Predictive Ecological Modeling of Harmful Algal Blooms

We have thus far constructed a series of coupled ecological/physical models to predict the origin and fate of harmful algal blooms of the toxic dinoflagellate, Gymnodinium breve, on the West Florida shelf. We find that (1) the maximal population growth rate of G. breve must be ～0.80 day^?1 during initiation of a red tide, but as little as 0.08 day^?1 during its decay, (2) diatoms dominate when estuarine and shelf-break supplies of nitrate are made available to a model community of small and large diatoms, coccoid cyanophytes and Trichodesmium, non-toxic and red-tide dinoflagellates, microflagellates, and coccolithophores, (3) a numerical recipe for large red tides of G. breve requires DON supplies, mediated by iron-starved, nitrogen-fixers, while small blooms may persist on sediment sources of DON, (4) selective grazing must be exerted on the non-toxic dinoflagellates, and (5) vertical migration of G. breve in relation to seasonal changes of summer downwelling and fall/winter upwelling flow fields determines the duration and intensity of red tide landfalls along the barrier islands and beaches of the west coast of Florida, once other losses are specified. Given poorly known initial and boundary conditions and the expense of shipboard monitoring programs, however, bio-optical moorings or remote sensors are the most likely sources of model validation and improved HAB forecasts. Accordingly, the bio-optical implications of our ecological models must be included in future simulation analyses of HABs on both the West Florida shelf and within other coastal regions. Of particular importance for initiation of the coupled biophysical models is an improved understanding of the relationship of remotely sensed surface signals to shade-adapted dinoflagellates, aggregating below the first optical depth of the water column.     

Metabolic Microenvironmental Control by Photosynthetic Biofilms under Changing Macroenvironmental Temperature and pH Conditions

Ex situ microelectrode experiments, using cyanobacterial biofilms from karst water creeks, were conducted under various pH, temperature, and constant-alkalinity conditions to investigate the effects of changing environmental parameters on cyanobacterial photosynthesis-induced calcification. Microenvironmental chemical conditions around calcifying sites were controlled by metabolic activity over a wide range of photosynthesis and respiration rates, with little influence from overlying water conditions. Regardless of overlying water pH levels (from 7.8 to 8.9), pH at the biofilm surface was approximately 9.4 in the light and 7.8 in the dark. The same trend was observed at various temperatures (4°C and 17°C). Biological processes control the calcium carbonate saturation state (Ω) in these and similar systems and are able to maintain Ω at approximately constant levels over relatively wide environmental fluctuations. Temperature did, however, have an effect on calcification rate. Calcium flux in this system is limited by its diffusion coefficient, resulting in a higher calcium flux (calcification and dissolution) at higher temperatures, despite the constant, biologically mediated pH. The ability of biological systems to mitigate the effects of environmental perturbation is an important factor that must be considered when attempting to predict the effects of increased atmospheric partial CO₂ pressure on processes such as calcification and in interpreting microfossils in the fossil record.     

Fishers' knowledge and seahorse conservation in Brazil

From a conservationist perspective, seahorses are threatened fishes. Concomitantly, from a socioeconomic perspective, they represent a source of income to many fishing communities in developing countries. An integration between these two views requires, among other things, the recognition that seahorse fishers have knowledge and abilities that can assist the implementation of conservation strategies and of management plans for seahorses and their habitats. This paper documents the knowledge held by Brazilian fishers on the biology and ecology of the longsnout seahorse Hippocampus reidi. Its aims were to explore collaborative approaches to seahorse conservation and management in Brazil; to assess fishers' perception of seahorse biology and ecology, in the context evaluating potential management options; to increase fishers' involvement with seahorse conservation in Brazil. Data were obtained through questionnaires and interviews made during field surveys conducted in fishing villages located in the States of Piauí, Ceará, Paraíba, Maranhão, Pernambuco and Pará. We consider the following aspects as positive for the conservation of seahorses and their habitats in Brazil: fishers were willing to dialogue with researchers; although captures and/or trade of brooding seahorses occurred, most interviewees recognized the importance of reproduction to the maintenance of seahorses in the wild (and therefore of their source of income), and expressed concern over population declines; fishers associated the presence of a ventral pouch with reproduction in seahorses (regardless of them knowing which sex bears the pouch), and this may facilitate the construction of collaborative management options designed to eliminate captures of brooding specimens; fishers recognized microhabitats of importance to the maintenance of seahorse wild populations; fishers who kept seahorses in captivity tended to recognize the condtions as poor, and as being a cause of seahorse mortality.     

Science – A life fully lived: Joe Sodroski wins the 2006 Retrovirology Prize

The 2006 M Jeang Retrovirology Prize for HIV research has been awarded to Dr Joe Sodroski     

Actinomycotic mycetoma due to Streptomyces somaliensis: report of a case in South Africa.

The etiology of mycetomas due to aerobic actinomycetes in southern Africa is still not well understood. Martin and Berson (1973) have suggested that trauma plays an important initial part in this and several other subcutaneous mycotic infections but adequate documentation is often sadly lacking. The following case report is the first known for southern Africa in which Streptomyces somaliensis has been shown by culture and by histology to be the casual organism, and one of the few where the history is well known.     

Fungi associated with urea-formaldehyde foam insulation in Canada

Sixty-eight fungal taxa were identified from samples of urea-formaldehyde foam insulation taken from Canadian residences. Mesophilic taxa were predominant, with Penicillium spp., Trichoderma harzianum and Paecilomyces variotii observed most frequently. Extensive or conspicuous growth also was seen for Hormoconis resinae, Stachybotrys chartarum and Trichoderma viride in some samples. The potential for these fungi to have contributed to the adverse health effects reported in some homes containing UF-foam insulation is discussed.     

Diurnal patterns of photosynthesis, chlorophyll fluorescence, and PRI to evaluate water stress in the invasive species, Elaeagnus umbellata Thunb.

Photosynthesis, chlorophyll fluorescence, and hyperspectral reflectance were used to evaluate diurnal changes of Elaeagnus umbellata to quantify physiological responses of the invasive species during times of stress. Field measurements showed that E. umbellata is able to maintain higher levels of photosynthesis relative to nearby Quercus alba plants, with less water loss. Plants subjected to progressive drought were able to recover photosynthesis one day following re-watering. Laboratory and field measurements revealed decreasing ΔF/F′_m values in response to drought stress, with little corresponding decrease in photochemical reflectance index values. This research supports the view that xanthophyll cycle dissipation is not the photoprotective mechanism at work for Elaeagnus species under water stress. Elaeagnus umbellata maintains photosynthetic carbon assimilation even under drought conditions, in part, due to chemical dissipation of excess light, and in part because of morphological features that limit excess radiation while maximizing photosynthetic carbon gain. These characteristics may contribute to the invasive success of E. umbellata.     

Cervical screening in Perth and Kinross since introduction of the new contract.

OBJECTIVE--To determine changes in the cervical screening service since the introduction of the new general practitioner contract on 1 April 1990. DESIGN--Analysis of computerised records of cervical screening both before and after introduction of the new contract. SETTING--General practices in Perth and Kinross Unit, Tayside. PATIENTS--A total of 30,071 women aged 21-60 on 26 general practitioner partnership lists. MAIN OUTCOME MEASURES--Percentage average of target population for cervical screening in each practice for first three quarters on introduction of the contract. RESULTS--Perth and Kinross Unit completed a computerised cervical screening call programme in July 1989, which produced an increase from 71% to 78% in the mean percentage of women aged 20-60 who had had cervical smear tests within 5.5 years. Six months after the introduction of the new general practitioner contract the mean population coverage was increased to 85% in women aged 21-60 and only four practices had not attained the 80% upper target compared with 10 on 1 April 1990. Detailed examination of randomly selected practices immediately before the new contract was introduced showed an average artificial list inflation of 4.3% in health board records when compared with practice records, a hysterectomy rate of 6.2%, and an additional 3% of women who were considered to be ineligible for smear testing due to putative virginity or illness or infirmity, or both. There was a considerable shift away from use of well woman clinics (2.7% of smears in 1990 compared with 5.6% in 1988) for taking cervical smears, potentially threatening the long term viability of the clinics. CONCLUSION--The introduction of the new contract for general practitioners has brought about a further sustained increase in population coverage for cervical screening in a small Scottish unit with a stable population, well motivated general practitioners, and a fully integrated computerised call and recall system based on the community health index. To optimise the screening service revision of the targets levels is necessary.