Spatial and temporal patterns of predation on seeds of the surfgrass Phyllospadix torreyi

Spatial and temporal patterns of predation on seeds of the seagrass Phyllospadix torreyi S. Watson were quantified at four sites near Santa Barbara, California, USA. Over a period of four flowering seasons during 1995 to 1998, monthly patterns of seed fall and intensity of seed predation were similar among sites, but were temporally quite variable. Abundance of dispersed seeds varied greatly both among seasons and years. Within any one year, seeds were present in the environment every month, but they peaked in abundance during the fall months following the annual flowering period. Seeds were more abundant during the earlier years of the study. The intensity of predation steadily increased throughout the study period, from a low of ≤10% seeds consumed during 1995 to ∼50% consumption by 1997, and it was not correlated with abundance of seeds in the environment. Pre-dispersal seed loss also was estimated in two flowering seasons by counting the numbers of seeds consumed prior to release from the plant, and was relatively low (<15%). No differences were detected among the four study sites in patterns of pre-dispersal loss. Field surveys were done at two sites to identify potential seed predators. Three of the most abundant species identified in these surveys were tested in the laboratory to determine size-specific patterns of feeding activity and to assess which early life stages of P. torreyi (fruits within spadices, dehisced fruits, seedlings) were most vulnerable to predation. All three of the early life stages were consumed. The crabs Pugettiaproducta (Randall) and Pachygrapsus crassipes Randall were much more voracious predators than the isopod Idotea resecata Stimpson. Received: 8 June 1999 / Accepted: 2 February 2000     

调节细胞通透性促进天蓝色链霉菌蓝色素生物合成

在天蓝色链霉菌分批发酵中，36h时一次加入20mg/L的青霉素，色素浓度和分泌率分别提高了26．2％和39．2％；与一次性添加青霉素相比，分多次添加可使色素浓度再提高9％，但分泌率没有明显变化。DMSO浓度为6g/L时，色素浓工和分泌率较对照分别提高了20．5％和50％；2－50g/L的DMSO对菌体生长没有影响。36h时lg/L的吐温80，色素浓度和分泌率分别提高了16．9％和37．5％，60h时加入0.2g/L浓度的SDS，色素浓度较对照基本相当，但分泌率却提高了16．1％。图4表1参7     

A basidiomycete isolated from the skeleton of<Emphasis Type="Italic"> Pocillopora damicornis</Emphasis> (Scleractinia) selectively stimulates short-term survival of coral skeletogenic cells

Endolithic fungi bore through the extracellular calcium carbonate skeleton of reef-building scleractinian corals, both healthy and dead, and effect net erosion of coral reefs. Potential fungal interactions with coral tissue were investigated using an in vitro approach suggested by earlier observations of skeletal repair cones at the site of fungal perforation in Porites sp. A fungal strain was isolated from the skeleton of a long-term culture of healthy, tissue-covered, Pocillopora damicornis Linnaeus colonies maintained in a recirculating system in Monaco. As coral soft tissue spontaneously dissociated in vitro, the skeleton became exposed and hyaline hyphae emerged radially from 15% of the total clipped branches. In this study, which was performed between January 2001 and March 2003, 35 skeleton–hypha explants were embedded in agar-based solid medium, yielding 60% hyphal growth. A fungal strain (F19-3-1) of the dominant (80%) morphology was isolated and propagated in agar-based solid medium. The strain was identified by 18S and 26S rDNA gene sequence analysis as a basidiomycete in the genus Cryptococcus. Co-cultures were used to provide experimental exposure of coral soft tissue to the fungus. The fungus extended the survival of coral cells by 2 days, selectively maintaining skeletogenic cell types. This effect may be interpreted as stimulation by the fungus of a short-term coral defense response.Communicated by J.P. Grassle, New Brunswick     

Potassium carbonate-based ternary transition temperature mixture (deep eutectic analogues) for CO2 absorption: Characterizations and DFT analysis

•Addition of hindered amine increased thermal stability and viscosity of TTTM. •Addition of hindered amine improved the CO₂ absorption performance of TTTM. •Good the CO₂ absorption of recycled solvents after two regenerations. •Important role of amine group in CO₂ absorption of TTTM confirmed by DFT analysis. Is it possible to improve CO₂ solubility in potassium carbonate (K₂CO₃)-based transition temperature mixtures (TTMs)? To assess this possibility, a ternary transition-temperature mixture (TTTM) was prepared by using a hindered amine, 2-amino-2-methyl-1,3-propanediol (AMPD). Fourier transform infrared spectroscopy (FT-IR) was employed to detect the functional groups including hydroxyl, amine, carbonate ion, and aliphatic functional groups in the prepared solvents. From thermogravimetric analysis (TGA), it was found that the addition of AMPD to the binary mixture can increase the thermal stability of TTTM. The viscosity findings showed that TTTM has a higher viscosity than TTM while their difference was decreased by increasing temperature. In addition, Eyring’s absolute rate theory was used to compute the activation parameters (ΔG*, ΔH*, and ΔS*). The CO₂ solubility in liquids was measured at a temperature of 303.15 K and pressures up to 1.8 MPa. The results disclosed that the CO₂ solubility of TTTM was improved by the addition of AMPD. At the pressure of about 1.8 MPa, the CO₂ mole fractions of TTM and TTTM were 0.1697 and 0.2022, respectively. To confirm the experimental data, density functional theory (DFT) was employed. From the DFT analysis, it was found that the TTTM+ CO₂ system has higher interaction energy (|ΔE |) than the TTM+ CO₂ system indicating the higher CO₂ affinity of the former system. This study might help scientists to better understand and to improve CO₂ solubility in these types of solvents by choosing a suitable amine as HBD and finding the best combination of HBA and HBD.     

山谷型垃圾填埋场渗沥液水量计算方法比较研究

山谷型垃圾填埋场渗沥液水量是工程设计中的一个重要基础参数，主要由场内降雨转化为场外地下径流组成。对于场外地下径流，目前国内外尚无成熟的计算方法。作者针对几种常用的水量平衡法，通过实验，验证了每种方法的精度。结果表明，考虑了树冠戴流、表层土调蓄作用等因素的模型具有相当的精度，可以作为场外地下径流的计算模型。     

Lack of population subdivision among the minke whales (Balaenoptera acutorostrata) from Icelandic and Norwegian waters based on mitochondrial DNA sequences

The minke whale (Balaenoptera acutorostrata) is subject to commercial whaling, but stock identification and assessment are still uncertain. Mitochondrial DNA (mtDNA) sequences were determined to examine the population structure of minke whales from the central and northeastern parts of the North Atlantic, as well as the Antarctic regions IV and V. The analyses include 345 nucleotide positions of the control region of 110 individuals, and 250 nucleotide positions of the NADH dehydrogenase subunit 2 gene for a representative selection of North Atlantic minke whales. Maximum parsimony analyses and sequence divergence calculations did not reveal any genetic differentiation between individuals from the central and northeastern parts of the North Atlantic. These results do not support the International Whaling Commission's separation of minke whales in this area into different management units, and they are in conflict with previously reported results from allozyme analyses. Comparison of minke whale control region sequences showed that the sequence diversity of North Atlantic minke whales is substantially lower (0.0065) than that of Antarctic minke whales (0.0166), and clearly demonstrated that individuals from these two areas represent genetically distinct populations.