Burrow Linings Research Articles

Earthworms and the dissipation and distribution of atrazine in the soil profile

The influence of earthworms ( Lumbricus terrestris L.) on the persistence and transport of 14C-labelled atrazine [2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine] in soil was studied in laboratory incubations using flask microcosms and packed columns. In soil microcosm incubations (12 or 30°C), [U-ring- 14C]atrazine was dissipated and mineralized more rapidly in soil that had been conditioned (preincubated) with earthworms (e.g. soil containing worm castings) than in soil without earthworms. Earthworms added to soil following herbicide application accelerated the formation of non-extractable (soil-bound) atrazine residues and reduced atrazine mineralization rates over 68 d, compared to soil that did not contain earthworms. In packed soil columns (24 cm×6.3 cm i.d.), earthworms promoted the formation of non-extractable residues and modified the vertical distribution of herbicide residues. Following a 68-d incubation of soil columns (12°C) receiving a surface application of [U-ring- 14C]atrazine-sprayed corn leaves, total non-extractable radioactivity in soil columns containing earthworms was 21% greater than that in soils without earthworms. Earthworm consumption of the [U-ring- 14C]atrazine-sprayed corn leaves and subsequent activity translocated 60% of the total radioactivity below 4 cm. In contrast, more than 65% of the initially applied [U-ring- 14C]atrazine remained in the top 4 cm surface layer in columns containing no earthworms. Earthworms also influenced the distribution of herbicide residues in the soil matrix, depositing about twice as much MeOH-extractable radioactivity in their burrow linings as in the surrounding soil.

Effects of organic enrichment and burrowing activity of the polychaete Neries diversicolor on the fate of tetrachlorobiphenyl in marine sediments

AbstractThe effects of organic enrichment and burrowing activity of the infaunal polychaete Nereis (Hediste) diversicolor on the distribution of 14C‐3,3′,4,4′‐tetrachlorobiphenyl (TCB) were studied in an experimental benthic system. Organic enrichment of the sediment was provided by a mixture of the diatom Skeletonema costatum and the sea lettuce Ulva lactuca. Organic matter and TCB were both initially added to a surface sediment layer of the microcosms. A factorial design with organic enrichment (control vs enriched) and bioturbation (presence or absence of N. diversicolor) as fixed factors and concentration of TCB in sediment, water, and biota as dependent variables allowed us to test the four combinations. Release of TCB from the sediment to the water column was measured in the outflowing water of the aquaria. After 28 d of exposure, TCB concentrations were measured in animals, feces, sediment cores, burrows, sediment surface, and in sulfur bacteria mats. Both bioturbation and organic enrichment enhanced the release of TCB from the sediment to the water column. The greatest effect was caused by the combination of the two factors, which increased release rates by 280% compared with controls. No general downward transport and vertical redistribution of TCB in the sediment were observed. However, TCB concentrations were significantly higher in the burrow linings of the worms than in the bulk sediment. Increased TCB accumulation by the animals was observed following organic enrichment, which was considered to be the result of selective feeding on TOC‐rich contaminated food particles. The organic enrichment also stimulated the production of sulfur bacteria mats, which were found to accumulate high TCB concentrations. Our results contradict those of several other studies that have reported a reduced bioavailability of organic contaminants with increasing sedimentary organic carbon content. Our study suggests that the quality of the organic matter should be considered in the evaluation of exposure in benthic organisms.

Influence of bioturbating animals on flux of cadmium into estuarine sediment

The role of bioturbation in downward transport of cadmium from the water phase into a sandy marine sediment was investigated in a series of laboratory experiments, where dissolved 109Cd was added to overlying water in sediment cores with and without bioturbating animals. The polychaetes Nereis diversicolor and Arenicola marina and the crustacean Corophium volutator initially stimulated the downward transport of water-phase cadmium into uncontaminated sediments by a factor of 1.5–2 compared to control sediments without benthic macrofauna. N. diversicolor and A. marina transferred cadmium to > 4 and 13 cm depth in the sediment, respectively, whereas in the presence of C. volutator no cadmium was detectable below 1.5–2 cm. Cadmium transported to the deeper layers in N. diversicolor bioturbated sediments was primarily adsorbed to the 0–3-mm radial zone around burrows. It is suggested that the higher downward transport of cadmium from the water-column into sediments with infaunal burrows is driven by adsorption to metal oxides (iron and manganese) and to the mucus cement in burrow linings combined with the increased area of oxidized sediment-water interfaces. In the case of A. marina, percolation of irrigated water through the reduced head-shaft sediment may cause cadmium adsorption to sulfides as well.

DYNAMICS OF CARBON AND NITROGEN MINERALIZATION, MICROBIAL BIOMASS, AND NEMATODE ABUNDANCE WITHIN AND OUTSIDE THE BURROW WALLS OF ANECIC EARTHWORMS (LUMBRICUS TERRESTRIS)

We conducted a laboratory study using soil cores to determine whether anecic earthworm (Lumbricus terrestris) burrow linings (the drilosphere) are sites for enhanced carbon and nitrogen mineralization and increased microbial biomass and nematode abundance. We compared microbial biomass C, C mineralization rates, metabolic quotient, levels of inorganic N (NO − [over] 3 and NH + [over] 4), and nematode abundance over the course of 11 weeks in soil from earthworm burrows, bulk soil away from burrows, and a control soil in cores to which no earthworms were added. Significant differences were observed in microbial biomass carbon, which was 38 to 84% lower, and carbon mineralization and metabolic quotient, which were 2.3 to 7.5 and 5.6 to 17.4 times, respectively, higher in burrow than in control soil. No significant differences were observed in these variables between bulk and control soil. In addition, nematodes were 3.7 to 6.5 times more abundant, and inorganic N levels 21 to 78% higher in burrow than in control soil, with no significant differences observed between bulk and control soil. Dynamics of microbial biomass carbon and inorganic N followed the same general pattern in burrow, bulk, and control soil. By contrast, dynamics of nematode abundance, carbon mineralization, and metabolic quotient differed between burrow and both bulk and control soil, with peak values observed at 5, 7, and 11 weeks for nematode abundance, C mineralization, and metabolic quotient, respectively. Our results suggest that earthworms may have an indirect effect on soil C and N dynamics by stimulating the activities of nematodes and their interaction with microbial biomass in the drilosphere to a greater degree than is observed in soil that has not come in direct contact with earthworms.

Burrow architecture and turbative activity of the thalassinid shrimp Callianassa subterranea from the central North Sea

The architecture and development of the burrows of the endobenthic shrimp Callianassa subterranea from the central North Sea were studied in sediment-filled containers and thin cuvettes in the laboratory. Three-dimensional burrows of 81 shrimps were used to describe the 3-dimensional burrow architecture. In total, 41 shrimps made 2-dimensional burrows in cuvettes tailored to their body widths. Development of 8 burrows over time was registered by regularly mapping burrow outlines and sediment surface levels. Excavation Velocities and sediment expulsion rates were derived from changes in the burrow outlines and sediment surface levels on the maps. The total tunnel length increased at a rate of 23.4 +/- 6.0 mm h(-1) during the initial stage of burrow development. The length increase levelled off during the completion of the first and second U-tubes to 5.6 +/- 1.8 mm h(-1). Initial sediment expulsion rates up to 15.0 cm(3) d(-1) were established. The average sediment expulsion rate was 1.080 +/- 0.096 cm(3) d(-1). Extrapolation to a yearly dry weight (dry wt) sediment turnover, including population density and water temperature effects, resulted in an estimate of 15.5 +/- 2.7 kg dry wt m(-2) yr(-1), equivalent to a 1.2 cm layer. Samples of burrow lining, expelled sediment and unprocessed sediment did not show changes in grain size distributions or organic content due to manipulation or processing by C. subterranea. Burrow development experiments carried out in enriched seawater systems did not reveal consistent effects of particulate organic matter (POM) on sediment expulsion rates or on the composition of processed or unprocessed sediment.

Sediment bioturbation by the echiuran worm Maxmuelleria lankesteri (Herdman) and its consequences for radionuclide dispersal in Irish Sea sediments

Bioturbation by the deep-burrowing echiuran Maxmuelleria lankesteri was studied in Loch Sween, Scotland. Results were used to evaluate the animal's likely effects on the movement of radionuclides in sediments of the NE Irish Sea, where the species is also common. Individual burrow openings were monitored by video for up to 23 days. There was no consistent relationship between the frequencies of sediment intake and ejection, an anomaly which suggests that the burrow of M. lankesteri has two surface openings rather than one, as believed previously. Sediment output was measured by changes in ejecta mound volume and by direct collection of vented material. Both methods gave a value of approximately 13 g dry matter · day −1, of which about 0.8 g (6%) was faecal matter. The remainder consisted of non-faecal fluidized sediment, for which concentrations of 234Th suggested a surface origin. There were no significant differences in particle size composition between burrow ejecta and ambient surface sediment. Sediment ingestion rate was not directly measurable, but was estimated at about 1.7 g · day −1 using a model derived from studies of other marine deposit feeders. Bioturbation by M. lankesteri seems to result in a short-term redistribution of material (about 13 g · day −1) on the sediment surface, with about 0.9 g · day −1 incorporated into the burrow lining as faecal pellets. In the NE Irish Sea, burrows will act as sinks for surface-derived radionuclides and there is probably little return of deeply-buried material to the sediment surface.

Cornulatichnus: a new trace fossil from the Old Red Sandstone of Orkney

Synopsis A large, sub-vertical, conical burrow, Cornulatichnus edayensis ichnogen. nov., ichnosp. nov. occurring in the Eday Marls and Upper Eday Sandstone of Orkney is described. C. edayensis occurs in both the massive sandy siltstone and in the laminated sandstone of the Eday Marls, suggesting excavation in a floodplain environment. A sub-aqueous origin is indicated by the presence of a well developed burrow lining and by the absence of cavities within the fill and of scratch-marks on the burrow walls. It is suggested to have been excavated as an open shelter burrow, possibly by an eel-like fish.

Sorption and Retention of Herbicides in Vertically Oriented Earthworm and Artificial Burrows

AbstractIn many temperate region no‐tillage agro‐ecosystems, the vertically oriented burrows of the nightcrawler earthworm (Lumbricus terrestris L.) function as preferential flow paths and may promote the rapid downward transport of surface‐applied chemicals. The burrows of nightcrawlers, however, are lined with a material that is enriched in organic C relative to the surrounding soil matrix that may affect transport of organic chemicals. Vie investigated the effect of this lining on the sorption and retention of four herbicides: atrazine [6‐chloro‐N‐ethyl‐N′‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine], metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N(2‐methoxy‐1‐methylethyl)acetamide], dicamba (3,6‐dichloro‐2‐methoxybenzoic acid), and primisulfuron [3‐[4,6‐bis(difluoromethoxy)‐pyrimidin‐2yl]‐1‐(2‐methoxy carbonylphenyl sulfonyl) urea]. Batch sorption isotherms were determined using burrow lining and bulk soil collected from seven depth intervals from 0 to 50 cm. Sorption of the more strongly sorbed herbicides (atrazine and metolachlor) was enhanced by a factor of up to three on burrow lining relative to bulk soil, while there was little or no enhancement of the weakly sorbed herbicides (dicamba and primisulfuron). Transport and retention of these herbicides was measured in intact burrows in undisturbed soil blocks. Concentrations of the two strongly sorbed herbicides decreased during flow through nightcrawler and artificial (unlined) burrows, with the largest decreases occurring in earthworm burrows. Concentrations of the two weakly sorbed herbicides decreased very little during flow through either type of burrow. Retained herbicide concentrations were higher in nightcrawler than in artificial burrow walls, and decreases in concentration from the surface to the second 1‐mm wall layer were greater in nightcrawler than in artificial burrow walls. These results indicate the material lining nightcrawler burrows may significantly retard herbicide transport during lateral flow into and out of burrows.

Characteristics of Earthworm Burrow Lining Affecting Atrazine Sorption

AbstractVertically oriented earthworm burrows exist in many agricultural sites, especially in no‐tillage soils where the burrows are left intact from year to year. Earthworm burrows can function as preferential flow conduits and may enhance downward transport of surface‐applied pesticides. Earthworm activity induces changes in the soil characteristics of the burrow walls that may affect pesticide sorption and transport. Little information is available describing the properties of the lining material. Earthworm (Lumbricus terrestris L.) burrow lining and bulk soil at seven depth intervals from 0 to 50 cm were characterized with respect to pH, clay content, total organic C (TOC), water‐soluble organic C (WSOC), and alkaline phosphatase (AP) activity. Atrazine [6‐chloro‐N‐ethyl‐N′‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine] sorption‐desorption isotherms were conducted on the same materials. Burrow linings were found to have a narrower range of pH and clay content than the bulk soil within the 0‐ to 50‐cm depth. Levels of TOC and WSOC in burrow linings were two to three times higher than in the bulk soil at the profile surface. This difference increased to eight times at the 35‐cm depth although concentrations were lower than at the profile surface. Activity of AP in burrow lining from 0 to 20 cm was three times greater than in the surface bulk soil, and at depths of 20 to 40 cm AP activity in burrow lining was similar to that of the surface bulk soil. Freundlich Kf values for atrazine sorption and desorption were higher for burrow lining than bulk soil at almost every depth. The largest differences (1.5‐ to 3‐fold) occurred in the 15‐ to 30‐cm depth range. Multivariate regression analysis of atrazine sorption‐desorption indicated that of the parameters measured, TOC could account for most of the variability in atrazine sorption‐desorption.

Dehalogenation in marine sediments containing natural sources of halophenols.

Halophenols such as 2,4-dibromophenol (DBP) occur naturally in some marine sediments, as a consequence of various animal and algal activities. In an earlier study, DBP was observed in the burrow microenvironment of the hemichordate Saccoglossus kowalewskii. At the concentrations found in the burrow lining, aerobic respiration appeared to be inhibited significantly relative to anaerobic catabolism. This effect, as well as factors contributing to the degradation of DBP, has been documented further here. Results from the addition of radiolabeled DBP to oxic and anoxic sediment slurries and growth experiments with aerobic and anaerobic enrichments suggested that aerobes did not significantly metabolize DBP and that concentrations likely to be encountered on the inner surfaces of the burrow wall were inhibitory. In contrast, only minimal inhibition of growth occurred for anaerobes exposed to 1 mM DBP; in addition, DBP was substantially degraded in both enrichments and sediments under anaerobic conditions. Dehalogenation with the consequent production of phenol appeared to initiate anaerobic degradation. Sulfate-reducing bacteria did not dehalogenate DBP but appeared to degrade phenol. Decreased bacterial numbers and marked differences in the concentration and chemical speciation of iron in sediments from S. kowalewskii burrows may be attributed to toxic effects of DBP on aerobic bacteria.

Burrowed Phacops rana from the Moscow Formation of New York

The trilobite Phacops rana has previously been documented in two life positions: horizontally outstretched and enrolled (Hall and Clarke, 1888). A specimen of Phacops rana was recovered in an unusual life position from the Windom Member of the Moscow Formation (Figure 1). It was collected from a borrow pit along Castle Hill Road, 1 km east of Earlville in Chenango County, New York. The trilobite appears to have burrowed tail first into the substrate, with only part of the cephalon and one or two thoracic segments exposed above the sediment surface. The orientation of the eyes indicate that the visual field was horizontal. The thorax angled into the substrate at an angle of approximately 50° from the horizontal, with the pygidium tilted dorsally relative to the thorax. Compaction effects appear to be slight. Because the specimen was found in situ, no doubt exists as to its orientation with respect to bedding. It is also evident from bedding plane surfaces that this trilobite had burrowed, and was not simply draped over an uneven substrate, as it intersects three bedding planes. There is no evidence of any object over which it could have been draped. No burrow trace, lining, or scratch marks are preserved. No other specimens of Phacops in this position have been reported.

Palaeoenvironmental and stratigraphic significance of worm burrow linings from the Lower Oil-Shale Group (Dinantian) of West Lothian

In an earlier paper, one of us drew attention to tube-like microproblematica as unusual, but potentially valuable, environmental and stratigraphic indicators in British Jurassic lagoonal deposits ([Andrews 1986][1]). In this note we develop the theme of the earlier paper by describing tube-like microproblematica in Upper Palaeozoic rocks, the Lower Oil-Shale Group of Dinantian age, in West Lothian, Central Scotland. It is suggested that shallow-lagoonal environments have been important habitats for small infaunal worms during much of Phanerozoic time. The Oil-Shale Group rocks mainly represent deposition of fluvio-deltaic and non-marine lagoonal sediments and the lithologies are dominated by sandstones, shales and dolostones. Although occasional, thin, marine horizons occur (e.g. the Pumpherston Shell-Bed), fossil assemblages are dominated by fish remains, bivalves, gastropods, conchostracans, spirorbid worms, ostracodes, cyanobacteria, calcareous green- and phytoplanktonic-algae, representing a non-marine fauna and flora. Tube-like microproblematica have been known from the Lower Oil Shale Group of West Lothian for almost a century ([Cadell 1906][2]; [Carruthers 1912][3]; [Greensmith 1960][4]; [Loftus 1985][5]). They occur in the Queensferry Beds of [Mitchell and Mykura (1962)][6] including dolostones (the ‘Bogwood Limestones’ of [Loftus 1985][5]) some ten metres below the Burdiehouse Limestone, the base of which divides the Upper and Lower Oil Shale Groups ([Francis 1983][7]). The tubes are seen at two localities, beds 1 and 68 of [Maddox and Andrews (1987][8], Fig. 4) on the southern foreshore of the Firth of Forth at South Queensferry [NT 140 785], and beds 1 and 52 on the southern foreshore of the Firth of Forth near Hopetoun . . . [1]: #ref-1 [2]: #ref-2 [3]: #ref-3 [4]: #ref-6 [5]: #ref-8 [6]: #ref-10 [7]: #ref-5 [8]: #ref-9

Distribution of trace elements in Callichirus laurae burrows and nearby sediments in the gulf of Aqaba, Jordan (Red Sea)

In nearshore waters of the Jordanian sector of the Gulf of Aqaba, the distributions of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn, as well as Ca and Mg, were determined in the mucus-rich burrow lining made by the locally abundant Crustacea Callichirus laurae (Thalassinidea: Callianassideae), and compared with concentrations obtained in surface sediments surrounding the burrows. The highest concentrations of trace elements were observed in a sewage affected area. At uncontaminated stations, a marked increase from surface sand values was observed in the burrow lining. The correlations between the concentration of trace elements in this biogenic micro-environment and both the concentration of organic carbon and the mean granulometric diameter were highly significant. This study shows that the C. laurae burrow acts as a chemical reservoir that may reach several meters deep into the sediment. This special reservoir is created as an indirect consequence of the building of a mucus-rich, metal-reacting lining. It is demonstrated that the absolute quantity of trace elements incorporated in the lining is much higher (c. 85 to 250 times more, depending on the element) than in the dense and healthy Halophila stipulacea seagrass bed covering the surface. The environmental significance of large lined burrows for the distribution of trace elements is discussed.

Burrow distribution of thalassinidean shrimp on a Fraser Delta tidal flat, British Columbia

Burrows of the thalassinidean shrimp Callianassa californiensis and Upogebia pugettensis, which resemble the trace fossils Thalassinoides and Ophiomorpha, respectively, occur on the southern tidal flats at the western front of the Fraser Delta. Burrow densities for both shrimp species are highest at lower intertidal levels immediately inshore of an extensive bed of Zostera marina eelgrass, but the high-density shrimp populations are segregated: the highest densities of C. californiensis burrows (350–450 burrow openings/m2) occur in a strip of clean sandy sediments, whereas U. pugettensis burrows are most abundant (30–80 burrow openings/m2) in a patch of muddy sands and sandy muds. On the tidal flats of the Fraser Delta as a whole, however, textural properties of the sediment show no consistent correlation with the burrow density of either shrimp.In the eelgrass bed, eelgrass root mats appear to markedly restrict the density of C. californiensis burrows. Towards the shore, the well-lined dwelling burrows of U. pugettensis occur no higher than mean sea level where maximum continuous exposure is ≤0.5 days. In contrast, C. californiensis, which has an unlined feeding burrow and a higher tolerance for anoxia, is present up to the margin of the local salt marsh which lies near the mean higher high water level where the flats can be exposed continuously up to 5 days.In situ experiments indicate that C. californiensis extrudes 18 ± 9 ml of wet sediment/shrimp/ day onto the substrate surface, while U. pugettensis seldom forms a mound around its burrow entrance. Burial of filter-feeding postlarval U. pugettensis under the mounds produced by C. californiensis may increase postlarval mortality and reduce adult populations of U. pugettensis in areas of high C. californiensis burrow density.The results of this study suggest that in distinguishing Ophiomorpha from Thalassinoides more emphasis should be placed on the presence of an extensive burrow lining in Ophiomorpha than on the presence of a knobby burrow exterior, because the former characteristic has a more profound bearing on burrow function, physiology of the occupant organism, and, consequently, burrow distribution.

Ophiomorpha isabeli; nov. icnoesp. (plioceno marino) en el sector suroccidental del valle del Guadalquivir (Palos de la Frontera, Huelva, España)

The marine Lower Pliocene at the Southwestern Sector of the Guadalquivir Valley is characterized by sorne rich ichnocoenoses clayey facies in the bottom series. A new ichnospecies is defined in this assemblages: Ophiomorpha Isabeli . An exterior pseudopelletal structure on the burrow lining produced by compactation or differential dissolution are the main distinguishing characteristics. Secondary peculiar features are the geometrical burrows systems: one is vertical or inclined, very long shafts, with Y-branches at the top, and another, is a cuasirectangular boxwork with horizontal tunnels and vertical shafts, both bifurcated at nearly right angles. A protective offshore environments is established where alternate, low dominant with not too heavy energetic conditions. This changes in the sedimentation rate is reflected in the morphology of the burrow systems. The tracemaker of Ophiomorpha isabeli is discused and a callianassid origin is assumed.

Bacterialike (Filamentous) Structures Associated with Pyritized Burrow Linings, Arnheim Formation (Upper Ordovician), Southeastern Indiana: ABSTRACT

Much naturally occurring pyritization is biologically mediated, with specific types of bacteria (sulfate reducers) promoting the reactions. Among the criteria required for pyritization in a marine environment are the presence of: (1) interstitial iron ions, (2) a primarily anaerobic (reducing) environment; (3) an organic-rich substrate, and (4) sulfate-reducing bacteria (releasing sulfide). However, the direct connection between pyritization and bacteria (microfloral remains) is difficult to visualize in the fossil record. This study focuses specifically on pyritized burrow linings that occur in strongly bioturbated wackestones from the Arnheim Formation (Cincinnatian Series, Upper Ordovician). Specific reducing microenvironments (i.e. mucoidal burrow linings) were the sites of early diagenetic pyritization in otherwise oxygenated, organic-rich sediments. Material examined under both the light and electron microscopes revealed occasional evidence of pyrite associated with filamentous structures. These structures possess a shape and size consistent with certain types of bacteria. This relationship, bacterialike structures with pyrite, may be more common in the fossil record than previously suspected.

The incorporation of plutonium, americium and curium into the Irish Sea seabed by biological activity

Previous studies have shown that radionuclides of the transuranium elements plutonium, americium and curium have penetrated the sediment column in the N.E. Irish Sea to depths of at least half a metre. The distribution of 239,240Pu, 238Pu, 241Am, 244Cm and 242Cm concentrations and the 239,240Pu/ 238Pu quotient in samples taken in April and May 1983 from the sediment surface, burrow linings, sediment adjacent to burrows, and the gut contents and body of a large echiuran Maxmülleria lankesteri clearly indicate that bioturbation is responsible, at least in part, for the incorporation of these radionuclides to depths of up to 140 cm.

Plutonium redistribution by biological activity in Irish Sea sediments.

As part of a programme investigating the fate of transuranium nuclides discharged to coastal waters we have studied the effects of benthic animals on plutonium redistribution in Irish Sea sediments. From analyses of burrow linings of the large echiuroid Maxmulleria lankesteri, which penetrates to depths exceeding 40 cm, we now show that this animal may have a significant effect on the removal of plutonium to deeper layers in the sea bed.

The importance of the diffusive permeability of animal burrow linings in determining marine sediment chemistry

The importance of the diffusive permeability of animal burrow linings in determining marine sediment chemistry

The importance of the diffusive permeability of animal burrow linings in determining marine sediment chemistry

The importance of the diffusive permeability of animal burrow linings in determining marine sediment chemistry