Predominance of picoplankton and nanoplankton in eutrophic Calder Lake

A study was conducted to examine factors regulating the biomass of algal picoplankton in Calder Lake, a small eutrophic lake in southern New York state. A particular focus was a current paradigm which suggests that larger cells may dominate in nutrient-rich waters, while smaller cells may predominate only in oligotrophic waters. Over two years, phytoplankton biomass consisted predominantly (74% on average) of very small organisms; nanoplankton (<20 to 2 µm: 39%) and picoplankton (<2 µm to 0.2 µm: 35%), despite the presence of surface blooms of colonial cyanobacteria (Microcystis aeruginosa, Anabaena limnetica), and dense metalimnetic populations of the dinoflagellate Ceratium hirundinella. This dimictic system is characterized by relatively high levels of total P (max = 85, % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmiEayaara% aaaa!3702!\[\bar x\] = 9.7 µg P/L), inorganic P (max = 26, % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmiEayaara% aaaa!3702!\[\bar x\] = 4.5 µg P/L), and total inorganic N (max = 285, % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmiEayaara% aaaa!3702!\[\bar x\] = 85 µg P/L), but larger forms were rarely the most abundant. Unlike some marine systems, greater abundance of algal picoplankton was not associated with deeper strata (low light), or warmer temperatures. Data suggest that midsummer nutrient limitation, especially P-limitation, favors the development of pico- and nanoplankton in the limnetic zone of eutrophic lakes.     

The ecology of the Turbellaria with special reference to the freshwater triclads

To attempt a complete review of turbellarian ecology in the time and space available would result in superficiality. Therefore, I have restricted this account to the four basic ecological processes which have and continue to determine flatworm distribution and abundance. These are: (1) historical or zoogeographical events which permit or prevent a species from reaching a habitat; (2) physiological limitations of the species vis à vis the habitat; (3) access to suitable energy sources and (4) the effects of competition, predation and parasitism, referred to collectively as bionomic processes.     

The genusPicris (Asteraceae,Lactuceae) in Tropical Africa

Three species of the genusPicris L. are native in Tropical Africa:P. abyssinica Sch. Bip. (Ethiopia),P. xylopoda Lack, spec. nova (Nigeria, Ethiopia) andP. humilis DC. (Senegal, Mali). There are indications that the two perennial species,P. abyssinica andP. xylopoda, are related to and have evolved from a primitive Central Asiatic stock in a manner parallel to many African species ofCrepis L.P. humilis, on the other hand, is a small annual plant with a high number of derived characters. The introduced species of European origin growing south of the Sahara are briefly mentioned.     

Species specificity and intraspecific variation in the chemical profiles of Heliconius butterflies across a large geographic range

In many animals, mate choice is important for the maintenance of reproductive isolation between species. Traits important for mate choice and behavioral isolation are predicted to be under strong stabilizing selection within species; however, such traits can also exhibit variation at the population level driven by neutral and adaptive evolutionary processes. Here, we describe patterns of divergence among androconial and genital chemical profiles at inter‐ and intraspecific levels in mimetic Heliconius butterflies. Most variation in chemical bouquets was found between species, but there were also quantitative differences at the population level. We found a strong correlation between interspecific chemical and genetic divergence, but this correlation varied in intraspecific comparisons. We identified “indicator” compounds characteristic of particular species that included compounds already known to elicit a behavioral response, suggesting an approach for identification of candidate compounds for future behavioral studies in novel systems. Overall, the strong signal of species identity suggests a role for these compounds in species recognition, but with additional potentially neutral variation at the population level.     

Insights into the feeding ecology of the Seychelles Black Parrot Coracopsis barklyi using two monitoring approaches

Feeding ecology is an important factor for the survival of a species and knowledge of its parameters is a prerequisite for successful conservation work. In this study we describe the feeding ecology of the endemic Seychelles Black Parrot Coracopsis barklyi on Praslin, Seychelles, the only island on which this parrot is resident. We compared two methods to evaluate feeding choices: incidental observations and feeding walks on 25 transects in all habitat types. Black parrots fed on 46 different species, bringing the total number of known food plants to 53 species. They predominantly consumed endemic and native species (58% of observed feeding bouts), mainly their fruit pulp (in 68% of feeding bouts), followed by buds (15%) and seeds (37%) with occasional observations of leaves, bark and scale insects. The incidental method rendered many more observed bouts than the transect approach and the ratios of consumed species differed between methods but the transect results are regarded as more representative. The incidental method is not suitable for quantitative conclusions but complements the transect method, providing information about rarely occurring feeding events.     

Environmental Supply Chain Cooperation and Its Effect on the Circular Economy Practice‐Performance Relationship Among Chinese Manufacturers

Due to resource scarcity and environmental degradation, a new development concept emphasizing environmental concerns, called the circular economy (CE), has been enacted in legislation in China. This environmental management concept can be implemented at three levels, namely, region, industrial zone, and individual enterprise, with the objective of boosting economic development while lessening environmental and resource challenges. Environmental supply chain cooperation (ESCC), an approach that utilizes customer and supplier cooperation in environmental management, has been initiated among Chinese enterprises. Using survey data collected from 396 Chinese manufacturers, we examine the role of ESCC practices in influencing the relationship between implementing CE practices and the achievement of performance outcomes by testing the moderation and mediation effects of ESCC practices on the CE practice‐performance relationship through hierarchical regression analysis. Our data analyses indicate that ESCC practices are useful by moderation and, in some cases, essential by mediation, for Chinese manufacturers seeking to realize the performance targets desired in CE practices. The results highlight the need for Chinese manufacturers to improve supply chain coordination in their implementation of CE. On the policy side, our research findings suggest that ESCC practices are beneficial and, in some cases, necessary for the development of CE in China.     

Fungal laccases - occurrence and properties

Laccases of fungi attract considerable attention due to their possible involvement in the transformation of a wide variety of phenolic compounds including the polymeric lignin and humic substances. So far, more than a 100 enzymes have been purified from fungal cultures and characterized in terms of their biochemical and catalytic properties. Most ligninolytic fungal species produce constitutively at least one laccase isoenzyme and laccases are also dominant among ligninolytic enzymes in the soil environment. The fact that they only require molecular oxygen for catalysis makes them suitable for biotechnological applications for the transformation or immobilization of xenobiotic compounds.     

Hormonema schizolunatum, a new species of dothideaceous black yeasts from phyllosphere

Two black yeast isolates from plants from the Canary Islands (Spain) are described and illustrated. Absence of Woronin bodies at simple septal pores, local coralloid terminal hyphal cells, indeterminate thallus maturation, the presence of budding cells and local conversion to meristematic growth all indicate a relationship to the Dothideaceae (Dothideales, Ascomycota). Morphological properties were consistent with the genus Hormonema Lagerberg & Melin, as defined by presence of percurrent conidiogenous loci alongside undifferentiated hyphae, and results of PCR-ribotyping supported this classification. The isolates were judged to belong to a hitherto undescribed species, characterized in particular by curved conidia soon developing transverse septa. The physiological profile of this species is also described.