Satellite sensor requirements for monitoring essential biodiversity variables of coastal ecosystems.

The biodiversity and high productivity of coastal terrestrial and aquatic habitats are the foundation for important benefits to human societies around the world. These globally distributed habitats need frequent and broad systematic assessments, but field surveys only cover a small fraction of these areas. Satellite-based sensors can repeatedly record the visible and near-infrared reflectance spectra that contain the absorption, scattering, and fluorescence signatures of functional phytoplankton groups, colored dissolved matter, and particulate matter near the surface ocean, and of biologically structured habitats (floating and emergent vegetation, benthic habitats like coral, seagrass, and algae). These measures can be incorporated into Essential Biodiversity Variables (EBVs), including the distribution, abundance, and traits of groups of species populations, and used to evaluate habitat fragmentation. However, current and planned satellites are not designed to observe the EBVs that change rapidly with extreme tides, salinity, temperatures, storms, pollution, or physical habitat destruction over scales relevant to human activity. Making these observations requires a new generation of satellite sensors able to sample with these combined characteristics: (1) spatial resolution on the order of 30 to 100-m pixels or smaller; (2) spectral resolution on the order of 5 nm in the visible and 10 nm in the short-wave infrared spectrum (or at least two or more bands at 1,030, 1,240, 1,630, 2,125, and/or 2,260 nm) for atmospheric correction and aquatic and vegetation assessments; (3) radiometric quality with signal to noise ratios (SNR) above 800 (relative to signal levels typical of the open ocean), 14-bit digitization, absolute radiometric calibration <2%, relative calibration of 0.2%, polarization sensitivity <1%, high radiometric stability and linearity, and operations designed to minimize sunglint; and (4) temporal resolution of hours to days. We refer to these combined specifications as H4 imaging. Enabling H4 imaging is vital for the conservation and management of global biodiversity and ecosystem services, including food provisioning and water security. An agile satellite in a 3-d repeat low-Earth orbit could sample 30-km swath images of several hundred coastal habitats daily. Nine H4 satellites would provide weekly coverage of global coastal zones. Such satellite constellations are now feasible and are used in various applications.

The Schistosoma mansoni Cytochrome P450 (CYP3050A1) Is Essential for Worm Survival and Egg Development.

Schistosomiasis affects millions of people in developing countries and is responsible for more than 200,000 deaths annually. Because of toxicity and limited spectrum of activity of alternatives, there is effectively only one drug, praziquantel, available for its treatment. Recent data suggest that drug resistance could soon be a problem. There is therefore the need to identify new drug targets and develop drugs for the treatment of schistosomiasis. Analysis of the Schistosoma mansoni genome sequence for proteins involved in detoxification processes found that it encodes a single cytochrome P450 (CYP450) gene. Here we report that the 1452 bp open reading frame has a characteristic heme-binding region in its catalytic domain with a conserved heme ligating cysteine, a hydrophobic leader sequence present as the membrane interacting region, and overall structural conservation. The highest sequence identity to human CYP450s is 22%. Double stranded RNA (dsRNA) silencing of S. mansoni (Sm)CYP450 in schistosomula results in worm death. Treating larval or adult worms with antifungal azole CYP450 inhibitors results in worm death at low micromolar concentrations. In addition, combinations of SmCYP450-specific dsRNA and miconazole show additive schistosomicidal effects supporting the hypothesis that SmCYP450 is the target of miconazole. Treatment of developing S. mansoni eggs with miconazole results in a dose dependent arrest in embryonic development. Our results indicate that SmCYP450 is essential for worm survival and egg development and validates it as a novel drug target. Preliminary structure-activity relationship suggests that the 1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethan-1-ol moiety of miconazole is necessary for activity and that miconazole activity and selectivity could be improved by rational drug design.

Hyperspectral temperature and salt dependencies of absorption by water and heavy water in the 400-750 nm spectral range.

The temperature and salt dependencies of absorption by liquid water (H2O) and heavy water (D2O) were determined using a hyperspectral absorption and attenuation meter (WET Labs, AC-S). Sodium chloride (NaCl) was used as a proxy for seawater salts. There was no significant temperature (PsiT) or salt (PsiS) dependency of absorption at wavelengths <550 nm. At wavelengths >550 nm, PsiT exhibited peaks at approximately 604, 662, and 740 nm. A small negative trough in PsiS occurred at approximately 590 nm, followed by a small positive peak approximately 620 nm, a larger negative trough at approximately 720 nm, and a strong positive peak at approximately 755 nm. The salt dependency of absorption by heavy water, Psis(H), exhibited a negative power-law shape with very low Psis(H), at wavelengths >550 nm. Our experiments with NaCl, clean open ocean seawater, and artificial seawater support the hypothesis that salts modify the absorption spectra of seawater by modifying the molecular matrix and vibrations of pure water.

In situ optical variability and relationships in the Santa Barbara Channel: implications for remote sensing.

Relationships and variability of bio-optical properties in coastal waters are investigated. Optical proxies indicate that these coastal waters are optically complex and highly variable and are categorized as follows: (1) relatively clear and dominated by high index of refraction, biogenic particles, (2) more turbid, consisting of mostly inorganic particles and little phytoplankton, (3) extremely turbid with high concentrations of inorganic particles, and (4) more turbid and dominated by biogenic particles. We present a method, alternative to traditional remote-sensing algorithms, of classifying coastal waters [the Spectral Angle Mapper (SAM)] and utilize the SAM to successfully isolate plume conditions in time series of downwelling irradiance and total absorption coefficient. We conclude with a discussion of the use of the SAM for coastal management operations.