In Situ Biological Contamination Studies of the Moon: Implications for Planetary Protection and Life Detection Missions

NASA and ESA have outlined visions for solar system exploration that will include a series of lunar robotic precursor missions to prepare for, and support a human return to the Moon, and future human exploration of Mars and other destinations, including possibly asteroids. One of the guiding principles for exploration is to pursue compelling scientific questions about the origin and evolution of life. The search for life on objects such as Mars will require careful operations, and that all systems be sufficiently cleaned and sterilized prior to launch to ensure that the scientific integrity of extraterrestrial samples is not jeopardized by terrestrial organic contamination. Under the Committee on Space Research’s (COSPAR’s) current planetary protection policy for the Moon, no sterilization procedures are required for outbound lunar spacecraft, nor is there a different planetary protection category for human missions, although preliminary COSPAR policy guidelines for human missions to Mars have been developed. Future in situ investigations of a variety of locations on the Moon by highly sensitive instruments designed to search for biologically derived organic compounds would help assess the contamination of the Moon by lunar spacecraft. These studies could also provide valuable “ground truth” data for Mars sample return missions and help define planetary protection requirements for future Mars bound spacecraft carrying life detection experiments. In addition, studies of the impact of terrestrial contamination of the lunar surface by the Apollo astronauts could provide valuable data to help refine future Mars surface exploration plans for a human mission to Mars.     

Environmental geology: our professional public responsibility

 Conflicts between different interest groups for use of natural resources is one area where state geological surveys can provide assistance. A state geological survey working within the scientific constraints of specific issues can remain objective in its presentations and maintain the faith of both the conflicting interest groups and the public. One cannot vary from the objective view or you will quickly be criticized. Criticism can still occur from one side of a natural resource issue as your data might counter their views. However, the final decisions are almost always made in some legislators, or regulators, area of responsibility. The responsibility of the state geological survey is to provide the important data that will assist in making correct decisions. Should one party in the conflict become extreme in their demands, a potential compromise that is beneficial to both sides can be lost. In Kansas, the classical natural resource problem of resource/recreation in a populated area is presented as a case study. The state geological survey presented data on sand resources in the Kansas River and its valley in northeast Kansas. That information was important to both recreation and dredging interests where the political problem is a conflict of sand use as a construction material resource versus use of the alluvial river as an important recreation area, especially for canoeing. However, when a reasonable compromise was near completion in the Kansas Legislature one side, in a bold move to develop an advantage, ruined that potential for compromise. Received: 12 May 1998 · Accepted: 6 July 1998     

High resolution profiles of vertical particulate organic matter export off Cape Blanc,Mauritania: Degradation processes and ballasting effects

Vertical carbon fluxes between the surface and 2500 m depth were estimated from in situ profiles of particle size distributions and abundances me/asured off Cape Blanc (Mauritania) related to deep ocean sediment traps. Vertical mass fluxes off Cape Blanc were significantly higher than recent global estimates in the open ocean. The aggregates off Cape Blanc contained high amounts of ballast material due to the presence of coccoliths and fine-grained dust from the Sahara desert, leading to a dominance of small and fast-settling aggregates. The largest changes in vertical fluxes were observed in the surface waters (<250 m), and, thus, showing this site to be the most important zone for aggregate formation and degradation. The degradation length scale (L), i.e. the fractional degradation of aggregates per meter settled, was estimated from vertical fluxes derived from the particle size distribution through the water column. This was compared with fractional remineralization rate of aggregates per meter settled derived from direct ship-board measurements of sinking velocity and small-scale O₂ fluxes to aggregates measured by micro-sensors. Microbial respiration by attached bacteria alone could not explain the degradation of organic matter in the upper ocean. Instead, flux feeding from zooplankton organisms was indicated as the dominant degradation process of aggregated carbon in the surface ocean. Below the surface ocean, microbes became more important for the degradation as zooplankton was rare at these depths.     

Review study on near-natural conditions of Central European mountain streams, with particular reference to debris and beaver dams: Results of the “REG meeting” 2000

This paper summarises the results of the “Rhithron Ecology Group” meeting in Essen (March 2000), supplemented by a literature evaluation.An extended view of small mountain streams in Central Europe under “potentially natural conditions” is presented. We focus on the potential impact of natural transverse structures (debris dams and beaver dams) on stream morphology, hydrology, habitat composition and communities. Furthermore, impact of other stream morphological features, which are presently lacking in the Central European landscape, is described.We suggest that Central European mountain streams are characterised by a higher proportion of lentic zones under “potentially natural conditions”. Morphological degradation leads to a loss of lentic zones and to an increase of current velocities and corresponding changes in faunal composition, particularly higher abundance and proportion of rheophilic species and a decrease of species preferring lentic zones. This should be regarded in future stream assessment.     

Zur Albedomessung auf Gletschern

Zusammenfassung Auf Grund gleichzeitiger Messungen der Gletscheralbedo mit einem Solarimeter und einem Selen-Photoelement wird versucht, bei verschiedenen Strahlungsbedingungen eine Beziehung zwischen den mit beiden Empfängern gemessenen Albedowerten zu finden. Bei bedecktem Himmel ohne Sonne werden annähernd gleiche Albedowerte gemessen; bei heiterem Himmel weist ihr Verhältnis einen ausgeprägten Tagesgang auf, wobei um Mittag mit dem Photoelement ein um etwa 25% größerer Wert der Albedo festgestellt wird als mit dem Solarimeter. Albedobestimmungen, die nach diesen zwei Methoden ausgeführt wurden, sind daher nicht unter allen Bedingungen miteinander vergleichbar.

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Summary On the basis of simultaneous measurements of glacier albedo with a solarimeter and a selenium photo-element the author is trying to find a relation between the albedo values measured with the two receivers under different radiation conditions. Approximately equal values of albedo are found with overcast sky without sun; their relation shows on the other hand a pronounced daily course with clear sky, whereby the photo-element yields at noon an albedo value higher than that of the solarimeter by about 25%. Determinations of albedo carried out according to these two methods are thus not comparable under every condition.

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Résumé On a mesuré l'albédo d'un glacier simultanément au moyen d'un solarimètre et d'une cellule photoélectrique au sélénium. On essaie alors d'établir la relation existant entre les valeurs de l'albédo résultant des relevés de ces deux instruments et cela dans des conditions diverses de rayonnement. Ces valeurs sont à peu près égales par ciel couvert et sans soleil. Par ciel serein, le rapport présente par contre une évolution diurne marquée. Dans ce cas, les valeurs fournies par la cellule à midi sont de 25% supérieures à celles du solarimètre. Les mesures de l'albédo faites au moyen de ces deux instruments ne sont donc pas comparables entre elles dans toutes les conditions de nébulosité.

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Mit 2 Textabbildungen     

Zeitliche Beziehung zwischen variskischer Tektonik und initialem Magmatismus in Ostthüringen

Zusammenfassung Die voroberdevonischen Kerngesteine des Bergaer Sattels werden von wenige Meter mächtigen konkordanten und diskordanten Diabas-Gängen durchschlagen. Die diskordanten Gänge liegen ausnahmslos in der achsenflächenparallelen Transversalschieferung (s₁). Die Erklärung dieser Lagerungsform durch eine voroberdevonische Schieferung oder durch die Annahme eines nachsudetischen Intrusionsalters stünde im Widerspruch zu den bisherigen Ansichten. Eine genaue Überprüfung dieser s₁-parallelen Gänge erweist deutlich deren Bindung an die Mittelschenkel der Falten niederer Ordnung. Die aus der Schichtung abweichende Intrusion folgte demnach achsenflächenparallelen Schenkelbrüchen tiefoberdevonisch angelegter Embryonalfalten. Sie werden der reußischen Phase v.Gaertners (1951) zugeschrieben. Diese Bewegung an der Wende Mittel-/Oberdevon wird als intrageosynklinale Vorfaltung der saxothuringischen Zone des variskischen Orogens aufgefaßt.Dieser Beitrag ist das Teilergebnis einer regionalgeologischen Untersuchung, deren Anregung und Betreuung Verf. Herrn Professor Dr. F.Deubel verdankt.     

Sedimentation patterns of diatoms in Lake Holzmaar, Germany - (on the transfer of climate signals to biogenic silica oxygen isotope proxies)

The seasonal sedimentation pattern of diatom valves in Lake Holzmaar was investigated during 1995 by deploying sediment traps at three different lake depths. According to the sedimentation pattern, the major reproduction zone of diatoms was restricted to the upper 6 m of the water body. The population growth started late in April and blooms of Cyclotella cf. comensis Grun., which dominates the plankton diatoms, and Fragilaria crotonensis Kitton were collected in traps during June and September, and July, respectively. During summer, the seasonal sedimentation pattern of each taxon, as collected in the upper traps, was reflected in the concentrations in the lowest trap. However, in May and from September onwards, the community composition in the lowest trap and augmented trapping rates suggest both sediment focusing and resuspension of bottom sediments.The temperature signals as recorded by 18O values of diatom valves should, therefore, reflect integrated temperatures between 0 and 6 m depth. However, temperatures during summer and autumn are expected to be accentuated in the sedimentary record since the isotopic signal is weighted by both the number and the weight-mass of the valves. During summer, the transfer of these signals by the sedimenting diatoms retains the information pattern recorded, while in spring and autumn/winter additional influxes caused by resuspension may somewhat alter those temperature informations. The proxy signals finally stored in the sediments, may, therefore, not precisely represent the successive temperatures currently recorded during 1995 within mid-lake.