Integrating the Microbial Loop and the Classic Food Chain Into a Realistic Planktonic Food Web. In: Polis GA, Winemiller KO, editors. Food Webs. Boston: Springer US; 1996. pp. 51-9. [DOI: 10.1007/978-1-4615-7007-3_5]

The chytrid insurance hypothesis: integrating parasitic chytrids into a biodiversity-ecosystem functioning framework for phytoplankton-zooplankton population dynamics

In temperate lakes, eutrophication and warm temperatures can promote cyanobacteria blooms that reduce water quality and impair food-chain support. Although parasitic chytrids of phytoplankton might compete with zooplankton, they also indirectly support zooplankton populations through the "mycoloop", which helps move energy and essential dietary molecules from inedible phytoplankton to zooplankton. Here, we consider how the mycoloop might fit into the biodiversity-ecosystem functioning (BEF) framework. BEF considers how more diverse communities can benefit ecosystem functions like zooplankton production. Chytrids are themselves part of pelagic food webs and they directly contribute to zooplankton diets through spore production and by increasing host edibility. The additional way that chytrids might support BEF is if they engage in "kill-the-winner" dynamics. In contrast to grazers, which result in "eat-the-edible" dynamics, kill-the-winner dynamics can occur for host-specific infectious diseases that control the abundance of dominant (in this case inedible) hosts and thus limit the competitive exclusion of poorer (in this case edible) competitors. Thus, if phytoplankton diversity provides functions, and chytrids support algal diversity, chytrids could indirectly favour edible phytoplankton. All three mechanisms are linked to diversity and therefore provide some "insurance" for zooplankton production against the impacts of eutrophication and warming. In our perspective piece, we explore evidence for the chytrid insurance hypothesis, identify exceptions and knowledge gaps, and outline future research directions.

SIMULATION OF BIOMASS DYNAMICS IN PLANKTON OF A HIGH-ALTITUDE ANDEAN TROPICAL RESERVOIR IN COLOMBIA

The understanding of the relationships between the planktonic communities in a reservoir allows us to infer possible changes in the redistribution of matter and energy flows in these systems. This work proposes a dynamic model for the trophic network of the Riogrande II tropical reservoir, which integrates the planktonic trophic chains of detritus and grazing, limiting the prey-predator interactions by introducing the prey meeting factor (pmf). We built a dynamic model of mass balance supported by an extensive bibliographic search. The limitations of consumers and resources were represented simultaneously by means of the pmf. The data used to validate the model were compiled from previous investigations carried out in this reservoir from 2010 to 2013. The values of pmf that we found in each simulation suggest that the top predator can access its main prey in certain concentrations of total phosphorus, with a probability of encounter ranging from 9.3 % to 17.7 %. Our simulations indicate that most of the primary production is poorly used by the primary consumers in the photic zone, however, it enters in the flows of the detrital chain and supports the production of zooplankton almost entirely. According to this finding, the biomass densities obtained in the previous studies can be better explained by the causal relationships assumed in this model.

EARLY HISTORY AND PROGRESS OF WOMEN ECOLOGISTS: Emphasis Upon Research Contributions

▪ Abstract  Although women are increasingly prominent as ecologists, a report on their progress through the history of ecology in overcoming personal and societal obstacles provides interesting insights regarding their research achievements. Selected, predominantly American, women ecologists are presented within five time frames according to the date of their PhD, an event marking the beginning of their careers. A general view is given for pre-1900 Protoecologists, followed by brief professional sketches for 10 Early Pioneers (1900–1934), 16 Late Pioneers (1935–1960), and 28 members of the irst Modern Wave (1961–1975). The relatively large number of women who earned doctorates after 1975 precludes discussion of individuals from this time in this review. The following issues are discussed in the context of their research contributions: 1) motivating factors, 2) graduate education and subfield entered, 3) mentors and role models, 4) employment, 5) marriage and family constraints, and 6) recognition. These issues are compared with data from recent surveys for post-1976 women doctorates. Each selected woman still alive was contacted for her assessment of her research; 156 research citations display the significance and range of subjects studied. A steady, albeit slow, progress since 1900 is evident, although some problems regarding gender equality in professional development of women ecologists persist. These issues, however, are now more clearly recognized and addressed.