Estimating population birth rates of zooplankton when rates of egg deposition and hatching are periodic

I present a general method of computing finite birth and death rates of natural zooplankton populations from changes in the age distribution of eggs and changes in population size. The method is applicable to cases in which eggs hatch periodically owing to variable rates of oviposition. When morphological criteria are used to determine the age distribution of eggs at the beginning and end of a sampling interval, egg mortality can be incorporated in estimates of population birth rate. I raised laboratory populations of Asplanchna priodonta , a common planktonic rotifer, in semicontinuous culture to evaluate my method of computing finite birth rate. The Asplanchna population became synchronized to a daily addition of food but grew by the same amount each day once steady state was achieved. The steady-state rate of growth, which can be computed from the volume-specific dilution rate of the culture, was consistent with the finite birth rate predicted from the population's egg ratio and egg age distribution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47764/1/442_2004_Article_BF00410359.pd

CREAM: A European project on mechanistic effect models for ecological risk assessment of chemicals

Examples that clearly demonstrate the power of mechanistic effect models (MEMs) for risk assessment are urgently needed, and industry, academia, and regulatory authorities across Europe need scientists that are trained in MEMs, principles of ecotoxicology, and regulatory risk assessment. To meet these needs, Chemical Risk Effects Assessment Models (CREAM), a European project including 20 Ph.D. and three postdoctoral projects, has been launched for September 2009 and will last for 4 years. CREAM is a “Marie Curie Initial Training Network (ITN)” funded by the European Commission within the 7th Framework Programme. ITNs are part of the commission’s “People” Programme and focus on mobility and first-class training of early stage researchers. CREAM is very likely the largest joint project worldwide developing MEMs for risk assessment of chemicals. The aims and scope of CREAM are: 1. Formulate and test guidance for Good Modeling Practice (GMoP) that ensures transparent and reliable decision support for chemical risk assessment. 2. Develop a suite of well-tested and validated mechanistic ecological effect models for a range of organisms and ecosystems relevant for chemical risk assessments. 3. Provide world-class training for the next generation of modelers, emphasizing transparency and rigorous model evaluation as core elements of models for decision support

Long-term coral community records from Lugger Shoal on the terrigenous inner-shelf of the central Great Barrier Reef, Australia

Long-term (millennial timescale) records of coral community structure can be developed from the analysis of corals preserved in radiometrically dated reef cores. Here, we present such a record (based on six cores) from Lugger Shoal, a turbid zone, nearshore reef on the inner-shelf of the central Great Barrier Reef. Lugger Shoal initiated growth *800 cal yBP. It is constructed of large in situ Porites bommies, between which a framework of coral rubble (dominated by Acropora pulchra, Montipora mollis, Galaxea fascicularis and Cyphastrea serailia) has accumulated.\ud Reef accretion occurred under conditions of net long-term fine-grained, terrigenous sediment accumulation, and with a coral community dominated throughout by a consistent, but low diversity, suite of coral taxa. This dataset supports recent suggestions that nearshore coral communities that establish themselves under conditions that are already close to the thresholds for coral survival may be resilient to water quality deteriorations associated with human activities