course of the experiment earthworms increase cumulative CO2 emissions by at least 25%, indicating a higher C loss compared to the situation without earthworms. Yet, in the presence of earthworms the incorporation of residue-derived C into all measured soil aggregate fractions also increased, indicating that earthworm activity can simultaneously enhance CO2 emissions and C incorporation into aggregate fractions.
In conclusion, the revealed dominance of GHG emissions over C sequestration as affected by earthworms implies that their presence in agro-ecosystems results in a negative impact on the soil greenhouse gas balance.
Interactions between microbial-feeding and predatory soil fauna trigger N2O emissions
Thakur, M.P. ; Groenigen, J.W. van; Kuiper, I. ; Deyn, G.B. de - \ 2014
Soil Biology and Biochemistry 70 (2014). - ISSN 0038-0717 - p. 256 - 262.
nitrogen mineralization - enchytraeid worms - trophic cascades - food webs - raw humus - decomposition - biodiversity - nitrification - oligochaeta - microarthropods
Recent research has shown that microbial-feeding invertebrate soil fauna species can significantly contribute to N2O emissions. However, in soil food webs microbial-feeding soil fauna interact with each other and with their predators, which affects microbial activity. To date we lack empirical tests of whether or not these interactions play a significant role in N2O emissions from soil. Therefore we studied how interactions between soil microbes, two groups of microbial-feeding soil fauna (enchytraeids and fungivorous mites) and their predators (predatory mites) affect soil N2O emissions. We hypothesized that: 1) the presence of two microbial-feeding fauna groups (enchytraeids and fungivorous mites) together increase N2O emissions more than when only a single group is present; and 2) the addition of predatory mites further enhances N2O emissions. We assembled soil food webs consisting of soil microbes, enchytraeids, fungivorous and predatory mites in microcosms with sandy loamy soil and sterilised hay as a substrate for the soil microbes. N2O emissions were measured during 56 days. We found no support for our first yet support for our second hypothesis. Addition of predatory mites to microcosms with enchytraeids and fungivorous mites increased N2O emissions significantly from 135.3 to 482.1 mg N m-2, which was also significantly higher than the control without fauna (83 mg N m-2) (P <0.001). In presence of enchytraeids, fungivorous and predatory mites, we found much higher nitrate availability at the time of the N2O peak on Day 35 (10.9 versus 5.5 mg N per kg soil without soil fauna), indicating that the major increase in N2O emissions in this treatment may be due to increased nitrification. Increased nitrification may be attributed to higher availability of N from the dead tissues of fungivorous mites and increased activity of the enchytraeids that might also have affected soil structure and contributed to increased N2O emissions. This study demonstrates the importance of interactions between microbial-feeding invertebrate soil fauna and their predators in understanding N2O emissions.
Two approaches using traits to assess ecological resilience: A case study on earthworm communities
Lange, H.J. de; Kramer, K. ; Faber, J.H. - \ 2013
Basic and Applied Ecology 14 (2013)1. - ISSN 1439-1791 - p. 64 - 73.
river floodplains - species traits - wet grassland - biodiversity - diversity - macroinvertebrates - lumbricidae - oligochaeta - populations - pollutants
The relation between biological diversity and ecosystem functioning is a central theme in ecology. Ecological traits of species are often regarded as a link between structure and function, and trait distributions in a community may change in response to environmental stressors. Likewise, resilience in a community may be derived from the diversity in traits and trait values relevant to a particular stressor. We combine two approaches to test this: a novel trait frequency analysis and a multivariate ordination approach. The two methods are applied on a case study of an earthworm community in a frequently flooded floodplain in the Netherlands. Periodic flooding in floodplains restricts population growth and recolonization of earthworms. The strategies employed by different earthworm species for coping with this stress can be described by a combination of ecological traits. From the literature we compiled 10 ecological traits for the earthworm species encountered along an inundation gradient in the Duursche Waarden floodplain area flanking the river IJssel. Trait frequency analysis showed a greater diversity at low elevation sites of traits considered to be associated to flood tolerance, suggesting greater community resilience to flooding. The ordination analysis using trait composition provided information on which trait classes in the community were related with the inundation stress. Results from both analyses showed that important traits in species to deal with flooding are active dispersal, high hydrophily, diapause and parthenogenetic reproduction. Thus, a further understanding of community resilience was gained by combining traditional ordination analysis with trait diversity analysis
Operation of an aquatic worm reactor suitable for sludge reduction at large scale
Hendrickx, T.L.G. ; Elissen, H.J.H. ; Temmink, B.G. ; Buisman, C.J.N. - \ 2011
Water Research 45 (2011)16. - ISSN 0043-1354 - p. 4923 - 4929.
afvalwaterbehandeling - huishoudens - rioolslib - geactiveerd slib - bioreactoren - ontwerp - slibzuivering - aquatische wormen - oligochaeta - waste water treatment - households - sewage sludge - activated sludge - bioreactors - design - sludge treatment - aquatic worms - oligochaeta - eating waste sludge - activated-sludge
Treatment of domestic waste water results in the production of waste sludge, which requires costly further processing. A biological method to reduce the amount of waste sludge and its volume is treatment in an aquatic worm reactor. The potential of such a worm reactor with the oligochaete Lumbriculus variegatus has been shown at small scale. For scaling up purposes, a new configuration of the reactor was designed, in which the worms were positioned horizontally in the carrier material. This was tested in a continuous experiment of 8 weeks where it treated all the waste sludge from a lab-scale activated sludge process. The results showed a higher worm growth rate compared to previous experiments with the old configuration, whilst nutrient release was similar. The new configuration has a low footprint and allows for easy aeration and faeces collection, thereby making it suitable for full scale application.
Earthworms as colonisers: Primary colonisation of contaminated land, and sediment and soil waste deposits
Eijsackers, H.J.P. - \ 2010
Science of the Total Environment 408 (2010)8. - ISSN 0048-9697 - p. 1759 - 1769.
colliery spoil heaps - introduced earthworms - lumbricus-rubellus - floodplain soils - metal pollution - risk-assessment - new-zealand - populations - oligochaeta - succession
This paper reviews the role of earthworms in the early colonisation of contaminated soils as well as sediment and waste deposits, which are worm-free because of anthropogenic activities such as open-cast mining, soil sterilisation, consistent pollution or remediation of contaminated soil. Earthworms live in close interaction with their soil environment and are able to change it considerably by their burrowing and litter comminuting behaviour. While earthworms have been studied extensively, several questions still remain unanswered such as: What are the characteristics of successful early colonisers? Do they function well in dispersal, individual establishment or population growth? Do the negative environmental conditions in these kinds of anthropogenic soils hamper colonization or are these colonizers relatively resistant to it? To what extent does colonization change the characteristics of the colonized substrate? In short, do earthworms impact the soil? In this paper, the characteristics that make earthworms successful colonisers are briefly described as well as which species are the most successful and under what circumstances, and what do earthworms contribute to the total process of succession. We propose that it is not so much eco-type or r-K strategy that govern success and succession of earthworm colonisation but rather environmental flexibility not only towards pH, desiccation, and temperature but also towards contaminants such as heavy metals. Moreover, the formation of an organic litter layer, in close connection with re-vegetation of the area, is essential for establishing earthworm populations, which, at first, are mainly superficially and shallow active species. The burrowing and organic matter digesting activity of these earthworms changes the upper soil to a well mixed humus layer suitable for deep burrowing earthworm species.
Effects of intraspecific variation in white cabbage (Brassica oleracea var. Capitata) on soil ogranisms
Kabouw, P. ; Putten, W.H. van der; Dam, N.M. van; Biere, A. - \ 2010
Plant and Soil 336 (2010)1-2. - ISSN 0032-079X - p. 509 - 518.
enzymatic-hydrolysis products - gradient gel-electrophoresis - food-web structure - body-surface area - community structure - glucosinolate - root - oligochaeta - enchytraeidae - biodiversity
Intraspecific variation in plants can affect soil organisms. However, little is known about whether the magnitude of the effect depends on the degree of interaction with the roots. We analyzed effects of plant intraspecific variation on root herbivores and other soil organisms that interact directly with living plant roots, as well as on decomposer organisms that interact more indirectly with roots. We used four different white cabbage (Brassica oleracea var. capitata) cultivars exhibiting a high degree of intraspecific variation in root glucosinolate profiles. Intraspecific variation affected root-feeding nematodes, whereas decomposer organisms such as earthworms and Collembola were not affected. Root-feeding nematodes were most abundant in one of the cultivars, Badger Shipper, which lacked the glucosinolate gluconasturtiin. The effect of the intraspecific variation in glucosinolate composition may have been restricted to root-feeding nematodes due to the rapid degradation of glucosinolates and their breakdown products in the soil. Additionally, the low biomass of root-feeding nematodes, relative to other soil organisms, limits the possibility to affect higher trophic level organisms. Our results show that variation in root chemistry predominantly affects belowground herbivores and that these effects do not extend into the soil food web.
Gaining Insight in the Interaction of Zinc and Population Density with a Combined Dynamic Energy Budget and Population Model
Klok, T.C. - \ 2008
Environmental Science and Technology 42 (2008)23. - ISSN 0013-936X - p. 8803 - 8808.
lumbricus-rubellus - growth rate - consequences - soil - reproduction - oligochaeta - dependence
Laboratory tests are typically conducted under optimal conditions testing the single effect of a toxicant. In the field, due to suboptimal conditions, density dependence can both diminish and enhance effects of toxicants on populations. A review of the literature indicated that general insight on interaction of density and toxicants is lacking, and therefore no predictions on their combined action can be made. In this paper the influence of zinc was tested at different population densities on the demographic rates: growth, reproduction, and survival in the earthworm Lumbricus rubellus. Changes in these rates were extrapolated with a combined Dynamic energy budget (DEB) and a population model to assess consequences at the population level. Inference from the DEB model indicated that density decreased the assimilation of food whereas zinc increased the maintenance costs. The combined effects of density and zinc resulted in a decrease in the intrinsic rate of population increase which suddenly dropped to zero at combinations of zinc and density where development is so strongly retarded that individuals do not mature. This already happened at zinc levels where zinc induced mortality is low and therefore density enhances zinc effects and density dependent compensation is not expected.
Life-history strategies in freshwater macroinvertebrates
Verberk, W.C.E.P. ; Siepel, H. ; Esselink, H. - \ 2008
Freshwater Biology 53 (2008)9. - ISSN 0046-5070 - p. 1722 - 1738.
developed ecological theory - upper rhone river - species traits - habitat templet - aquatic insects - parental care - communities - oligochaeta - evolution - future
1. Explaining spatial and temporal differences in species assemblages is a central aim of ecology. It requires a sound understanding of the causal mechanisms underlying the relationship of species with their environment. A species trait is widely acknowledged to be the key that links pattern and process, although the enormous variety of traits hampers generalization about which combination of traits are adaptive in a particular environment. 2. In three steps, we used species traits to match species and environment, and chose lentic freshwater ecosystems to illustrate our approach. We first identified key environmental factors and selected the species traits that enable the organism to deal with them. Secondly, we investigated how investments in these traits are related (e.g. through trade-offs). Thirdly, we outlined 13 life-history strategies, based on biological species traits, their interrelations known from life-history theory and their functional implications. 3. Species traits and environmental conditions are connected through life-history strategies, with different strategies representing different solutions to particular ecological problems. In addition, strategies may present an integrated response to the environment as they are based on many different traits and their interrelationships. The presence and abundance of (species exhibiting) different life-history strategies in a location may therefore give direct information about how a particular environment is experienced by the species present. 4. Life-history strategies can be used to (i) explain differences in species assemblages either between locations or in different periods; (ii) compare waterbodies separated by large geographical distances, which may comprise different regional species pools or span species distribution areas and (iii) reduce often very complex, biodiverse assemblages into a few meaningful, easily interpretable relationships.
Effects of organic matter content on earthworms and nitrogen mineralization in grassland soils
Vliet, P.C.J. van; Stelt, B. van der; Rietberg, P.I. ; Goede, R.G.M. de - \ 2007
European Journal of Soil Biology 43 (2007)suppl. 1. - ISSN 1164-5563 - p. S222 - S229.
lumbricus-terrestris l - land-use history - agroecosystems - assimilation - dynamics - oligochaeta - consumption - abundance - quality - systems
Earthworms play an important role in the nitrogen cycle in the soil. Through their activities they affect the mineralization of organic matter directly and indirectly. However, the presence of organic matter also affects earthworm abundances. For this study, we selected 2 grasslands differing in organic matter content at nine dairy farms on sandy soils in the Noordelijke Friese Wouden (NFW) in the Netherlands. We expected a larger number of earthworms and a higher mineralization rate in grasslands with a higher organic matter content. We also expected a positive relationship between earthworm abundance and nitrogen mineralization. At each farm the grassland with the highest organic matter content contained the largest number of earthworms (up to 858 worms m(-2)), (r = 0.286 (p = 0.036)). These grasslands also had the highest root biomass (r = 0.504 (p = 0.0001). With an increase in organic matter in the soil (from 5 to 10.2%), potential nitrogen mineralization increased from 138 to 310 kg N-1 ha 6 months(-1). No relationships between the calculated amount of nitrogen mineralized by earthworms and the potential and actual nitrogen mineralization were found. Nitrogen mineralization due to earthworm activities, calculated using production ecological formulas, ranged from 4 to 24 ka N ha(-1) month(-1). (c) 2007 Elsevier Masson SAS. All rights reserved.
Effects of earthworms density on growth, development and reproduction in Lumbricus rubellus (Hoffm.) and possible consequences for the intrinsic rate of population increase
Klok, C. - \ 2007
Soil Biology and Biochemistry 39 (2007)9. - ISSN 0038-0717 - p. 2401 - 2407.
burrow systems - oligochaeta - dynamics - soil - organisms - culture - cores
In this paper, the influence of earthworm density is assessed on the life-history parameters: growth, development, reproduction, and survival of Lumbricus rubellus (Hoffm.). Density ranges from two to nine earthworms in 1-1 containers, corresponding to field densities of 300-1350 earthworms m(-2). Earthworms were kept under optimal laboratory conditions, with a surplus of food. The results show that at high earthworm density, individual growth is retarded, maturation delayed and cocoon production decreased, even when food is optimal. The integration of these results into a Dynamic Energy Budget model suggests that the food intake of individual earthworms is lower at the higher tested densities. This lower food intake is most probably driven by competition for space at the higher densities. The lower food intake results in a lower intrinsic rate of population increase which is negative at the highest tested density. (C) 2007 Elsevier Ltd. All rights reserved.
Field effects of pollutants in dynamic environments; a case study on earthworm populations in river floodplains contaminated with heavy metals
Klok, C. ; Goedhart, P.W. ; Vandecasteele, B. - \ 2007
Environmental Pollution 147 (2007)1. - ISSN 0269-7491 - p. 26 - 31.
lumbricus-rubellus - risk-assessment - organic-matter - soils - zinc - growth - consequences - oligochaeta - grassland - responses
In industrialized countries river floodplains can be strongly polluted with heavy metals. Published studies on effects of heavy metal pollution on soil invertebrates in floodplains, however, are inconclusive. This is unexpected since studies in other less dynamic environments reported clear effects at even lower levels of pollution. Flooding induces extra variation in invertebrate biomass and abundance which may reduce the probability to detect heavy metal effects. In this paper we combine reported data from studies on river floodplains in The Netherlands and Belgium and statistically analyze the effect of heavy metals on species composition, biomass, density and individual weight of earthworms. Interaction effects of heavy metal stress and flooding are also considered. The results suggest clear effects of zinc and copper on all variables and interaction of heavy metals and flooding for individual weight. (c) 2006 Elsevier Ltd. All rights reserved.
Effects of pesticides on soil invertebrates in model ecosystem and field studies: a review and comparison with laboratory toxicity data
Jänsch, S. ; Frampton, G.K. ; Römbke, J. ; Brink, P.J. van den; Scott-Fordsmand, J.J. - \ 2006
Environmental Toxicology and Chemistry 25 (2006)9. - ISSN 0730-7268 - p. 2490 - 2501.
species sensitivity distributions - earthworms - chemicals - tests - collembola - lumbricidae - oligochaeta - sublethal
A systematic review was carried out to investigate the extent to which higher-tier (terrestrial model ecosystem [TME] and field) data regarding pesticide effects can be compared with laboratory toxicity data for soil invertebrates. Data in the public domain yielded 970 toxicity endpoint data sets, representing 71 pesticides and 42 soil invertebrate species or groups. For most pesticides, the most frequent effect class was for no observed effects, although relatively high numbers of pronounced and persistent effects occurred when Lumbricidae and Enchytraeidae were exposed to fungicides and when Lumbricidae, Collembola, and Arachnida were exposed to insecticides. No effects of fungicides on Arachnida, Formicidae, or Nematoda or of herbicides on Lumbricidae, Formicidae, or Nematoda were observed in any studies. For most pesticides, higher-tier no-observed-effect concentration or lowest-observed-effect concentration values cannot be determined because of a lack of information at low pesticide concentrations. Ten pesticides had sufficient laboratory data to enable the observed higher-tier effects to be compared with 5% hazardous concentrations (HC5) estimated from acute toxicity laboratory data (atrazine, carbendazim, chlorpyrifos, diazinon, dimethoate, ¿-hexachlorocyclohexane, lambda-cyhalothrin, parathion, pentachlorophenol, and propoxur). In eight cases, higher-tier effects concentrations were within or below the 90% confidence interval of the HC5. Good agreement exists between the results of TME and field tests for carbendazim, but insufficient information is available for a comparison between TME and field studies for other pesticides. Availability and characteristics (e.g., taxonomic composition and heterogeneity) of the higher-tier effects data are discussed in terms of possible developments in risk assessment procedures.
Aquatic oligochaete biology IX; selected papers from the 9th symposium on aquatic oligochaeta, 6-10 October 2003 Wageningen, the Netherlands
Verdonschot, P.F.M. ; Wang Hongzhe, ; Pinder, A. ; Nijboer, R.C. - \ 2006
Dordrecht : Springer (Hydrobiologia vol. 564) - ISBN 9781402047817 - 222
oligochaeta - aquatisch milieu - ecologie - oligochaeta - aquatic environment - ecology
Population growth and development of the earthworm Lumbricus rubellus in a polluted field soil: possible consequences for the godwit (Limosa limosa)
Klok, C. ; Hout, A. van der; Bodt, J.M. - \ 2006
Environmental Toxicology and Chemistry 25 (2006)1. - ISSN 0730-7268 - p. 213 - 219.
heavy-metal pollution - eisenia-foetida - netherlands - toxicity - reproduction - oligochaeta - responses - quality - copper - rates
Many soils are polluted with Mixtures of moderate levels of contaminants. In The Netherlands 175,000 sites in rural areas are classified as highly polluted. However, it remains unclear to what extent local ecosystems are endangered. In this paper, we report on the effect of contaminants on earthworms in a meadow system. We tested a polluted and a reference field soil with similar soil characteristics and agricultural use. In the polluted soil copper, mercury, and lead were elevated by more than 200% compared with the reference soil. Bioassays on growth and reproduction in the earthworm species Lumbricus rubellus were executed in both soils, and a population model was used to assess the population-level consequences of changes in growth and reproduction. No significant effects were seen on reproduction and Survival in L. rubellus, but development was retarded in the polluted soil. This resulted in a 23% lower growth rate and a change in demography toward younger individuals. Field data on population composition of earthworms were used to support the laboratory results, and the relevance of the results for the godwit (Limosa limosa), which mainly feeds on earthworms during the breeding season, is discussed.
Species-specific earthworm population responses in relation to flooding dynamics in a Dutch floodplain soil
Zorn, M.I. ; Gestel, C.A.M. van; Eijsackers, H.J.P. - \ 2005
Pedobiologia 49 (2005)3. - ISSN 0031-4056 - p. 189 - 198.
lumbricus-rubellus - habitats - netherlands - oligochaeta - environment - macrofauna
Earthworms dominate the animal biomass in moist floodplain soils. They are known to survive long periods in aerated water, but little is known about earthworm population dynamics in floodplain systems with changing inundation frequencies. This study determined earthworm population dynamics in a floodplain system, in relation to frequency and duration of flooding events. From October 2000 to May 2003 earthworms were hand sorted in the `Afferdensche en Deestsche Waarden¿, a floodplain on the south bank of the river Rhine, near Druten, The Netherlands. Earthworm numbers and biomasses per age class (adult, subadult, juvenile) were recorded. Numbers and biomasses tend to decrease during flooding. Lumbricus terrestris was found in high numbers (>10/m2) only at the end of a flooding period. Allolobophora chlorotica was hardly affected by flooding; their biomass remained stable during the year. Aporrectodea caliginosa showed fluctuating numbers and biomasses during the sampling period that did not correlate with flooding frequency. Numbers and biomasses of Lumbricus rubellus were strongly reduced at the end of each flooding event, but their population densities fully recovered until next flooding event. Earthworm populations in floodplains fluctuate in time, depending on the season and on the time, duration and frequency of flooding. Different earthworm species react differently towards these flooding dynamics.
The implications of copper fungicide usage in vineyards for earthworm activity and resulting sustainable soil quality
Eijsackers, H.J.P. ; Beneke, P. ; Maboeta, M. ; Louw, J.P.E. ; Reinecke, A.J. - \ 2005
Ecotoxicology and Environmental Safety 62 (2005)1. - ISSN 0147-6513 - p. 99 - 111.
oligochaeta - oxychloride - biomarker - reproduction - sublethal - growth
To investigate the impact of copper-containing fungicides (copper oxychloride) on earthworms in South African vineyards, field inventories of earthworms in and between vine rows were carried out and compared to directly adjacent grassland. Also copper content, pH, organic matter content, and soil porosity were determined in these soils. This was combined with laboratory experiments to study the impact of vineyard soil characteristics on the burrowing and dispersal behavior of earthworms. Moreover, the direct toxic action of copper oxychloride on different endpoints of the earthworms (survival and growth) was studied. Copper oxychloride had a negative impact on these endpoints (decreased growth and survival related to increased copper body content) as well as on the behavioral aspect (decreased burrowing rate and avoidance of copper-containing soil). Moreover, there was an inverse relation between burrowing activity and soil bulk density that could also be related to the copper content. This may lead to a decrease in sustainable soil quality in vineyards
The effect of Lumbricus rubellus and Lumbricus terrestris on zinc distribution and availability in artificial soil columns
Zorn, M.I. ; Gestel, C.A.M. van; Eijsackers, H.J.P. - \ 2005
Biology and Fertility of Soils 41 (2005)3. - ISSN 0178-2762 - p. 212 - 215.
earthworms - runoff - bioturbation - infiltration - oligochaeta - erosion - system - casts - water
This study investigated the impact of epigeic and (epi)anecic earthworms on the distribution and availability of zinc in the soil profile. Experiments were carried out with Lumbricus rubellus and Lumbricus terrestris in perspex columns (circle divide 10 cm), filled with 20 to 23 cm non-polluted soil [organic matter 2%, clay 2.9%, pH 6.4 (0.01 M CaCl2)], that was covered by a 3- to 5-cm layer of aged zinc-spiked soil (500 mg Zn/kg dry soil) and another 2 cm non-polluted soil on top. After 80 days, columns were sacrificed and sampled in a depth profile. Earthworm casts, deposited on top of the soil, were collected. Each sample was analyzed for total and 0.01 M CaCl2-exchangeable zinc concentrations. L. rubellus did not go deeper than 3 cm into the soil and therefore no effect on zinc distribution in the soil could be detected. For L. terrestris, total zinc concentrations in the non-polluted layers were slightly but significantly higher in columns with earthworms, and so were the CaCl2-exchangeable zinc concentrations in the polluted layers of these columns. Casts of L. terrestris collected from the soil surface showed higher total zinc concentrations than those from non-polluted soil. Casts were mainly placed on top of the soil. This study showed that these epigeic and (epi)anecic species have only a slight effect on zinc availability, and that deep burrowing species, like L. terrestris, are able to transport polluted soil from deeper layers to the soil surface.
Soil organic matter distribution and microaggregate characteristics as affected by agricultural management and earthworm activity
Pulleman, M.M. ; Six, J. ; Breemen, N. van; Jongmans, A.G. - \ 2005
European Journal of Soil Science 56 (2005)4. - ISSN 1351-0754 - p. 453 - 467.
no-tillage agroecosystems - arable soil - carbon - casts - aggregation - dynamics - pasture - sequestration - oligochaeta - grassland
Stable microaggregates can physically protect occluded soil organic matter (SOM) against decomposition. We studied the effects of agricultural management on the amount and characteristics of microaggregates and on SOM distribution in a marine loam soil in the Netherlands. Three long-term farming systems were compared: a permanent pasture, a conventional-arable system and an organic-arable system. Whole soil samples were separated into microaggregates (53–250 µm), 20–53 µm and <20 µm organo-mineral fractions, sand and particulate organic matter, after complete disruption of macroaggregates. Equal amounts of microaggregates were isolated, irrespective of management. However, microaggregates from the pasture contained a larger fraction of total soil organic C and were more stable than microaggregates from the two arable fields, suggesting greater SOM stabilization in microaggregates under pasture. Moreover, differences in the relative contribution of coarse silt (> 20 µm) versus fine mineral particles in the microaggregates of the different management systems demonstrate that different types of microaggregates were isolated. These results, in combination with micromorphological study of thin sections, indicate that the great earthworm activity under permanent pasture is an important factor explaining the presence of very stable microaggregates that are relatively enriched in organic C and fine mineral particles. Despite a distinctly greater total SOM content and earthworm activity in the organic- versus the conventional-arable system, differences in microaggregate characteristics between both arable systems were small. The formation of stable and strongly organic C-enriched microaggregates seems much less effective under arable conditions than under pasture. This might be related to differences in earthworm species' composition, SOM characteristics and/or mechanical disturbance between pasture and arable land.