Salmon-derived nitrogen in terrestrial invertebrates from coniferous forests of the Pacific Northwest

Background  

Bi-directional flow of nutrients between marine and terrestrial ecosystems can provide essential resources that structure communities in transitional habitats. On the Pacific coast of North America, anadromous salmon (Oncorhynchus spp.) constitute a dominant nutrient subsidy to aquatic habitats and riparian vegetation, although the contribution to terrestrial habitats is not well established. We use a dual isotope approach of δ¹⁵N and δ¹³C to test for the contribution of salmon nutrients to multiple trophic levels of litter-based terrestrial invertebrates below and above waterfalls that act as a barrier to salmon migration on two watersheds in coastal British Columbia.     

Competition between the invasive macrophyte <Emphasis Type="Italic">Caulerpa taxifolia</Emphasis> and the seagrass <Emphasis Type="Italic">Posidonia oceanica</Emphasis>: contrasting strategies

Background  

Plant defense strategy is usually a result of trade-offs between growth and differentiation (i.e. Optimal Defense Theory – ODT, Growth Differentiation Balance hypothesis – GDB, Plant Apparency Theory – PAT). Interaction between the introduced green alga Caulerpa taxifolia and the endemic seagrass Posidonia oceanica in the Mediterranean Sea offers the opportunity to investigate the plausibility of these theories. We have accordingly investigated defense metabolite content and growth year-round, on the basis of an interaction gradient.     

Assessment of long-term changes in nitrogen pollution load potential from sewage treatment water in the Tedori River Alluvial Fan Area, Japan

Long-term changes (1974–2007) in the nitrogen pollution load potential (NPLP) arising from sewage treatment water were assessed in the Tedori River Alluvial Fan Area of Japan. The total NPLP from sewage treatment systems (STS) during the 34 year period was 439 t (10³ kg) year⁻¹ from about 260,000 users in 1974 increasing to a peak of 793 t year⁻¹ in 1992 from about 363,000 users, and then decreasing to 676 t year⁻¹ from about 400,000 users in 2007. The NPLP outflow into the area increased from 356 t year⁻¹ in 1974 to a peak of 596 t year⁻¹ in 1985 followed by a rapid decrease to 98 t year⁻¹ in 2007. The NPLP outflow from the public STS to the Japan Sea began in 1979 and rapidly increased to 575 t year⁻¹ in 2007 from about 362,000 users. This represents 85.5% of the total NPLP. The NPLP from septic tanks in the area was 356 t year⁻¹ from about 107,000 users in 1974 gradually increasing to a peak of 587 t year⁻¹ from about 177,000 users in 1985 before rapidly decreasing to 60 t year⁻¹ from about 15,000 users in 2007. Although the current NPLP is about 98 t year⁻¹ in the study area, the average NPLP during 34 years was very different at 424 t year⁻¹. NPLP assessments affecting groundwater and closed water bodies should consider long-term processes of nitrogen pollution from STS over time periods compatible with the residence time of the receiving waters.     

Assessment of environmental nitrogen pollution load potential from sewage treatment water in the Tedori River Alluvial Fan Area, Japan

An evaluation of the nitrogen pollution load potential (NPLP) arising from several sewage treatment systems in the Tedori River Alluvial Fan Area was evaluated by determining the removal percentage of nitrogen as a result of sewage treatment and amounts of nitrogen lost from the different treatment systems. These data were applied to the entire area resulting in an estimated total NPLP of 734 t year⁻¹ (10³ kg year⁻¹), of which 548 t year⁻¹ discharges into the Japan Sea and so does not contribute to the pollution of the environment considered here. The residual 186 t year⁻¹ of the NPLP has a high probability of causing groundwater or downstream pollution, with 58% of the NPLP being contributed from septic tanks not connected to public sewage systems. Rural sewage system accounted for about 18% of the NPLP. Material directly flowing into the middle stream of the Tedori River together with sewage water from small companies and untreated sewage water from local family dwellings made up about 3–12% of the NPLP. To improve water quality due to sewage effluent, it is essential to increase the number of connections to public sewage systems from septic tanks.     

GIS habitat analysis for lesser prairie-chickens in southeastern New Mexico

Background  

We conducted Geographic Information System (GIS) habitat analyses for lesser prairie-chicken (LPCH, Tympanuchus pallidicinctus) conservation planning. The 876,799 ha study area included most of the occupied habitat for the LPCH in New Mexico. The objectives were to identify and quantify: 1. suitable LPCH habitat in New Mexico, 2. conversion of native habitats, 3. potential for habitat restoration, and 4. unsuitable habitat available for oil and gas activities.     

Zn, Cu, Cd and Hg binding to metallothioneins in harbour porpoises Phocoena phocoena from the southern North Sea

Background  

Harbour porpoises Phocoena phocoena from the southern North Sea are known to display high levels of Zn and Hg in their tissues linked to their nutritional status (emaciation). The question arises regarding a potential role of metallothioneins (MTs) with regard to these high metal levels. In the present study, metallothionein detection and associated Zn, Cd, Cu and Hg concentrations were investigated in the liver and kidney of 14 harbour porpoises collected along the Belgian coast.     

Toxic effects of methoxychlor on the episodic prolactin secretory pattern: Possible mediated effects of nitric oxide production

Background  

This work addresses the issue of whether methoxychlor (MTX) exposure may modify the ultradian secretion of prolactin through changes in the synthesis of nitric oxide (NO) induced by N^ω-nitro-L-arginine methyl ester (L-NAME) in the hypothalamic-pituitary axis. Associated changes in dopamine (DA) content in the anterior (AH), mediobasal (MBH) and posterior hypothalamus (PH) and median eminence (ME) were evaluated.     

Antioxidant Activities of Four Edible Seaweeds from the Southern Coast of Thailand

The aqueous extracts of four marine algae, Caulerpa racemosa var. macrophysa, Gracilaria tenuistipitata var. tenuistipitata, Sargassum sp., and Ulva lactuca, from the coastal areas in Southern Thailand, were prepared by boiling dried seaweed powder in water for 3 h, and by autoclaving each sample at 120 °C for 3 h. They were then freeze-dried and evaluated for their antioxidant activities using DPPH (1, 1-diphenyl-2-picrylhydrazyl), hydroxyl radical (OH^•) and superoxide anion (O₂^•−) scavenging assays. Boiling extracts of the seaweeds, except C. racemosa, were found to have higher total phenolic contents (TPC) than those obtained from the autoclave method. The antioxidant results also showed that O₂^•− scavenging activity existed only in the boiling extracts of C. racemosa, G. tenuistipitata, and U. lactuca. In DPPH and OH^• assays, however, almost all the boiling extracts were less active than the autoclave ones. Among the four alga species, Sargassum sp. was the most active. Both extracts of this seaweed had the highest TPC and also displayed the strongest DPPH^• and OH^• inhibitory activities. A strong positive-correlation between the antioxidant potency and TPC of the autoclave extracts was found, while for the boiling extracts such relation was very weak. This result thus reflected that in addition to the phenolic compounds, there might be some other active components present in these extracts involved in the antioxidant activity.     

Enhancing the performance of transplanted coarse rice by seed priming

Raising the rice seedlings in the nursery and its transplantation into the flooded fields is principal method of rice cultivation in the world. Traditional nursery raising method in Pakistan is tedious and produces week seedlings, which reduces the final yield due to high mortality. The potential of seed priming to improve the nursery seedlings and thus the transplanted rice was evaluated in the present study. Seed priming tools employed during the investigation included traditional soaking (pre-germination), hydropriming for 48 h, osmohardening (KCl or CaCl₂) (ψs-1.25 MPa) for 24 h (1 cycle), ascorbate priming (with 10 ppm ascorbate) for 48 h or seed hardening for 24 h. Priming improved nursery seedling vigor and resulted in improved growth, yield and quality of transplanted rice. Osmohardening (KCl) consequently resulted in the best performance, followed by osmohardening (CaCl₂)_, hardening and ascorbate priming. Osmohardening (KCl) produced 4.28 t ha⁻¹ (vs. 3.51 t ha⁻¹ from untreated control) kernel yield, 10.27 t ha⁻¹ (vs. 9.34 t ha⁻¹ from untreated control) straw yield and 29.41% (vs. 27.31% from untreated control) harvest index. The improved yield was attributed to increase in number of fertile tillers.     

Feeding behaviour of free-ranging walruses with notes on apparent dextrality of flipper use

Background  

Direct observations of underwater behaviour of free-living marine mammals are rare. This is particularly true for large and potentially dangerous species such as the walrus (Odobenus rosmarus). Walruses are highly specialised predators on benthic invertebrates – especially bivalves. The unique feeding niche of walruses has led to speculations as to their underwater foraging behaviour. Based on observations of walruses in captivity and signs of predation left on the sea floor by free-living walruses, various types of feeding behaviour have been suggested in the literature. In this study, however, the underwater feeding behaviour of wild adult male Atlantic walruses (O. r. rosmarus) is documented for the first time in their natural habitat by scuba-divers. The video recordings indicated a predisposition for use of the right front flipper during feeding. This tendency towards dextrality was explored further by examining a museum collection of extremities of walrus skeletons.     

Circadian phase-shifting effects of a laboratory environment: a clinical trial with bright and dim light

Background  

Our aims were to examine the influence of different bright light schedules on mood, sleep, and circadian organization in older adults (n = 60, ages 60–79 years) with insomnia and/or depression, contrasting with responses of young, healthy controls (n = 30, ages 20–40 years).     

Wildlife reintroduction: considerations of habitat quality at the release site

Background  

Assessing the suitability of a habitat prior to the release of animals is vital. Proper assessment of the flora will allow reintroduction programmes to determine whether the area will be capable of supporting the released animals in the long-term. Here data are presented from an island in Central Kalimantan, Indonesia which has been used as a release site for agile gibbons (Hylobates agilis albibarbis) since January 2003.     

The world's richest tadpole communities show functional redundancy and low functional diversity: ecological data on Madagascar's stream-dwelling amphibian larvae

Background  

Functional diversity illustrates the range of ecological functions in a community. It allows revealing the appearance of functional redundancy in communities and processes of community assembly. Functional redundancy illustrates the overlap in ecological functions of community members which may be an indicator of community resilience. We evaluated patterns of species richness, functional diversity and functional redundancy on tadpole communities in rainforest streams in Madagascar. This habitat harbours the world's most species-rich stream tadpole communities which are due to their occurrence in primary habitat of particular interest for functional diversity studies.     

Differential expression of the heat shock protein Hsp70 in natural populations of the tilapia, Sarotherodon melanotheron, acclimatised to a range of environmental salinities

Background  

The relationship between environmental variation and induction of heat shock proteins (Hsps) has been much documented under experimental conditions. However, very little is known about such induction in natural populations acclimatised to prevailing environmental conditions. Furthermore, while induction of stress proteins has been well documented in response to environmental contaminants and thermal stressors, little is known about whether factors, such as extreme salinity, are also potential inductors. The black-chinned tilapia Sarotherodon melanotheron is unusual for its ability to colonise estuarine environments in West Africa that are characterised by extremely high salinities. The relationships between mRNA levels of the 70 kDa heat shock protein (Hsp70) and Na⁺, K⁺-ATPase1α (Naka) in the gills, environmental salinity, and a life-history trait (condition factor) were investigated in wild populations of this species sampled from three locations in the Saloum estuary, at salinities ranging from 40 to 100 psu.     

Nitrogen and phosphorus leaching losses from paddy fields with different water and nitrogen managements

While many water-saving rice production techniques have been adopted in China, the environmental effects of these techniques require further investigation. This study aims to assess nitrogen (N) and phosphorus (P) leaching losses under real conditions in different water and N managements. Two water and three N treatments are conducted in the Taihu Lake region of China. Results show that the total N leaching losses during the rice season under flooding irrigation (FI) are 12.4, 9.31, and 7.17 kg ha⁻¹ for farmers’ fertilization practices (FFP), site-specific N management (SSNM), and controlled-release nitrogen fertilizer management (CRN), respectively. Under controlled irrigation (CI), the respective losses were 7.40, 5.86, and 3.79 kg ha⁻¹ for the same management methods. The total P leaching losses during the rice season under FI were 0.939, 0.927, and 0.353 kg ha⁻¹ for FFP, SSNM, and CRN, respectively. Under CI, the losses were 0.424, 0.433, and 0.279 kg ha⁻¹, respectively, for the same management methods. Ammonium and nitrate N accounted for 42.2–65.5% and 11.8–14.7% of the total nitrogen leaching losses under different water and N management methods, respectively. Due to significant decrease of volumes of percolation water and nitrogen and phosphorus concentrations in percolation water, N and P leaching losses were reduced in the CI treatment compared to the FI treatment under the same N management. The reduction of N input and application of controlled-release nitrogen fertilizer can reduce N and P leaching losses from paddy fields.     

Microtuberization of Potato (Solanum tuberosum L.) as Influenced by Supplementary Nutrients, Plant Growth Regulators, and In Vitro Culture Conditions

Five experiments with in vitro-grown plantlets of potato cvs ‘Superior,’ ‘Early Valley,’ ‘Golden Valley,’ and ‘Winter Valley’ were carried out to investigate in a stepwise approach the potential for enhancing microtuber production of (1) adding supplementary nutrients (SN) including KNO₃, NH₄H₂PO₄, Ca(NO₃)₂.4H₂O, and MgSO₄ in full- or half-strength Murashige and Skoog (MS) medium, (2) adding a pretested combination of plant growth regulators (PGRs), i.e., 10 mg l⁻¹ 6-benzyl aminopurine plus 200 mg l⁻¹ succinic acid 2,2-dimethylhydrazide, (3) varying the timing of the supplemental applications, and (4) varying the replenishment of the medium. Plantlets of ‘Superior’ for microtuberization were grown from two-node explants for 75 days under environmental conditions consisting of 22 ± 2 °C and a 16-h photoperiod on a solid basal medium consisting of half-strength MS (1/2 MS) medium containing 6 % sucrose and a moderate concentration of supplementary nutrients, SN-2 (KNO₃, 1.22 g l⁻¹; NH₄H₂PO₄, 1.41 g l⁻¹; Ca(NO₃)₂4H₂O, 0.23 g l⁻¹; and MgSO₄, 0.74 g l⁻¹). Thereafter, plantlets were grown for 60 days under dark conditions. Liquid media containing different combinations of MS, SN, and PGR levels plus 8 % sucrose were added as a supplement and were evaluated for their ability to increase tuberization compared to the control composition of the supplement (MS with 8 % sucrose). In the first experiment, addition of 1/2 MS liquid medium containing 8 % sucrose and SN-2 before dark incubation induced the highest total number of microtubers (on average 1.4 per plantlet), a significantly higher weight and size than the control, and the highest percentage (50 %) of large-sized (>500 mg) microtubers. In the second experiment, addition of 1/2 MS liquid medium containing 8 % sucrose, SN-2, and PGRs produced the highest number (on average 1.5 per plantlet) and total yield (on average 971 mg per plantlet) of microtubers, and significantly the highest percentage (66 %) of large-sized (>500 mg) microtubers. The size of the microtubers was higher than for the treatment without growth regulators. The optimum time for addition of supplemental medium containing 8 % sucrose, SN-2, and PGRs was shown in experiment 3 to be latest 1 week before dark incubation. This timing resulted in both the highest microtuber number (on average 1.6 per plantlet) and yield (on average 1208 mg per plantlet), and the highest percentage (64 %) of large-sized microtubers. Finally, it was found that a second supplemental treatment consisting of 50 % replacement of the liquid medium (by volume) 2 weeks after transfer to dark conditions gave rise to the highest number (on average 1.9 per plantlet), yield (on average 1346 mg per plant), and also significantly the highest percentage (25 %) of large-sized microtubers (>1000 mg) as compared to replacement of a greater or smaller proportion of the medium. Four potato cultivars, ‘Superior,’ ‘Early Valley,’ ‘Golden Valley,’ and ‘Winter Valley’ produced acceptable numbers and yield of microtubers of relatively large-sized tubers using a process that included supplemental liquid medium with 1/2 MS, 8 % sucrose, moderate concentration (SN-2) of SNs and PGRs, followed by a 50 % replacement of the same medium.     

Assessment of the long-term variation in the nitrogen pollution load potential from farmland to groundwater in the Tedori River Basin, Japan

The long-term nitrogen pollution load potential (NPLPg) to groundwater from farmlands was examined in the Tedori River Basin. The NPLPg was estimated using the difference between N in the fertilizer application rate and N outputs in crop yield at 5-yearly intervals from 1960 to 2005. The total yearly NPLPg of 1,085 t (103 kg) in the 1960s decreased to 774 t by 1975. Thereafter, the NPLPg gradually increased to 976 t in the 1990s, but decreased again to 369 t in 2005. The NPLPg decreased by 23% for rice and by 37% for horticultural crops from 1960 to 2005 with an overall decrease of 34%. The NPLPg per unit area was relatively stable over time for rice, soybean, barley, and horticultural crops, but there were significant differences among them. The NPLPg for rice ranged from 39 to 85 kg ha⁻¹ year⁻¹ with an average of 65 kg ha⁻¹ year⁻¹ and that of the horticultural crops ranged from 273 to 357 kg ha⁻¹ year⁻¹ with an average of 302 kg ha⁻¹ year⁻¹ The significant long-term changes in the NPLPg suggest that evaluation at a specific point in time is insufficient for an integrated assessment of groundwater pollution.     

Developmental dynamics of Ambystoma tigrinum in a changing landscape

Background  

Loss of pond habitat is catastrophic to aquatic larval amphibians, but even reduction in the amount of time a breeding site holds water (hydroperiod) can influence amphibian development and limit reproductive success. Using the landscape variation of a glacial valley in the Greater Yellowstone Ecosystem as the context for a natural experiment, we examined variation in growth pattern and life history of the salamander Ambystoma tigrinum melanostictum and determined how these developmental characteristics varied with hydroperiod over several summers.     

Relative efficiency of vermicompost as direct application manure in pisciculture

Wide variation (>10.28 times) of fish yield (Cyprinus carpio Linnaeus, 1758) was obtained in a trial arranged in concrete cisterns (100 l) receiving compost (T-2), Diammonium phosphate (=DAP) (T-3) and vermicompost (T-4) as direct application fertilizer and manure in those systems. Significant (P < 0.005) differences were observed in diversity and abundance of plankton in response to manure application among treatments. Highest phyto- and zooplankton population was found in the cistern treated with vermicompost followed by DAP, compost and control. In all the treatments dry weight and population of both phyto- and zooplankton population were significantly (P < 0.005) higher than control. The highest production of fish was obtained in the cisterns treated with vermicompost (3,970.56 kg ha⁻¹ 90 day⁻¹), followed by diammonium phosphate (3,080.45 kg ha⁻¹ 90 day⁻¹), compost (1,952.64 kg ha⁻¹ 90 day⁻¹) and the lowest in the control (385.92 kg ha⁻¹ 90 day⁻¹). Vermicompost might be cost-effective manure in carp culture, replacing the expensive chemical fertilizer diammonium phosphate.