Joseph Yavitt - Academia.edu (original) (raw)

Papers by Joseph Yavitt

International Journal of Systematic and Evolutionary Microbiology, 2014

Two mesophilic, hydrogenotrophic methanogens, designated strains SWAN1T and AL-21, were isolated ... more Two mesophilic, hydrogenotrophic methanogens, designated strains SWAN1T and AL-21, were isolated from two contrasting peatlands: a near circumneutral temperate minerotrophic fen in New York State, USA, and an acidic boreal poor fen site in Alaska, USA, respectively. Cells of the two strains were rod-shaped, non-motile, stained Gram-negative and resisted lysis with 0.1 % SDS. Cell size was 0.6×1.5–2.8 µm for strain SWAN1T and 0.45–0.85×1.5–35 µm for strain AL-21. The strains used H2/CO2 but not formate or other substrates for methanogenesis, grew optimally around 32–37 °C, and their growth spanned through a slightly low to neutral pH range (4.7–7.1). Strain AL-21 grew optimally closer to neutrality at pH 6.2, whereas strain SWAN1T showed a lower optimal pH at 5.4–5.7. The two strains were sensitive to NaCl with a maximal tolerance at 160 mM for strain SWAN1T and 50 mM for strain AL-21. Na2S was toxic at very low concentrations (0.01–0.8 mM), resulting in growth inhibition above these...

Soil Biology & Biochemistry, Nov 1, 2019

Geophysical Research Letters, Jun 1, 1994

The authors report on measurements of carbon dioxide fluxes from two beaver ponds in the Adironda... more The authors report on measurements of carbon dioxide fluxes from two beaver ponds in the Adirondacks in New York. They measured emissions of carbon dioxide on ice free days, concentrations of dissolved organic carbon in the water, both with and without ice cover, and estimated carbon dioxide production rates from sediments below the water column. The COâ emitted from the ponds comes both from release from pond components, and from flow in from the drainage area. Their results show that the ponds are a significantly more intense source of COâ, than the corresponding land surface areas.

Parasitology, Jan 14, 2019

The blacklegged tick (Ixodes scapularis) spends up to 10 months in the soil between feeding as la... more The blacklegged tick (Ixodes scapularis) spends up to 10 months in the soil between feeding as larvae and questing for hosts as nymphs the following year. We tracked the survival and energy use of 4320 engorged larvae evenly divided across 288 microcosms under field conditions from September to July on sites with high (>12 nymphs/150 m2) and low (<1.2 nymphs/150 m2) densities of naturally questingI. scapularisin New York State. Subsets of microcosms were destructively sampled periodically during this period to determine tick survivorship and physiological age. Across all sites tick mortality was low during the winter and increased in the spring and early summer, coincident with increasing energy use. Neither energy use nor mortality differed significantly between sites with highvslow natural tick density, but we did observe a significant positive relationship between soil organic matter content and the survival ofI. scapularisduring the spring. Our results suggest that the off-host mortality and energy use ofI. scapularisnymphs is relatively low in the winter and increases significantly in the spring and early summer.

Research Square (Research Square), Dec 21, 2022

Journal of Medical Entomology, Jul 18, 2019

Ticks are widespread vectors for many important medical and veterinary infections, and a better u... more Ticks are widespread vectors for many important medical and veterinary infections, and a better understanding of the factors that regulate their population dynamics is needed to reduce risk for humans, wildlife, and domestic animals. Most ticks, and all non-nidicolous tick species, spend only a small fraction of their lives associated with vertebrate hosts, with the remainder spent in or on soils and other substrates. Ecological studies of tick-borne disease dynamics have emphasized tick–host interactions, including host associations, burdens, and efficiencies of pathogen transmission, while under emphasizing tick biology during off-host periods. Our ability to predict spatiotemporal trends in tick-borne diseases requires more knowledge of soil ecosystems and their effect on host and tick populations. In this review, we focus on tick species of medical and veterinary concern and describe: 1) the relationships between soil factors and tick densities; 2) biotic and abiotic factors within the soil ecosystem that directly affect tick survival; 3) potential indirect effects on ticks mediated by soil ecosystem influences on their vertebrate hosts; 4) the potential for tick-mediated effects on vertebrate host populations to affect ecosystems; and 5) possible nontarget impacts of tick management on the soil ecosystem. Soils are complex ecosystem components with enormous potential to affect the survival and behavior of ticks during their off-host periods. Hence, tick-borne disease systems present an excellent opportunity for soil ecologists and public health researchers to collaborate and improve understanding of these medically important and ecologically complex disease cycles.

Geomicrobiology Journal, Feb 23, 2017

The Journal of Ecology, 1986

SUMMARY (1) The dynamics of organic matter and nutrient elements in the forest floor of Pinus con... more SUMMARY (1) The dynamics of organic matter and nutrient elements in the forest floor of Pinus contorta spp. latifolia (lodgepole pine) forests in Wyoming, U.S.A., were investigated by combining three related measurements: leaching of the forest floor; long-term decay of leaf litter; and steady-state residence times in the forest floor. (2) Elemental fluxes (g m-2 yr-1) resulting from leaching by spring snowmelt were: Ca = 135, Mg = 0.30, K = 0*65, N = 0-46, P = 0.022 and C = 8.3. Over 95% of the N flux was in organic forms. (3) Most of the organic compounds were acidic, and anions of these organic acids were the principal mobile species accompanying cation flux; smaller, but important, contributions were S04 and HCO3. The chemical nature of the dissolved organic compounds changed as snowmelt proceeded, with polyphenolics and carbohydrates (leached from fresh litter) being important in the early stages, and polymeric acid compounds (fulvic and humic acids) dominating in the later stages. (4) About 35% of the original mass of leaf litter remained after 84-96 months. Potassium and magnesium were lost rapidly from leaf litter, whereas there was temporary immobilization of Ca. Nitrogen accumulated in decaying leaves for 72 months, reaching 180% of the original content before net mineralization and release occurred. Relatively small changes in P content of leaf litter were noted during the decay process. The loss of soluble organic constituents (polyphenols, carbohydrates, lipids) was more rapid than for solid residues (holocellulose, lignin). (5) The combination of approaches enabled several features of organic matter and nutrient dynamics in the forest floor, which would not be apparent using any of the methods in isolation, to be deduced: (i) about 30% of annual C release from the forest floor resulted from leaching of organic compounds; (ii) over 20% of the leaching flux for Ca and Mg was attributed to release from 01 litter, compared with less than 10% for K; (iii) high amounts of organic-N leaching from forest-floor layers, combined with rapid accumulation in 0- to 8-year-old litter, indicated rapid translocation of N from subsurface layers to 01 litter via heterotrophs; and (iv) leaching of polyphenols from the forest floor was 50% lower than the apparent loss from 01 litter, suggesting chemical transformation and changes in solubility of these compounds during litter decay. An association of this phenomenon with protein accumulation observed in the 02 horizon is postulated.

Soil Research

Context Minerals and organic matter physically associate in many soils, yet the precise nature, e... more Context Minerals and organic matter physically associate in many soils, yet the precise nature, either via a hierarchy of aggregate particles or by build-up of organo–mineral associations, remains obscure, especially in tropical forest environments. Aims We investigated physically protected organic matter by comparing soils with contrasting parent material, topography, and pedogenesis, but with similar tropical moist forest on Barro Colorado Island in the lowlands of Panama. Methods Bulk soil from 10 sites was separated by size into free-floating particles, macroaggregates (>250 μm), microaggregates (53–250 μm), and <53-μm particles. A subsample of macroaggregates was disintegrated and separated into coarse particles (>250 μm), occluded microaggregates, and occluded <53-μm particles. Concentrations and natural abundance of stable isotopes for carbon (C) and nitrogen (N) were determined for each fraction, and ratios (C:N, stable isotopes) were used to characterise organic...

Ecosystems, 2017

Decomposing leaf litter is a large supply of energy and nutrients for soil microorganisms. How lo... more Decomposing leaf litter is a large supply of energy and nutrients for soil microorganisms. How long decaying leaves continue to fuel anaerobic microbial activity in wetland ecosystems is poorly understood. Here, we compare leaf litter from 15 tree species with different growth forms (angiosperms and gymnosperms, deciduous, and longer life span), using litterbags positioned for up to 4 years in a forested peatland in New York State. Periodically, we incubated partially decayed residue per species with fresh soil to assess its ability to fuel microbial methane (CH4) production and concomitant anaerobic carbon dioxide (CO2) production. Decay rates varied by leaf type: deciduous angiosperm > evergreen gymnosperm > deciduous gymnosperm. Decay rates were slower in leaf litter with a large concentration of lignin. Soil with residue of leaves decomposed for 338 days had greater rates of CH4 production (5.8 µmol g−1 dry mass d−1) than less decomposed (<0.42 µmol g−1 dry mass d−1) or more decomposed (2.1 µmol g−1 dry mass d−1) leaf residue. Species-driven differences in their ability to fuel CH4 production were evident throughout the study, whereas concomitant rates of CO2 production were more similar among species and declined with degree of decomposition. Methane production rates exhibited a positive correlation with pectin and the rate of pectin decomposition. This link between leaf litter decay rates, biochemical components in leaves, and microorganisms producing greenhouse gases should improve predictions of CH4 production in wetlands.

Atmospheric Environment, 1996

American Midland Naturalist, 1983

... His work illustrated the importance of wind shelters in raising leaf temperatures several deg... more ... His work illustrated the importance of wind shelters in raising leaf temperatures several degrees above air temperature. Krog (1955) found that the hairy insulated catkins of Salix polaris were 15-25 С above air temperature. ...

American Journal of Botany, 1987

... DONALD R. YOUNG2 AND JOSEPH B. YAVITT Department of Biology, Virginia Comnmonwealth Universit... more ... DONALD R. YOUNG2 AND JOSEPH B. YAVITT Department of Biology, Virginia Comnmonwealth University ... using 80% acetone: 20% water and measured spec-trophotometrically (Amon, 1949 ... 10 leaves, after oven drying, grinding and digestion in H2SO4 (Allen, Grimshaw, and ...

... We thank Tim Fahey, Eugene Madsen and reviewers for helpful comments on the manuscript. Refer... more ... We thank Tim Fahey, Eugene Madsen and reviewers for helpful comments on the manuscript. References Baldocchi, D., A. Guenther, P. Harley, L. Klinger, P. Zimmerman, B. Lamb, and H. Westberg, The fluxes and air chemistry of isoprene above a deciduous hardwood forest ...

Canadian Journal of Soil Science

The amounts and arrangements of polysaccharides (cellulose and hemicellulose), proteins, phenolic... more The amounts and arrangements of polysaccharides (cellulose and hemicellulose), proteins, phenolic lignin, and pectin that make up plant tissue, in part, determine its decay rate. Lignin-rich and/or nitrogen-poor tissue has been described as biochemically recalcitrant causing a slow decay rate. Although a controversial mechanism for organic matter storage in soils with mineral particles, biochemical recalcitrance is still poorly understood in organic peat soil (Histosols). To investigate the role of Sphagnum in formation of peat soil, we characterize biochemical components for 10 species and examine persistence of the components in soil to 150 cm depth in three peatland ecosystems. We hypothesize that species from hummock microforms have more biochemical structural components and cohesion than species from hollows. Relative proportions of biochemical components changed markedly between plant material and the top 10 cm of peat soil, suggesting that decomposition occurred at the peat s...