ALBERT

Description: In Madroño (1936) Herre has lamented the disappearance of lichen species through the disastrous interference of man. Unavoidably, the advance of civilised modern life is linked with destruction of the vegetation. This applies all the more as the endangered area is more densely populated and it certainly applies most alarmingly to the lichen flora of the Netherlands. Here, every way-side tree felled is an irreparable loss to the epiphytic lichen communities, every acre of heath burnt or turned into arable land is a blow to our stock of terrestrial lichen species, whereas the use of dry fertilisers and the spraying of orchards are very effective in killing any lichen in the neighbourhood that otherwise might have survived. A comparison of the material preserved in the older collections with what can be found nowadays, clearly shows what has gone lost. It is sad to think that an ever increasing number of species are on their way to total extermination. However, from a thorough investigation of the epiphytic communities of cryptogams latterly started by Mr J. J. Barkman, it becomes apparent that at least to some extent the losses may be compensated by the discovery of species hitherto overlooked or not recognised. It is on such and other finds that I intend to report from time to time.

Description: Of this series of preparations to the definite publication of the Burseraceae in “Flora Malesiana”, the present part is giving an additional note on VI. Garuga and dealing with the genera VII. Triomma, VIII. Dacryodes and IX. Santiria (and a new combination in Protium). The present paper gives only additions to and alterations of Lam’s monograph (H. J. Lam, Bull. Jard. Bot. Buitenz., Sér. 3, 12, 1932, 281— 561); descriptions, synonyms, litterature, specimens cited, ecological and other notes are only mentioned insofar as they are not given by Lam.

Description: A study has been made of the Indo-Malaysian species of Cnestis. The mutual length ratio of sepals and petals, — brevi- and aequipetaly —, is the main differentiating character for the species; there are no transitions. The areas of distribution overlap in the Malay Peninsula (fig. 1); brevipetalous types are known from the Malay Peninsula, Sumatra, Borneo and Celebes, aequipetalous types from Burma, Siam, Indo-China and the Andaman Islands, the Malay Peninsula and the Philippines. Fruits are of two different shapes: beaked in aequipetalae of the Andamans, Burma, Siam, and Indo-China, pear-shaped in remaining aequipetalae and in brevipetalae. Leaves tend to be longer and jugae more numerous in brevipetalae than in aequipetalae. Other characters do not have so clear a separating value, such as texture and indumentum of leaflets, indumentum of inflorescence, texture and indumentum of petals, length of stamens, type and length of pistils, length ratio of stamens and pistils. However, even on the strength of these characters there is some reason to distinguish both groups mentioned above. As to the indumentum of petals there is a remarkable cline in a decreasing sense from the Philippines to continental Asia, the Andamans and the Malay Peninsula and back to the east through the brevipetalae of Malay Peninsula, Sumatra, Borneo and Celebes. Brevi- and aequipetalae have been considered to represent two species, viz Cnestis platantha Griff. and Cnestis palala (Lour.) Merrill. The latter one has been divided into two subspecies, viz subsp. palala with beaked fruits and subsp. diffusa (Blanco) Andreas with pear-shaped fruits. For their area of distribution see fig. 1. In many respects some plants of the Andamans, Burma, Siam, Indo-China (and the Malay Peninsula) are different from the remaining aequipetalae, but not in a uniform way as to the various characters. Although there are some arguments for a further taxonomic subdivision, we did not think it advisable to introduce such a division at present. Our classification differs from the division as given by Schellenberg (1938). This was caused by the material on one hand, being more heterogeneous than Schellenberg described it, and, on the other hand, by the fact that some of the diagnostic characters used by him, in our opinion were not fit for use as such. Therefore a revision of Schellenberg’s system of the genus Cnestis seems desirable.

Description: While engaged on working out the beautiful pycnogonid material dredged by Dr Th. Mortensen in shallow waters near the Virgin Islands, I thought it useful to compare this dredged material with material collected between the tide marks, or just below the low tide line. So I was very glad to meet Dr P. Wagenaar Hummelinck, who has made extensive collections of littoral marine animals during his various trips to the West Indies, and who kindly entrusted me with about 50 lots of pycnogonids which had already been sorted from his material. A definitive paper will be published as soon as his entire marine material has been searched for the presence of sea spiders.

Description: En Zélande, province des Pays-Bas, l’on trouve différentes stations où croissent des algues marines. Ce sont: 1. Les digues, 2. Les canaux d’eau de mer, 3. Les parcs à huîtres, 4. Les slikkes et les schorres. La Zélande comprend une bande continentale et deux séries d’îles. Comparé aux autres provinces des Pays-Bas, le climat est assez tempéré. La température moyenne à Flessingue (Vlissingen) est de 3°C en janvier, le mois le plus froid, et de 18°C durant les mois les plus chauds, juillet et août. La température moyenne de l’eau de mer en surface est de 1— 3°C en janvier et de 19°C en juillet et août.

Description: Premna brongersmai, nov. spec. — Frutex? Ramuli teretes conspicue subdistanter lenticellati 0.3—0.5 cm crassi, internodia in specimine 7—11 cm longa. Folia coriacea subrigida, decussatim opposita glaberrima petiolata, ovata vel oblongo-ovata vel subovata vel oblongo-lanceolata, basi plus minusve late rotundata, marginibus integra, apice abrupte vel subabrupte peracute acuminata, latiora 8.5—11 X 4.7—5.7 cm, angustiora (in eodem specimine, ut apparet) 12—14.5 X 4—4.5 cm ; nervi haud prominentes, costa media subtus prominente excepta; nervi secundarii graciles utrimque 5—7, curvati, margines versus diminuti haud confluentes, tertiarii pertenues subdistanter transversi, reticulatione minutissima areolata; petioli e basi incrassata 1— 1.7 cm longi tenues. Inflorescentiae paniculatae terminales, partiales inferiores ex axillis foliorum parvorum, superiores ex axillis bractearum subulatarum 0.3—0.1 cm longarum ortae, totae 12—17 cm longae, 17—29 cm latae, partiales medianae longiores, e pedunculo gracili 10—14 cm longae, pseudodichotomice late divaricatae, ramificationes ultimae dichasiales minute pubescentes. Flores parvi tetrameri subsessiles, alabastris pyriformibus, glabris; calyx glaber cupularis subbilabiatus, c. 0.25 cm altus, labio inferiore acute integro vel leviter acuto-bidentato, superiore 2 lobis majoribus acutis suffulto, calyx intus praecipue dimidio superiore multis glandulis in sicco opacis munitus; corolla in regione staminum insertionis tantum intus pilosa, cetera glabra, 0.4—0.45 cm alta, tubo subcylindrico 0.3—0.35 cm longo, limbo aestivatione cochleata subbilabiato, labio inferiore trilobo (lobo medio in alabastro ceteros tegente, 0.15 cm longo, rotundato, lateralibus 0.1 cm longis, subtruncatis), superiore integro 0.1 cm longo subtruncato, in alabastro omnino tecto; regio pilosa sub labio superiore paulo infirmior; stamina alternipetala in regione pilosa aequa altitudine inserta, subdidynamia, filamentis sub labio superiore paulo brevioribus in alabastro sigmoideo-sinuatis 0.2 cm longis, sub labio inferiore 0.25 cm longis, omnibus vittatis apice abrupte contractis filiformibus; antherae 0.05 X 0.1 cm, subreniformes, thecae poris ovatis dehiscentes; ovarium globosum glabrum 0.15 cm altum 4-loculatum, loculis uniovulatis; ovula longa apotropa medio affixa; stylus filiformis 0.25 cm longus, stigma bilobum, lobis acutis piano mediano patentibus. Fructus ignoti. Shrub? Branchlets (all?) apparently long and drooping, 0.3—0.5 cm in diam.. Leaves decussate, entirely glabrous, ovate to ovate-oblong, base more or less broadly rounded, apex more or less abruptly and very acutely acuminate, margins entire, 8.5—14.5 X 4—5.7 cm, nerves not prominent except midrib below, secondary ones 5—7, curved, reticulation minutely areolate between the almost inconspicuous transverse tertiary ones; petioles 1—1.7 cm long, incrassate at base. Inflorescences widely paniculate, terminal, 12—17 cm long, 17—29 cm broad, the lower partial panicles in the axils of ever smaller leaves, the upper ones in those of subulate bracts; ultimate ramifications dichasial, minutely pubescent. Flowers subsessile, 4-merous, glabrous but for a hair ring inside at the insertion of the filaments. Calyx cupular, more or less bilabiate, 0.25 cm high, lower lip entire or shallowly acutely bidentate, upper one with two larger acute teeth, inside with dispersed dark glands: corolla tube suibcylindrical 0.3—0.35 cm long, aestivation cochleate, slightly 2-lipped, lower lip 3-lobed, midlobe rounded and 0.15 cm long, lateral ones subtruncate and 0.1 cm long; upper lip entire, 0.1 cm long, subtruncate. Stamens 4, subdidynamous, those below upper lip with slightly shorter filaments; filaments ribbon-shaped, 0.2 and 0.25 cm long respectively, subabruptly narrowed below the anther and ending into a very thin apex; anthers kidney-shaped, 0.05 X 0.1 cm, with two ovate pores; ovary globose, glabrous, 0.15 cm high, 4-celled, cells uniovulate, ovules long, apotropous, attached in the middle of the cell; style filiform, 0.25 cm long, stigma with two acute lobes spreading medianly. Fruits unknown.

Description: Casearia amplectens Sleum. sp. nov. — Arbuscula 1.5 m alta; ramulornm apicibus dense breviter flavido-pilosis, partibus vetustioribus cito glabratis corticeque cinerascenti obtectis. Folia elliptico-oblonga vel oblonga, apicem versus breviter (1—2 cm) subcaudato-acuminata, apice ipso paullo falcato obtusa, basi late cuneata fere rotundata, inferiora usque ad 2 mm longe petiolata, superiora subsessilia, membranacea, arcte pellucido-punctata et -lineata, petiolo, costa nervisque subtus brevissime pilosulis exceptis glabra, in sicco brunnescentia, utrinque opaca, regulariter crenato-serrata (dentibus obtusiusculis glandula terminatis 1 mm altis et c. 3—6 mm distantibus), 9—15 cm longa, 4—4.5 cm lata, costa utrinque elevata, nervis lateralibus utroque latere 6—8 curvato-ascendentibus praeter marginem excurrentibus supra subimpressis, subtus elevatis, venis supra obscuris, subtus parum conspicuis. Stipulae reniformes fere amplectentes, membranaceae, 4—6 mm altae, 6—8 mm latae, persistentes. Flores pro axilla. 1—2 fere sessiles, in statu nondum plane evoluto tantum visi; bracteae paucae membranaceae glabrae 1—2 mm longae. Calyx tubulosus, carnosulus, c. 3 mm longus, extus fulvo-sericeus, intus glaber, lobis oblongis c. 1 mm longis. Stamina 10, alte ad faucem inserta; filamenta glabra, medio dilatata, alternatim 0.6 et 0.3 mm longa. Staminodia rudimentaria parum pilosa. Ovarium columnare, glabrum, c. 3 mm longum, 1 mm crassum. Fructus carnosus, ruber, 1.5—2 cm longus, 1 cm diam., trivalvis, basi calycis lobis accrescentibus 4 mm longis et 1.5 mm latis fultus, 2 mm longe pedunculatus. NEW GUINEA. W. New Guinea, 4 km SW of Bernhard Camp, Idenburg Riv., rain-forest undergrowth, 850 m: L. J. Brass 13470 (A; L, typus), fl. fr. March 1939.

Description: The X-ray powder method for determining minerals has been applied to the important rock-forming mineral group of the pyroxenes in this thesis. The purpose of the investigation was to seek the relationship between the variations of the intensities and positions of the reflections in the powder diagram and the variations in optical properties and chemical composition. For that purpose a number of pyroxenes from different localities were investigated optically, chemically and röntgenographically. The orthopyroxenes. — The optical examination of the orthopyroxenes indicates, that the variation of the optical properties is related to the chemical composition (see Table 1). A difference between plutonic and volcanic orthopyroxenes lies in the size of the optic axial angle 2 V; this appears to be smaller with volcanic orthopyroxenes between En80 and En15 than with plutonic orthopyroxenes (see fig. 5). Further a lamellar structure can be observed in the plutonic orthopyroxenes (see figs. 2 and 3) while the volcanics do not have these lamellae but often show zoning (see fig. 1). It is seen from chemical investigation of the orthopyroxenes that both the plutonic and volcanic orthopyroxenes show about the same variation in Al- and Ca-atomic proportions (see Table 3). It is quite possible that a part of the Ca content of the plutonic orthopyroxenes is present in exsolved diopside lamellae according to the hypothesis of Hess and Philips (1938). The orthopyroxenes can be distinguished from the clinopyroxenes by X-ray powder diagrams on the ground of their characteristic reflection pattern. These powder diagrams are made by means of a camera with a diameter of 9 centimeters and FeK\u03b11 radiation (\u03bb = 1.93597 Å). All powder diagrams of the orthopyroxenes are classed as one group (Group A, see fig. 6). The variation in the relative distance between the reflections 10 31 and 0 6 0 appears to be connected with the chemical composition. These distances are measured very accurately in millimeters by means of a Cambridge Universal Measuring Machine and plotted against the chemical composition in fig. 8. Through the influence of Al and Ca, the Mg content cannot be determined unequivocally from this diagram. Therefore also X-ray powder photographs are made of a mixture of 70 % orthopyroxene and 30 % quartz (see fig. 9). The relative distance between quartz reflection 2 1 3 1 and pyroxene reflection 0 6 0 in millimeters and the distance between quartz reflection (2 0 2 3) (3 0 3 1) and pyroxene reflection 11 3 1 in millimeters depend on the chemical composition which can be seen in figs. 10 and 11, respectively. In fig. 10 two curves are shown, one for orthopyroxenes with an atomic proportion of Al of about 0.010 and one for those with an atomic proportion of Al of about 0.050 in BVI position. In fig. 11 two curves can be seen which are related to orthopyroxenes with an atomic proportion of Ca of about 0.020 and those with an atomic proportion of Ca of about 0.060. One may determine the chemical composition of an orthopyroxene from these three diagrams (figs. 8, 10 and 11). For that purpose one should measure three relative distances. In each diagram one can find two values for the Mg content. From these, a total of six values, three will lie close to each other; the average of these three values indicates the Mg content. With this Mg content one can determine the Al and Ca contents in the diagrams. This röntgenographic method meets with difficulties when there do not occur certain proportions of Al and Ca in the orthopyroxene. Then there may be present two groups of three Mg's which lie close together (see Table 9). In such cases of doubt one must use the optical method to determine the Mg content. By substitution of Fe for Mg, Nz changes strongly, the unit cell dimensions do not, however, and neither do the relative distances. The Al and Ca contents then may be determined by the röntgenographic method. By substitution of Al and Ca for Mg, the unit cell dimensions change strongly and with them the relative distances between the reflections, which are very sensitive. The variation in the relative distance between the reflections mentioned has been explained by means of a crystal model of enstatite (see figs. 12 and 13). This variation results from the substitution of Fe, Al and Ca for Mg and of Al for Si. The substitution of Fe for Mg increases the unit cell dimensions only slightly so that the shape of the unit cell also changes little. The substitution of Ca for Mg has a great influence on the a- and the c dimension, which both become much greater. The substitution of Al for Mg and of Al for Si strongly decreases the b dimension. These changes in the unit cell occur because all substituting ions have a different ionic radius from Mg and moreover because in the structure of enstatite two kinds of Mg ions occur with altogether different positions and which are linked with the tetrahedra in very different ways. Since the relative distance in millimeters between certain reflections depends on the camera and radiation used, in Tables 7a, 7b and 7c these distances are stated for a few types of camera and radiation. In addition the differences between the lattice spacings of these reflections are given in Ångström units. The clinopyroxenes. — In this thesis the optical investigation on clinopyroxenes consists of a description of the specimens, both macroscopieally and microscopically and a determination of 2 V and Z \u039b c. For a few clinopyroxenes the values of Nz and Nx have also been determined. The described clinopyroxenes are subdivided in a number of groups; this classification is based upon the chemical composition (see p. 224). It turned out that the optical properties of the röntgenographically investigated clinopyroxenes do not differ much from the data mentioned in the literature about this group of minerals (see fig. 20 and Table 10). The chemical investigation is restricted to the analysis of a few clinopyroxenes; the results are stated in Table 11. On the basis of difference in position and intensity of certain reflections in the X-ray powder diagrams a classification in four groups has been established for the clinopyroxenes. Group B 1 (figs. 21 and 23) The group includes, hedenbergite, diopside, augite and diallage. Group B 2 (figs. 21 and 23) Pigeonite belongs to this group. Group B 3 (figs. 21 and 22) This group includes, aegirite and jadeite. Group B 4 (figs. 21 and 22) Spodumene belongs to this group. No sharp limits can be drawn between these groups and transitions may exist between some of these groups, as between groups B 1 and B 2 and also between groups B 1 and B 3. Through lack of clinoenstatite and ferrosilite samples we could not check whether any more groups may be distinguished. Of each of these groups the principal features are discussed on p. 245. Each group has its own characteristic reflection pattern; the similarity between these patterns, however, is great enough to conclude that all the investigated clinopyroxenes have a similar structure. The grouping of the X-ray powder diagrams agrees in the main with the classification of the pyroxenes according to the chemical composition. The chemical composition of the different clinopyroxenes of the groups B 1 and B 2 may be determined by a combined optical and röntgenographic investigation. This combination is necessary because the substitution of Fe for Mg has practically no influence on the dimensions of the unit cell, but it does have on the refractive indices. On the other hand the substitution of Ca for Mg strongly influences the shape of the unit cell. For the different clinopyroxenes of groups B1 and B 2 the variation of the relative distance in millimeters between the reflections 2 2 0 and 2 2 1, the reflections 2 2 1 and 3 1 0 and the reflections 1 3 1 and 2 2 1 is plotted against the chemical composition in figs. 25 and 26. From these diagrams one may determine the chemical composition by measuring the relative distances mentioned, on the X-ray powder diagrams. In figs. 27, 28 and 29 the relation between the chemical composition and the difference between the lattice spacings of the reflections in question in Å can be seen. Further Tables 16a, 16b and 16c indicate the distances between these reflections for a few types of camera and radiation. The X-ray powder diagrams of the alkali pyroxenes can be distinguished from those of the other pyroxenes, while they also show great mutual differences. It may be noted, however, that transitions between these pyroxenes always are possible. The powder diagram of spodumene has its own character, so that this pyroxene can be distinguished very simply from the other pyroxenes by the röntgenographic method. The X-ray investigation on clinopyroxenes is not yet completed, because much can still be done, for instance in the jadeite-diopside-aegirite field.

Description: During the study of the Xyridaceae of the Malaysian area it was desirable to study those of Australia and Continental Asia as well. The Malaysian species now have, in the meantime, been published (Flora Malesiana, ser. 1, 4, 1953, 366—376). To the new taxa described in Blumea 7, 1953, 307—308 the Latin diagnoses of the following new species and a new section may here be added: 1. Xyris linifolia van Royen, nov. spec. — Fig. 1. Herba mediocris, ad 40 cm alta. Folia subulata, ad 25 cm longa, c. 1 cm diam., subfalcata, acuta, sparse papillata; vaginae 6—8 cm longae, basi 3—6 mm latae; ligula brevis acuta c. 1 mm longa. Scapus 20—40 cm, c. 1 mm diam., teretiusculus, 2- vel pluricostatus, minute papillatus. Capitula ovoidea ad globosa, pauciflora, ad 7 X 6 mm, bracteae basales suborbiculares, 4.5—5.5 X 3.5—4 mm, obtusae, enerves, in parte superiori minute papillatae, papillis arcum triangularem formantibus, medianae obovatae, 6—6.5 X 4.5—5 mm, nervosae, nervis nervo mediano et uno nervo completo in costae utroque latere orto ad bracteae apicem laxe reticulato compositis, in parte mediana superiori minute papillatae, papillis aream suborbicularem formantibus. Flores masculini ignoti, florum femineorum sepala lateralia angusta, 5.5—6.5 X c. 1.5 mm, acutiuscula, emarginata, ecristata, alata, alis sat latis, sepalum medianum cucullatum, 4.5—5 X c. 2 mm, binerve. Petala nondum evoluta limbo orbiculari 4 mm longo et lato munita, margine serrata, unguiculo c. 2 mm. Stamina c. 3 mm, antherae c. 2 mm, apice profunde emarginatae, basi apiceque obtusae thecis emarginatis. Staminodia 2.5—3 mm, penicillata bifida? Ovarium incomplete cognitum, stylus 4.5—5 mm (vel longior?), trifidus, ramificationibus c. 2.5 mm, apice capitatis. Capsula ignota. Typus: Smiles s. n. in K. Distr.: Siam — in open grassland near base of Mt Kau. This species differs from all Malaysian species except X. borneensis in the terete leaves and the three complete nerves of the bracts. Though the leaves of X. borneensis are also terete, the bracts are provided with numerous complete nerves. Moreover, the lateral sepals in X. borneensis are ciliate, those of X. linifolia smooth and entire. In its anthers the present species resembles X. ridleyi, X. pauciflora, X. borneensis, X. capensis, X. complanata etc., the anthers being deeply incised at the top and the thecae emarginate. 2. Xyris nigromucronata van Royen, nov. spec. — Fig. 2. Herba annua parva, ad 6 cm alta. Folia linearia, 1—2.5 cm X c. 1 mm, mucronata, apice nigra et pilis robustis paucis hispida, anguste bi-alata, alis tenuiter et sparse papillatis, in parte basali elliptica in sectione transversa, apice incrassata et triangularia in sectione transversa, vaginae 3— 6 cm longae, apice pilis multis albis munitae, margine membranacea, marginibus pedunculi basin includentibus, pedunculo ligula biloba pilis destituta praedito. Scapus ad 6 cm longus, subangularis, valde obscure alatus, alis 1 vel 2, proxime infra capitulum elatus ubi 3- vel 4-alatus. Capitula oblongo-ellipsoidea, c. 7 X 5 mm, bracteae omnes cristatae, basales ovatae, c. 6.5 X 3 mm, sat brunneo-nigrae, mucronatae, mucrone ad 2.5 mm longa, cristata, nigra, crista pallide flava in parte apicali tantum tenuiter et sparse papillata, medianae subcirculares ad panduriformes, 4—5 X 2—5 mm, margine sat brunneo-nigrae, uninerves, nervo completo laevi, in parte basali membranaceae. Sepala lateralia naviculata, fere ad apicem connata, c. 5 X 1 mm, membranacea ecristata. Petala 6, alba, 6—7 mm longa, unguiculata, ungui 4—5 mm, arcte cohaerentia et quasi tubulosa, limbo elliptico-oblongo, obtuso, c. 2 X 0.8 mm. Stamina 6, c. 1.2 mm, antheris ovoideis, c. 0.6 mm, truncatis, emarginatis thecae basi obtusae; filamenta subulata, c. 0.6 mm. Staminodia desunt. Ovarium subovoideum ad ellipsoideum, c. 2 X 1 mm, trilobum, in parte basali 3-, in parte superiori 1-loculare, stigmatibus 3 terminatum. Capsula ovario similis, sed ad 3 X 1.5 mm metiens; semina sparse papillatae. Typus: Pritzel 635 a in L. Distr.: Australia — in scrub between Moore and Murchinson river. This specimen was found mixed with Stylidium bulbiferum Benth. var. septentrionale Mild braed in Pritzel 635. Therefore it is separated from that species under 635 a. This highly characteristic species differs from all other species of Xyris by the fimbriate top of the sheath, the united lateral sepals (also found in the Brasilian X. obtusiuscula Nilsson), the 6 united petals, the 6 stamens (also once found by the author in X. bancana Miquel), the more or less campylotropous ovules, the entire style, and the papillate curved seeds. Moreover, the flowers seem to be white but owing to the dried material it can not be stated for certain whether this is the proper colour. These details warrant the establishment of a separate section in Xyris, Australoxyris with the following Latin diagnosis: Xyris Linnaeus, sect. Australoxyris van Royen, nov. sect. Folia apice in sectione transversa triangularia, vaginae exteriores apice ciliatae, flores capitati; sepala lateralia maxime connata; petala 6, connata; stamina 6; stylus simplex; ovarium in parte basali 3-loculare, in parte superiori 1-loculare; ovula plus minusve campylotropa; semina papillata. Typus: Xyris nigromucronata van Royen.

Description: The present paper deals with the results of my investigations on the Tenebrionidae of the Leeward Group and the xerophilous regions of Venezuela and Colombia. I am much indebted to Dr P. Wagenaar Hummelinck for giving me the opportunity to study the material he collected during his trips to this area. Some other specimens used were collected by the present writer himself. Material for comparison has been obtained through the courtesy of several people, particularly the Director of the British Museum (N.H.), Mr H. Kulzer (Frey collection, Munich), and Prof. E. Tortonese (Museum of Zoology, Turin University), to all of whom I am deeply obliged. In particular I also wish to thank Prof. E. Gridelli, Director of the Natural History Museum, Trieste, to whom I am greatly indebted for his constant help and advice in my work, and to Prof. R. Malaroda, of the Institute of Geology, Padua University, for the useful criticism about my geological considerations. Not the last, I would express my gratitude to Dr E. MacC.Callan of the I.C.T.A. (Trinidad, B.W.I.) for the communication of material of that Institute. — The photographs were made by Dr P. Wagenaar Hummelinck, with the expert assistance of Mr H. van Kooten, at the Zoological Laboratory of the State University, Utrecht. The material has been deposited with the Zoological Museum of Amsterdam and the State Museum at Leyde. The material indicated as “Marcuzzi leg.” is included in author’s private collection, excepting some specimens which have been given to the Biological Department of the Caracas University, Venezuela.

Description: Verrucaria maas-geesterani Servít sp. n. (fig. 1). Thallus epilithinus, maculas 1—4 cm latas formans, atrofuscescens, H2O ater, sat tenuis, continuus vel h. i. imperfecte rimulosus, superficie verruculis atris 0.03 mm latis ± tecta et levissime asperata, protothallo indistincto. Stratum corticale usque ad cca 20 μ altum, p.p. pallidum usque ad fuscum, p.p. nigrum, cellulis in partibus pallidioribus ut in strato basali, in partibus atris ad 4 μ in diam. Stratum algarum 40—80 μ altum, prosoplectenchymaticum, cellulis 4—6 μ altis, 3—4 μ latis, algis 6—12 μ altis, 4—6 μ latis, in seriebus sat distinctis verticalibus, incoloratum, maculis obscuris interruptum. Stratum basale fusco-atrum vel carbonaceum, usque ad 60 μ altum, supra cum maculis obscuris strati algarum concrescens.

Description: Exbucklandia R. W. Brown ( Bucklandia R. Br. non Pr. ex Sternb., Symingtonia Steen.) In an article on “Alterations in some fossil and living floras” (J. Wash. Ac. Sc. 36: 348. Oct. 1946) R. W. Brown proposed the new generic name Exbucklandia for the Hamamelidaceous genus Bucklandia R. Br., non Pr. ex Sternb., while describing a new fossil species from the United States. He also transferred B. populnea to the new genus. Unfortunately I had overlooked this publication when proposing Symingtonia to replace Bucklandia R. Br. (Acta Bot. Neerl. 1: 443—444. 1952). Exbucklandia will have to be accepted for it in future. The Indo-Chinese species B. tonkinensis Lecomte should be referred to as Exbucklandia tonkinensis (Lecomte) Steen. comb. nov. I have to thank Dr E. H. Walker for pointing my attention to R. W. Brown’s paper.

Description: This charming and handy book printed on excellent paper, with its numerous clear pictures of well-known Malayan plants, reminds one in many ways of Merrill’s “Plant Life of the Pacific World” (MacMillan 1946, New York), which has perhaps served Prof. Holttum as an example. Its size being only slightly smaller than Merrill’s book and the area covered being very considerably smaller, its descriptions of plants are naturally more detailed; the more so as only a choice has been made, in which the special interests of the author — ferns, orchids, gingers — are evident though not predominant. The plants described are not regionally arranged. The 17 chapters are rather headed by names of life-forms, striking organs, and special habitats. As is pointed out in the Preface, the book is “intended primarily for the Malayan resident who wishes to begin a study of Malayan plants”. In this purpose the book will doubtless prove to be a success: the reader is gradually taught quite a bit of botany of various fields, morphology, anatomy, ecology, hybridisation, etc. These are demonstrated at plants which are within easy reach of the ordinary layman for which it is destined. Short opening and concluding chapters deal with general features of tropical plants and with the Malayan forest. Since the author is a well-known expert and the Malayan flora as here described is a very good example of any flora between, say, Calcutta and Fiji, it may well be useful to residents of many other countries as well.

Description: The Netherlands Antilles may be divided into: (1) The Curaçao Group (or Netherlands Leeward Islands): Curaçao, Aruba and Bonaire. (2) The St. Martin Group (or Netherlands Windward Islands): (Netherlands) St. Maarten, Saba and St. Eustatius. The latter islands are very small, forming together only 8.1 per cent of the total area of the Netherlands Antilles, and 2.2 per cent of its population. The Curaçao Group often has a desert-like aspect with a “tropical dry-forest” vegetation. Therefore on these islands the mosquito pest is nothing like so bad as it usually is in the tropics. There are few permanent breeding places, except man-made receptacles in and around the houses to store rainwater or well-water in as the Government waterworks do not always produce sufficient and adequate water. The St. Martin Group has a higher rainfall and a more abundant vegetation. In the preceding pages the morphological characteristics which are of taxonomic value have been described. Keys to the mosquitoes, their classification, their geographical distribution and their biology observed in the Netherlands Antilles have been given. Mosquitoes may be spread by automobiles, ships and airplanes on the islands. Fortunately, all airplanes from foreign airports and St. Maarten are sprayed on Curaçao and Aruba. Except this measure little was done before 1951 to control mosquitoes, except in the areas occupied by the oil companies. An anti-Aëdes aegypti campaign was initiated on Curaçao in October 1951 and on Aruba in March 1952 (residual DDT house spraying and larviciding). Because of the paucity of mosquito records of the Netherlands Antilles a rather thorough survey was made on Curaçao from 1941- 1947, while the other islands were visited only for a short time. At the moment 20 species are known from the Netherlands Antilles. Anopheles pseudopunctipennis pseudopunctipennis was found on Curaçao and rarely on Aruba, and An.albimanus once on St. Maarten, but never an indigenous case of malaria has been reported from the Netherlands Antilles. The larvae of An. pseudopunctipennis were found in earth-lined breeding places, but also frequently in manmade receptacles. Nearly all these breeding places contained clear, fresh or slightly brackish water with green algae; the majority were sunlit. Though the females of An.pseudopunctipennis attacked man, they were more attracted to animals. Culex quinquefasciatus was a common domestic pest mosquito on all of the islands. Though it often bred in earth-lined breeding places, it was found more frequently in man-made receptacles. The water was fresh or slightly brackish and usually polluted. Wuchereriasis bancrofti prevailed at a low rate on the Curaçao Group (4.2%, of which at least 2.7% was indigenous) and at a higher rate on the St. Martin Group (10.3% of which at least 5.1% was autochthonous). Elephantiasis was very rare. Aëdes aegypti was the most common domestic pest mosquito on both groups of islands. It was usually caught in clear, fresh water in man-made receptacles in or around human dwellings. The females bit in the daytime and at night. Several epidemics of yellow fever occurred in the previous century; the last one was on Curaçao in 1901. The last sporadic case occurred on Curaçao in 1914. Dengue was very common in newcomers from non-endemic areas. Haemagogus anastasionis was collected on Curaçao and rarely on Aruba. The larvae were mainly found in tree holes after occasional rains. All the breeding places contained dark brown rainwater with a layer of humus. The bite of the female is painful. Fortunately it has not been incriminated as a vector of jungle yellow fever. Besides, there are no wild monkeys on the Netherlands Antilles. Wyeomyia celaenocephala was found in various species of bromeliads on the Christoffelberg on Curaçao. The females will bite fiercely in the jungle. Uranotaenia lowii was collected from a pond on Bonaire. Aëdes taeniorhynchus was mainly caught in stagnant, sunlit beach pools with clear, dark brown, brackish water on Curaçao, and once in a well on Saba. The females are severe biters. Aëdes busckii was found in a tree hole on St. Eustatius. Psorophora cyanescens was reported from Aruba only once. Psorophora confinnis bred in rock holes and other earth-lined breeding places, and rarely in man-made receptacles on the Curaçao Group. The majority of the breeding places were temporary and sunlit, and contained clear or turbid rainwater. The females are fierce biters. They entered houses. Psorophora pygmaea was collected from a ditch on St. Maarten. Deinocerites cancer was mainly found in crab holes on both groups of islands. The water of the breeding places was turbid and brackish. Adults lived in the crab holes. Females did not bite the author. Culex erraticus was caught in clear fresh water near the airport on Curaçao. Culex americanus was found in various bromeliads on the St. Martin Group. Culex bahamensis was collected from fresh or brackish water on the St. Martin Group. Culex habilitator adults and larvae were found in crab holes on St. Maarten. Culex maracayensis was caught in earth-lined breeding places and sometimes in concrete tanks and troughs on Curaçao. The water was usually clear, shaded and fresh or slightly brackish. Culex nigripalpus was collected near the airport on Curaçao from a temporary ground pool with rainwater. Megarhinus guadeloupensis was found once in a bromeliad on Saba.

Description: The border region between Coahuila and Zacatecas is part of the mountainous country south of Parras in northeastern Mexico. It includes a thickness of about 2,600 meters of Jurassic and Cretaceous rocks that were deposited along the northern border of the Mexican geosyncline along the southern margin of the Coahuila Peninsula massif. During early Tertiary time these sediments were compressed into folds parallel to the borders of the massif. The majority of the anticlines in the area mapped is overturned to the north. After the compressive stage a tensional stage developed and a system of tensional faults was formed. Block faulting found place on a large scale. A suggestion by de Sitter that some longitudinal faults may be comparable to schistosity planes in microfolds is tested in the horizontal outcrop pattern of this area, and no indications are found which could contradict this hypothesis. It is suggested that this horizontal outcrop pattern should also vary with the relative competency of the rock formation. The stratigraphic column is divided into formations. The Jurassic includes the Zuloaga limestone of Oxfordian age and the equivalent La Caja and La Casita formations of Kimmeridgian-Portlandian age. The Cretaceous from the base upward includes the Taraises formation of Lower Neocomian age, the Cupido limestone of upper Neocomian-lower Aptian age, the La Peña formation of upper Aptian-lower Albian age, the Aurora limestone of middle Albian age, the Indidura formation of upper Cenomanian-Turonian age, the Caracol formation of Coniacian age, and the Parras shale of Santonian age. The La Caja formation contains a variable amount of phosphorites, the genesis of which is discussed. The conclusion is reached that there are indications that this deposit had a biochemical mode of origin rather than a purely chemical one as advocated by Kazakov.

Description: We present new high-resolution snow depth data on Arctic sea ice derived from airborne microwave radar measurements from the IceBird campaigns of the Alfred Wegener Institute (AWI) together with a new retrieval method using signal peakiness based on an intercomparison exercise of colocated data at different altitudes. We aim to demonstrate the capabilities and potential improvements of radar data, which were acquired at a lower altitude (200 ft) and slower speed (110 kn) and had a smaller radar footprint size (2-m diameter) than previous airborne snow radar data. So far, AWI Snow Radar data have been derived using a 2-18-GHz ultrawideband frequency-modulated continuous-wave (FMCW) radar in 2017-2019. Our results show that our method in combination with thorough calibration through coherent noise removal and system response deconvolution significantly improves the quality of the radar-derived snow depth data. The validation against a 2-D grid of in situ snow depth measurements on level landfast first-year ice indicates a mean bias of only 0.86 cm between radar and ground truth. Comparison between the radar-derived snow depth estimates from different altitudes shows good consistency. We conclude that the AWI Snow Radar aboard the IceBird campaigns is able to measure the snow depth on Arctic sea ice accurately at higher spatial resolution than but consistent with the existing airborne snow radar data of NASA Operation IceBridge. Together with the simultaneous measurements of the total ice thickness and surface freeboard, the IceBird campaign data will be able to describe the whole sea-ice column on regional scales.

Description: The West Antarctic Ice Sheet (WAIS) is one of the largest potential sources of future sea-level rise, with glaciers draining the WAIS thinning at an accelerating rate over the past 40 years. Due to complexities in calibrating palaeoceanographic proxies for the Southern Ocean, it remains difficult to assess whether similar changes have occurred earlier during the Holocene or whether there is underlying centennial- to millennial-scale forcing in oceanic variability. Archaeal lipid-based proxies, specifically glycerol dialkyl glycerol tetraether (GDGT; e.g. TEX86 and TEXL86), are powerful tools for reconstructing ocean temperature, but these proxies have been shown previously to be difficult to apply to the Southern Ocean. A greater understanding of the parameters that control Southern Ocean GDGT distributions would improve the application of these biomarker proxies and thus help provide a longer-term perspective on ocean forcing of Antarctic ice sheet changes. In this study, we characterised intact polar lipid (IPL)-GDGTs, representing (recently) living archaeal populations in suspended particulate matter (SPM) from the Amundsen Sea and the Scotia Sea. SPM samples from the Amundsen Sea were collected from up to four water column depths representing the surface waters through to Circumpolar Deep Water (CDW), whereas the Scotia Sea samples were collected along a transect encompassing the sub-Antarctic front through to the southern boundary of the Antarctic Circumpolar Current. IPL-GDGTs with low cyclic diversity were detected throughout the water column with high relative abundances of hydroxylated IPL-GDGTs identified in both the Amundsen and Scotia seas. Results from the Scotia Sea show shifts in IPL-GDGT signatures across well-defined fronts of the Southern Ocean. Indicating that the physicochemical parameters of these water masses determine changes in IPL-GDGT distributions. The Amundsen Sea results identified GDGTs with hexose-phosphohexose head groups in the CDW, suggesting active GDGT synthesis at these depths. These results suggest that GDGTs synthesised at CDW depths may be a significant source of GDGTs exported to the sedimentary record and that temperature reconstructions based on TEX86 or TEXL86 proxies may be significantly influenced by the warmer waters of the CDW.

Description: In this paper we analyze how oceanic circulation affects sediment deposition along a sector of the Ross Sea continental margin, between the Iselin Bank and the Hillary Canyon, and how these processes evolved since the Late Miocene. The Hillary Canyon is one of the few places around the Antarctic continental margin where the dense waters produced onto the continental shelf, mainly through brine rejection related to sea ice production, flow down the continental slope and reach the deep oceanic bottom layer. At the same time the Hillary Canyon represents a pathway for relatively warm waters, normally flowing along the continental slope within the Antarctic Slope Current, to reach the continental shelf. The intrusion of warm waters onto the continental shelf produces basal melting of the ice shelves, reduces their buttressing effect and triggers instabilities of the ice sheet that represent one of the main uncertainties in future sea level projections. For this study we use seismic, morpho-bathymetric and oceanographic data acquired in 2017 by the R/V OGS Explora. Seismic profiles and multibeam bathymetry are interpreted together with age models from two drilling sites (U1523 and U1524) of the International Ocean Discovery Program (IODP) Expedition 374. Oceanographic data, together with a regional oceanographic model, are used to support our reconstruction by showing the present-day oceanographic influence on sediment deposition. Regional correlation of the main seismic unconformities allows us to identify eight seismic sequences. Seismic profiles and multibeam bathymetry show a strong influence of bottom current activity on sediment deposition since the Early Miocene and a reduction in their intensity during the mid-Pliocene Warm Period. Oceanographic data and modelling provide evidence that the bottom currents are related to the dense waters produced on the Ross Sea continental shelf and flowing out through the Hillary Canyon. The presence of extensive mass transport deposits and detachment scarps indicate that also mass wasting participates in sediment transport. Through this integrated approach we regard the area between the Iselin Bank and the Hillary Canyon as a Contourite Depositional System (ODYSSEA CDS) that offers a record of oceanographic and sedimentary conditions in a unique setting. The hypotheses presented in this work are intended to serve as a framework for future reconstructions based on detailed integration of lithological, paleontological, geochemical and petrophysical data.

Description: The Data Science Symposium at Haus der Wissenschaft on 8/9 November 2021 in Bremen was the 6th Symposium in this series since 2017.

Description: Currently, little is known about the population identity of fin whales (Balaenoptera physalus) in Antarctic waters but initial analyses of acoustic recordings from the Southern Ocean (SO) have shown that fin whale calls differ between regions, possibly representing different fin whale populations. In the Atlantic Sector of the Southern Ocean, the typical fin whale 20-Hz song is often accompanied by simultaneous higher frequency (HF) component at around 89Hz or 99Hz. However, the distribution of these call types throughout the area and whether there is a clear spatial separation between these call types is so far unknown. In this study fin whale calls were examined between two locations, the Greenwich Meridian and Elephant Island across the Weddell Sea (from 2009, 2011, 2013, and 2015) to gain further insights into the connections between fin whales in this region. The HF call component was found to be significantly (p-value 〈 2.2e^-16) unique in its frequency at the two locations with 99Hz (97.14Hz ± 3.19) at Greenwich Meridian and 86Hz (86.26Hz ± 1.36) at Elephant Island. The inter-pulse interval (IPI) of both low frequency (LF) (20-Hz) and HF calls were also found to differ between geographic regions, with a median IPI of 14.5 seconds at Elephant Island and median IPI around 10 seconds at Greenwich Meridian. Variation in song IPIs were also investigated between geographic locations, Elephant Island was determined to have a majority singlet song type and Greenwich Meridian was found to have mostly triplet songs. The occurrence of HF and LF calls showed a strong positive correlation, indicating that both call components are produced simultaneously. The characteristic elements for fin whale calls examined in this study all indicate that the fin whale calls recorded at Elephant Island and Greenwich Meridian belong to two distinct acoustic populations. An understanding of how potentially distinct fin whale stocks utilize different geographic regions is fundamental for management and conservation measures aiming to improve the conservation status of this vulnerable species.

Description: Salt marshes, along with seagrass and mangroves, are known to be globally important carbon sinks. Salt marsh plants absorb CO2 from the air. Through photosynthesis, they use the carbon to build plant parts such as leaves and roots, i.e. organic biomass. Salt marsh plants produce a considerable amount of belowground biomass. This organic matter is persistent and only decays over a long period of time. Over time, some of the carbon-containing biomass is permanently buried in the marsh soil. Here, conditions are usually favourable for the preservation of the organic material, which can lead to carbon storage for thousands of years. In this way, salt marshes absorb CO2 from the air and store it as organic carbon in the soil - a mechanism that removes CO2 from the atmosphere and counteracts climate change. In addition, salt marshes act as a filter and trap for sediment and organic material that enters the salt marsh from outside. When water levels are high, salt marshes are flooded and the salt marsh plants literally fish out sediment and organic material from the water above them. Organic material in particular also contains carbon, which is then deposited in the salt marsh and later stored in the soil. The accumulation of carbon from sources outside the salt marsh also contributes to the role of salt marshes as carbon sinks.

Description: Just like salt marshes and mangroves, seagrasses are ecologically important habitats in coastal ecosystems and are also important carbon storages. Seagrasses absorb CO2 and other forms of inorganic carbon from water and air and produce organic biomass, i.e. new plant components, by means of photosynthesis. Dead parts of the seagrass plant can be buried into the deeper, oxygen-poor layers of the tidal flat sediment by current-induced sediment reallocation or burrowing activity of animals. Bacteria that are responsible for decomposing the organic material and would thus release the carbon again can hardly become active there due to the lack of oxygen. The carbon incorporated in the plant parts can thus be stored in the seabed for many centuries. In addition to this internal source, seagrasses also act as filters for sediment and organic material, which is transported into the seagrass bed from outside. Sediment and organic material may originate from deeper areas of the sea and then be transported towards the coast, or may be directly from nearby coastal vegetation. Above a seagrass bed, these components are literally fished out of the seawater near the bottom as if with a comb. In this way, new layers of sediment and organic material are continuously deposited in the seagrass meadow, leading to a further accumulation of organic material that can be stored in the seabed for up to thousands of years.

Description: The introduction of non-indigenous species may cause strong effects on biodiversity, species interactions and functioning of native soft-bottom coastal ecosystems. Especially introduced bioengineering organisms modify existing benthic habitat structures and thereby habitat-specific species interactions. In the Wadden Sea, beds of native blue mussels have been invaded by Pacific oysters Magalana gigas, which caused a large-scale shift from pure epibenthic Mytilus edulis beds to current mixed reefs of mussels and oysters. These newly developed biotic habitats may affect the occurrence of former associated key organisms and their ecological functions. In this context, we studied the grazing activity of native periwinkles Littorina littorea and the spatial distribution of M. edulis in oyster reefs in the northern Wadden Sea and explored the resulting distribution patterns of barnacle epibionts attached to oyster and mussel shells. A manipulative field experiment revealed that density of L. littorea significantly affects the recruitment success of barnacles Semibalanus balanoides on oyster shells. The highest number of barnacles recruited at periwinkle exclusion and this relationship was already known for pure blue mussel beds in the past. Barnacle epigrowth on blue mussel shells, however, changed with the new position of mussels within the oyster matrix and is nowadays lower than in former times. Our results demonstrate that introduced bioengineering organisms may alter, native biotic habitats but associated species interactions may remain the same. Additionally, it shows that native species may profit from the new structures by, for example, being less overgrown with detrimental barnacle overgrowth.

Description: The introduction of non-indigenous species may cause strong effects on biodiversity, species interactions and functioning of native coastal ecosystems. Especially introduced bioengineering organisms may fundamentally change native soft-bottom ecosystems by modifying existing benthic habitat structures and thereby habitat-specific species interactions. The introduction of Pacific oysters Crassostrea gigas into the sedimentary coastal area of the south-eastern North Sea and its preferred settlement on native blue mussel shells caused a large-scale shift from pure epibenthic Mytilus edulis beds to current mixed reefs of mussels and oysters. To investigate whether the newly developed biotic habitat affects the occurrence of associated key organisms and their ecological functions, we studied the long-term occurrence of periwinkles Littorina littorea and their grazing activity on barnacles attached to Pacific oyster shells in the northern Wadden Sea. We found no negative effects of oyster density increase on periwinkle population dynamics in the last two decades, which spans a time-period from the beginning of Pacific oyster establishment on mussel beds to oyster dominance today. A manipulative field experiment revealed that density of L. littorea significantly affects the recruitment success of barnacles Semibalanus balanoides on oyster shells. The highest number of barnacle recruited at periwinkle exclusion. Thus, snail density and resulting grazing activity may control barnacle overgrowth on oyster shells, which is known to cause detrimental effects on overgrown bivalves. The company of introduced oysters and native periwinkles in the Wadden Sea shows that alien species may find native friends in newly conquered ecosystems with mutual benefits.

Description: The number of input-output assessments focused on energy has grown considerably in the last years. Many of these assessments combine data from multi-regional input-output (MRIO) databases with energy extensions that completely or partially depict the different stages through which energy products are supplied or used in the economy. The improper use of some energy extensions can lead to double accounting of some energy flows, but the frequency with which this happens and the potential impact on the results are unknown. Based on a literature review, we estimate that around a quarter of the MRIO-based energy assessments reviewed incurred into double accounting. Using the EXIOBASE MRIO database, we also analyse the effects of double accounting in the absolute values and rankings of different countries' and products' energy footprints. Building on the insights provided by our analysis, we offer a set of key recommendations to MRIO users to avoid the double accounting problem in the future. Likewise, we conclude that the harmonisation of the energy data across MRIO databases led by experts could simplify the choices of the data users until the provision of official energy extensions by statistical offices becomes a widespread practice.

Description: The Nutrient Enhanced Coastal Ocean Productivity (NECOP) Program is a component of NOAA's Coastal Ocean Program. The central hypothesis of this research is: Anthropogenic nutrient inputs have enhanced coastal ocean productivity with subsequent impacts on coastal ocean water quality, living resource yields, and the global marine carbon cycle. The initial study area for this program is the Mississippi/Atchafalaya River Outflow and adjacent Louisiana shelf region.

Description: Deutschlands Klimaschutzstrategie baut auf den Einsatz von grünem Wasserstoff aus erneuerbaren Energien. Doch wo soll der Wasserstoff herkommen, aus heimischer Produktion oder importiert aus dem Ausland? Eine Studie des Wuppertal Instituts und DIW Econ schafft einen Überblick über die aktuelle Datenlage und ermittelt Wertschöpfungs- und Beschäftigungseffekte beider Strategien. Das Resümee: Es trifft nicht zu, dass importierter Wasserstoff allgemein günstiger ist, entscheidend sind je nach Herkunftsland die tatsächlich realisierbaren Strom- und Transportkosten. Wird der grüne Wasserstoff stattdessen im eigenen Land produziert, wird dies zudem eine positive Beschäftigungswirkung und Wertschöpfung entfalten. Mit der Erreichung der Klimaziele 2050 betrüge die zusätzliche Wertschöpfung bei einer stark auf die heimische Erzeugung ausgerichtete Strategie bis zu 30 Milliarden Euro im Jahr 2050 und es könnten bis zu 800.000 Arbeitsplätze geschaffen werden.

Description: Greenhouse gas (GHG) emissions from abrupt thaw beneath thermokarst lakes were projected to at least double radiative forcing from circumpolar permafrost-soil carbon fluxes by the end of this century, primarily through the release of methane, a much stronger GHG than CO2. Thermokarst lagoons represent the first stage of a thermokarst lake transition to a marine setting with so far neglected consequences for GHG production and release. We expected that along the transition from a thermokarst lake to a thermokarst lagoon, sediment concentrations of terminal electron acceptors like sulfate increase with an associated drop in methanogenic activity, a shift towards non-competitive methylotrophic methanogenesis, and the occurrence of sulfate-driven anaerobic methane oxidation (AOM). To explore this, we targeted a variety of geochemical and microbial parameters including sediment methane and CO2 concentrations, gaseous carbon isotopic signatures, hydrochemistry, GHG production rates, ratios of CH4/CO2, and occurrence of methane-cycling microbial taxa in sediments of two thermokarst lakes and a thermokarst lagoon on the Bykovsky Peninsula located in northeastern Siberia adjacent to Tiksi Bay. We found multiple lines of evidence that AOM in sediment layers influenced by Tiksi Bay water (i.e. the lagoon) functions as effective microbial methane filter. Annually, the lagoon is decoupled from Tiksi Bay for more than six months, resulting in more saline conditions below the ice cover compared to Tiksi Bay. Despite sub-zero near-surface sediment temperatures for approximately nine months per year, we show that, at least in early spring, AOM led to near-surface sediment methane concentrations approximating only about 1% of those measured in near-surface thermokarst lake sediments. Structural equation modelling stresses pore-water chemistry and increases in anaerobic methanotrophic abundance as main controls for the drop of in-situ methane concentrations and the corresponding increase in carbon isotopic signature. Shallow sediment layers (i.e. younger carbon) corresponded with higher rates of potential methane production, especially in the non-lagoon settings but even in the lagoon, potential methane production rates in the surface sediment layers were relatively unaffected by the marine influence. We propose that this reflects the overall dominance of non-competitive methylotrophic methanogenesis independent of pore-water chemistry and sediment depth. Overall, our study suggests that thermokarst lake to lagoon transitions have the potential to offset atmospheric methane fluxes from abrupt thaw lake structures long before thermokarst lakes fully transgress onto the Arctic shelf.

Description: Subsea permafrost is perennially cryotic earth material that lies offshore. Most submarine permafrost is relict terrestrial permafrost beneath the Arctic shelf seas, was inundated after the last glaciation, and has been warming and thawing ever since. It is a reservoir and confining layer for gas hydrates and has the potential to release greenhouse gases and affect global climate change. Furthermore, subsea permafrost thaw destabilizes coastal infrastructure. While numerous studies focus on its distribution and rate of thaw over glacial timescales, these studies have not been brought together and examined in their entirety to assess rates of thaw beneath the Arctic Ocean. In addition, there is still a large gap in our understanding of sub-aquatic permafrost processes on finer spatial and temporal scales. The degradation rate of subsea permafrost is influenced by the initial conditions upon submergence. Terrestrial permafrost that has already undergone warming, partial thawing or loss of ground ice may react differently to inundation by seawater compared to previously undisturbed ice-rich permafrost. Heat conduction models are sufficient to model the thaw of thick subsea permafrost from the bottom, but few studies have included salt diffusion for top-down chemical degradation in shallow waters characterized by mean annual cryotic conditions on the seabed. Simulating salt transport is critical for assessing degradation rates for recently inundated permafrost, which may accelerate in response to warming shelf waters, a lengthening open water season, and faster coastal erosion rates. In the nearshore zone, degradation rates are also controlled by seasonal processes like bedfast ice, brine injection, seasonal freezing under floating ice conditions and warm freshwater discharge from large rivers. The interplay of all these variables is complex and needs further research. To fill this knowledge gap, this thesis investigates sub-aquatic permafrost along the southern coast of the Bykovsky Peninsula in eastern Siberia. Sediment cores and ground temperature profiles were collected at a freshwater thermokarst lake and two thermokarst lagoons in 2017. At this site, the coastline is retreating, and seawater is inundating various types of permafrost: sections of ice-rich Pleistocene permafrost (Yedoma) cliffs at the coastline alternate with lagoons and lower elevation previously thawed and refrozen permafrost basins (Alases). Electrical resistivity surveys with floating electrodes were carried out to map ice-bearing permafrost and taliks (unfrozen zones in the permafrost, usually formed beneath lakes) along the diverse coastline and in the lagoons. Combined with the borehole data, the electrical resistivity results permit estimation of contemporary ice-bearing permafrost characteristics, distribution, and occasionally, thickness. To conceptualize possible geomorphological and marine evolutionary pathways to the formation of the observed layering, numerical models were applied. The developed model incorporates salt diffusion and seasonal dynamics at the seabed, including bedfast ice. Even along coastlines with mean annual non-cryotic boundary conditions like the Bykovsky Peninsula, the modelling results show that salt diffusion minimizes seasonal freezing of the seabed, leading to faster degradation rates compared to models without salt diffusion. Seasonal processes are also important for thermokarst lake to lagoon transitions because lagoons can generate cold hypersaline conditions underneath the ice cover. My research suggests that ice-bearing permafrost can form in a coastal lagoon environment, even under floating ice. Alas basins, however, may degrade more than twice as fast as Yedoma permafrost in the first several decades of inundation. In addition to a lower ice content compared to Yedoma permafrost, Alas basins may be pre-conditioned with salt from adjacent lagoons. Considering the widespread distribution of thermokarst in the Arctic, its integration into geophysical models and offshore surveys is important to quantify and understand subsea permafrost degradation and aggradation. Through numerical modelling, fieldwork, and a circum-Arctic review of subsea permafrost literature, this thesis provides new insights into sub-aquatic permafrost evolution in saline coastal environments.

Description: Thermokarst lagoons, forming when thermokarst lakes are inundated by the sea, are an transition stage where terrestrial permafrost is introduced into the subsea realm. Here, permafrost and lacustrine carbon pools are transformed along Arctic coasts. During thaw previously frozen organic carbon can be converted into the greenhouse gases (GHG) carbon dioxide (CO2) and methane by microorganisms and leading to further climate warming. Especially for transition ecosystems like thermokarst lagoons it is largely unknown how GHG release is changing and whether thermokarst lagoons are a carbon source or sink. For getting a first glimpse of the consequences of saltwater inundation, we mimic the inundation of coastal permafrost in an experiment by incubating permafrost and thermokarst samples with artificial sea water under controlled conditions (4°C, dark, anaerobic) for 12 month. We used terrestrial samples from a 2.5 m high Yedoma outcrop, a thermokarst lake core, as well as samples from two neighboring thermokarst lagoons (a nearly-closed and a semi-closed) from the Bykovsky Peninsula, Northeast Siberia. By applying two different scenarios we aim to estimate (1) future GHG releases from newly formed Arctic lagoons by adding artificial seawater with a constant concentration and (2) the impact of increasing salinity on GHG production by incubating the samples under freshwater, brackish and marine conditions. Here we present (1) total organic carbon and dissolved organic carbon content for deep-drilled sediment cores (~ 30m) and (2) preliminary results on GHG production (methane and CO2) rates measured over 6 month. First results show that (1) GHG production is higher for inundated terrestrial sediments than for inundated lagoon sediments and (2) increasing salinity is favoring carbon dioxide production while methane production is low. In conclusion newly formed thermokarst lagoons, if upscaled to the thermokarst affected shorelines, are likely produce a significant amount of GHG under our experiment set-up.

Description: Three strains of methanotrophic bacteria (EbAT, EbBT and Eb1) were isolated from the River Elbe, Germany. These Gram-negative, rod-shaped or coccoid cells contain intracytoplasmic membranes perpendicular to the cell surface. Colonies and liquid cultures appeared bright-pink. The major cellular fatty acids were 12:0 and 14:0, in addition in Eb1 the FA 16:1ω5t was also dominant. Methane and methanol were utilized as sole carbon sources by EbBT and Eb1, while EbAT could not use methanol. All strains oxidize methane using the particulate methane monooxygenase. Both strains contain an additional soluble methane monooxygenase. The strains grew optimally at 15–25 °C and at pH 6 and 8. Based on 16S rRNA gene analysis recovered from the full genome, the phylogenetic position of EbAT is robustly outside any species clade with its closest relatives being Methylomonas sp. MK1 (98.24%) and Methylomonas sp. 11b (98.11%). Its closest type strain is Methylomonas methanica NCIMB11130 (97.91%). The 16S rRNA genes of EbBT are highly similar to Methylomonas methanica strains with Methylomonas methanica R-45371 as the closest relative (99.87% sequence identity). However, average nucleotide identity (ANI) and digital DNA-DNA-hybridization (dDDH) values reveal it as distinct species. The DNA G + C contents were 51.07 mol% and 51.5 mol% for EbAT and EbBT, and 50.7 mol% for Eb1, respectively. Strains EbAT and EbBT are representing two novel species within the genus Methylomonas. For strain EbAT we propose the name Methylomonas albis sp. nov (LMG 29958, JCM 32282) and for EbBT, we propose the name Methylomonas fluvii sp. nov (LMG 29959, JCM 32283). Eco-physiological descriptions for both strains are provided. Strain Eb1 (LMG 30323, JCM 32281) is a member of the species Methylovulum psychrotolerans. This genus is so far only represented by two isolates but Eb1 is the first isolate from a temperate environment; so, an emended description of the species is given.

Description: Climate warming alters plant composition and population dynamics of arctic ecosystems. In particular, an increase in relative abundance and cover of deciduous shrub species (shrubification) has been recorded. We inferred genetic variation of common shrub species (Alnus alnobetula, Betula nana, Salix sp.) through time. Chloroplast genomes were assembled from modern plants (n = 15) from the Siberian forest-tundra ecotone. Sedimentary ancient DNA (sedaDNA; n = 4) was retrieved from a lake on the southern Taymyr Peninsula and analyzed by metagenomics shotgun sequencing and a hybridization capture approach. For A. alnobetula, analyses of modern DNA showed low intraspecies genetic variability and a clear geographical structure in haplotype distribution. In contrast, B. nana showed high intraspecies genetic diversity and weak geographical structure. Analyses of sedaDNA revealed a decreasing relative abundance of Alnus since 5,400 cal yr BP, whereas Betula and Salix increased. A comparison between genetic variations identified in modern DNA and sedaDNA showed that Alnus variants were maintained over the last 6,700 years in the Taymyr region. In accordance with modern individuals, the variants retrieved from Betula and Salix sedaDNA showed higher genetic diversity. The success of the hybridization capture in retrieving diverged sequences demonstrates the high potential for future studies of plant biodiversity as well as specific genetic variation on ancient DNA from lake sediments. Overall, our results suggest that shrubification has species-specific trajectories. The low genetic diversity in A. alnobetula suggests a local population recruitment and growth response of the already present communities, whereas the higher genetic variability and lack of geographical structure in B. nana may indicate a recruitment from different populations due to more efficient seed dispersal, increasing the genetic connectivity over long distances.

Description: To provide a contribution to the Thematic Strategy for Soil Protection, here we present the results of a study focused on the potentially toxic elements (PTE) content in agricultural soils’ representative for the Mediterranean region. To reach this aim, samples of 22 Italian (NE Peloritani Mountains, Sicily) and 18 Turkish (Amik Plain, Hatay) soils were collected and analyzed to evaluate their PTE content. The Italian and Turkish sites have been selected because they represent very important cultivation zones. In Amik Plain (Turkey), the dominant crops consist of cotton, wheat, corn and olives, whereas in NE Peloritani Mountains, Sicily (Italy), an appreciate citrus variety, known as the “Interdonato lemon”, guaranteed by Protected Geographical Indication label, is produced. The collected results include: (1) the assessment of PTE levels in soils; (2) the identifcation of the PTE sources; (3) the relationships between PTE contents and soil properties (pH, electrical conductivity, organic matter, CaCO3, and clay). Several multivariate statistical methods such as correlation matrix, cluster analysis and main component analysis were applied to individuate the anthropogenic vs natural origin of the PTE sources. The detected PTE levels are in decreasing order Mn〉Zn〉V〉Cr〉Cu〉Ni〉As〉Pb〉Co〉Sb〉Se〉Cd for the Italian soils, and Mn〉 Ni〉V〉Zn〉Cr〉Cu〉Pb〉Co〉As〉Se〉Sb〉Cd for the Turkish soils. The overall obtained results allowed to defne: (a) a main lithogenic source for PTE detected in the Italian soils, except for Zn which origin is also associated to anthropogenic input; (b) a lithogenic origin for all of the PTE detected for the Turkish soils, with an associate anthropogenic contribution for Cr, Ni, V, Cu and V. The results obtained in this work enhance the knowledge in the individuation of PTE pollution sources in agricultural soils of the European Mediterranean region.

Description: Published

Description: 499

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: JCR Journal

Description: Crystalline rocks can produce dangerous radiation levels on the basis of their content in radioisotopes. Here, we report radiological data from 10 metamorphic and igneous rock samples collected from the crystalline basement of the Peloritani Mountains (southern Italy). In order to evaluate the radiological properties of these rocks, the gamma radiation and the radon emanation have been measured. Moreover, since some of these rocks are employed as building materials, we assess the potential hazard for population connected to their use. Gamma spectroscopy was used to measure the 226Ra, 232Th and 40K activity concentration, whereas the radon emanation was investigated by using a RAD 7 detector. The results show 226Ra, 232Th and 40K activity concentration values ranging from (17 ± 4) to (56 ± 8) Bq kg-1, (14 ± 3) to (77 ± 14) Bq kg-1 and (167 ± 84) to (1760 ± 242) Bq kg-1, respectively. Values of the annual effective dose equivalent outdoor range from 0.035 to 0.152 mSv y-1, whereas the gamma index is in the range of 0.22-0.98. The 222Rn emanation coefficient and the 222Rn surface exhalation rate vary from (0.63 ± 0.3) to (8.27 ± 1.6)% and from (0.12 ± 0.03) to (2.75 ± 0.17) Bq m-2 h-1, respectively. The indoor radon derived from the building use of these rocks induces an approximate contribution to the annual effective dose ranging from 8 to 176 μSv y-1. All the obtained results suggest that the crystalline rocks from the Peloritani Mountains are not harmful for the residential population, even though they induce annual effective doses due to terrestrial gamma radiation above the worldwide average values. Moreover, their use as building materials does not produce significant health hazards connected to the indoor radon exposure.

Description: Published

Description: 452–464

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: JCR Journal

Description: In the North Patagonian fjord region, the cold-water coral (CWC) Desmophyllum dianthus occurs in high densities, in spite of low pH and aragonite saturation. If and how these conditions affect the energy demand of the corals is so far unknown. In a laboratory experiment, we investigated the carbon and nitrogen (C, N) budget of D. dianthus from Comau Fjord under three feeding scenarios: (1) live fjord zooplankton (100 2,300 mm), (2) live fjord zooplankton plus krill (〉7 mm), and (3) four-day food deprivation. In closed incubations, C and N budgets were derived from the difference between C and N uptake during feeding and subsequent C and N loss through respiration, ammonium excretion, release of particulate organic carbon and nitrogen (POC, PON). Additional feeding with krill significantly increased coral respiration (35%), excretion (131%), and POC release (67%) compared to feeding on zooplankton only. Nevertheless, the higher C and N losses were overcompensated by the threefold higher C and N uptake, indicating a high assimilation and growth efficiency for the krill plus zooplankton diet. In contrast, short food deprivation caused a substantial reduction in respiration (59%), excretion (54%), release of POC (73%) and PON (87%) compared to feeding on zooplankton, suggesting a high potential to acclimatize to food scarcity (e.g., in winter). Notwithstanding, unfed corals `lost' 2% of their tissue-C and 1.2% of their tissue-N per day in terms of metabolism and released particulate organic matter (likely mucus). To balance the C (N) losses, each D. dianthus polyp has to consume around 700 (400) zooplankters per day. The capture of a single, large krill individual, however, provides enough C and N to compensate daily C and N losses and grow tissue reserves, suggesting that krill plays an important nutritional role for the fjord corals. Efficient krill and zooplankton capture, as well as dietary and metabolic flexibility, may enable D. dianthus to thrive under adverse environmental conditions in its fjord habitat; however, it is not known how combined anthropogenic warming, acidification and eutrophication jeopardize the energy balance of this important habitat-building species.

Description: Global warming has been a topic of discussion for many decades, however its impact on the thaw of permafrost and vice-versa has not been very well captured or documented in the past. This may be due to most permafrost being in the Arctic and similarly vast remote areas, which makes data collection difficult and costly. A partial solution to this problem is the use of Remote Sensing imagery, which has been widely used for decades in documenting the changes in permafrost regions. Despite its many benefits, this methodology still required a manual assessment of images, which could be a slow and laborious task for researchers. Over the last decade, the growth of Deep Learning has helped address these limitations. The use of Deep Learning on Remote Sensing imagery has risen in popularity, mainly due to the increased availability and scale of Remote Sensing data. This has been fuelled in the last few years by open-source multi-spectral high spatial resolution data, such as the Sentinel-2 data used in this project. Notwithstanding the growth of Deep Learning for Remote Sensing Imagery, its use for the particular case of identifying the thaw of permafrost, addressed in this project, has not been widely studied. To address this gap, the semantic segmentation model proposed in this project performs pixel-wise classification on the satellite images for the identification of Retrogressive Thaw Slumps (RTSs), using a U-Net architecture. In this project, the successful identification of RTSs using Satellite Images is achieved with an average of 95% Dice score for the 39 test images evaluated, concluding that it is possible to pre-process said images and achieve satisfactory results using 10-meter spatial resolution and as little as 4 spectral bands. Since these landforms can be a proxy for the thaw of permafrost, the aim is that this project can help make progress towards the mitigation of the impact of such a powerful geophysical phenomenon.

Description: Fjords are recognized as hotspots of organic carbon (OC) burial in the coastal ocean. In fjords with glaciated catchments, glacier discharge carries large amounts of suspended matter. This sedimentary load includes OC from bedrock and terrigenous sources (modern vegetation, peat, soil deposits), which is either buried in the fjord or remineralized during export, acting as a potential source of CO2 to the atmosphere. In sub-Antarctic South Georgia, fjord-terminating glaciers have been retreating during the past decades, likely as a response to changing climate conditions. We determine sources of OC in surface sediments of Cumberland Bay, South Georgia, using lipid biomarkers and the bulk 14C isotopic composition, and quantify OC burial at present and for the time period of documented glacier retreat (between 1958 and 2017). Petrogenic OC is the dominant type of OC in proximity to the present-day calving fronts (60.4 ± 1.4% to 73.8 ± 2.6%) and decreases to 14.0 ± 2.7% outside the fjord, indicating that petrogenic OC is effectively buried in the fjord. Beside of marine OC, terrigenous OC comprises 2.7 ± 0.5% to 7.9 ± 5.9% and is mostly derived from modern plants and Holocene peat and soil deposits that are eroded along the flanks of the fjord, rather than released by the retreating fjord glaciers. We estimate that the retreat of tidewater glaciers between 1958 and 2017 led to an increase in petrogenic carbon accumulation of 22% in Cumberland West Bay and 6.5% in Cumberland East Bay, suggesting that successive glacier retreat does not only release petrogenic OC into the fjord, but also increases the capacity of OC burial.

Description: Invited lecture about Arctic kelp forests and fieldwork in Kongsfjorden in the lecture series “Meeresforschung früher, heute und in Zukunft” of the Bremen Society for Natural Sciences on the occasion of the “UN-Dekade der Meeresforschung für nachhaltige Entwicklung 2021 – 2030”: “Bunte Vielfalt – Arktische Makroalgen im Wandel”

Description: Macroalgae are major primary producers and ecosystem engineers along rocky shores of the Arctic. With Svalbard being a hotspot of global warming, macroalgal species distribution and biomass is undergoing rapid changes, presumably affecting all associated life forms. The overall retreat of the yearly ice cover is only the centerpiece in a complex interplay of environmental drivers noticeably altering light availability, disturbance regimes and nutrient supply for Arctic seaweeds. Between 1996/1998 and 2012/2013 ecosystem changes were observed at our study site Hansneset in Kongsfjorden, as algal biomass in the littoral zone doubled and the macroalgal biomass peak, as well as the lower distribution limit of most dominating kelp species, shifted upwards by several meters. In summer 2021, we seek to complement these datasets. Our interdisciplinary group will repeat the quantitative monitoring study to examine how the community pattern of seaweeds and their associated fauna has changed since the last expedition. In detail, we will quantify macroalgal biomass and biodiversity, the age structure and fertility of kelp species, and the biomass and biodiversity of associated animals along a depth gradient between 0 and 15 m. Incorporated into the European Horizon 2020 project FACE-IT and two associated Svalbard Science Forum field grants, our superior aim is to analyse the response of benthic macroalgal assemblages to observed cryosphere changes in a broad context. In this poster, we will share the first results from this year’s field samplings and show how abundances, biomass and species diversity of macroalgae have changed over the last decades at our investigation site and what this means in general for the development of macroalgae on Arctic coasts.

Description: In this study, we investigate the role of macrozooplankton in the biogeochemistry of the Southern Ocean using a three-dimensional global ocean ecosystem model (FESOM- REcoM2). The macrozooplankton group was parameterized according to characteristics of Antarctic krill and a related fast-sinking detritus class (larger particles, e.g. fecal pellets) was introduced in the model. It was then analyzed how the ecosystem structure and major carbon export pathways in the Southern Ocean changed through this extension of the model. The spatial distribution of macrozooplankton biomass in the Southern Ocean was reproduced reasonably well. Preliminary results showed that the zooplankton proportion of living compartments (phytoplankton and zooplankton groups) in the model increased. Thus, zooplankton contribution to the particulate organic carbon (POC) flux increased. The contribution of macrozooplankton to POC export at 100 m depth was 0.12 Pg C per year or 15% of total export in the Southern Ocean. The transfer efficiency of organic carbon nearly doubled and reached up to 50% in regions with high macrozooplankton biomass. These results emphasize the important role of macrozooplankton in the Southern Ocean carbon cycle and have implications for studies of the biological carbon pump.

Description: The size and shape of snow grains directly impacts the reflection by a snowpack. In this article, different approaches to retrieve the optical-equivalent snow grain size (ropt) or, alternatively, the specific surface area (SSA) using satellite, airborne, and ground-based observations are compared and used to evaluate ICON-ART (ICOsahedral Nonhydrostatic—Aerosols and Reactive Trace gases) simulations. The retrieval methods are based on optical measurements and rely on the ropt-dependent absorption of solar radiation in snow. The measurement data were taken during a three-week campaign that was conducted in the North of Greenland in March/April 2018, such that the retrieval methods and radiation measurements are affected by enhanced uncertainties under these low-Sun conditions. An adjusted airborne retrieval method is applied which uses the albedo at 1700 nm wavelength and combines an atmospheric and snow radiative transfer model to account for the direct-to-global fraction of the solar radiation incident on the snow. From this approach, we achieved a significantly improved uncertainty (〈25%) and a reduced effect of atmospheric masking compared to the previous method. Ground-based in situ measurements indicated an increase of ropt of 15 μm within a five-day period after a snowfall event which is small compared to previous observations under similar temperature regimes. ICON-ART captured the observed change of ropt during snowfall events, but systematically overestimated the subsequent snow grain growth by about 100%. Adjusting the growth rate factor to 0.012 μm2 s�1 minimized the difference between model and observations. Satellite-based and airborne retrieval methods showed higher ropt over sea ice (〈300 μm) than over land surfaces (〈100 μm) which was reduced by data filtering of surface roughness features. Moderate- Resolution Imaging Spectroradiometer (MODIS) retrievals revealed a large spread within a series of subsequent individual overpasses, indicating their limitations in observing the snow grain size evolution in early spring conditions with low Sun.

Description: By use of macro-economic model EXIOMOD, the expected impacts of actions described in the Strategic Research and Innovation Agenda (SRIA) have been analyzed. The results of this analysis show that the R&I actions described in the SRIA contribute to decoupling economic growth from resource use. The actions are expected to cause an increasing gross domestic product and a decreasing raw material demand. This results in an increasing extracted resource productivity, a measure used to show the decoupling of economic growth and resource use. It can however be questioned whether the actions in the SRIA - or the measures implemented in the model - assume a strong enough pace for decoupling economic growth and material use. The actions contribute to the climate goals of the European Commission, by showing a pathway through which the emissions of greenhouse gas can be reduced.

Description: Der Klimawandel ist die wahrscheinlich größte Herausforderung unserer Zeit. Und längst handelt es sich dabei nicht mehr um ein rein theoretisches Problem der Zukunft. Denn jeder von uns spürt schon jetzt, dass sich die Lebensbedingungen auf der Erde massiv verändern. So häufen sich weltweit die Extremwetter-Ereignisse in Form von längeren Trocken- oder Dürrephasen, extremen Hitzewellen und Starkniederschlägen. Auch der Anstieg des Meeresspiegels bedroht unser Leben an den Küsten. Nirgendwo auf der Erde aber ist der Klimawandel bereits heute so sichtbar wie in der Arktis. Denn die Jahresmitteltemperatur steigt hier schon jetzt doppelt so stark wie im weltweiten Durchschnitt. Grund dafür ist vor allem die Eis-Albedo-Rückkopplung. Das helle Meereis auf dem Arktischen Ozean reflektiert einen großen Teil der eingestrahlten Sonnenenergie zurück ins All. Die weltweit steigenden Temperaturen lassen das Eis nun schmelzen und legen die dunkle Meeresoberfläche darunter frei. Der Arktische Ozean absorbiert dadurch mehr Sonnenenergie und erwärmt sich. Daraufhin schmilzt das Meereis noch schneller und der Trend zu höheren Temperaturen verstärkt sich. Die Folgen sind sogar aus dem All zu sehen: Im Vergleich zu vor 40 Jahren schmilzt das arktische Meereis heute bis zum Ende des Sommers auf mehr als die Hälfte seiner Fläche zusammen. Das alles hat massive Auswirkungen auf die Artenvielfalt und die hochspezialisierten Ökosysteme, die sich an die harschen Lebensbedingungen der Arktis angepasst haben. Und auch das Leben der Menschen verändert sich radikal. In der russischen Teilrepublik Nord-Jakutien etwa taut an vielen Stellen der bislang gefrorene Permafrost-Boden auf, so dass ganze Dörfer im Schlamm versinken. Tatsächlich zeigen Messungen, dass sich weite Teile des arktischen Permafrost-Bodens in Kanada und Sibirien bereits seit Jahrzehnten erwärmen. Taut dieser Boden großflächig auf, könnten große Mengen an Treibhausgasen zusätzlich in die Atmosphäre gelangen und die globale Erwärmung noch verstärken. Tauender Dauerfrostboden hat somit nicht nur Auswirkungen auf die Ökosysteme und Menschen vor Ort, sondern beeinflusst das weltweite Klima und damit das Leben von uns allen. Dieser Beitrag stellt auf Basis aktueller wissenschaftlicher Forschungsergebnisse den Einfluss des Klimawandels auf den arktischen Permafrost vor und nimmt dabei besonders die Region Ost-Sibirien / Nord Jakutien in den Fokus. Darüber hinaus beschreibt das Kapitel mögliche Entwicklungsszenarien für die Zukunft.

Description: The East Siberian and the Chukchi Shelf are of general interest concerning the distribution of regional ice sheets. Both shelves felt dry during glacial times, which is named Beringia. From geological onshore mapping it was proposed that Beringia did not host large ice sheets during glacial times. Instead, a widespread mountain glaciation was suggested. However, geophysical data of the last two decades imaged a complex pattern of glaciogenic erosion of even the shallow shelf areas. The results indicate the presence of several streams in bathymetric troughs and point to an ice sheet on the outer shelf of Beringia with unknown size. Advancing ice sheets deliver large amounts of sediments to the continental margins and change the slope properties. However, the amount of delivered sediments varies along the ice sheet margin. In seismic data, these deposits form chaotic or opaque wedges separated by strong semi-continuous to continuous reflections. We use published and reprocessed 2D multi-channel seismic reflection data from R/V Marcus G. Langseth located between 147°E in the East Siberian Sea to the to 149°W in the Beaufort Sea to investigate in greater detail the glacial deposited sediments along the northern margins of Beringia. We found in this data glacial deposits relocating the shelf break up to 13 km along the slope between 175° E and 161° W. The maximum thickness of these sediments reaches up to 450 m. Deposits in the Northwind Basin between 165° W and 161° W are separated by strong reflections indicating 3-5 glacial advances. On the Kucherov Terrace between 175°E to 176°W, we found erosion and grounded ice deposits in water depths shallower than 1200 m. However, slopes in the western East Siberian Sea and in the Beaufort Sea lack of thick glacial deposits. This might indicate either less intense or no glaciation. The amounts of glacial deposited sediments along the margins of Beringia are significant smaller than the reported amounts along the Norwegian and Greenland margins. In conclusion, our results indicate a less intense glaciation of Beringia compared to other glaciated margins during the Quaternary.

Description: The Arctic Ocean is mainly surrounded by continents and large shelf seas. During glacial times the ocean was covered by thick sea ice and/or fragments of ice sheets and ice shelfs. Evidences for this are erosion of the seafloor along the surrounding margins and also in the center of the Arctic Ocean. Glacial processes have modified the present and past seafloor down to water depths of more than a kilometer. This observation triggered a discussion about the existence of a 1 km thick pan-Arctic ice shelf during the LGM or earlier. The Lomonosov Ridge is a continental sliver and submarine ridge in the Arctic Ocean which rises several kilometers above the adjacent deep sea plains. It has no onshore catchment areas like the glaciated margins surrounding the Central Arctic Ocean which are strongly modified by glaciers and ice streams. Nevertheless, evidences for glacial erosion are found on the ridge. In our contribution, we investigate the Siberian termination of the Lomonosov Ridge between 81˚-84˚N with bathymetric, sediment echosounder and multichannel seismic reflection data acquired with RV Polarstern in 2014 and 2018. Bathymetry data reveal three sets of glacial lineations, differentiated by their orientation, which are traced to a maximum water depth of ~1250 m. A flat-topped ridge crest shows recessional moraines and pockmarks that might be glacially induced. Sediment echosounder and multichannel seismic reflection data show deeper units with well stratified reflections that are truncated and incised. Based on these data, we will discuss the pros and cons for the existence of a past 1 km thick pan-Arctic ice shelf on the Siberian termination of Lomonosov ridge.

Description: The Rio Grande Rise and Walvis Ridge were formed during the opening of the South Atlantic. Both structures were emplaced in the Late Cretaceous when the Tristan-Gough plume was located on or close to the Mid-Atlantic spreading ridge. In the last decade, several wide-angle seismic experiments unraveled the crustal structure of the Walvis Ridge, showing that it is composed of thickened oceanic crust. In contrast, it is debated if the RGR is entirely of volcanic origin or if it also contains fragments of continental crust. In 2019, Wide-angle refractions and gravity data were acquired along two NNE-SSW trending transects crossing the western and eastern RGR to study the nature of the crust and the evolution of the RGR. We will present first results from the new transect crossing the eastern RGR (profile AWI-20190100) and compare it with the crustal structure of the transect crossing the western Rio Grande Rise (profile AWI-20190200). P-wave velocity models derived by forward modelling, supplemented by a gravity models, constrain its crustal and upper mantle structure along both profiles. Our results show that the crust of the eastern RGR is thinner and only half as thick (15 km) in comparison to the western RGR. The crustal velocities along both lines are very similar. Evidences from the seismic velocities for the existence of a continental fragment are missing along both transects. While a high-velocity upper mantle is partly present below the western RGR, such high upper mantle velocities are not observed along the eastern profile. In summary, the seismic velocity structure of the RGR and the conjugate Walvis Ridge are very similar.

Description: The potential of shortwave infrared (SWIR) remote sensing to detect hotspots has been investigated using satellite data for decades. The hotspots detected by satellite SWIR sensors include very high-temperature heat sources such as wildfires, volcanoes, industrial activity, or open burning. This study proposes an automated classification method of heat source detected utilizing Landsat 8 and Sentinel-2 data. We created training data of heat sources via visual inspection of hotspots detected by Landsat 8. A scheme to classify heat sources for daytime data was developed by combining classification methods based on a Convolutional Neural Network (CNN) algorithm utilizing spatial features and a decision tree algorithm based on thematic land-cover information and our time series detection record. Validation work using 10,959 classification results corresponding to hotspots acquired from May 2017 to July 2019 indicated that the two classification results were in 79.7% agreement. For hotspots where the two classification schemes agreed, the classification was 97.9% accurate. Even when the results of the two classification schemes conflicted, either was correct in 73% of the samples. To improve the accuracy, the heat source category was re-allocated to the most probable category corresponding to the combination of the results from the two methods. Integrating the two approaches achieved an overall accuracy of 92.8%. In contrast, the overall accuracy for heat source classification during nighttime reached 79.3% because only the decision tree-based classification was applicable to limited available data. Comparison with the Visible Infrared Imaging Radiometer Suite (VIIRS) fire product revealed that, despite the limited data acquisition frequency of Landsat 8, regional tendencies in hotspot occurrence were qualitatively appropriate for an annual period on a global scale.

Description: Published

Description: 102491

Description: 7A. Geofisica per il monitoraggio ambientale

Description: JCR Journal

Description: Integrated electron microprobe analyses (EMPAs) on glass and Sr–Nd isotope analyses have been performed on 17 tephras from the Middle Pleistocene Mercure lacustrine succession, southern Apennines. Two 40Ar/39Ar ages and the recognition of four relevant tephras from Colli Albani, Sabatini and possibly Roccamonfina volcanoes allowed us to ascribe the investigated succession to the late Marine Isotope Stage (MIS) 15–12 interval (560–440 ka). The Sr–Nd isotopes and major element glass compositions allowed us to attribute 10 out of the other 13 tephras to a poorly known activity of the Roccamofina volcano, whereas two layers were tentatively attributed to previously unknown Middle Pleistocene activity of Ponza Island or Campanian volcanoes, and one to Salina Island. The tephrostratigraphic correlation of the Mercure tephras with the Acerno lacustrine pollen record (Campania) also allowed us to evaluate the climatostratigraphic position of the tephras within the framework of the MIS 15–12 climatic variability. These results were obtained by combining the Sr–Nd isotope ratio with EMPA and 40Ar/39Ar geochronological data. This confirms the notable consistency of this approach for studying the Mediterranean Middle Pleistocene tephrostratigraphy, which, despite its great potential for both volcanology and Quaternary studies, has been hitherto barely explored.

Description: Published

Description: 232–248

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Description: 4V. Processi pre-eruttivi

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: JCR Journal

Description: We describe the diagnostic lithological and chemical features of distal tephras from major MiddleLate Pleistocene (560e36 ka) explosive eruptions of the Colli Albani volcanic district, central Italy. In particular, we explore the time-dependent variability of the Sr and Nd isotope compositions as a tool for recognising and pinpointing individual Colli Albani tephra in distal settings. The distal tephras investigated are in lacustrine and fluvial sediments of central Apennine intermountain basins located 70 kme100 km east of Colli Albani. The recognition of the Colli Albani tephras is essentially based on the K-foiditic composition of their glass, which, within the Italian volcanological framework, is a distinctive character of the Colli Albani pyroclasts. In detail, these tephras are attributed to the following eruptive units: Tufo Pisolitico di Trigoria (561 2 ka); Tufo del PalatinoeTufo di Bagni Albule (530 2/527 2 ka), Tufo di Bagni AlbuleePozzolane Rosse air-fall sequence (517 1 to 500 3 ka), Pozzolane Rosse (457 4 ka), Villa Senni (365 4 ka), and Albano 5e7 (41 7 to 36 1 ka). These correlations are supported by 40Ar/39Ar dating of the distal tephras correlated to the Pozzolane Rosse (457.4 1.7 ka), Villa Senni (365 2 ka) and Albano 5e7 (41 9 ka) and by 87Sr/86Sr measured on clinopyroxene crystals and fresh glassy scoria from distal Colli Albani tephras that range from w0.711 to w0.709. These ratios are similar to those that characterise the individual proximal correlative units, and show the same decreasing trend over time. In contrast, the 143Nd/144Nd ratios for proximal and distal bulk samples and clinopyroxene increase from w0.51212 to w0.51215 from the oldest to the youngest tephra deposit. In summary, the study of Sr and Nd isotope compositions that is here applied on products from the Colli Albani volcanic district is a powerful, complementary tool to the more traditional tephrostratigraphic methods (e.g., componentry and electron microprobe analysis) for fingerprinting of distal tephras over a large region of the central Mediterranean, and over a large time interval, such as from 560 ka to 36 ka.

Description: Published

Description: 190-206

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: New geochemical and isotopic data on volcanic rocks spanning the period ~75–50 ka BP on Ischia volcano, Italy, shed light on the evolution of the magmatic system before and after the catastrophic, caldera-forming Monte Epomeo Green Tuff (MEGT) eruption. Volcanic ac tivity during this period was influenced by a large, composite and differentiating magmatic system, replenished several times with isotopically distinct magmas of deepprovenance. Chemical and isotopic variations highlight that the pre-MEGT eruptions were fed by trachytic/phonolitic magmas from an isotopically zoned reservoir that were poorly enriched in radiogenic Sr and became progressively less radiogenic with time. Just prior to the MEGT eruption, the magmatic system was recharged by an isotopically distinct magma, relatively more enriched in radiogenic Sr with respect to the previously erupted magmas. This second magma initially fed several SubPlinian explosive eruptions and later supplied the climactic, phonolitic-to-trachytic MEGT eruption(s). Isotopic data, together with erupted volume estimations obtained for MEGT eruption(s), indicate that 〉5–10 km3of this relatively enriched magma had accumulated in the Ischia plumbing system. Geochemical modelling indicates that it accumulated at shallow depths (4–6 km), over a period of ca. 20 ka. After the MEGT eruption, volcanic activity was fed by a new batch of less differentiated (trachyte-latite) magma that was slightly less enriched in radiogenic Sr. The geochemical and Sr–Nd-isotopic variations through time reflect the upward flux of isotopically distinct magma batches, variably contaminated byHercynian crust at 8–12 km depth. The deep-sourced latitic to trachytic magmas stalled at shallow depths (4–6 km depth), differentiated to phonolite through crystal fractionation and assimilation of a feldspar-rich mush, or ascended directly to the surface and erupted.

Description: Published

Description: 1035

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Description: 4V. Processi pre-eruttivi

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: JCR Journal

Description: The European Alps are the site where classic geologic concepts such as nappe theory, continental subduction and slab breakoff have been first proposed. However, the deep tectonic structure of the Alps has long been poorly constrained by independent geophysical evidence. This review paper summarizes the main results of the CIFALPS passive seismic experiment, that was launched by Chinese, French and Italian scientists in the 2010s to provide new insights on the deep tectonic structure of the Alpine region. The application of a wide range of tomographic methods to the analysis of a single fossil subduction zone makes the CIFALPS experiment a potential reference case for the analysis of other orogenic belts. Major results include: (i) the first seismic evidence of European continental crust subducted into the Adriatic upper mantle, beneath the place where coesite was first recognized in continental (U)HP rocks in the Alps; (ii) evidence of a major involvement of the mantle wedge during (U)HP rock exhumation; (iii) evidence of a serpentinized plate interface favouring continental subduction; (iv) evidence of a continuous slab beneath the Western and Central Alps, ruling out the classic model of slab breakoff magmatism; (v) evidence of a polyphase development of anisotropic fabrics in the Alpine mantle, either representing active mantle flows or fossil fabrics inherited from previous rifting stages. Detection of these major tectonic features allows to propose interpretive geologic cross sections at the scale of the lithosphere and upper mantle, providing a baseline for future analyses of active continental margins.

Description: Published

Description: e2020GC009466

Description: 1T. Struttura della Terra

Description: JCR Journal

Description: During the past millennia, several eruptions have occurred within the La Fossa caldera on the island of Vulcano (Aeolian Islands, Italy), some being also described in historical documents dating back to Republican Roman times (first to second century BC). The absolute and relative timing of such activity, however, has remained poorly defined and controversial, due to contrasting ages provided by radiometric and unconventional palaeomagnetic methods. Here, we present a detailed recon- struction of the eruptive history focused on the ninth to fifteenth century AD period that occurred at both La Fossa cone and Vulcanello. This integrated approach involves tephrostratigraphy, standard palaeomagnetic methodology and radiocarbon dating. The new dataset confirms that the lavas exposed above sea level at Vulcanello were erupted between the tenth and eleventh century AD, and not between the first and second century BC as previously suggested. In this same time interval, La Fossa cone was characterized by long-lasting, shoshonitic, explosive activity followed by a discrete, sustained, rhyolitic explosive eruption. Between AD 1050 and 1300, activity was focused only on La Fossa cone, with alternating explosive and effusive eruptions that emplaced four rhyolitic and trachytic lava flows, resulting in significant growth of the cone. After the violent, phreatic event of the Breccia di Commenda (thirteenth century), the eruption continued with a substantial, long- lasting emission of fine ash until activity ceased. Magmatic explosive activity resumed at La Fossa cone at the beginning of the fifteenth century marking the onset of the Gran Cratere cycle. This phase lasted until the mid-sixteenth century and produced at least seven explosive eruptions of intermediate magma composition and a couple of lateral explosions (Forgia Vecchia I and II). During this time interval, a third cinder cone was emplaced at Vulcanello, and the activity produced the lava flows of Punta del Roveto and Valle dei Mostri. From the seventeenth to twentieth centuries, volcanic activity was concentrated at La Fossa cone, where it ended in 1890. This work confirms that Vulcanello island formed in Medieval times between the tenth and eleventh centuries. Moreover, between the tenth and mid-sixteenth centuries, La Fossa caldera was the site of at least 19 eruptions with an average eruption rate of one event every 34 years. This rate makes volcanic hazard at Vulcano higher than that suggested to date.

Description: Published

Description: 12

Description: 1A. Geomagnetismo e Paleomagnetismo

Description: JCR Journal

Description: Il progetto RETRACE-3D (centRal italy EarThquakes integRAted Crustal modEl) è volto alla caratterizzazione tridimensionale, geologica e sismotettonica, del volume di crosta terrestre che a partire dal 24 agosto 2016 è stato interessato dai terremoti di Amatrice, Visso e Norcia, e dalla relativa sequenza sismica. Il progetto è il risultato di una collaborazione tra il Dipartimento della Protezione Civile, l’Istituto Nazionale di Geofisica e Vulcanologia (INGV), il Consiglio Nazionale delle Ricerche che partecipa con l’Istituto di Geologia Ambientale e Geoingegneria (CNR-IGAG) e l’Istituto per il Rilevamento Elettromagnetico dell’Ambiente (CNR-IREA) e l’Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), con la collaborazione di Eni e Total, realtà private ma anch’esse parte del Servizio nazionale della Protezione Civile, che hanno messo a disposizione i propri dati di sottosuolo.

Description: INGV, ISPRA, CNR-IGAG, DPC

Description: Published

Description: 1T. Struttura della Terra

Description: 2T. Deformazione crostale attiva

Description: 3T. Fisica dei terremoti e Sorgente Sismica

Description: 4T. Sismicità dell'Italia

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: 2IT. Laboratori analitici e sperimentali

Description: 3IT. Calcolo scientifico

Description: 4IT. Banche dati

Description: Three-dimensional geological model of the area of the central Apennines affected by the 2016-2018 seismic sequence. The model consists of stratigraphic surfaces (top or basal unconformity of units, or sequences of units, with homogeneous behavior) and main faults of the area. The stratigraphic surfaces are, from the oldest to the most recent: the top of pre-Upper Triassic units, the top of the intra-Triassic units, the top of Calcare Massiccio, the top of the Marne

Description: INGV, ISPRA, CNR-IGAG, DPC.

Description: Published

Description: 1T. Struttura della Terra

Description: 2T. Deformazione crostale attiva

Description: 3T. Fisica dei terremoti e Sorgente Sismica

Description: 4T. Sismicità dell'Italia

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: 2TR. Ricostruzione e modellazione della struttura crostale

Description: We identify the source of the Mw = 6.4 earthquake that rocked north-central Albania on November 26, 2019 02:54 UTC. We use synthetic aperture radar interferograms tied to the time series of coordinates of two permanent Global Navigation Satellite System (GNSS) stations (DUR2 and TIR2). We model the source by inverting the displacement data. Assuming in our model a half-space elastic medium and uniform slip along a rectangular fault surface, we invert the 104 picked measurements on a couple of ascending and descending interferograms to calculate the parameters of the fault. All inversions made with di erent input parameters converge towards a stable and robust solution with root mean square (r.m.s.) residual of 5.4 mm, thus ~1/5 of a fringe. They reveal that the earthquake occurred deep in the crust on a low-angle fault (23 ) dipping towards east with a centroid at 16.5 km depth. The best-fitting length and width of the fault are 22 and 13 km, and the reverse slip, 0.55 m. The seismic moment deduced from our model agrees with those of the published seismic moment tensors. This geometry is compatible with a blind thrust fault that may root on the main basal thrust, i.e., along the thrust front that separates Adria–Apulia from Eurasia. It is notable that there is a 123 ns yr-1 active shortening of the crust between the GNSS stations DUR2-TIR2 (equivalent to a shortening rate of 3.6 mm yr-1), and roughly in the east–west direction. Given this amount of strain the recurrence time of M6+ earthquakes along this fault should be of the order of 150 years.

Description: Published

Description: 210

Description: 3T. Sorgente sismica

Description: JCR Journal

Description: In recent years, new approaches for developing earthquake rupture forecasts (ERFs) have been proposed to be used as an input for probabilistic seismic hazard assessment (PSHA). Zone- based approaches with seismicity rates derived from earthquake catalogs are commonly used in many countries as the standard for national seismic hazard models. In Italy, a single zone- based ERF is currently the basis for the official seismic hazard model. In this contribution, we present eleven new ERFs, including five zone-based, two smoothed seismicity-based, two fault- based, and two geodetic-based, used for a new PSH model in Italy. The ERFs were tested against observed seismicity and were subject to an elicitation procedure by a panel of PSHA experts to verify the scientific robustness and consistency of the forecasts with respect to the observations. Tests and elicitation were finalized to weight the ERFs. The results show a good response to the new inputs to observed seismicity in the last few centuries. The entire approach was a first attempt to build a community-based set of ERFs for an Italian PSHA model. The project involved a large number of seismic hazard practitioners, with their knowledge and experience, and the development of different models to capture and explore a large range of epistemic uncertainties in building ERFs, and represents an important step forward for the new national seismic hazard model.

Description: Published

Description: SE220

Description: 6T. Studi di pericolosità sismica e da maremoto

Description: JCR Journal

Description: In order to monitor long-term variability in or eventual change of the planktonic community a semiquantitative analysis of microplankton based on net sampling is ongoing since 1987 in the Sylt-Rømø Bight, a region of high ecological importance within the Marine Protect Area National Park Schleswig Holsteinisches Wattenmeer. The sampling is tightly linked to the LTER Sylt Roads time series thus enabling the coupling of species occurrence to the respective hydrochemical and physical conditions in the water column. These long-term data allow to quantify realized niches of frequently occurring micro-plankton species and to pinpoint rarely occurring species which cannot be detected in the quantitative plankton analysis.

Description: In order to monitor long-term variability in or eventual change of the planktonic community a semiquantitative analysis of microplankton based on net sampling is ongoing since 1987 in the Sylt-Rømø Bight, a region of high ecological importance within the Marine Protect Area National Park Schleswig Holsteinisches Wattenmeer. The sampling is tightly linked to the LTER Sylt Roads time series thus enabling the coupling of species occurrence to the respective hydrochemical and physical conditions in the water column. These long-term data allow to quantify realized niches of frequently occurring micro-plankton species and to pinpoint rarely occurring species which cannot be detected in the quantitative plankton analysis.

Description: In order to monitor long-term variability in or eventual change of the planktonic community a semiquantitative analysis of microplankton based on net sampling is ongoing since 1987 in the Sylt-Rømø Bight, a region of high ecological importance within the Marine Protect Area National Park Schleswig Holsteinisches Wattenmeer. The sampling is tightly linked to the LTER Sylt Roads time series thus enabling the coupling of species occurrence to the respective hydrochemical and physical conditions in the water column. These long-term data allow to quantify realized niches of frequently occurring micro-plankton species and to pinpoint rarely occurring species which cannot be detected in the quantitative plankton analysis.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.

Description: Due to changing temperature regimes in the North- and the Wadden Sea, a fish survey in the Sylt Rømø bight (SRB) was established in 2007 for at least ten years. The aim is to investigate the Wadden Sea fish fauna with special interest in changes of migration behavior, species composition and feeding habits. Seven stations are sampled monthly inside the SRB. Two additional stations, one outside the bight, one close to the Danish border are sampled as references four times a year. For sampling a mini bottom trawl, total length 17 m, trawl opening 7 m, height 3 m with a mesh size of 36 mm in the wings, 16 mm in the mid part and 6 mm in the cod end is used. At every station one haul in the water column and another at the bottom are sampled, for 15 minutes at a speed of approximately 2 knots. The data will help to give a more detailed picture of food chains and energy flows inside the Wadden Sea.