Impacts of biodiversity loss on ocean ecosystem services

Human-dominated marine ecosystems are experiencing accelerating loss of populations and species, with largely unknown consequences. We analyzed local experiments, long-term regional time series, and global fisheries data to test how biodiversity loss affects marine ecosystem services across temporal and spatial scales. Overall, rates of resource collapse increased and recovery potential, stability, and water quality decreased exponentially with declining diversity. Restoration of biodiversity, in contrast, increased productivity fourfold and decreased variability by 21%, on average. We conclude that marine biodiversity loss is increasingly impairing the ocean's capacity to provide food, maintain water quality, and recover from perturbations. Yet available data suggest that at this point, these trends are still reversible.     

Nest inheritance is the missing source of direct fitness in a primitively eusocial insect

Animals that cooperate with nonrelatives represent a challenge to inclusive fitness theory, unless cooperative behavior is shown to provide direct fitness benefits. Inheritance of breeding resources could provide such benefits, but this route to cooperation has been little investigated in the social insects. We show that nest inheritance can explain the presence of unrelated helpers in a classic social insect model, the primitively eusocial wasp Polistes dominulus. We found that subordinate helpers produced more direct offspring than lone breeders, some while still subordinate but most after inheriting the dominant position. Thus, while indirect fitness obtained through helping relatives has been the dominant paradigm for understanding eusociality in insects, direct fitness is vital to explain cooperation in P. dominulus.     

Amplification of acetylcholine-binding catenanes from dynamic combinatorial libraries

Directed chemical synthesis can produce a vast range of molecular structures, but the intended product must be known at the outset. In contrast, evolution in nature can lead to efficient receptors and catalysts whose structures defy prediction. To access such unpredictable structures, we prepared dynamic combinatorial libraries in which reversibly binding building blocks assemble around a receptor target. We selected for an acetylcholine receptor by adding the neurotransmitter to solutions of dipeptide hydrazones [proline-phenylalanine or proline-(cyclohexyl)alanine], which reversibly combine through hydrazone linkages. At thermodynamic equilibrium, the dominant receptor structure was an elaborate [2]-catenane consisting of two interlocked macrocyclic trimers. This complex receptor with a 100 nM affinity for acetylcholine could be isolated on a preparative scale in 67% yield.     

The unusual nature of recent snowpack declines in the North American cordillera

In western North America, snowpack has declined in recent decades, and further losses are projected through the 21st century. Here, we evaluate the uniqueness of recent declines using snowpack reconstructions from 66 tree-ring chronologies in key runoff-generating areas of the Colorado, Columbia, and Missouri River drainages. Over the past millennium, late 20th century snowpack reductions are almost unprecedented in magnitude across the northern Rocky Mountains and in their north-south synchrony across the cordillera. Both the snowpack declines and their synchrony result from unparalleled springtime warming that is due to positive reinforcement of the anthropogenic warming by decadal variability. The increasing role of warming on large-scale snowpack variability and trends foreshadows fundamental impacts on streamflow and water supplies across the western United States.     

Carbon storage and spatial distribution patterns of paddy soils in China

Carbon storage in agricultural soils plays a key role in terrestrial ecosystem carbon cycles. Paddy soil is one of the major cultivated soil types in China and is of critical significance in studies on soil carbon sequestration. This paper estimated the organic and inorganic carbon density and storage in paddy soils, and analyzed the paddy soil stock spatial distribution patterns in China based on subgroups and regions using the newly compiled 1:1 000 000 digital soil map of China as well as data from 1 490 paddy soil profiles. Results showed that paddy soils in China cover an area of about 45.69 Mhm², accounting for 4.92% of total soil area in China. Soil organic and inorganic carbon densities of paddy soils in China showed a great heterogeneity. Paddy soil organic carbon densities (SOCD) in soil profile ranged from 0.53 to 446.2 kg/m² (0 to 100 cm) while the paddy soil inorganic carbon densities (SICD) ranged from 0.05 to 90.03 kg/m². Soil organic carbon densities of paddy soils in surface layer ranged from 0.17 to 55.38 kg/m² (0 to 20 cm), with SICD of paddy soils ranging from 0.01 to 21.85 kg/m². Profile based and surface layer based paddy soil carbon storages (SCS) are 5.39 Pg and 1.79 Pg, respectively. Paddy soil organic carbon storage (SOCS) accounts for 95% of the total carbon storage. Profile based and surface layer based SOCS of paddy soils are 5.09 Pg and 1.72 Pg, respectively. Soil inorganic carbon storage (SICS) of paddy soils accounts for 5% of the total carbon storage in China. Profile based and surface layer based paddy SICS are 0.30 Pg and 0.07 Pg respectively. Among all the eight paddy soil subgroups, hydromorphic, submergenic and percogenic paddy soils account for 85.2% of the total paddy soil areas all over China. Consequently, profile based carbon storages of these three subgroups account for 78.1% of the total profile based paddy SCS in China. Most paddy soils in China are distributed in the East-China, South-China and South-west China regions, therefore, 92.6% of China’s profile based paddy SCS focuses on these three regions. The estimates of soil carbon stocks in paddy soils will help to identify areas or soil subgroups which are of particular interest for soil carbon gains and losses. Translated from Ecology and Environment, 2006, 15(4): 659–664 [译自: 生态环境]     

Evaluation of tulathromycin for the treatment of pneumonia following experimental infection of swine with Mycoplasma hyopneumoniae

Tulathromycin was evaluated in the treatment of pneumonia in weaned pigs inoculated intranasally with Mycoplasma hyopneumoniae. Five days postchallenge, the pigs were randomized to treatment with a single IM administration of saline, a single IM administration of tulathromycin (2.5 mg/kg; day 0), or three IM administrations of enrofloxacin (5.0 mg/kg; days 0, 1, 2). Pigs were necropsied on day 12 or 13. Unchallenged controls remained healthy with no lung pathology. Compared with saline, coughing, mean lung lesion score, and proportional lung weight were significantly reduced and weight gain was significantly greater for tulathromycin-treated pigs (P < .05). Compared with enrofloxacin, there were no significant differences in proportional lung weight or weight gains, but coughing and lung lesion scores were greater for tulathromycin-treated pigs (P < .05). Tulathromycin was effective in the treatment of pneumonia following experimental infection with M. hyopneumoniae.     

Detection,characterization, and control of bovine viral diarrhea virus infection in a large commercial dairy herd

Detection, genetic characterization, and control of bovine viral diarrhea virus (BVDV) disease in a large commercial dairy herd is reported. Precolostral BVDV serum antibody was detected in 5.3% (12/226) of newborn calves before the test and removal of persistently infected (PI) animals and in 0.4% (2/450) of newborn calves after the removal of PI heifers.