Twelve years of tracking 52-Hz whale calls from a unique source in the North Pacific

A unique whale call with 50–52 Hz emphasis from a single source has been tracked over 12 years in the central and eastern North Pacific. These calls, referred to as 52-Hz calls, were monitored and analyzed from acoustic data recorded by hydrophones of the US Navy Sound Surveillance System (SOSUS) and other arrays. The calls were noticed first in 1989, and have been detected and tracked since 1992. No other calls with similar characteristics have been identified in the acoustic data from any hydrophone system in the North Pacific basin. Only one series of these 52-Hz calls has been recorded at a time, with no call overlap, suggesting that a single whale produced the calls. The calls were recorded from August to February with most in December and January. The species producing these calls is unknown. The tracks of the 52-Hz whale were different each year, and varied in length from 708 to 11,062 km with travel speeds ranging from 0.7 to 3.8 km/h. Tracks included (A) meandering over short ranges, (B) predominantly west-to-east movement, and (C) mostly north-to-south travel. These tracks consistently appeared to be unrelated to the presence or movement of other whale species (blue, fin and humpback) monitored year-round with the same hydrophones.     

Marine geology in the environs of Bouvet Island and the South Atlantic triple juction

It is suggested that Bouvet Island is the surface manifestation of a mantle plume which has resulted in the creation of a chain of seamounts in the South Atlantic and a general shoaling of the region.The strike of two newly defined large fracture zones borth and south of the Bouvet Island pedestal have been utilized to determine a pole of rotation at 12.5°S, 12.5°W for the Africa-Antarctica motion. A pole at 75°S, 13°E has been calculated for the South America-Antarctica motion. At the triple junction the South America-Africa relative motion is 3.3 cm yr^-1 (whole rate) at 075°. The Africa-Antarctica motion is 1.7 cm yr^-1 at 065° and the South America-Antarctica motion is 1.6 cm yr^-1 at 085.     

A note on the seafloor coupling characteristics of the new ONR ocean-bottom seismometer

A series of transient tests were conducted to determine the seafloor coupling characteristics of a new ocean-bottom seismometer (OBS) developed for the United States Office of Naval Research (ONR). The OBS comprises a large recording package and a separate sensor package that is deployed from the recording package. In addition to the coupling characteristics of both the sensor and the recording packages, the seismic energy radiated from the main recording package as a result of motion of the recording package was measured. The observed vertical coupling resonances of both the recording package and the sensor package are in good agreement with those predicted by a simple model of soil-structure interaction. The most important result of this study is that significant energy is radiated from the recording package in response to horizontal motions of the recording package. When the sensor package is 1 m from the recording package, the amplitude of the recorded signal is similar to that recorded in the recording package. In the field, this effect will result in distortion of seismic signals and increased background noise recorded by the sensor package if the recording package is disturbed by seafloor currents or biological activity. The amplitude of this signal attenuates by approximately a factor of two as sensor/recorder separation is increased from 1 to 6 m, suggesting that an improved response can be achieved by increasing the separation between the recording package and the sensors. This effect is much less severe for vertical disturbances of the recording package.     

Some responses of transplanted Mytilus edulis to metal-enriched sediments and sewage sludge

Approximately 25 % of the sewage sludge produced in the United Kingdom (about 10 million wet tonnes anually) is disposed of to British coastal waters at 15 sites. A series of tests is being evaluated in order to determine the effects of this practice in relation to the effects due to other polluting inputs, both natural and man-made, to the marine environment. The results presented here are for one site on the south-west coast of Britain. They indicate that the increased metal content of the tissue and the presence of sulphydryl-rich metal-binding proteins in the lysosomes of digestive cells in transplanted mussels can be correlated with exposure at sites overlying metal-rich sediments and to a lesser extent an area used for the disposal of sewage sludge containing metallic contaminants.     

Book reviews

THE IMPACT OF VOLCANIC HAZARDS AT RABAUL, PAPUA NEW GUINEA (Discussion Paper No. 33) by R. J. Blong and C. Aislabie. 17 × 25 cm, xiv and 207 pages. Institute of National Affairs: Port Morseby 1988 (ISBN 9980 77 086 4).

A PRACTICAL APPROACH TO SEDIMENTOLOGY by R. C. Lindholm. 15 × 23 cm, xviii and 279 pages. Allen & Unwin: London 1987 (ISBN 0 04 551132 2) $A45.00 (soft).

THE ATMOSPHERE AND WEATHER OF SOUTHERN AFRICA by R. A. Preston‐Whyte and P. D. Tyson. 18 × 24 cm, xiii and 375 pages. Oxford University Press: Cape Town 1988 (ISBN 0 19 570 514 9) R56.00 (hard); (ISBN 0 19 570 496 7) R39.14 (soft).

QUATERNARY PALEOCLIMATOLOGY: Methods of Paleoclimatic Reconstruction by R. S. Bradley. 15 × 23 cm, xvii and 472 pages. Allen & Unwin: Boston 1985 (ISBN 0 04 551067 9) $A69.95 (hard); (ISBN 0 04 551068 7) $A39.95 (soft).

PROCESSES IN PHYSICAL GEOGRAPHY by R. D. Thompson, A. M. Mannion, C. W. Mitchell, M. Parry and J. R. Townsend. 24 × 19 cm, xii and 380 pages. Longman: London 1986 (ISBN 0 582 30136) $A44.95.

PERSPECTIVES ON A DYNAMIC EARTH by T. R. Paton. 16 × 24 cm, 142 pages. Allen & Unwin: London 1986 (ISBN 0 04 55 0043 6) $A23.95 (soft).

LAND DEGRADATION AND SOCIETY edited by P. Blaikie and H. Brookfield. 15 × 23 cm. xxiv and 296 pages. Methuen: London 1987 (ISBN 0 416 40150 3) $A32.95 (soft).

THE PENGUIN DICTIONARY OF HUMAN GEOGRAPHY by B. Goodall. 13 × 20 cm, 509 pages. Penguin: Harmondsworth 1987 (ISBN 0 14 051095 8) $A19.95 (soft).

MAKING SENSE OF DEVELOPMENT: An Introduction to Classical and Contemporary Theories of Development and Their Application to South‐east Asia by P. W. Preston. 14 × 22 cm, xxi and 318 pages. Routledge & Kegan Paul: London 1986 (ISBN 0 7102 0813 8) $A87.95 (hard).

THE DEMOGRAPHIC DIMENSION IN INDONESIAN DEVELOPMENT by G. J. Hugo, T. H. Hull, V. J. Hull and G. W. Jones. 16 × 25 cm, xxv and 417 pages. Oxford University Press: Singapore 1987 (ISBN 0 19 582699 X) $A49.95 (hard).

GLOBAL ISSUES AND OUTLOOK IN PULP AND PAPER edited by G. F. Schreuder, 18 × 26 cm, ix and 302 pages. University of Washington Press: Seattle 1988 (ISBN 0 295 96642 4) $US40.00 (hard).

AN HISTORICAL GEOGRAPHY OF MODERN AUSTRALIA: The Restive Fringe (Cambridge Studies in Historical Geography No. 11) by J. M. Powell. 16 × 33 cm, xx and 400 pages. Cambridge University Press: Cambridge 1988 (ISBN 0 521 25619 4) $A39.95 (hard).

HISTORICAL GEOGRAPHY: Progress and Prospect edited by M. Pacione. 14 × 22 cm, 306 pages. Croom Helm: London 1987 (ISBN 0 7099 40467) $A27.50 (hard).

THE ROLE OF THEORY IN URBAN PLANNING: A Study of Metropolitan Planning in Perth, Western Australia (Geowest No. 24) by O. Yiftachel. 21 × 29 cm, 102 pages. Department of Geography, University of Western Australia: Nedlands 1987 (ISBN 0 86422 063 4).

SYDNEY INTO ITS THIRD CENTURY: Metropolitan Strategy for the Sydney Region by NSW Department of Environment and Planning. 21 × 29 cm, 72 pages. NSW department of Environment and Planning: Sydney 1988 (ISBN 0 7305 4312 9).

BUS SERVICES IN WESTERN SYDNEY: Private Bus Operators and Government Transport Departments (Monograph Series No. 3) by P. Tranter. 21 × 29 cm, v and 98 pages. Department of Geography and Oceanography, University College, Australian Defence Force Academy: Campbell, ACT 1988 (ISBN 0 7317 0036 8).

AGEING IN VICTORIA: An Electronic Social Atlas by A. L. Howe, P. Newton and P. Sharwood. 30 × 21 cm, 105 pages. National Research Institute for Gerontology and Geriatric Medicine, Mt. Royal Hospital and University of Melbourne: Melbourne 1987 (ISBN 0 958326 6 2) $A10.00 (soft).

READINGS IN AUSTRALIAN GEOGRAPHY: Proceedings of the 21st Institute of Australian Geographers’ Conference, Perth 10–18 May 1986, edited by A. Conacher. 21 × 29 cm, vi and 493 pages. Institute of Australian Geographers (WA Branch) and Department of Geography, University of Western Australia: Perth 1987 (ISBN 0 909678 30 B) $A25.00 (soft).

GEOGRAPHY RESEARCH PROJECTS: A Senior Student's Handbook by H. Binden and H. Williams. 18 × 26 cm, 149 pages. Edward Arnold Australia: Caulfield East 1988 (ISBN 0 7131 8311 X) $A 14.95 (soft).

OUR AMERICAN LAND: 1987 Yearbook of Agriculture, ix and 323 pages. US Government Printing Office, Washington, DC: 1987 $US9.50.

THE ENCYCLOPAEDIC DICTIONARY OF PHYSICAL GEOGRAPHY edited by A. Goudie et al. 17 × 24 cm, xvi and 528 pages. Basil Black‐well: Oxford 1988 (ISBN 0 631 15581 3) $A34.95 (soft).

THE CONSERVATION OF ECOSYSTEMS AND SPECIES by Gareth E. Jones, 14 × 22 cm, 277 pages. Croom Helm: London 1987 (ISBN 0 7099 1463 6) $A87.95 (hard).

SO CAME THEY SOUTH by R. Clancy and A. Richardson. 35 × 35 cm, 176 pages. Shakespeare Head: Sydney 1988 (ISBN 0 7302 0864 8) $A34.95.     

Do Spur-Throated Grasshoppers, <Emphasis Type="Italic">Melanoplus</Emphasis> spp. (Orthoptera: Acrididae), Exert Top-Down Control on Smooth Cordgrass <Emphasis Type="Italic">Spartina alterniflora</Emphasis> in Northern New England?

Recently, strong top-down (consumer) control of cordgrass (Spartina alterniflora) has been demonstrated. Here, we manipulated the densities of cordgrass consumers, acridid grasshoppers (Melanoplus bivittatus and Melanoplus femurrubrum), to examine their impact on cordgrass in the Plum Island Estuary (PIE), MA, USA. After 1 month, there was no detectable effect of grasshopper density on S. alterniflora biomass and grasshoppers at the highest densities (34 individuals per square meter) consumed only ~14% of the standing stock biomass. However, significant impacts of grasshopper density on grazing damage were seen. For example, plant damage and scarring length increased by 160% and 6,156%, respectively, at the highest grasshopper densities relative to exclusion (zero grasshoppers) densities. Plant height was significantly reduced with increasing grasshopper densities, although this may be a function of leaf tip removal instead of reduced plant growth. No other strong consumers of cordgrass (e.g., Littoraria irrorata, Prokelisia marginata) were observed in PIE and we suggest that consumer regulation of cordgrass is weak in this system.     

Possible consequences of absence of “jupiters” in planetary systems

The formation of the gas giant planets Jupiter and Saturn probably required the growth of massive 15 Earth-mass cores on a time scale shorter than the 10⁷ time scale for removal of nebular gas. Relatively minor variations in nebular parameters could preclude the growth of full-size gas giants even in systems in which the terrestrial planet region is similar to our own. Systems containing failed Jupiters, resembling Uranus and Neptune in their failure to capture much nebular gas, would be expected to contain more densely populated cometary source regions. They will also eject a smaller number of comets into interstellar space. If systems of this kind were the norm, observation of hyperbolic comets would be unexpected. Monte Carlo calculations of the orbital evolution of region of such systems (the Kuiper belt) indicate that throughout Earth history the cometary impact flux in their terrestrial planet regions would be 1000 times greater than in our Solar System. It may be speculated that this could frustrate the evolution of organisms that observe and seek to understand their planetary system. For this reason our observation of these planets in our Solar System may tell us nothing about the probability of similar gas giants occurring in other planetary systems. This situation can be corrected by observation of an unbiased sample of planetary systems.Paper presented at the Conference onPlanetary Systems: Formation, Evolution, and Detection held 7–10 December, 1992 at CalTech, Pasadena, California, U.S.A.     

A preliminary study of the carbon-isotopic content of ambient formic acid and two selected sources: Automobile exhaust and formicine ants

Relatively large quantities (1 mg) of formic acid have been collected from the atmosphere and subjected to carbon-isotopic analysis, as a means of source discrimination. Ambient formic acid was captured on Ca(OH)₂-treated filters using a high-volume sampler. The collection method was not only efficient (>96%), but also appears to have low artifact production.Most of the samples (36 out of 52) were collected over a two-year period at the summit of Mount Lemmon, Arizona, where a strong seasonality in HCOOH mixing ratio was observed (0.2 ppb during winter months to 1.5 ppb in the summer). Other collection sites included the Oregon coast, Colorado Rockies, urban Tucson, and the North Dakota prairie. The carbon-13 content of atmospheric HCOOH was found to be have little variation (–18 to –25), regardless of location or season. This is consistent with a single dominant source of formic acid. The carbon-14 measurements of 6 Mount Lemmon samples showed high levels of modern carbon (93–113% modern).The emissions from formicine ants and automobile combustion were selected as two other potential sources for isotopic analysis. The HCOOH collected from auto exhaust was much more depleted in¹³C than the atmospheric samples, with a ¹³C of –28.0 and –48.6 from a leaded and unleaded automobile, respectively. Formicine ants, on the other hand, ranged from –17.2 to –20.6.     

Effects of ageing and overconsolidation on the elastic stiffness of a remoulded clay

Summary Results of resonant column tests were used to determine values of low amplitude shear modulus (G ₀) of a remoulded kaolinite clay for different durations of ageing and for different values of consolidation stress (₀) and overconsolidation ratio (OCR). It was found that after completion of primary consolidation the values of G ₀ increased linearly with the logarithm of time and after a week of confinement the value of normalized rate of secondary increase of shear modulus (N _G ) could be reliably estimated. Values of N _G were found to derease linearly with the logarithm of OCR and with the logarithm of ageing duration. This similarity of behaviour provided a basis for establishing an equivalency between age and equivalent overconsolidation ratio (OCR)_eq. The effects of ₀ and OCR on the value of G ₀ were also established in a functional form that indicated a stronger influence compared to that predicted by the Hardin Equation.     

Geochronology and geochemistry of eclogites from the Mariánské Lázně Complex,Czech Republic: Implications for Variscan orogenesis

The Mariánské Lázn complex (MLC) is located in the Bohemian Massif along the north-western margin of the Teplá-Barrandian microplate and consists of metagabbro, amphibolite and eclogite, with subordinate amounts of serpentinite, felsic gneiss and calcsilicate rocks. The MLC is interpreted as a metaophiolite complex that marks the suture zone between the Saxothuringian rocks to the north-west and the Teplá-Barrandian microplate to the south-east. Sm-Nd geochronology of garnet-omphacite pairs from two eclogite samples yields ages of 377±7, and 367±4 Ma. Samples of eclogite and amphibolite do not define a whole rock Sm-Nd isochron, even though there is a large range in Sm/Nd ratio, implying that the suite of samples may not be cogenetic. Eclogites do not have correlated _Nd values and initial ⁸⁷Sr/⁸⁶Sr ratios. Five of the eight eclogite samples have high _Nd values (+10.2 to +7.1) consistent with derivation from a MORB-like source, but variable ⁸⁷Sr/⁸⁶Sr ratios (0.7033 to 0.7059) which probably reflect hydrothermal seawater alteration. Three other eclogite samples have lower _Nd values (+ 5.4 to –0.8) and widely variable ⁸⁷Sr/⁸⁶Sr ratios (0.7033 to 0.7096). Such low _Nd values are inconsistent with derivation from a MORB, source and may reflect a subduction or oceanic island basalt component in their source. The MLC is an important petrotectonic element in the Bohemian Massif, providing evidence for Cambro-Ordovician formation of oceanic crust and interaction with seawater, Late Devonian (Frasnian-Famennian) high- and medium-pressure metamorphism related to closure of a Saxothuringian ocean basin, Early Carboniferous (Viséan) thrusting of the Teplá terrane over Saxothuringian rocks and Late Viséan extension.