Early-Mid Holocene climatic variations in Tasmania, Australia: multi-proxy records in a stalagmite from Lynds Cave

Mass spectrometric uranium-series dating and C-O isotopic analysis of a stalagmite from Lynds Cave, northern Tasmania, Australia provide a high-resolution record of regional climate change between 5100 and 9200 yr before present (BP). Combined delta(18)O, delta(13)C, growth rate, initial U-234/U-238 and physical property (color, transparency and porosity) records allow recognition of seven climatic stages: Stage I ( > 9080 yr BP) - a relatively dry period at the beginning of stalagmite growth evidenced by elevated U-234/U-238; Stage II (9080-8600 yr BP) - a period of unstable climate characterized by high-frequency variability in temperature and bio-productivity; Stage 111 (8600-8000 yr BP) - a period of stable and moderate precipitation and stable and high bio-productivity, with a continuously rising temperature; Stage IV (8000-7400 yr BP) - the warmest period with high evaporation and low effective precipitation (rainfall less evaporation); Stage V (7400-7000 yr BP) - the wettest period with highest stalagmite growth and enhanced but unstable bio-productivity; Stage VI (7000-6600 yr BP) - a period with a significantly reduced precipitation and bio-productivity without noticeable change in temperature; Stage VII (6600-5100 yr BP) - a period of lowest temperature and precipitation marking a significant climatic deterioration. Overall, the records suggest that the warmest climate occurred between 8000 and 7400 yr BP, followed by a wettest period between 7400 and 7000 yr BP. These are broadly correlated with the so-called 'Mid Holocene optimum' previously proposed using pollen and lake level records. However, the timing and resolution of the speleothem. record from Lynds Cave are significantly higher than in both the pollen and lake level records. This allows us to correlate the abrupt change in physical property, delta(18)O, delta(13)C, growth rate, and initial U-234/U-238 of the stalagmite at similar to8000 yr BP with a global climatic event at Early-Mid Holocene transition. (C) 2001 Elsevier Science B.V. All rights reserved.

Amphicreadium n. g. (Digenea : Lepocreadiidae) from monacanthid fishes (Tetraodontiformes) from the coast of northern Tasmania

A new lepocreadiid genus, Amphicreadium, is erected for the species A. denspeniculus n. sp. from Acanthaluteres vittiger and for an unnamed species from Meuschenia freycineti, both from off northern Tasmania. The new genus is distinguished from all other members of its family by its amphistomatous body plan.

Lepocreadiinae lepocreadiids (Digenea) from tetraodontiform fishes in the waters off Tasmania, Queensland and Moorea, French Polynesia

Two new species of Pseudocreadium are described from off northern Tasmania, P maturini sp. nov. from Meuschenia freycineti and P aubreyi sp. nov. from Acanthaluteres vittiger. They differ from the only other recognised species in the genus by the number of ovarian lobes and by size, and they differ from each other by size, shape, caecal length, forebody length, pre-oral lobe size, uterine position, excretory vesicle length and oral sucker shape. Lobatocreadium exiguum is redescribed from Sufflamen bursa, off Moorea, French Polynesia and Abalistes stellatus, Swain Reefs, Great Barrier Reef, Queensland. Records and measurements are given for Hypocreadium cavum from Sufflamen fraenatus and Lepotrema clavatum from Melichthys vidua, both off Heron Island, Great Barrier Reef, Queensland.

Eucryphia honeys of Tasmania

A total of 22 honey samples from the west of Tasmania were analysed. All of them were monofloral leatherwood honeys containing between 79.9% and 99.1% of Eucryphia sp. pollen. Furthermore, 27 different pollen types were identified, the most frequent of which were Eucalyptus, Leptospermum (Myrtaceae), Trifolium (Fabaceae), Rosaceae, Banksia (Proteaceae), Lotus (Fabaceae), Bursaria (Pittosporaceae) and Brassica (Brassicaceae), which appeared in a great number of honeys with different percentages. The pollen spectrum characteristics of Tasmania's monofloral leatherwood honeys differentiate them from Chilean honeys of the same floral origin.

New species of Opechona Looss, 1907 and Cephalolepidapedon Yamaguti, 1970 (Digenea: Lepocreadiidae) from fishes off northern Tasmania

Two new species of lepocreadiid trematodes are described from teleost fishes from off the coast of northern Tasmania. Opechona kahawai sp. nov. from Arripis sp. (Arripidae) differs from congeners by a combination of a longer prepharynx, longer excretory vesicle and the genital pore antero-sinistral to the ventral sucker. Cephalolepidapedon warehou sp. nov. from Seriolella punctata (Centrolophidae) differs from its only congener in the vitellarium reaching into the posterior forebody, a heavy concentration of eye-spot pigment in the forebody, a relatively narrower and more elongate body, a longer prepharynx and a more distinct oesophagus.

Paleoclimates in Southwestern Tasmania during the Last 13,000 Years

Plant-sociological and climatic classification of the Australian Nothofagus cunninghamii rain forest provides the basis for a new, semiquantitative approach to interpretations of late-Quaternary paleoclimates from four pollen sequences in southwestern Tasmania. Varying proportions of rain-forest pollen types in the records were related to different modern rain-forest alliances and their specifc climatic regimes, such as Eastern Rain Forest, Leatherwood Rain Forest, and sclerophyllous, Subalpine Rain Forest. According to this interpretation, early Holocene climates were characterized by 1,600 mm annual precipitation and 10°C annual temperature, conditions substantially warmer and drier than previously thought. Maximum precipitation levels of 2,500 mm annually were not reached until 8,000 years B.P. A short-term cooling episode between 6,000 and 5,000 years B.P. led to the establishment of modern rain-forest distribution in western Tasmania, characterized either by a precipitation gradient steeper than before, or by greater climatic variability. To interpret paleoclimates from before 12,000 years B. P., when non-arboreal environments dominated in western Tasmanian bollen records, various modern treeless environments were studied in search for analogs. Contrary to earlier interpretations, late-glacial environments were not alpine tundra with a treeline at modern sea level, but steppe, with marshes or shallow lakes instead of the modern lakes. Climate was characterized by 50% less precipitation than today, resulting in substantial summer droughts. To explain such drastic precipitation decrease, the westerlies that dominate Tasmanian climate today must have been shifted polewards. This suggestion is supported by climate models that take Milankovitch-type insolation differences into account as well as sea-surface temperatures. Paleolimnological information based on diatom analyses support the general paleoclimatic reassessment.

Late Pleistocene and Holocene Paleolimnology of Two Mountain Lakes in Western Tasmania

The analysis of diatoms from two lake-sediment cores from southwestern Tasmania that span the Pleistocene-Holocene boundary provides insight about paleolimnological and paleoclimatic change in this region. Both Lake Vera (550 m elevation), in west-central Tasmania, and Eagle Tarn (1,033 m elevation), in south-central Tasmania, have lacustrine records that begin about 12,000 years ago. Despite significant differences in location, elevation, and geologic terrane, both lakes have, had similar, as well as synchronous, limnological histories. Each appears to have been larger and more alkaline 12,000 years ago than at present, and both became shallower through time. Fossil diatom assemblages about 11,500 years old indicate shallow-water environments that fluctuated in pH between acidic and alkaline, and between dilute and possibly slightly saline hydrochemical conditions ( The synchroneity and similar character of the paleolimnological changes at these separate and distinctive sites suggests a regional paleoclimatic cause rather than local environmental effects. Latest Pleistocene climates were apparently more continental and drier than Holocene climates in southwestern Tasmania.

A 950 yr temperature reconstruction from Duckhole Lake, southern Tasmania, Australia

A lack of quantitative high resolution paleoclimate data from the Southern Hemisphere limits the ability to examine current trends within the context of long-term natural climate variability. This study presents a temperature reconstruction for southern Tasmania based on analyses of a sediment core from Duckhole Lake (43.365°S, 146.875°E). The relationship between non-destructive whole core scanning reflectance spectroscopy measurements in the visible spectrum (380–730 nm) and the instrumental temperature record (ad 1911–2000) was used to develop a calibration-in-time reflectance spectroscopy-based temperature model. Results showed that a trough in reflectance from 650 to 700 nm, which represents chlorophyll and its derivatives, was significantly correlated to annual mean temperature. A calibration model was developed (R = 0.56, p auto < 0.05, root mean squared error of prediction (RMSEP) = 0.21°C, five-year filtered data, calibration period 1911–2000) and applied down-core to reconstruct annual mean temperatures in southern Tasmania over the last c. 950 years. This indicated that temperatures were initially cool c. ad 1050, but steadily increased until the late ad 1100s. After a brief cool period in the ad 1200s, temperatures again increased. Temperatures steadily decreased during the ad 1600s and remained relatively stable until the start of the 20th century when they rapidly decreased, before increasing from ad 1960s onwards. Comparisons with high resolution temperature records from western Tasmania, New Zealand and South America revealed some similarities, but also highlighted differences in temperature variability across the mid-latitudes of the Southern Hemisphere. These are likely due to a combination of factors including the spatial variability in climate between and within regions, and differences between records that document seasonal (i.e. warm season/late summer) versus annual temperature variability. This highlights the need for further records from the mid-latitudes of the Southern Hemisphere in order to constrain past natural spatial and seasonal/annual temperature variability in the region, and to accurately identify and attribute changes to natural variability and/or anthropogenic activities.

Recent environmental change and trace metal pollution in World Heritage Bathurst Harbour, southwest Tasmania, Australia

Bathurst Harbour in World Heritage southwest Tasmania, Australia, is one of the world’s most pristine estuarine systems. At present there is a lack of data on pollution impacts or long-term natural variability in the harbor. A ca. 350-year-old 210Pb-dated sediment core was analysed for trace metals to track pollution impacts from local and long-range sources. Lead and antimony increased from AD 1870 onwards, which likely reflects remote (i.e. mainland Australian and global) atmospheric pollution sources. Variability in the concentrations of copper and zinc closely followed the history of mining activities in western Tasmania, which began in the AD 1880s. Tin was generally low throughout the core, except for a large peak in AD 1989 ± 0.5 years, which may be a consequence of input from a local small-scale alluvial tin mine. Changes in diatom assemblages were also investigated. The diatom flora was composed mostly of planktonic freshwater and benthic brackish-marine species, consistent with stratified estuarine conditions. Since mining began, however, an overall decrease in the proportion of planktonic to benthic taxa occurred, with the exception of two distinct peaks in the twentieth century that coincided with periods of high rainfall. Despite the region’s remoteness, trace metal analyses revealed evidence of atmospheric pollution from Tasmanian and possibly longer-range mining activities. This, together with recent low rainfall, appears to have contributed to altering the diatom assemblages in one of the most pristine temperate estuaries in the world.

The Tasmanian law reports : cases determined in the Supreme Court of Tasmania.

Earlier reports in: Reports of cases determined in the Supreme Court of Tasmania / Herbert Nicholls and W. J. T. Stops.