1 OF I. ORNL P 3065 . " N' - - EEEFEEEE MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS - 1963 orori p-3065 Conf.670503--10 JUN 1 3 1967 MASTE TROPHIC LEVEL CONCENTRATIONS OF CESI-137, * SODIUM, AND POTASSIUM IN FOREST ARTHROPODS CFSTI RRICSS HC. HC 63.00 ww.des . - - . . David E. Reichle and D. A. Crossley, Jr, - . - - - - -- - Radiation Ecology Section, Health Physics Division Oak Ridge National Laboratory, Oak Ridge, Tennessee - - - -- -- -- . .. - - • . - LEGAL NOTICE This report was propurod u an Account of Government sponsored work. Neither the Vasted States, nor the commosion, nor any person acting on behalf of the Communion: A. Makes any warraaty or representation, expresand or implied, with respect to the rooge, racy, complotaneus, or wustulness of the information contained in this report, or that the une of any information, apparatu, method, or procon discloud la the report may not tabrigo, printely owned righta, or B. Asmunan any liabilidas with rospect to the sof, or for damage rondton from the un of Lny information, apparatus, method, or procent disclound ban the report. As used in the above, "por on acting on behy of the Commission" tooludes may om. ploys or contructor of the Commission, or employme of much contructor, to the extent that such employee or contractor of the Commisoloa, or employme al much coatrnotor preparos, disseminates, or provides sccuu to, kay information pursuant to Wo employment or contract with the Commiusion, or fils employment with much contractor. *Research sponsored by the U. S. Atomic Energy Commission under contract with the Union Carbide Corporation. DISTRIBUTION OF THIS DOCUMENT IS UNLIMITED. UCNE567 ABSTRACT In a forest ecosystem experimentally tacked with 137cs, the trophic dynamic aspects of arthropod food chains are being investigated using radiotraces tech niques. Cesium-137 concentrations in organisms in isotopic equilibrium with food have shown progressive reduction during dispersion through food chairs, although the fractional transfer between food and consumer increased with each . . . .- successive trophic level. The distribution of other alkali retals in arthropod -- - - -- - - - food chains varied from that of cesium. Potassium concentrations in primary consumers (saprovores) were a factor of 3.5 higher than in detritus, although 10 they decreased (similar to +37cs) by a factor or 0.5 from primary consumers to u predators. Sodium concentrations in primary consumers increased by a factor of 12 117 above leaf litter, and by an additional factor of 1.5 in predators. There 13 were no significant differences in 'Cs to K ratios between arthropod tropnic levels. Changing elemental composition of litter during decay, nutrient availa- 15 þility and assimilation efficiency by arthropods, and biological half-lives of 16 each element were parameters affecting absolute concentrations and +'cs to K -- ratios in each trophic level. INTRODUCTION Nutrient levels at various positions in the trophic structure of ecosystems may reflect eventual availability to higher order consumers and, potentially, w can affect dietary limitations on the productivity of consumer populations. Radioactive tracers have proven valuable in defining nutrient transfers betweet ecosystem components. The movement and ultimate distribution of radionuclides! in ecosystems can provide information on food chain pathways, nutrient budgets, and nutrient turnover by biota at various trophic levels in the system. Radio Isotopes or chemical analogs, e.g., BORD and 370s in the case of akart metals, 86 UCN.8867 i brten have been utilized to elucidate the concral behavior or relevant 2 in ecosysiems. Conversely, relationships have been sought totwce who own 3 of radioisotope contaminants and the stable cher.istry of related cirerte den i 4 Tood chains to enable prediction of the fate of these isotopes in the envi:.:-, 5 brent, although insufficient emphasis has been given to applicatio. (relsor. 1767) O of specific activity ratios in assessing the environmental consequences of radioactive contamination. Many of the environmental studies of 13'cs (e.., swanson 1967; Whicker, Farris and Dahl 1967; Pendleton, Lloya, Mays and. Curc?. 9 196|t; and Nelson, this volume) have shown contrasting food chain rovement and 10 concentration of 137cs, K and particularly 237cs to x ratios in different eco- 11 systems. These data demonstrate the need for additional informatior. on other -. . .. .. - -.--.. 12 systems and suggest constraint in extrapolating particular results to other . .. . . . . . . . . . 1 . 13 ecosystems and food chains of different structure and complexity. 14 This report presents data on the 1370s, K and Na levels in forest floor 15 detritus fooá chains consisting or a leal litter base, arthropod consumers 16 (saprovores), and primary arthropod predators. The dominant trees (Liriodendroz. 17 tulipifera) in this forest were tagged with slcs in May 1962 (Auerbach, Olson 18 and Waller 1964) establishing a chronic radiocesium input to associated rood 19 chains. Although levels of t1cs in foliage have decreased progressively ir. 20 subsequent years, with soil acting as a major reservoir, the relatively rapii 21 turnover of cesium by arthropods (Tm – several days) — in contrast to the minor 22 Long-term fluctuations in detritus (foliage) input — has resulted in an e:- 23 fective state of dynamic equilibrium between arthropods and their food bases. : 24 Eleven saprovore species and nine predator species were examined during all 25 seasons from field collections spanning several years. Comparisons of speciais 26 activity measurements (13708:total Cs) in arthropods with similar measuremen UCN-8567 . '........ :i on detritus in various stages or decuy (L, 7., F., and i mori 20746; IV 1970- 2 vided additional information on the food preferences of these ora s . 3 Concentrations (per unit dry wt) of Sics in this cryptozouri Canicy were reported to decrease through food chain transfer ( Reichle u..d Crossic; 5 1965). During the period of study, leaf litter averaged 24.? Ci/ns, while 6 mean concentrations of +3'cs in saprovores and predators were 4.9 PC:/zeena 7 2.5 pci/ng, respectively. Preliminary data indicated that food chain beravior 8 br ICs was not dissimilar from K, although information on the distribution of 9 Na vas inconclusive. These results suggested that +31cs to K ratios would not 10 display the trophic level. increases which were reported for some other terres- 11 trial and aquatic food chains (Pendleton, Lloyd, Mays and Church 1964; Pendle- 12 ton, Mays, Lloyd and Church 1965). Som Additional data have been obtained on the stable- and radiochemistry of 14 these arthropods. The steady-state whole-body concentrations of +30s, K, and 15 Na were examined with respect to their dependence upon several interacting 16 factors: (1) in the case of +370s, the stable chemistry of the organisms and 17 the specific activity of their food bases, (11) the rates of input (consumption) 18 and digestive assimilation foz each element, and (111) the turnover (excretion 19 rates of each element by organisms. Biological half-lives and assimilation 20 efficiencies for 134cs, 42, and 24Na were determined for the cricket Achete 21 domesticus for comparison of the uptake and turnover of these elements by ar- 22 thropods. Ratios of 237Cs to K decreased through trophic levels, although this re- 24 auction was not statistically significant between saprovores and predators. 25 Experimental data on the availability of each element to higher order consumers 26 have resulted in accurate predictions of trophic level changes in tire +10s to'x ratio. UCN•1807 METHODS Arthropods were collected weekly in pitfall traps from September 1964 13 -- - - through April 1965. Similar collections were made of leaf litter, which were separated into various stages of decomposition. These samples formed the cases Lor+cs analyses. Specimens from 1962 and 1963 were use for stable chemical analyses. Arthropods were analyzed for 13C8, Cs, K, and Na. Comparisoris of these data assume no change in K and Na levels in components of this ecosystem during this period; constancy of these stable chemical concentrations has been analytically verified. Whole-body homogenates of arthropods were processed to obtain dry weights, us ash weights (24 hrs at 450°c), and then dissolved in 0.1 N HCl for chemical analyses. Flame spectrophotometric techniques were used exclusively for Na and K. Radiocesium was assayed on a spetrometer system using a 3-in. Ti- -- .-. . - 10 activated NaI well crystal. Stable cesium analyses were performed by the Analytical Chemist:y Division of Oak Ridge National Laboratory. Oral dosing solutions for biological half-life determinations consisted of the chloride salts of 134C8, 43, or 24Na dissolved in Hc1 diluted to 10 uC1/mi 18 Hn distilled water and neutralized with Cacog. Young adult crickets, Acheta 19 domesticus, were obtained from laboratory stocks and kept at 27°c during reten 20 lion experiments. All animals were maintained on Purina protein-supplemented 21 cricket mash. 22 Ratios of exchangeable +37C8 to K from detritus were obtained by treating 23 kg dry wt aliquots with 50 ml of 1 N Mg (MgC1.) solution for a contact time of 24 hrs. Under these conditions, Mg desorbs less than 6% of the 137C8 from 11- 25 pitic soils (Tamura 1967). In the study area, 1111tic surface soils underlie 26 and are intimately mixed with decomposing organic matter. The ratio of exchangeable UCN.S101 M Cs to K was assumed to be similar to that available from organic matter to 2 saprovore consumers. RESULTS +37C8 Levels in the Forest Floor Community Cesium-137 concentrations in trophic levels of the forest floor decomposer 6 community were strongly affected by the annual input of fresh litter. Leaf litter on the forest floor showel maximum-sics levels (pci/mg) in mid-September, 8 shortly after leaf fall. Thereafter, 13/Cs concentrations declined through 9 þctober as a result of leaching, and then rose slightly due to selective re- 10 tention of 137cs by microflora (Patten and Witkarp 1967), decomposition of 1. prganic materials, and mixing of high-leve). 131cs soil with organic horizons 12 as a result of the activities of the soil fauna and rain splattering. Corres- 13 ponding peaks of +31Cs also appeared in the arthropod populations: in November, 14 60 days leter, for saprovores and in December, 90 days later, for predators. 15 The form of these curves was that of a dampened harmonic which stabilized by 16 parly spring and decreased slowly, but progressively, until leaf drop the fol- 17 Lowing autumn. The temporal shift in peaks of 137C8 concentration can result 18 kn apparent discrepancies in the overall pattern of +Cs concentration through 19 trophic levels. This phenomenon results from the lag in +37C8 transfer between 20 trophic levels, and illustrates the necessity of interpreting -TCs concentrations 22 Although trophic transfer of a given amount of 137c8 could be very rapid, es- 23 pecially 18 predation immediately followed a aaprovore's consumption of tagged 24 bitter, more time 18 required for an entire trophic level to equilibrate with 25 lts food base. This equilibration period is typically a function of the turnover 26 rate (1.6., the biological half-time) of the isotope in each trophic level. UCN-4107 Nutrient Levels in the Detritus Food Base Nutrient levels in detritus are time-dependent, and vary according to the 3 state of organic decomposition. Typically, nutrient concentrations are highest in newly fallen litter, but thereafter decrease with time. The overall nutrient 5 content of detritus resulted from the differential decomposition and turnover 6 92 material in the various organic horizons (Table I). The upper L layer rep- 7 resents essentially intact, but slightly decomposed, leaves. The F, and F, layers are successive stages of fragmentation and decomposition. The H horizon 9 18 humus of unrecognizable organic origin. During decomposition, Na and K content of detritus remained relatively stable although both elements showed an increase (mg/g dry wt) in humus (Table I). 12 Both +57Cs and stable cesium concentrations progressively increased through the 13 litter profile. Sodium and potassium are readily leachable through both the 14 organic and upper soil horizons. Cesium, however, is more tightly bound to 15 mineral soils and is concentrated in the upper soil layers (Waller and Olson 16 1967). The successive increases in 1-3%C8 concentrations (PC1/mg) and total cs 17 concentrations (ug/8) in lower litter layers can be attributed to 8011 contami 18 nation, as 18 evidenced by greater ash composition. Approximately 19% of L 19 Layer 13%Cs 18 e:changeable (24 hic contact with 1 N Mg) opposed to 83% for K. 20 this 4.4:1 (K:137c8) exchangeability ratio increased with each successive lit- ter horizon. Althougla exchangeable amounts of K remained relatively constant, 22 exchangeable Cs values decreased (13%, F,; 7%, Fg; and 4%, H) as a result of the increasing soll +31C8 contribution to detritus - mineral-bound +3Cs which is 24 bot organic associated and 18 essentially unavailable to saprovores. Specific activities (pc1 237C8/ug total Cs) were relatively uniform in the lower litter layers; greater variation was evident in the L and F, horizons UCM.RIA . i composed of more recently deposited organic materials. Fluctuation in Cs spe- cific activities would be expected to occur as the introduceà -51cs tag equili- brated with the stable Cs in the soil-plant phase of the ecosystem. Nutrient levels in Arthropod Trophic Levels The results of whole-body chemical analyses of forest floor arthropods from the study area are given in Table II. Cesium-137 data are expressed as :Ci/mg dry wt, while Na and K values are given as ug/mg dry body wt. Arthro- pods were classed into two trophic groups: saprovores (detritus-feeders) and predators. Saprovore species included millipedes (Aphe Loria, Cambala, Dixides mus, Ptyoiulus, and Scytonotus); crickets (Ceuthophilus ind Nemobius); beetle (Geotrupes); wood roach (Parcoblatta); isopod (Ligidium); and the phalangid Leiobunum. For some of these species it was difficult to establish whether their food base consisted of leaf litter or microflora thereon. Nevertheless, cher : cal assays of detritus included both microbial and litter contributions. Predator species consisted of spiders (Araneida, essentially Lycosidae and ctenizidae); beetles (Dicaelus, Evarthrus, Hololepta, Sphaeroderus, and Staphy- linus); and the centipede Otocryptops. In both trophic levels Na and K concentrations (Table II) were in the range of from one to several parts per thousand (ug/mg dry wt). Mean K content of saprovores was 4.42 ug/mg, but only 2.35 ug/mg in predators. Mean Na con- centrations increased from 3.57 kg/mg in saprovores to 5.38 ug/mg in predators. Similar to the initial litter trophic level, total cs concentrations in arthro- pods were three orders of magnitude (parts per million or us/& dry wt) lower than Na and K. Cesium-137 concentrations in the species examined averaged 5.95 PC1/mg in saprovores and 3.00 pC1/mg in predators. Specific activities - - UCN.6667 ........ ..... . . ... .. . . ... . . .. . .... .. . . . . : . .. :: -- -.- . . .. .. during 1965 averaged 3.25 x 104 pci -3'cs/ug Cs in millipedes inü 3.06 % 10" pci Sics/ug Cs in beetles (Evarthrus). Similarity of these specific activity values between trophic levels further supports the basic assumptions of our tropkic model; 1.e., thać upper litter layers form the food base of saprovores, ard that 137cs equilibrates rapidly within the animal compartments of these food chairs. Von S Assimilation and Biological Half-Lives of 134cs, '2K, and 24Na Studies of uptake and turnover of 134cs, 42K and 24Na by the cricket Acheta domesticus, served as a basis for comparison of the relative behavior or the se elements in arthropod trophic levels. More extensive data on +34Cs biological half-lives in a number of forest floor arthropods were reported by Reichle and Crossley (1965). Biological half-lives of 134cs (76.6 hrs + 9.9) and "<(69. hrs + 6.4) were not statistically different (Table III). The biological half- life of <*Na (46.6 hrs + 6.0), however, was appreciably shorter. Since a 1 to 1 ratin between 134cs and 42x turnover was evident, no correction for differential turnover of these two elements was made in subsequent analyses of trophic level exchanges. Assimilation values for each isotope were calculated from whole-body iso- tope retention patterns (log % initial radioactivity remaining through time) by using the standard mathematical "peel-off" procedure to separate the two- culating the percentage unassimilated isotope in gut and that proportion as- similated by body tissue (Table III), Only slight discrimination occurred bet tween 24Na (89.9% = 7.7) and 4% (96.6% + 1.1) assimilation; both values, howt ever, were significantly higher than that for 134cs assimilation (73.0% + 1.11. The resulting assimilative 34cs to 4% ratio of 0.75 was subsequently used to Lpredict the change in the 137 co to Kratio for arthropods at each trophic transfer. UCN-6667 .'.. .- DISCUSSION K, and Na Concentrations in Trophic Levels OV For comparison of nutrient values in the various trophic levels, meant element concentrations of only the L and F, litter horizons for the September to March period were used as the reference base. Cesium-137 concentrations decreased by a factor of 0.67 from litter (17.94 pci/ng) to sparovores (5.95 pci/mg). Presumably, much of the 1316s in detritus was associated with mineral soil and unavailable to consumer organisms. Concentrations of 137cs in the predator trophic level (3.00 pCi/mg) showed a further decrease from saprovores 10 by a factor of 0.50. Potessium concentrations in the sacrovore trophic level u 1(4.42 ug/mg) were a factor of 3.51 higher than in detritus (1.26 kg/mz) but thereafter dropped similar to tlcs by a factor of 0.47 to 2.35 ug/mg in the 12 predator trophic level. Sodium concentrations progressively increased through all trophic levels. Sodium concentrations in the saprovore trophic level 15. (3.57 vs/mg) was nearly 18 times greater than that of the detritus food base (0.20 ug/mg). In arthropoda, Na concentration continued to increase by a factor of 1.51 betweer the saprovore (3.57 mg/mg) and predator (5.38 ug/mg) trophic levels. The movement and concentration of +5'Cs and K were similar in arthropod trophic levels. Apparent differences in the transier of these elements between 21 detritus and saprovores resulted from differential availability from detritus, and are discussed subsequently in consideration of Cs to K ratios in trophic 23 levels. The pattern of Na concentration in trophic levels veried from that of Cs and K. Sodium concentrations increased with each trophic exchange. Abd 25 solute magnitude of trophic concentration of each element was subject to the variable ash composition of trophic levels, since concentrations were expressed per unit dry body wt. Mean sa provore ash content (26%) was considerably higher UCN.8867 10 than other trophic levels because this group was dominated by species (milli- pedes and 1sopods ) with heavily calcified exoskeletons. Similar concentration patterns persisted when element content was expressed per unit ash-free dry wt. It is difficult to explain the trophic level concentration of Na within the context of turnover rates and assimilation efficiencies alone. The high digestive assimilation and rapid biological half-life of <*Na compared to 134cs and *** (Table III) suggest that Na concentrations should decrease through successive trophic exchanges even more rapialy than +5lcs and K. Such is not the case for Acheta (4.38 ug Na/mg vs 10.94 ug K/mg) nor for the overall tro- phic ordination (Table II) when compared with the detritus food base (Table 1). One explanation for the observed Na concentration in food chains might be the 10 nutritive demands of the consumer. If Na is a conservative nutrient in the diet, saprovores could be eating excessively to satisfy Na requirements from a low initial concentration in food. Consequently, actual tics and K uptake from detritus might be lower than that projected from laboratory experiments. 16 Fungal mycelia generally contain more k than any other metal and Na does not 17 appear to be an essential element (Lilly 1965). Therefore, it is unlikely that 18 mycoflora on detritus would appreciably alter the Na to K ratio of the saprovore food base. Once critical Na concentrations have been attained by saprovores, 20 only slight subsequent increase occurs in the predator trophic level (1.5 in- crease relative to dry wt and 1.2 relative to the ash-free dry wt concentration). 22 Roeder (1953) cited studies which showed a high correlation in insects beiween 23 Na to K ratios of diet and hemolymph, although carnivorous insects generally had higher Na to K ratios than dia herbivores. This pattern is similar to 25 that of these detritus-based food chains, with the exception of high Na con- centration between detritus and saprovores. UCN.5867 13 0.05) . .. w . 11 0 1510s to K Ratios Between Trophic Levels From September 1964 to March 1965, +37Cs concentrations in the L a:id I, litter horizons averaged 17.94 poi/mg + 5.52. The 137cs to K ratio (pci 23705 to ng K) in this litter averaged 14.25 + 4. 12 (Table IV). The 137ce to kratko (mean of species ratios, Table II) decreased by a factor of ten to 1.49 + 0.21 in saprovores, and thereafter decreased to 1.22 + 0.36 in predators. There was no significant difference between the -'cs to K ratios of saprovore er.d predator trophic levels. The change in the 137cs to K ratio between litter and saprovore trophic levels was due to the fact that +37Cs and K were not equally available to saprovore consumers. The ratio of organic exchangeable 137 Cs to K was 2.58 + 0.80. The ratio of available +31cs to K from the detrit, 12 tus food base was considerably lower than the total elemental composition in- |dicated. The cricket, Acheta domesticus, displayed a discrimination between uptake (assimilation) of ionic 134cs and 42. If this assimilation factor of 10.75 for 134cs:43 is generally applicable to the arthropod trophic levels, then it would contribute toward a further reduction in the +57Cs to K ratio between litter and saprovores. By adjusting the total 1370s to K ratio of litter for differential exchangeability and assimilation of each element, a predicted 15'Cs to K ratio of 2.08 + 0.65 is obtained for saprovores. This 20 pz dicted ratio is not significantly different from the ratio (1.49 + 0.21) actually determined from independent chemical analyses. Similarly, the+sics to K ratio of saprovores was adjusted to a hypothetical assimilative ratio available to the predator trophic level. There was no significant difference between the prelicted predator ratio (1.20 + 0.17) and the ratio observed (1.22 + 0.36). UCN-8867 13 .08) Comparison with other Trophic Level Studies sey For certain terrestrial ecosystem ; - especially the arctic lichen-caribou - Eskimo food chain (e.8., Hanson 1967; Tianson, Watson and Perkins 1967) - fallout 4510s has been found to increase in concentration in organisms of higher trophic position. However, Hanson (1967) stressed that every ecosystem has unique features which may result in different radionuclide cycling charac- teristics. Cesium-137 and 15Cs to K ratios may increase in several aquatic and terrestrial food chains (Pendleton 1965; Pendleton, Mays, Lloyd and Church | 1965). Pendleton, Lloyd, Mays and Church (1964) reported a trophic level +5.cs increase factor of 3.4 in cougars feeding upon mule deer and a similar, but slightly higher, increase in the +37Cs to K ratio. Recognizing the time- | associated factors affecting the concentrations of fallout radionuclides in trophic levels, whicker, Farris and Dahl (1967) found that 131cs levels in mule deer approximated mean levels in vegetation (0.24 pci +37cs/& fresh muscle per pci +370s/g air-dry vegetation). A +37cs to K concentration factor of 0.9 between diet (rumen samples) and muscle was also reported for mule deer (Dahl, Whicker, Farris and Hakonson 1967). Hanson (1967) also found nearly equal ratios of pci +370s/g K in caribou and Alaskan Eskimos during 1964. In contrast, the concentration of cs in arthropod food chains generally 20 decreases from plant to primary consumer to predator. Crossley aná Howden 21 | (1961) reported mixed species populations of insects to have +Sics concentra- 22 tions about 70% of that in plants. More recent data (Crossley, this volume) has supported these results and shown a further decrease in +SICs concentrations between herbivorous and predaceous arthropods. In the canopy arthropod popu- lations of a Liriodendron tulipifera forest tagged with +sics, Reichle and Crossley (1967) found a general reduction in >'cs concentrations during food UCN.5567 13 815) 13 chain transfer with foliage-feedirg insects having the highest concentratior.s), omnivores intermediate concentrations, and predators the lowest concentration per unit wt. A similar trophic level relationship in concentrations of +sics was also reported for the forest floor arthropods in this sare forest (Reichle and Crossley 1965). Typically, detritus-feeders (saprovores) have shown a greater reduction in 13'Cs concentrations from their food base than have WOS ve foliage-feeders (herbivores). This paper shows that Na levels increased through successive trophic levels of forest floor arthropod food chains. Cesium-137 concentrations in saprovores were lower than in detritus, although K concentrations increased. Both 15Cs and K concentrations showed a reduction between the saprovore and predator trophic levels. The ratio of 1 cs to K decreased in the initial detritus-to-arthropod transfer but, thereafter, did not change significantly between arthropod trophic levels. Until additional radiochemical data become available for other food chains of different structure and complexity, any generalization of the trophic level behavior of +sics would appear presumptuous. Considerable information also is needed on stable element composition in trophic levels before, the applicability of specific relationships, i.e., tics to K ratios, can be fully interpreted. ACKNOWLEDGMENTS We are grateful to Dr. T. Tamura of the Health Physics Division, ORNL, for counsel in interpreting exchangeable 137Cs on soil and its contribution to detritus. Our colleagues, G. J. Dodson and M. H. Shanks, assisted with field collections and chemical analyses. Dr. D. J. Nelson, ORNL, generously criticized the manuscript. UCN-8867 (3 6-08) 14: 2 . . . . - 9 . 1!; ........ ... LITERATURE CITED Auerbach, S.I., J. S. Olson and H. D. Waller. 1964. Landscape investication using caesium-137. Nature 201:761-764. Crossley, D.A., Jr. This volume. Comparative movement of ruthenium-106, cobalt-60, and cesium-137 in arthropod food chains. Crossley, D. A., Jr. and H. F. Howden. 1961. Insect-vegetation relation- ships in an area contaminated by radioactive wastes. Ecology 42:302-55.7. Crossley, D.A., Jr. and M... Shanks. 1966. Efficiency of radioisotope trars- fer in predator-prey systems, p. 71-72. In Progress in terrestrial and i freshwater ecology. ORNL-4007 (Oak Ridge National Lab.). Dahl, A.H., F.W.Whicker, G.C. Farris and T.E.Hakonson. 1967. A study of the food chain pattern of strontium-90, cesium-137, and lodine-131 in a wila deer population. USAEC COO-1156-22. Hanson, W.c. 1967. Radioecological concentration processes characterizing arctic ecosystems, p. 183-191. In Radioecological concentration processes B. Aberg and F.P. Hungate (ed.) Pergamon Press. Hanson, W.C., D. G. Watson and R.W. Perkins. 1967. Concentration and reten- tion of fallout radionuclides in Alaskan arctic ecosystems, p. 233-245. In Radioecological concentration processes, B. Åberg and F.P. Hungate (ea). Pergamon Press. Lilly, v.g. 1965. Chemical constituents of the fungal cell, p. 163-177. In The fungi, G.C.Ainsworth and A.S.Sussman (ed.). Ace.demic Press. Nelson, D.J. 1964. Interpretation of radionuclide uptake from aquatic en- vironments. Nucl. Safety 5:196-199. Nelson, D.J. This volume. Cesium, cesium-137 and potassium concentrations in white crappie and other clinch River fish. 16 26 UCN-8667 _19 Pendleton, R.C. 1965. Accumulation. of cesium-137 through the aquatic food (ed.). HEW PHS 999-WP-25, 424 p. Patten, B.C. and M. Witkamp. 1967. Systems analysis of 134cs kinetics in terrestrial microcosms. Ecology (in press). Pendleton, R.C., R.D. Lloyd, C.W. Mays and B.W.Church. 1964. Trophic levei i effect of the accumulation of caesium-317 in cougars feeding on vale deer! Nature 204:708-709 Pendleton, R.C., C.W.Mays, R.D. Lloyd and B.W. Church. 1965. A trophic level effect on +37c8 concentration. Health Phys. 11:1503-1510. Reichle, D. E. and D. A. Crossley, Jr. 1965. Radiocesium dispersion in a cryptozoan food web. Health Phys. 11:1375-1384. Reichle, D.E. and D.A. Crossley, Jr. 1967. Investigations on heterotrophic productivity in forest insect comunities, (in press). In Proc. working meeting on the principles and methods of secondary productivity of ter- tertrial ecosystems, Warsaw, 1966. Roeder, K.D. 1953. Insect physiology. J. Wiley and Sons, Inc. New York. Tamura, T. 1967. Sorptive and desorptive characteristics of radiocesium by three contrasting soils. (Submitted to Soil Sci. Soc. Proc.). 20 Waller, H.D. and J.S.Olson. 1967. Prompt transfers of cesium-137 to the soils of a tagged Liriodendron forest. Ecology 48: 15-25. Whicker, F.W., G.C. Farris and A.H.Dahl. 1967. Concentration patterns of Yosr, +370s and 134 in a wild deer population and environment, p. 621-635. In Radioecological concentration processes, B. Aberg and F.W. Hungate (eal). Pergamon Prens. UCN.8867 3 TABLE I. i'utrient attributes of Liriodendron tulipifera leaf litter at various stages of decay, ., . based upon isseys of February 1966 collections. Data illustrate the general distribu- . . . tion in organic horizons of radiocesium, total cesium, potassium and scdium, as well . . as ash and organic constituents. Upper litter horizons typically comprise the food . . . . base of saprovolous arthropods considered in this study. .. . Litter Layer Percent Ash & dry, wt/m ics Ci/mg pci3/cs/mg total cs CS Na, ug/g mg/g mg/g 1 14.8 16.7 209.6 0.62 1.58 0.20 . 147.5 0.60 1.40 23.2 19.6 25.7 42.5 2.12 x 104 3.28 x 104 2.71 x 104 2.73 x 104 25.3 82.1 0.21 0.20 0.95 1.29 A . 36.5 31.4 1.56 1.60 0.30 . TABLE I. Whole-body elemental composition of litter arthropods from the floor of a tulip poplar (Liriodendron tulipifera) forest at Oak Ridge, Tennessee. Concentrations of potassium and sodium are expressed as ug/mg dry wt (parts per thousand); 13'cs concentrations are given as picocuries (10-12 curies) per mg dry wt. Trophic level separation groups species into saprovores (detritus-feeders) and their predators. 137cs Таха K ash. pCi/mg dry wt ug/mg dry wt % dry wt # s.E. (N) + S.E. (N) Na ug/mg dry wt **SEN + S.E. (N)___ 137cs:K PCi/ug 137cs :Na PCi/ug SAPROVORES Apheloria montana 0.37 Carbala annulata 61.88 43.03 9.54 47.81 2.11 1.67 + 0.12 (6) 1.98 + 0.06 (3) 5.11 $ 0.42 (3) Ceuthophilus gracili pes 5.75 +0.72 3.36 + 0.07 6.80 + 1.60 (3) 6.31 + 1.32 (2) 0.59 + 0.22 0.72 (3) 1.29 3.57 0.96 5.62 0.17 Dividesmus erasus 2.16 + 0.22 (5) 7.08 + 4.10 (47) 4.91 + 1.53 (22) 11.01 + 4.93 (21) 0.57 + 0.19 (10) 10.39 + 1.46 (84) 5.47 + 1.66 (21) 5.44 $ 1.92 (16) 5.59 Geotrupes spp. 4.01 1.714 0.97 1.55 Ieiobunum flavum 1.96 + 0.10 (2) 3.34 + 0.66 5.34 + 1.09 (3) 3.60 (1) 6.67 + 3.48 6.93 28.83 1.98 0.82 1.52 Ligidium sp. lemobius maculatus 11.70 1.43 (3) 0.82 0.84 Parcoblatta sp. (3) 6.72 (i) 3.80 + 1.78 (3) 2.24 (1) 3.76 + 0.16 (7) 2.45 (1) 6.42 2.50 6.64 (1) 1.90 + 0.08 44.26 1.88 3.73 Ftpoiulus impressus Suytonotus granulatus 25.25 7.08 + 4.10 (47) 5.51 + 0.76 (50) : 1.01 .: 2.25 5.45 - . I : * XXX 1 . . :: - - - TABIE II (Continued) Таха 137cs K .: :... . ash y dry wt 1. VI... pCi/mg dry wt + S.E. (N) Na # ug/mg dry wt + S.E. (N) + S.E. (N) ug/mg dry wt +S.E. (N) - 237cs:K pi/48 PCI/18 137cs:Na pi/ng . .. PREDATORS Araneida 8.13 3.83 1.16 0.90 1.08 0.14 3.22 0.40 Dicaelus spp. Evarthrus spp. Hololepta sp. Otocryptops sexspinosus Sphaeroderus stenostomus Staphylinus badipes 4.02 7.47 + 2.94 (28) 0.79 (1) 0.74 + 0.34 (9) 0.72 (1) 6.76 + 1.73 (33) 0.53 + 0:06 3.99 $ 2.42 (2) 6.45 + 0.79 0.88 0.12 (3) 1.84 + 0.26 (4) 0.82 (1) 2.28 0.46 (5) 2.12 6.91 + 0.25 5.70 + 0.20 (3) 4.20 $ 0.23 (4) 2.61 (1) 11.74 +0.52 (5) 3.71 (1) 2.78 (1) 0.27 S 0.58 7.20 3.00 4.32 0.88 2.96 0.25 1.96 (12) 0.14 (2) 2.03 (1) 1.44 - TABLE III. Biological half-lives of sodium-24, potassium-42, and cesium-134 in the cricket Acheta domesticus. Efficiencies of isotope essini- lation from water are derived from isotope retention patterns. Isotope Assimilation (%) ^ S. E. (N) Biological Half-Life (Hrs.) + S. E. (N) 89.8 + 7.7 46.6 + 6.0 (9) a 196.6 + 1.0 1+ 69.2 + 6.4 (11) 73.0 + 1.2 76.6 + 9.9 (7) ' . . $1 & TABLE IV. Cesium-137 to potassium ratios in trophic levels of a forest floor arthropod community, expressed as pci ics per le K + S.E. Litter rutio adjusted to the exchangeable cation ratio. Assimilative ratios represent further adjustment for differential assimilation of each element (Table IIT) by the next trophic level. Food Base Total Exchangeable Assimilative Leaf Litter (N = 4) 14.25 2.58 2.08 +0.80 +0.65 +4.12 1.49 Saprovores (N = 11) +0.21 1.20 +0.17 0.98 +0.30 * Predators (N = 7) 1.22 +0.36 Predatory transfer of cesium is highly efficient, and it appears feasible to use element concentration in saprovores as an estimate of concentration of food intake of predators (Crossley and Shanks 1966). -, DATE FILMED 8 / 15 /67 . i