Natural organic matter and sunlight accelerate the degradation of 17ss-estradiol in water.

Nanomolar concentrations of steroid hormones such as 17beta-estradiol can influence the reproductive development and sex ratios of invertebrate and vertebrate populations. Thus their release into surface and ground waters from wastewater facilities and agricultural applications of animal waste is of environmental concern. Many of these compounds are chromophoric and susceptible to photolytic degradation.

Medium-term and long-term priorities in ecological studies.

Research priorities in ecology and environmental sciences for the future are formulated. The priorities for both fundamental and applied ecology are proposed. The list of priorities includes 50 items.

Influence of a dominant macrophyte, Juncus effusus, on wetland plant species richness, diversity, and community composition.

Few studies have experimentally investigated the influence of competition for light on structure and composition of wetland vascular plant communities, despite the well-documented high productivity in such systems. Influences of the dominant emergent wetland plant Juncus effusus on the surrounding macrophyte community were evaluated in a shallow freshwater wetland through two consecutive growing seasons. Permanent transects were constructed along diagonals of randomly oriented 1 m plots centered around isolated, colonizing J.

Kinetic Analysis of Protein Degradation by a Freshwater Wetland Sediment Community.

The mineralization of proteins by the sediment microflora of a freshwater wetland conformed to a kinetic model developed for polymer degradation. The maximum velocity of protein mineralization ranged from 2,078 to 147 nmol of protein cm h from May to October. The turnover time of protein was 13 to 69 h.

Variations in growth and reproduction within populations of two rhizomatous plant species: Typha latifolia and Typha angustifolia.

Seasonal excavations of ramet systems in overlapping natural populations of Typha latifolia and T. angustifolia revealed intrapopulation variation in ramet size and reproduction. Reproductive "states" were recognized based on whether or not a ramet had flowered and the number of offspring ramets it possessed.

Effects of size and growth rate on vegetative reproduction in Typha.

The objective of this study was to separate the effects of plant biomass and growth rate on vegetative reproduction in two species of cat-tail, Typha latifolia and T. angustifolia. Replicate clones of both species were grown under conditions of 100%, 42%, 24%, and 9% full sunlight with harvests at 41, 70, and 91 days after shading.