Changes in bird populations as criteria of environmental changes

Järvinen, O. and Väisänen, R. A. 1979. Changes in bird populations as criteria of environmental changes. – Holarct. Ecol. 2: 75-80.
Birds are a powerful tool of environmental monitoring, on account of their ecological diversity. Because of this, bird populations seem best suited for monitoring biological, possibly non-linear effects of specified environmental changes, such as habitat modification, and for "general monitoring" aimed at detecting unexpected environmental changes as they occur. Because many population changes have multiple causes, monitoring specific environmental changes is most rewarding if birds are grouped by e.g. habitat, major strategy (e.g. resident vs. migrant species), or feeding guild. A blueprint for a Nordic monitoring system based on breeding land birds is presented. Local trends may be atypical, and representative coverage of the major habitats in large areas should thus be ensured. As annual population fluctuations usually give little information in environmental monitoring, long-term projects are necessary. The line transect method seems applicable to many monitoring purposes, as it is rapid, inexpensive, relatively accurate, and suitable for sampling the northern terrestrial biota of the Holarctic region, probably including the temperate deciduous forests.     

<Emphasis Type="Italic">Limnocnida tanganyicae</Emphasis> medusae (Cnidaria: Hydrozoa): a semiautonomous microcosm in the food web of Lake Tanganyika

Medusae are important members of marine food webs, but are rare in lakes. In one of the largest lakes in the world, Lake Tanganyika, a small medusa (Limnocnida tanganyicae) is a prominent component of zooplankton. We used field and laboratory methods to study the ecological role of Lake Tanganyika medusae, which occasionally reached high local densities in the whole epilimnion. The largest individuals showed low amplitude, diel vertical migration which minimized their exposure to harmful UV radiation and also may be important for picocyanobacteria regularly present in the medusae. The endosymbiotic picocyanobacteria differed morphologically among medusae and were predominantly one Lake Biwa type Cyanobium sp. that typically was abundant in the water column. Under light, some medusae were net primary producers. Although nitrogen stable isotopic ratios indicated that the free-living cyanobacteria were nitrogen-fixers, the picocyanobacteria in medusae obtained nitrogen predominantly from their host. Stable isotopic ratios of carbon and nitrogen further suggested that copepods were the most likely prey for the medusae. Lake Tanganyika medusae apparently base their metabolism both on animal and plant sources, with possible internal cycling of nutrients; however, the role of picocyanobacteria gardening in the Lake Tanganyika ecosystem and its medusae requires quantification.     

Lipidomic Analysis of Glycerolipid and Cholesteryl Ester Autooxidation Products

Thin-layer chromatography (TLC), gas chromatography (GC), and liquid chromatography (LC) in combination with mass spectrometry (MS) have been adopted for the isolation and identification of oxolipids and for determining their functionality. TLC provides a rapid separation and access to most oxolipids as intact molecules and has recently been effectively interfaced with time-of-flight (TOF) MS (TOF-MS). GC with flame ionization (FI) (GC/FI) and electron impact (EI) MS (GC/EI-MS) has been extensively utilized in the analysis of isoprostanes and other low-molecular-weight oxolipids, although these methods require derivatization of the analytes. In contrast, LC with ultraviolet (UV) absorption (LC/UV) or evaporate light scattering detection (ELSD) (LC/ELSD) as well as electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) MS (LC/ESI-MS) or LC/APCI-MS has proven to be well suited for the analysis of intact oxolipids and their conjugates without or with minimal derivatization. Nevertheless, kit-based colorimetric and fluorescent procedures continue to serve as sensitive indicators of the presence of hydroperoxides and aldehydes.

Structure of a Microbial Community in Soil after Prolonged Addition of Low Levels of Simulated Acid Rain

Humus samples were collected 12 growing seasons after the start of a simulated acid rain experiment situated in the subarctic environment. The acid rain was simulated with H₂SO₄, a combination of H₂SO₄ and HNO₃, and HNO₃ at two levels of moderate acidic loads close to the natural anthropogenic pollution levels of southern Scandinavia. The higher levels of acid applications resulted in acidification, as defined by humus chemistry. The concentrations of base cations decreased, while the concentrations of exchangeable H⁺, Al, and Fe increased. Humus pH decreased from 3.83 to 3.65. Basal respiration decreased with decreasing humus pH, and total microbial biomass, measured by substrate-induced respiration and total amount of phospholipid fatty acids (PLFA), decreased slightly. An altered PLFA pattern indicated a change in the microbial community structure at the higher levels of acid applications. In general, branched fatty acids, typical of gram-positive bacteria, increased in the acid plots. PLFA analysis performed on the bacterial community growing on agar plates also showed that the relative amount of PLFA specific for gram-positive bacteria increased due to the acidification. The changed bacterial community was adapted to the more acidic environment in the acid-treated plots, even though bacterial growth rates, estimated by thymidine and leucine incorporation, decreased with pH. Fungal activity (measured as acetate incorporation into ergosterol) was not affected. This result indicates that bacteria were more affected than fungi by the acidification. The capacity of the bacterial community to utilize 95 different carbon sources was variable and only showed weak correlations to pH. Differences in the toxicities of H₂SO₄ and HNO₃ for the microbial community were not found.     

Novel parameters of surface EMG in patients with Parkinson’s disease and healthy young and old controls

The aim of this study was to evaluate a variety of traditional and novel surface electromyography (SEMG) characteristics of biceps brachii muscle in patients with Parkinson’s disease (PD) and compare the results with the healthy old and young control subjects. Furthermore, the aim was to define the optimal biceps brachii loading level that would most likely differentiate patients from controls. The results indicated that such nonlinear SEMG parameters as %Recurrence, %Determinism and SEMG distribution kurtosis, correlation dimension and sample entropy were significantly different between the PD patients and healthy controls. These novel nonlinear parameters, unlike traditional spectral or amplitude parameters, correlated with the Unified Parkinson’s Disease Rating Scale (UPDRS) and finger tapping scores. The most significant between group differences were found in the loading condition where no additional weights were applied in isometric elbow flexion. No major difference of SEMG characteristics was detected between old and young control subjects. In conclusion, the novel SEMG parameters can differentiate the patients with PD from healthy control subjects and these parameters may have potential in the assessment of the severity of PD.     

Soil microbial activity in relation to dissolved organic matter properties under different tree species

Background and aims

The total concentration of dissolved organic carbon (DOC) has often been observed to correlate positively with soil microbial respiration. The aim was to explain the correlation with the properties of dissolved organic matter (DOM).

Methods

A dataset from previously published papers was gathered together and subjected to multivariate analyses. Samples were collected from five tree species experiments in Finland. The degradability of DOM was assessed by measuring bacterial and fungal growth in DOM. The chemical properties of DOM were assessed by XAD resin fractionation and molecular weight. Soil microbial activity was assessed as C and N mineralization and microbial biomass.

Results

Both low and high molecular weight compounds, as well as hydrophilic neutral compounds, seemed to be relatively easily degradable. In contrast to our presupposition, easily degradable DOM seemed to be less abundant in soil where variables describing microbial activity were higher. Birch soil with higher microbial biomass N seemed to contain less easily degradable DOM than spruce soil.

Conclusion

We suggest that DOM collected and characterized at a certain point reflects more the accumulation of refractory compounds following high microbial activity than the easily degradable compounds that microbes would be using when measured.

     

Copper mobility and toxicity of soil percolation water to bacteria in a metal polluted forest soil

In order to assess the success of in situ remediation of coniferous forest soil polluted by a Cu–Ni smelter, the total Cu concentration in soil percolation water, the fluxes of Cu down through the soil profile, and the toxicity of soil percolation water to soil bacteria were studied. Total Cu in percolation water was also fractionated into free ionic and complexed forms. The toxicity of the percolation water was measured by the [³H]-thymidine incorporation method, which measures bacterial growth rates. Soil percolation water was collected during one growing season by zero tension lysimeters inserted at depths of 0.2 and 0.4 m in the soil. The treatments consisted of a control, mulch application to the forest floor (M) and mulch application after removing the polluted organic soil layer (MR). The mulch consisted of a mixture of compost and woodchips (1/1; vol/vol). Analysis of Cu species and dissolved organic carbon (DOC) indicated that DOC leached from the mulch and complexed Cu into forms that were less toxic to soil bacteria. At 0.2 m depth percolation water toxicity was 19% lower in the M and 42% lower in the MR treatment than in the control. Toxicity correlated with the Cu²⁺ concentration, which was 61 and 84% lower in the M and MR treatments, respectively, compared to the control. However, there were signs that total Cu had leached down through the soil profile, the leaching being more pronounced in the MR treatment.     

The correlation of vectorcardiographic changes to blood lactate concentration during an exercise test

In this study, the correlations between blood lactate concentration (BLC), different vector electrocardiogram (VECG) parameters, ventilatory parameters and heart rate during exercise and recovery periods were investigated. The aim was to clarify the relationships between VECG parameters and different exercise intensity markers. Six (25–37 years old) nonathlete, healthy, male participants took part in the study. All participants performed two different bicycle ergospirometric protocols (P1 and P2) in order to attain different lactate levels with different heart rate profiles. A principal component regression (PCR) approach is introduced for preprocessing the VECG components. PCR was compared to Sawitzcy Golay and wavelet filtering methods using simulated data. The performance of the PCR approach was clearly better in low signal-to-noise ratio (SNR) situations, and thus, it enables reliable VECG estimates even during intensive exercise. As a result, strong positive mean individual correlations between BLC and T-wave kurtosis (P1: r = 0.86 and P2: r = 0.8, p < 0.05 in 12/12 measurements) and negative correlation between BLC and cos RT (P1: r = ?0.7, P2: r = ?0.62, p < 0.05 in 8/12 measurements) were observed. The results of this study indicate that VECG parameters (in addition to heart rate) can make a significant contribution to monitoring of exercise intensity and recovery.