Environmental controls, oceanography and population dynamics of pathogens and harmful algal blooms: connecting sources to human exposure

© 2008 Author et al. This is an open access article distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Environmental Health 7 (2008): S5, doi:10.1186/1476-069X-7-S2-S5.Coupled physical-biological models are capable of linking the complex interactions between environmental factors and physical hydrodynamics to simulate the growth, toxicity and transport of infectious pathogens and harmful algal blooms (HABs). Such simulations can be used to assess and predict the impact of pathogens and HABs on human health. Given the widespread and increasing reliance of coastal communities on aquatic systems for drinking water, seafood and recreation, such predictions are critical for making informed resource management decisions. Here we identify three challenges to making this connection between pathogens/HABs and human health: predicting concentrations and toxicity; identifying the spatial and temporal scales of population and ecosystem interactions; and applying the understanding of population dynamics of pathogens/HABs to management strategies. We elaborate on the need to meet each of these challenges, describe how modeling approaches can be used and discuss strategies for moving forward in addressing these challenges.The authors acknowledge the financial support for the NSF/NIEHS and NOAA Centers for Oceans and Human Healt

Air-sea fluxes with a focus on heat and momentum

Turbulent and radiative exchanges of heat between the ocean and atmosphere (hereafter heat fluxes), ocean surface wind stress, and state variables used to estimate them, are Essential Ocean Variables (EOVs) and Essential Climate Variables (ECVs) influencing weather and climate. This paper describes an observational strategy for producing 3-hourly, 25-km (and an aspirational goal of hourly at 10-km) heat flux and wind stress fields over the global, ice-free ocean with breakthrough 1-day random uncertainty of 15 W m–2 and a bias of less than 5 W m–2. At present this accuracy target is met only for OceanSITES reference station moorings and research vessels (RVs) that follow best practices. To meet these targets globally, in the next decade, satellite-based observations must be optimized for boundary layer measurements of air temperature, humidity, sea surface temperature, and ocean wind stress. In order to tune and validate these satellite measurements, a complementary global in situ flux array, built around an expanded OceanSITES network of time series reference station moorings, is also needed. The array would include 500–1000 measurement platforms, including autonomous surface vehicles, moored and drifting buoys, RVs, the existing OceanSITES network of 22 flux sites, and new OceanSITES expanded in 19 key regions. This array would be globally distributed, with 1–3 measurement platforms in each nominal 10° by 10° box. These improved moisture and temperature profiles and surface data, if assimilated into Numerical Weather Prediction (NWP) models, would lead to better representation of cloud formation processes, improving state variables and surface radiative and turbulent fluxes from these models. The in situ flux array provides globally distributed measurements and metrics for satellite algorithm development, product validation, and for improving satellite-based, NWP and blended flux products. In addition, some of these flux platforms will also measure direct turbulent fluxes, which can be used to improve algorithms for computation of air-sea exchange of heat and momentum in flux products and models. With these improved air-sea fluxes, the ocean’s influence on the atmosphere will be better quantified and lead to improved long-term weather forecasts, seasonal-interannual-decadal climate predictions, and regional climate projections

Mesoscale variability in the tropical thermocline during GATE

Data collected in the Atlantic equatorial Counter current during GATE, using a Neil Brown,WHOI CTD Microprofiler mounted in a eatfish arc analysed for mesoscale thermchaline variability en surfaces of constant at(isopycnals). The Batfish was towed from RIGS 'Discovery' and was made to cycle between about 10 and 70 m depth, in a series of survey patterns which were advected by the surface flow.After interpolation on to surfaces of constant density, potential temperature and pressure, corrupted data were edited by inspection of the T-S relationship on isopynals.within the stratum between the mixed layer and the salinity maximum, a region stable to double-diffusive effects, histograms of isopycnic salinity show a distinct bi-modal distribution and examination of isopycnic potential temperature fluctuations reveals a mesoscale front, with vertical extent of order 10 m.An associated disturhance in the density field, manifested as a large lateral change in the vertical separation of isopycnals, occurs at the same place but is masked in a conventional examination in pressure co-ordinates by the larger internal wave signal. The front is best delineated in terms of its thermoclinicity, represented as the separation of an isopycnal and an intersecting isotherm. Overturning events are concentrated in the region of large lateral gradients of static stability which are inferred to be the sites of large quasi-geostrophic current shears. The front exists and evolves, within the 22 hours of the survey, as an adiabatic process.</p

Fluorescence Switching for Temperature Sensing in Water

A water-soluble thermochromic molecular switch with spectrally resolvedfluorescence in its two interconvertiblestates can be assembled in three synthetic steps by integrating afluorescent coumarin chromophore, a hydrophilic oligo(ethyleneglycol) chain, and a switchable oxazole heterocycle in the same covalent skeleton. Measurements of its two emissions in separatedetection channels of afluorescence microscope permit the noninvasive and ratiometric sensing of temperature at the micrometerlevel with millisecond response in aqueous solutions and within hydrogel matrices. The ratiometric optical output of thisfluorescentmolecular switch overcomes the limitations of single-wavelengthfluorescent probes and enables noninvasive temperature mapping atlength scales that are not accessible to conventional thermometers based on physical contact

Sea surface temperature validation and blended analysis

Sea surface temperature is an essential variable for oceanography, meteorology, and climatology. In situ and satellite observations are used together in creating products that meet the requirements for both near-real-time and retrospective, consistent data sets. In situ measurements, particularly those of drifting buoys and moorings, are used to validate satellite sea surface temperature retrievals, and in some cases are also used to define those retrievals. The validation strategy should have clear objectives and be designed accordingly. A checklist of eight aspects to consider in designing a validation strategy is discussed, the question of independence being particularly crucial. Validation can and should assess both the retrieval characteristics and the uncertainty model attributed to the retrieval. The other usage of in situ data is in blending with satellite information to create higher level products, such as gap-filled analyses of sea surface temperature. While daily analyses are typical, the scope for capturing subdaily variability is discussed. For product validation, particularly of blended analyses, we emphasize the value of producers reserving an agreed set of in situ data; this is to help drive real reductions in product uncertainty to meet the more stringent emerging requirements for sea surface temperature observation in the context of coupled weather and climate models

MISST: The Multi-Sensor Improved Sea Surface Temperature Project

Sea surface temperature (SST) measurements are vital to global weather prediction, climate change studies, fisheries management, and a wide range of other applications. Measurements are taken by several satellites carrying infrared and microwave radiometers, moored buoys, drifting buoys, and ships. Collecting all these measurements together and producing global maps of SST has been a difficult endeavor due in part to different data formats, data location and accessibility, and lack of measurement error estimates. The need for a uniform approach to SST measurements and estimation of measurement errors resulted in the formation of the international Global Ocean Data Assimilation Experiment (GODAE) High Resolution SST Pilot Project (GHRSST-PP). Projects were developed in Japan, Europe, and Australia. Simultaneously, in the United States, the Multi-sensor Improved SST (MISST) project was initiated. Five years later, the MISST project has produced satellite SST data from nine satellites in an identical format with ancillary information and estimates of measurement error. Use of these data in global SST analyses has been improved through research into modeling of the ocean surface skin layer and upper ocean diurnal heating. These data and research results have been used by several groups within MISST to produce high-resolution global maps of SSTs, which have been shown to improve tropical cyclone prediction. Additionally, the new SSTs are now used operationally for marine weather warnings and forecasts