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[1] Wind speeds and directions were measured on the Phoenix Lander by a mechanical anemometer, the so-called Telltale wind indicator. Analysis of images of the instrument taken with the onboard imager allowed for evaluation of wind speeds and directions. Daily characteristics of the wind data are highly turbulent behavior during midday due to daytime turbulence with more stable conditions during nighttime. From L s ∼77°-123°winds were generally ∼4 m s −1 from the east, with 360°rotation during midday. From L s ∼123°-148°d aytime wind speeds increased to an average of 6-10 m s −1 and were generally from the west. The highest wind speed recorded was 16 m s −1 seen on L s ∼147°. Estimates of the surface roughness height are calculated from the smearing of the Kapton part of the Telltale during image exposure due to a 3 Hz turbulence and nighttime wind variability. These estimates yield 6 ± 3 mm and 5 ± 3 mm, respectively. The Telltale wind data are used to suggest that Heimdal crater is a source of nighttime temperature fluctuations. Deviations between temperatures measured at various heights are explained as being due to winds passing over the Phoenix Lander. Events concerning sample delivery and frost formation are described and discussed. Two different mechanisms of dust lifting affecting the Phoenix site are proposed based on observations made with Mars Color Imager on Mars Reconnaissance Orbiter and the Telltale. The first is related to evaporation of the seasonal CO 2 ice and is observed up to L s ∼95°. These events are not associated with increased wind speeds. The second mechanism is observed after L s ∼111°and is related to the passing of weather systems characterized by condensate clouds in orbital images and higher wind speeds as measured with the Telltale.

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[1] The Mars Exploration Rovers each carry a set of Magnetic Properties Experiments designed with the following objectives in mind: (1) to identify the magnetic mineral(s) in the dust, soil and rocks on Mars, (2) to establish if the magnetic material is present in the form of nanosized (d < 10 nm) superparamagnetic crystallites embedded in the micrometer sized airborne dust particles, and (3) to establish if the magnets are culling a subset of strongly magnetic particles or if essentially all particles of the airborne dust are sufficiently magnetic to be attracted by the magnets. To accomplish these goals, the Mars Exploration Rovers each carry a set of permanent magnets of several different strengths and sizes. Each magnet has its own specific objective. The dust collected from the atmosphere by the Capture magnet and the Filter magnet (placed on the front of each rover) will be studied by the Mössbauer spectrometer and the Alpha Particle X-ray Spectrometer, both of which are instruments located on the rover's Instrument Deployment Device. The captured dust particles will also be imaged by the Pancam and Microscopic Imager. The Sweep magnet will be imaged by Pancam and is placed near the Pancam calibration target. The four magnets in the Rock Abrasion Tool (RAT) are designed to capture magnetic particles originating from the grinding of Martian surface rocks. The magnetic particles captured by the RAT magnets will be imaged by Pancam.

Iron reduction and oxidation, as well as the microbial community involved in these processes, were investigated in a small pond that is continuously fed by slightly acidic, hypoxic, iron rich ground water. The seep area is located in a beech forest in central Jutland (Denmark), and beech litter is the dominant source of organic matter, carbon and energy for the microbial community. The pond is 30 to 50 cm deep with a water column depth ranging from 15 to 20 cm. Oxygen could only be detected down to 7 cm depth of the water column. Fe(II) concentrations increased with depth from about 30 µM close to the surface to ca. 100 µM at the bottom. The presence of Gallionella-and Sideroxidans-related strains was supported by clone library data, while Leptothrix-related 16S rDNA clones were not found. Samples amended with leaves, acetate, lactate and ethanol all showed stimulated iron reduction at the in situ temperature (about 10 • C). In particular, dried beech leaves stimulated iron reduction without a lag phase while acetate was only degraded after a 22 day lag period at the in situ pH. The long lag phase is most probably due to the low pH that is responsible for high acetic acid concentrations (0.8-1.2 mM ) at the start of the incubation. Light microscopy observations confirm the clone library data that Gallionella spp and other iron oxidizer related 16S rDNA sequences were relatively common. In addition, 16S rDNA sequences relatively similar to sequences of members of the iron reducer family Geobacteraceae were found. A clone library constructed with a primer set targeting specifically Geobacter-related strains revealed that strains most closely related to Geobacter thiogenes were predominant (19 out of 20 clones). By a combination of microscopy, cultivation and molecular investigations we have been able to provide several lines of evidence for a tight coupling of biological iron reduction and oxidation in this iron-rich fresh water seep.