Extant Biomass Research Articles

Global patterns in biomass models describing prey consumption by big cats

Widespread prey depletion forces carnivores to rely more on livestock, which may lead to increased persecution by humans. Reliable quantification of livestock consumption is essential for understanding depredation scales, but a comparative analysis of extant biomass models used for this purpose has never been done before. We conducted a global meta-analysis of two linear and three non-linear biomass models used to estimate consumption of prey biomass and individuals by seven big cat species. We applied the z-test to perform pairwise comparisons of estimates produced by five models for each prey record. Further, we used logistic regression to assess the effects of species of big cats and their prey, scat sample size, prey body mass, and study sites on significantly different and similar estimates. The analysis of 769 prey records from 47 sites demonstrated that, in over 95% of cases, linear and non-linear biomass models produced similar estimates of prey biomass and individuals consumed. Significantly different estimates of prey biomass consumed (in 1.5% of cases) and prey individuals consumed (4%) were obtained only in certain study sites and for a few big cat species (tiger Panthera tigris, leopard Panthera pardus, and puma Puma concolor). Due to the paucity of different estimates, the effects of predictors could not be ascertained. Our study demonstrated that linear models tend to estimate higher biomass of large prey, lower biomass of medium-sized prey and fewer individuals of large and medium-sized prey consumed than non-linear models. This disagreement in estimates suggests that the numbers of livestock lost to depredation can be underestimated by linear models, and that re-calculation by non-linear models is required. However, the difference between estimates produced by linear and non-linear models is generally small and such re-calculation may be recommended only for tiger, puma and leopard in certain areas.

Polyhydroxyalkanoate (PHA) storage within a mixed-culture biomass with simultaneous growth as a function of accumulation substrate nitrogen and phosphorus levels

The response of a mixed-microbial-culture (MMC) biomass for PHA accumulation was evaluated over a range of relative nitrogen (N) and phosphorus (P) availabilities with respect to the supply of either complex (fermented whey permeate – FWP) or simpler (acetic acid) organic feedstocks. Fed-batch feed-on-demand PHA accumulation experiments were conducted where the feed N/COD and P/COD ratios were varied ranging from conditions of nutrient starvation to excess. A feast-famine enrichment (activated sludge) biomass, produced in a pilot-scale aerobic sequencing batch reactor on FWP and with a long history of stable PHA accumulation performance, was used for all the experiments as reference material. FWP with N/COD ratios of (2, 5, 15, 70 mg/g all with P/COD = 8 mg/g) as well as simulated FWP with nutrient starvation (N/COD = P/COD = 0) conditions were applied. For the acetic acid accumulations, nutrient starvation as well as N/COD variations (2.5, 5, 50 mg/g all with P/COD = 9 mg/g) and P/COD variations (0.5, 2, 9, 15 mg/g all with N/COD = 10 mg/g) were evaluated. An optimal range of combined N and P limitation with N/COD from 2 to 15 mg/g and P/COD from 0.5 to 3 mg/g was considered to offer consistent improvement of productivity over the case of nutrient starvation. Productivity increased due to active biomass growth of the PHA storing biomass without observed risk for a growth response overtaking PHA storage activity. PHA production with respect to the initial active biomass was significantly higher even in cases of excess nutrient additions when compared to the cases of nutrient starvation. The 24-h PHA productivities were enhanced as much as 4-fold from a base value of 1.35 g-PHA per gram initial active biomass with respect nutrient starvation feedstock. With or without nutrient loading the biomass consistently accumulated similar and significant PHA (nominally 60% g-PHA/g-VSS). Based on results from replicate experiments some variability in the extant biomass maximum PHA content was attributed to interpreted differences in the biomass initial physiological state and not due to changes in feedstock nutrient loading. We found that the accumulation process production rates for mixed cultures can be sustained long after the maximum PHA content of the biomass was reached. Within the specific context of the applied fed-batch feed-on-demand methods, active biomass growth was interpreted to have been largely restricted to the PHA-storing phenotypic fraction of the biomass. This study suggests practical prospects for mixed culture PHA production using a wide range of volatile fatty acid (VFA) rich feedstocks. Such VFA sources derived from residual industrial or municipal organic wastes often naturally contain associated nutrients ranging in levels from limitation to excess.

Current status and future prospects for carbon forestry in Australia

Summary Carbon forestry is part of a suite of land-based activities that can be used to mitigate carbon emissions, and also provide a range of other environmental co-benefits. Components are included in the Carbon Credits (Carbon Farming Initiative) Act 2011. There is large divergence in Australian estimates of the areas of land that may be used for carbon forests and there has been a vigorous public debate about carbon forestry, partly based on concerns about displacement of food-producing land. We identify four distinct afforestation or reforestation (AR) activities that involve carbon mitigation and suggest a terminology based on these. These are (1) ‘plantations’ that also produce timber and wood products, (2) ‘carbon-focused’ sinks, (3) ‘environmental’ or natural resource management plantings and (4) ‘bioenergy’ plantings for use either as a feedstock for stationary energy production or transport fuels. After accounting for AR projects established for other purposes (e.g. timber and pulpwood), we estimate that the current area of carbon forests in Australia is 65000 ha. Despite the national Renewable Energy (Electricity) Act 2000 and its 2010 amendments there are few extant biomass projects. However this may change with the development of new technologies and the imposition of a carbon price on electricity production. The reasons for the gulf between actual and potential carbon AR activity are proposed to include (1) the absence of a formal carbon compliance scheme, (2) challenges in managing carbon through an entire product cycle, (3) the degree of understanding of carbon forestry by financiers, (4) landholder preference, (5) technical barriers and (6) regulatory uncertainty. We suggest an extension of the National Plantation Inventory from traditional plantations to carbon forestry, so that future policy can be developed on the basis of good-quality underpinning information that can be disaggregated to analyse trends in AR for different purposes. To encourage innovation in the sector, we also suggest either the extension or establishment of research and development funding arrangements, similar to those already existing for other rural industries.

Bacterial tetraether membrane lipids in peat and coal: Testing the MBT–CBT temperature proxy for climate reconstruction

Peatlands are widespread and important natural archives of environmental change. Here we explore the potential of the recently introduced MBT–CBT proxy (methylation index and cyclisation ratio of branched tetraethers) to estimate past annual mean air temperature (MAT) based on the distribution of bacterially-derived branched glycerol dialkyl glycerol tetraether (GDGT) membrane lipids in peat and coal. To this end, branched GDGTs in an ombrotrophic peat bog from Switzerland and three coal deposits of increasing maturity were analysed. For the surface of the bog, reconstructed annual MAT is higher than both measured annual MAT and measured in situ pore water temperature. Changes in the CBT ratio, considered a proxy for pH, with depth in the bog do not match with present day in situ pore water pH, but coincide with a peat stratigraphic boundary. This indicates that GDGTs down the bog profile are predominantly fossil and not derived from extant biomass. The MBT–CBT derived annual MAT record also shows a large drop at this stratigraphic boundary, which likely relates to past change in trophic status of the bog. Branched GDGTs are abundant in an immature lignite (vitrinite reflectance, R o 0.25%), but occur in low amount in a slightly more mature coal ( R o 0.32%). Annual MAT could be reconstructed for the lignite alone and is higher than other proxy-based estimates from approximately the same time and location. Our results indicate potential for the application of the MBT–CBT proxy in peat and immature coals, but improved constraints on the effects of different types of peat on branched GDGT distributions as well as improved calibration of MAT estimates are needed before the method can be confidently applied.

Levoglucosan and other cellulose and lignin markers in emissions from burning of Miocene lignites

Levoglucosan (L), mannosan (M), galactosan (G) and other cellulose and lignin markers from burn tests of Miocene lignites of Poland were determined by gas chromatography–mass spectrometry (GC–MS) to assess their distributions and concentrations in the smoke. Their distributions were compared to those in the pyrolysis products of the lignites. Levoglucosan and other anhydrosaccharides are products from the thermal degradation of cellulose and hemicellulose and are commonly used as tracers for wood smoke in the atmosphere. Here we report emission factors of levoglucosan in smoke particulate matter from burning of lignite varying from 713 to 2154 mg kg −1, which are similar to those from burning of extant plant biomass. Solvent extracts of the lignites revealed trace concentrations of native levoglucosan (0.52–3.7 mg kg −1), while pyrolysis yielded much higher levels (1.6–3.5 × 10 4 mg kg −1), indicating that essentially all levoglucosan in particulate matter of lignite smoke is derived from cellulose degradation. The results demonstrate that burning of lignites is an additional input of levoglucosan to the atmosphere in regions where brown coal is utilized as a domestic fuel. Interestingly, galactosan, another tracer from biomass burning, is not emitted in lignite smoke and mannosan is emitted at relatively low concentrations, ranging from 7.8 to 70.5 mg kg −1. Thus, we propose L/M and L/(M + G) ratios as discriminators between products from combustion of lignites and extant biomass. In addition, other compounds, such as shonanin, belonging to lignans, and some saccharides, e.g., α- and β-glucose and cellobiose, are reported for the first time in extracts of bulk lignites and of smoke particulate matter from burning these lignites.

Seepage Erosion from Dam-Regulated Flow: Case of Glen Canyon Dam, Arizona

Seepage erosion—in particular, slope failures (bank slumps, mass wasting)—is prevalent on most sandbars downstream from the Glen Canyon Dam, Ariz. The public is concerned about the loss of the extant biomass and recreational facilities on these sandbars. It is alleged that the operation of the Glen Canyon Dam is responsible for the erosion of the sandbars. In this contribution, a simple, approximate analysis is developed to determine the extent of slope failures due to seepage of bank stored water from transient dam flow. The analysis is intended to assist environmentalists, dam operators, planners, and others to predict zones in which riparian habitat and recreation use will be negatively impacted by fluctuating flows. The affected area of a sandbar was found to be dependent on the range of flows; the rate of rise of river stage; the duration of the peak discharge; and the permeability, friction angle, and cohesion of the soil. Comparison of the predictions of the analysis with field data show good agreement.

Instability of Sandbars in Grand Canyon

The Glen Canyon Dam, located in the northeastern corner of Arizona, is operated to satisfy peak power demands of neighboring states. The discharge regime of the dam is such that the river stage in the Colorado River downstream of the dam varies diurnally as much as 4 m in some sections. It is alleged that these fluctuations of the river stage are responsible for the destruction of sandbars and, as a result, the loss of the extant biomass and the reduction of recreational facilities. In this paper, an analysis is developed to determine the equilibrium slope below which slope failures (mass wasting, bank failures) due to seepage of bank‐stored water would be unlikely. The sediments enclosed by the equilibrium seepage slope (range 11°–14° for the sediments downstream of the Glen Canyon Dam) and the maximum slope angle (range from 26° to 32°) is subjected to ongoing aggradation and erosion. Field data from ground surveys support the analysis described in this paper.

37th Professor sir AC. Seward Memorial Lecture: Links with the past in the plant world: cuticles as recorders of diversity, kerogen formation and palaeoatmospheric CO2 level

The study and interpretation of plant cuticles may lead to the establishment of three important (taxonomic, biochemical, physiological) links with the past in the plant world; (1) Cuticles reflect characteristic patterns of epidermal cell organization; on the basis of cuticle analysis natural plant genera and families can be established as a necessary taxonomic background for recognizing past episodes of biodiversity change. (2) Cuticles have a high fossilization potential, due to the presence of resistant biopolymers in the cuticular matrix; chemical analysis of fossil and present-day cuticles can help to clarify interrelationship between extant biomass, kerogen and fossil fuels (3) Cuticles bear the plant’s stomata, essential for photosynthesis; stomatal frequencies are dependent on ambient CO2 concentration, so that calculation of stomatal indices has the potential of determining palaeoatmospheric CO2-levels with the time-scale of the last 10 million years.

Biotechnology and global climate change

Abstract Anthropogenic activities have dramatically altered the composition of the atmosphere over the past 100 years. The changes in infrared absorbing gas concentrations could potentially alter the radiative balance of the Earth. Direct remediation strategies, such as reducing the atmospheric levels of CO2 by stimulating photosynthetic processes, may actually exacerbate the problem if the biomass is anaerobically degraded. A much more effective, short-term remediative strategy would be to recycle extant biomass and reduce anthropogenic fixed nitrogen demands.

A reappraisal of kerogen formation

Comparative microscopical and chemical studies of recognizable entities in kerogen and their extant counterparts suggest a new and simple mechanism of kerogen formation which clarifies the interrelationships between extant biomass, kerogen, and fossil fuels.