Integrated environmental management: The Dutch Governmental view

In the last 10 years concern for the economic and ecological value of the North Sea has increased. Many different users are putting increasing pressure on the resources of the North Sea and its adjacent estuaries. Its uses include shipping, fisheries, the oil and gas industry, mineral extraction, and—along its shores—recreation. The North Sea suffers pollution directly from some of these sources, but also indirectly from discharges from land, from rivers and from the atmosphere. The resilience of the North Sea ecosystem puts limits on the human use. These limits have in a number of cases been exceeded. It is necessary to define and assess the sustainable use of the North Sea ecosystem. The sustainable use may be defined as the long-term use of current and future potential while ensuring sustainable conservation of the ecological value of the North Sea and adjacent vulnerable water systems. Integrated environmental management for the North Sea implies that policy-makers assess all interests and resolve any conflicts which arise. This paper considers the problem of input of organic substances into the North Sea. It considers a target scenario of sustainable use and ecological health, in relation to what concentrations of organic substances are permissible. Secondly, it considers a target percentage reduction in current inputs. Thirdly, it is necessary to give the measures to be taken to deal with the major sources of the pollution, i.e. to define target groups. Finally, the paper gives examples of the statutory instruments available to implement the chosen policy.     

Measurement requirements for a Near-Earth Asteroid impact mitigation demonstration mission

A concept for an Impact Mitigation Preparation Mission, called Don Quijote, is to send two spacecrafts to a Near-Earth Asteroid (NEA): an Orbiter and an Impactor. The Impactor collides with the asteroid while the Orbiter measures the resulting change in the asteroid's orbit, by means of a Radio Science Experiment (RSE) carried out before and after the impact. Three parallel Phase A studies on Don Quijote were carried out for the European Space Agency: the research presented here reflects the outcomes of the study by QinetiQ. We discuss the mission objectives with regard to the prioritisation of payload instruments, with emphasis on the interpretation of the impact. The Radio Science Experiment is described and it is examined how solar radiation pressure may increase the uncertainty in measuring the orbit of the target asteroid. It is determined that to measure the change in orbit accurately a thermal IR spectrometer is mandatory, to measure the Yarkovsky effect. The advantages of having a laser altimeter are discussed. The advantages of a dedicated wide-angle impact camera are discussed and the field-of-view is initially sized through a simple model of the impact.     

The pace of Holocene vegetation change – testing for synchronous developments

Mid to high latitude forest ecosystems have undergone several major compositional changes during the Holocene. The temporal and spatial patterns of these vegetation changes hold potential information to their causes and triggers. Here we test the hypothesis that the timing of vegetation change was synchronous on a sub-continental scale, which implies a common trigger or a step-like change in climate parameters. Pollen diagrams from selected European regions were statistically divided into assemblage zones and the temporal pattern of the zone boundaries analysed. The results show that the temporal pattern of vegetation change was significantly different from random. Times of change cluster around 8.2, 4.8, 3.7, and 1.2 ka, while times of higher than average stability were found around 2.1 and 5.1 ka. Compositional changes linked to the expansion of Corylus avellana and Alnus glutinosa centre around 10.6 and 9.5 ka, respectively. A climatic trigger initiating these changes may have occurred 0.5 to 1 ka earlier, respectively. The synchronous expansion of C. avellana and A. glutinosa exemplify that dispersal is not necessarily followed by population expansion. The partly synchronous, partly random expansion of A. glutinosa in adjacent European regions exemplifies that sudden synchronous population expansions are not species specific traits but vary regionally.     

Monitoring the development of intertidal habitats on former agricultural land after the managed realignment of coastal defences at Tollesbury, Essex, UK

The managed realignment of coastal defences and subsequent creation of intertidal habitats is one of several 'soft' engineering options that could reduce the costs of maintaining embankments and at the same time deliver environmental benefits. The managed realignment at Tollesbury was one of the first in the UK, undertaken as an experimental test case to improve understanding of the practical techniques and processes involved. Independent studies were undertaken on the development of soils, benthic invertebrates and vegetation within the site in addition to methods of enhancing the process of natural colonisation of saltmarsh plants. Bathymetric and vegetation monitoring were undertaken on the adjacent estuary to determine any breach effect that may be attributed to the realignment. This paper summarises the results from the vegetation, sedimentation and invertebrate monitoring and discusses the implications for other managed realignment schemes in the UK.     

Thermal infrared and optical observations of four near-Earth asteroids

We present thermal infrared photometry and spectrophotometry of four near-Earth asteroids (NEAs), namely (433) Eros, (66063) 1998 RO₁, (137032) 1998 UO₁, and (138258) 2000 GD₂, using the United Kingdom Infrared Telescope (UKIRT) in 2002. For two objects, i.e. (433) Eros and (137032) 1998 UO₁, quasi-simultaneous optical observations were also obtained, using the Jacobus Kapteyn Telescope (JKT). For (127032) 1998 UO₁, we obtain a rotation period P=3.0±0.1 h and an absolute visual magnitude HV=16.7±0.4. The Standard Thermal Model (STM), Fast Rotating Model (FRM) and near-Earth asteroid Thermal Model (NEATM) have been fitted to the IR fluxes to determine effective diameters Deff, geometric albedos pv, and beaming parameters η. The derived values are (433) Eros: Deff=23.3±3.5 km (at lightcurve maximum), pv=0.24±0.07, η=0.95±0.19; (66063) 1998 RO₁: , ; (137032) 1998 UO₁: Deff<1.13 km, pv>0.29; (138258) 2000 GD₂: Deff=0.27±0.04 km, , η=0.74±0.15. (66063) 1998 RO₁ is a binary asteroid from lightcurve characteristics [Pravec, P., and 56 colleagues, 2006. Icarus 181, 63-93] and we estimate the effective diameter of the primary (Dp) and secondary (Ds) components: and . The diameter and albedo of (138258) 2000 GD₂ are consistent with the trend of decreasing diameter for S- and Q-type asteroids found by Delbó et al. [Delbó, M., Harris, A.W., Binzel, R.P., Pravec, P., Davies, J.K., 2003. Icarus 166, 116-130]. A possible trend of increasing beaming parameter with diameter for small (less than about 3 km) S- and Q-type asteroids is found.     

Near-infrared spectra of 12 Near-Earth Objects

We present a number of spectra of Near-Earth Objects taken in the period 1998-2003 with two different instruments (CGS4 and UIST) on the UKIRT telescope. Since observations with CGS4 require multiple spectral fragments to be observed sequentially and then spliced together we assess the reliability of this technique using comparisons between multiple observations of the same object, between observations of the same object with both instruments and with independent spectra of common objects. We conclude that while problems in the spectral splicing can occur, they are usually intuitively obvious and that overall our dataset is sound. The objects for which we present new spectral data are: 1627 Ivar, 4179 Toutatis, 5381 Sekhmet, (5587) 1990 SB, 6489 Golevka, (11405) 1999 CV₃, (14402) 1991 DB, 25143 Itokawa, (25330) 1999 KV₄, (52760) 1998 ML₁₄, (66391) 1999 KW₄, and (101955) 1999 RQ₃₆. Our results, together with albedo data from the literature, suggest carbonaceous compositions for 25330 and 101955. The available data for 14402 suggest it may belong to the relatively rare M class. Our analysis suggests an S or Sq classification for 52760 and a V classification for 5381 Sekhmet. For all remaining objects the UKIRT data are consistent with published spectral classifications. We find that only 3 of the 12 objects are not S/Q/V-class, which is roughly consistent with the results of Binzel et al. [Binzel, R.P., Rivkin, A.S., Stuart, J.S., Harris, A.W., Bus, S.J., Burbine, T.H., 2004. Icarus 170, 259-294]. Four spectra of Toutatis taken over a range of solar phase angles between 0.7°-81° and at intervals of several weeks are indistinguishable within the uncertainties and therefore do not reveal any evidence for phase reddening or surface variegation.     

Optical and thermal infrared observations of six near-Earth asteroids in 2002

We present thermal infrared photometry and spectrophotometry of six Near-Earth Asteroids (NEAs) using the 3.8 m United Kingdom Infrared Telescope (UKIRT) together with quasi-simultaneous optical observations of five NEAs taken at the 1.0 m Jacobus Kapteyn Telescope (JKT). For Asteroid (6455) 1992 HE we derive a rotational period P=2.736±0.002 h, and an absolute visual magnitude H=14.32±0.24. For Asteroid 2002 HK₁₂ we derive . The Standard Thermal Model (STM), the Fast Rotating Model (FRM) and the Near-Earth Asteroid Thermal Model (NEATM) have been fitted to the measured fluxes to derive albedos and effective diameters. The derived geometric albedos and effective diameters are (6455) 1992 HE: pv=0.26±0.08, Deff=3.55±0.5 km; 1999 HF₁: pv=0.18±0.07, ; 2000 ED₁₀₄: pv=0.18±0.05, Deff=1.21±0.2 km; 2002 HK₁₂: , Deff=0.62±0.2 km; 2002 NX₁₈: pv=0.031±0.009, Deff=2.24±0.3 km; 2002 QE₁₅: , Deff=1.94±0.4 km. The limitations of using the NEATM to observe NEAs at high phase angles are discussed.     

Zur Ursache der Entstehung oberflächenparalleler Klüfte

ZusammenfassungZur Ursache der Entstehung oberflächenparalleler Klüfte Damit oberflächen- bzw. hangparallele Klüfte entstehen können, sind beträchtliche und dazu in den einzelnen Zonen unterschiedliche Verformungsbeträge notwendig. Das Maß der Gesteinsverformung auf Grund von Spannungsänderungen, die infolge allmählichen Abtrags und damit Entlastung bei einem Taleinschnitt von einigen Dekametern auftreten, ist — jedenfalls allen Spannungs-Dehnungsmessungen zufolge — für eine solche Auswirkung zu unbeträchtlich. Bei einem gesteinsmechanischen Untersuchungsprogramm an Kernproben aus der 6000 m tiefen Bohrung Münsterland 1 konntennach der Förderung an die Tagesoberfläche (Entlastung) keine weiteren Verformungen der Gesteine mehr festgestellt werden. Lediglich nahm die Bruchfestigkeit mit längerer Lagerzeit noch geringfügig ab, was aber auch auf Veränderungen der feinsten Wasserhüllen o. ä. zurückgeführt werden kann. Bei Proben aus größeren Teufen auftretende Entlastungsklüfte, durch welche Bohrkerne längsgeteilt an die Tagesoberfläche kamen, konnten mit Verformungsanisotropie erklärt werden, die an diesen Proben festgestellt wurden. Endlich aber bewiesen Verformungsmessungen bei schwellenden Belastungen, daß selbst nach einigen zehntausend Lastwechseln noch gleichzeitig mit der Spannungsänderung auch die Verformung einhergeht. Danach besteht z. B. bei Taleinschnitten kein Anlaß, anzunehmen, der Fels würde dort gelegentlich mit der Reaktion warten, bis ein größerer Abtrag erfolgt ist.Bei verschiedenen Gesteinen (Mergelkalkstein, Kalkstein, Sandstein, Tonstein, Granit und Basalt) wurde der Verformungsverlauf sowohl bei Temperaturänderung zwischen –20° und +80°C bei Normaldruck als auch bei Druckaufbringung zwischen 0 und 1800 kp/cm² bei Zimmertemperatur experimentell bestimmt. Die Verformungen infolge Temperaturänderungen sind beträchtlich. Ein Vergleich mit denen aus Entlastung zeigt, daß z. B. bei Granit, Kalkstein und Basalt eine Temperaturänderung um 100°C größere Verformungen nach sich zieht als 10000 m Gesteinsabtrag. Temperaturschwankungen im Tag-Nacht-Rhythmus oder im Jahresablauf sind selbst in unserem gemäßigten Klima noch beträchtlich und bedingen Verformungsbeträge, die auf Grund von Entlastung erst durch Abtrag von vielen Metern Überdeckung erreicht werden könnten. Dazu wiederholen sich diese Temperaturschwankungen ständig, wodurch — nach aufgezeigten Versuchsergebnissen — auch geringere Spannungen bereits zum Bruch führen. Die bei Talsperrenuntersuchungen im Rheinischen Schiefergebirge bis 30 m unter der Hochfläche festgestellte Auflockerungszone, deren untere Begrenzung horizontal verläuft und unter den Tälern nicht tiefer reicht — wie es bei Entspannung ja sein müßte —, kann als Folge der Temperaturerniedrigung während des Diluviums gedeutet werden. Für die Tektonik wird die Frage aufgeworfen, ob nicht eventuell sogar ein Kluftsystem bei der mit der Heraushebung eines Gebietes verbundenen Abkühlung entstehen kann.

---

SummarySome Reflections on the Cause of the Formation of Joints Parallel to the Surface For the origination of fissures parallel to the horizontal or inclined surface considerable strains are necessary, and that in varying degrees in the different zones. According to all measurements of stress-strain relations the rock deformation due to unloading by erosion and natural excavation of some decameters in a valley is far too small for such an effect. In a rock mechanical research program with samples from the boring Münsterland 1, which was 6000 meters deep, no further deformations could be detected after hauling the material to the surface (unloading). Only the failure strength of stored samples decreased slightly with time; this could have been due to small changes in the adsorbed water layers or similar effects. Samples from larger depths arrived at the surface axially dissected in two halves. This observation is explained with the anisotropic stress-strain relation of the material. Last not least deformation measurements during cyclic loading and unloading showed that even after ten thousands of repetitions stress and strain occur synchronously. Therefore no reason exists for an assumption that during excavation of valleys the deformation of the rock may be retarded until a larger unloading is reached.For different rocks (marly limestone, limestone, claystone, granite and basalt) the strains have been measured due to temperature variations between –20 and +80 degrees centigrade under ambient pressure as well as due to variation of this ambient pressure from 0 to 1800 kp/cm² at room temperature. The deformations due to temperature changes are quite considerable. A comparison with those due to unloading shows that a change in temperature of 100 degrees brings about larger strains than the abrasion of 10000 m of rock. Even in our temperate zone temperature variations from day to night or during a year are rather large and result in strains which would correspond to an abrasion of several meters. Moreover by the continuous repetition of this straining fracture is reached with comparatively small stresses as indicated by test results.The dissected zone observed during investigations for dam projects in the Rhein. Schiefergebirge reaches to a depth of up to 30 meters below the plateau; its lower boundary is horizontal not being deeper under the valleys as it should be if caused by unloading. This dissection can be explained as an effect of the drop in temperature during diluvial times. Concerning tectonics the question is raised if a system of joints can be produced by cooling connected with the uplift of a region.

---

RésuméSur l'origine des fissures parallèles à la surface du sol L'apparition de fissures parallèles à la surface du sol exige des déformations considérables, et variant d'un point à un autre.L'érosion d'une vallée, sur quelques dizaines de mètres, se traduit par des variations de contrainte, mais la valeur des déformations correspondantes est trop insignifiante, dans le cadre des relations entre les contraintes et les déformations.Dans un programme de recherches de mécanique des roches portant sur les carottes du sondage Münsterland 1 de 6000 m de profondeur, on n'a pas constaté de déformation de la roche après l'extraction. Seule la résistance à la rupture diminue légèrement en fonction de la durée de stockage, ce qu'on peut justifier par des modifications de l'eau des pores. Les carottes extraites des profondeurs plus grandes arrivaient au jour partagées en long, ce qui peut s'expliquer par l'anisotropie de leur déformation. Enfin et surtout les mesures de déformation pendant les cycles de charge et décharge, même après 10000 cycles, montrent que la déformation reste fonction des variations de contrainte, et simultanée. D'aprés cela, il n'y a pas de raison pour que dans une vallée par exemple la roche attende une érosion importante pour réagir.Pour différentes roches (calcaires marneux, calcaires, grès, argilites, granites, basaltes), les déformations ont été étudiées expérimentalement d'une part pour la pression atmosphérique entre –20° et +80°, d'autre part à la température ambiante sous des pressions de 0 à 1800 bars. Les déformations thermiques sont importantes. La comparaison avec les déformations mécaniques montre, par exemple pour du granite, du calcaire ou du basalte, qu'une variation de température de 100° produit des déformations plus grandes que l'enlèvement de 10000 m de roche. Les variations thermiques journalières ou annuelles sont importantes même sous notre climat tempéré et les déformations correspondantes peuvent être comparées à l'enlèvement de beaucoup de mètres de couverture. Comme ces variations se répètent régulièrement, et d'après les résultats d'essai déjà cités, même des contraintes modérées peuvent conduire à la rupture. Les reconnaissances de barrages dans le Massif schisteux Rhénan ont montré une zone désagrégée jusqu'à 30 m de profondeur, dont la limite est horizontale et ne s'approfondit pas sous les vallées comme ce serait le cas si la décharge en était la cause.Ceci peut s'expliquer par le refroidissement du début du quaternaire. En tectonique la question se pose de savoir si un système de fissures peut se développer à cause du refroidissement lié au soulèvement d'une région.

---

---

Vortrag im Geologischen Landesamt N.-W. am 5. 2. 1968.

---

Mit 9 Abbildungen     

Early Holocene environmental history of sunken landscapes: pollen, plant macrofossil and geochemical analyses from the Borkum Riffgrund, southern North Sea

A vibrocore from the sea floor of the southern North Sea provides a ~1,500-year record of early Holocene vegetation history and mire development in a landscape now 33 m below sea-level. Pollen, plant macrofossil and geochemical analyses of an AMS ¹⁴C dated sand–peat–marine mud sequence document the paludification on Pleistocene sands ~10,700 cal BP, the subsequent development of eutraphentic carr vegetation and the gradual inundation by the transgressing sea ~9,350 cal BP. Pinus–Corylus woodland prevailed on terrestrial grounds after hazel had immigrated ~10,700 cal BP. Salix dominated the carr vegetation throughout 1,300 years of peat formation, because Alnus did not spread in the Borkum Riffgrund area until 9,300 BP. Brackish reed vegetation with Phragmites established after inundation and siliciclastic marine sediments were being deposited. This article also examines the detection and suitability of key horizons indicative of marine influence. XRF-Scanning provides the most detailed results in the briefest possible time to pinpoint spectra best suitable for AMS ¹⁴C dating of classical key horizons such as start of peat formation and transgressive contact. The combined application of botanical and geochemical methods allows determining new key horizons indicative of marine influence, namely the earliest marine inundation and the onset of sea-level influence on coastal ground water level.     

Salt marsh surface survives true‐to‐scale simulated storm surges

A full‐scale controlled experiment was conducted on an excavated and re‐assembled coastal wetland surface, typical of floristically diverse northwest European saltmarsh. The experiment was undertaken with true‐to‐scale water depths and waves in a large wave flume, in order to assess the impact of storm surge conditions on marsh surface soils, initially with three different plant species and then when this marsh canopy had been mowed. The data presented suggests a high bio‐geomorphological resilience of salt marshes to vertical sediment removal, with less than 0.6 cm average vertical lowering in response to a sequence of simulated storm surge conditions. Both organic matter content and plant species exerted an important influence on both the variability and degree of soil surface stability, with surfaces covered by a flattened canopy of the salt marsh grass Puccinellia experiencing a lower and less variable elevation loss than those characterized by Elymus or Atriplex that exhibited considerable physical damage through stem folding and breakage. Copyright © 2015 John Wiley & Sons, Ltd.