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PubMed2005

Atmospheric mercury in Norway: contributions from different sources.

The environmental loadings of national Norwegian mercury emissions compared to the loadings of atmospheric long range transported mercury have been estimated using national emission data and EMEP model data. The results indicate that atmospheric long-range transport to Norway is somewhat larger than the national Norwegian emissions of mercury. Atmospheric deposition of mercury has been studied using data from Norwegian monitoring programs on mercury in precipitation, mosses, natural surface soils, and lake sediments. Precipitation data show no significant time trend during 1990-2002, whereas moss samples show similar concentrations from 1985 to 1995, but a 30% decrease from 1995 to 2000. Concentrations of mercury in peat cores and reference sediments indicate that the current mercury levels measured in surface sediments, surface soils and mosses at background sites in Norway are substantially affected by long-range atmospheric transport.

Air Movements↗
PubMed2005

A 2,000-year record of mercury and ancient civilizations in seal hairs from King George Island, West Antarctica.

The concentrations of total mercury (Hg(T)) and three bio-essential elements (phosphor, potassium, sodium) were analyzed in Antarctic seal hairs from a lake core spanning the past 2,000 years and collected from King George Island (63 degrees 23'S, 57 degrees 00'W), West Antarctica. The Hg(T) concentration shows a significant fluctuation while the levels of the three bio-essential elements remain almost constant. The rise and fall of the Hg(T) concentration in the seal hairs are found to be closely coincided with ancient activities of gold and silver mining using Hg-amalgamation process around the world, especially in the Southern Hemisphere. Briefly, Hg(T) levels are high during five episodes of extensive gold and silver mining activities--Rome Empire and China Han Dynasty (approximately 18-300 A.D.), Maya period and China Tang (750-900 A.D.), Incas civilization and Christian Kingdom (1200-1500 A.D.), New world (1650-1800 A.D.), and modern industry period (1840 A.D.-present); they are low during four time periods of reduced gold and silver mining activities--the China Han and Rome fall (since 300 A.D.), Maya fall and Wartime period in China (1050-1250 A.D.), Pizarro coming (ca. 1532 A.D.) and Independence War of South America (1800-1830 A.D.). Two profiles of Hg(T) in other two lake cores, one affected by seal excrements and the other by penguin droppings, from the same region are similar to the one in seal hairs. The Hg concentration profile in the seal hairs is significantly correlated with the one in a peat bog of Southern Chile near King George Island. Since Hg is existent mainly at the form of methyl-mercury in seal hairs, this correlation supports a relationship and link between atmospheric mercury concentration and methyl-mercury production. Comparing with samples from American and European continents, the Antarctic seal hairs provide an archive of total mercury concentration in surface seawater of the South Ocean less affected by regional human activities, and this archive may provide a good reference for assessing the global Hg emissions, depositions and recycling in the past thousand years.

Animals↗
PubMed2006

Increasing trends of total organic carbon concentrations in small forest lakes in Finland from 1987 to 2003.

Trends in total organic carbon (TOC) concentrations over the period 1987-2003 were studied in 13 small forest lakes. Recovery from acidification (reduced SO(4) deposition) and long-term changes in runoff as potential drivers for the trends were examined. The results showed that TOC concentrations have increased throughout Finland. Ten of the 13 lakes showed a significant increasing TOC trend (p<0.05), and included both clear water and humic lakes. The largest annual increase in TOC occurred in lakes with the largest average concentrations. The magnitude of the TOC trends were not significantly related to the proportion of peat soils in the catchment but the catchment size was an important predictor. Decreasing SO(4) deposition and improved acid-base status in soil due to the recovery from acidification implied an increased mobilisation of organic acids and TOC. There was little evidence that the long-term increasing trend in TOC concentrations was related to long-term changes in runoff. However, large seasonal and inter-annual fluctuations in runoff did appear to affect TOC concentrations for a number of years.

Carbon↗
PubMed2006

Seasonal variations in decomposition processes in a valley-bottom riparian peatland.

A year-long field survey was carried out at a valley-bottom riparian peatland site in North Wales, UK from January 2002 to December 2002 to examine the seasonal variation of decomposition processes and dissolved organic carbon (DOC) concentrations. Peat temperature, physicochemistry, organic carbon pools, basal CO(2) respiration and extracellular enzyme activities (beta-glucosidase, phosphatase, sulphatase and phenol oxidase) were monitored monthly. The results of a principle component eigenanalysis of field data show that concentrations of basal CO(2) respiration, soil solution DOC and phenolics were positively correlated to soil temperature (P<0.01, F=12.25; P<0.001, F=59.8; P<0.001, F=141.27) with Q(10) responses of 2.29, 6.42 and 14.42, respectively. Extracellular enzyme activities, however, were more strongly associated with seasonal changes in ion concentrations and did not correspond significantly to temperature alone suggesting limitations attributable to a combination of continuous anaerobiosis and/or the suppressive compounds. Restraints on soil enzyme activities may limit the loss of CO(2) from the microbial community that is dependent on soil enzyme activities for nutrient availability. The seasonal effect of temperature on DOC may be explained by increased plant rhizodeposition and microbial activity. These results do not imply that the long-term increasing trend in DOC export is explainable by temperature increase but suggest that temperature may be a key factor regulating the seasonal variation in DOC concentrations. Thus, seasonal temperature effects on DOC may represent an important component of long-term models of DOC export.

Carbon↗
PubMed2006

Removal of nutrients in various types of constructed wetlands.

The processes that affect removal and retention of nitrogen during wastewater treatment in constructed wetlands (CWs) are manifold and include NH(3) volatilization, nitrification, denitrification, nitrogen fixation, plant and microbial uptake, mineralization (ammonification), nitrate reduction to ammonium (nitrate-ammonification), anaerobic ammonia oxidation (ANAMMOX), fragmentation, sorption, desorption, burial, and leaching. However, only few processes ultimately remove total nitrogen from the wastewater while most processes just convert nitrogen to its various forms. Removal of total nitrogen in studied types of constructed wetlands varied between 40 and 55% with removed load ranging between 250 and 630 g N m(-2) yr(-1) depending on CWs type and inflow loading. However, the processes responsible for the removal differ in magnitude among systems. Single-stage constructed wetlands cannot achieve high removal of total nitrogen due to their inability to provide both aerobic and anaerobic conditions at the same time. Vertical flow constructed wetlands remove successfully ammonia-N but very limited denitrification takes place in these systems. On the other hand, horizontal-flow constructed wetlands provide good conditions for denitrification but the ability of these system to nitrify ammonia is very limited. Therefore, various types of constructed wetlands may be combined with each other in order to exploit the specific advantages of the individual systems. The soil phosphorus cycle is fundamentally different from the N cycle. There are no valency changes during biotic assimilation of inorganic P or during decomposition of organic P by microorganisms. Phosphorus transformations during wastewater treatment in CWs include adsorption, desorption, precipitation, dissolution, plant and microbial uptake, fragmentation, leaching, mineralization, sedimentation (peat accretion) and burial. The major phosphorus removal processes are sorption, precipitation, plant uptake (with subsequent harvest) and peat/soil accretion. However, the first three processes are saturable and soil accretion occurs only in FWS CWs. Removal of phosphorus in all types of constructed wetlands is low unless special substrates with high sorption capacity are used. Removal of total phosphorus varied between 40 and 60% in all types of constructed wetlands with removed load ranging between 45 and 75 g N m(-2) yr(-1) depending on CWs type and inflow loading. Removal of both nitrogen and phosphorus via harvesting of aboveground biomass of emergent vegetation is low but it could be substantial for lightly loaded systems (cca 100-200 g N m(-2) yr(-1) and 10-20 g P m(-2) yr(-1)). Systems with free-floating plants may achieve higher removal of nitrogen via harvesting due to multiple harvesting schedule.

Biodegradation, Environmental↗
PubMed2006

Nitrogen and phosphorus dynamics of a re-wetted shallow-flooded peatland.

Minerotrophic peatlands play an important role in the regulation of water quality and quantity but due to drainage and agricultural land use most of these systems have lost this function. In Central Europe, many re-wetting projects have been implemented to restore wetlands for multifunctional purposes during the last years. The Pohnsdorfer Stauung (Northern Germany) is a eutrophic fen which was used for intensive agriculture for 40 years. The peatland is divided in two subareas by a small stream. In the scope of re-wetting measures, one subarea (westpolder) was flooded by blockading the main drainage ditch in 1996/97, a second subarea (eastpolder) was re-connected to the stream by an inlet and outlet in 2001. Nitrogen and phosphorus dynamics were investigated in the surface water of these systems over a 5-year (westpolder) and 3-year (eastpolder) period, and balances were calculated. In both polders high dynamics of nitrogen and phosphate concentrations were observed in the surface water. Nitrate peaked in the winter months, whereas ammonium, phosphate and organically bound nitrogen (N(org)) revealed highest values during summer. Daily balances for the eastpolder and annual balances for both polders were calculated. In both polders nitrate was retained but phosphate and N(org) were exported. Differences of the nutrient dynamics and the absolute and relative balances between the polders were due to the different hydrology: the eastpolder received a high nitrate load by the stream, in the westpolder nutrient loads are low and internal nutrient cycles are dominating. During the summer months, high ammonium concentrations, oxygen depletion, and phosphate release occur in the warm, stagnant water of both polders. Normally, high phosphate and ammonium concentrations did not coincided with discharge phases from the polders. However, in August 2002 after heavy rainfall high phosphorus and ammonium discharge was observed. One important factor influencing the detected nutrient dynamics and balances is the change from a drained and fertilized peatland to a flooded wetland in only a few years. We conclude that continuous water flow and stable water levels are desired for flooded peatlands to prevent high concentrations of ammonium and phosphate and to utilize the potential for nitrate retention. In degenerated peatlands, flooding should only be regarded as an easy technological solution in order to conserve the peat mineralization, and to form the foundation for the further development of the peatland to a more efficient nutrient retaining system.

Conservation of Natural Resources↗
PubMed2006

Analysis of metals and EOX in sludge from municipal wastewater treatment plants: a case study.

The monitoring of extractable organic halogen (EOX) and heavy metal contents in sludge coming from 10 different municipal wastewater treatment plants (MWWTP) located in Friuli Venezia Giulia (Italy) is reported. In this work, sludge samples drawn from sludge treatment units have been digested and analyzed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) for metal evaluation. Samples were also extracted and analyzed by microcoulometric titrations, following modified DIN 38414 T17 standard, for EOX analysis. Analytical results showed a slight enrichment of the contents of certain metals (Cd< 2mg/kg, Cr< 51.5mg/kg, Cu<105.8 mg/kg, Hg<1.4 mg/kg, Ni<35.9 mg/kg, Pb<58.7 mg/kg, Zn<410.1 mg/kg, Ba<317.1 mg/kg, Co<1 mg/kg, Mo< 5 mg/kg, Mn<106.7 mg/kg), so almost all of the sludge would be suitable for agricultural use following Italian and European regulations. The evaluation of EOX was carried out by using hexane and ethyl acetate as extraction solvents, and a measurable organic halogen content (ranging from 0.31 to 39.5 mg Cl/kg DM) was clearly detected in the sludge. The lowest concentrations of EOX were found in sludge coming from the smallest MWWTPs, which is to be considered more suitable for agricultural use. Additionally, analytical assays on composts, peat and soils were performed to compare EOX concentrations between these matrices and sludge.

Conservation of Natural Resources↗
PubMed2004

A comparative study of Cyperus papyrus and Miscanthidium violaceum-based constructed wetlands for wastewater treatment in a tropical climate.

The treatment efficiencies of constructed wetlands containing Cyperus papyrus L. (papyrus) and Miscanthidium violaceum (K. Schum.) Robyns (synonymous with Miscanthus violaceum (K. Schum) Pilg.) were investigated in a tropical climate (Kampala, Uganda). Papyrus showed higher ammonium-nitrogen and total reactive phosphorus (TRP) removal (75.3% and 83.2%) than Miscanthidium (61.5% and 48.4%) and unplanted controls (27.9% ammonium-nitrogen). No TRP removal was detected in control effluent. Nutrients (N and P) were significantly higher (p<0.015) in papyrus than Miscanthidium plant tissues. Plant uptake and storage was the major factor responsible for N and P removal in treatment line 2 (papyrus) where it contributed 69.5% N and 88.8% P of the total N and P removed. It however accounted for only 15.8% N and 30.7% P of the total N and P removed by treatment line 3 (Miscanthidium violaceum). In addition, papyrus exhibited a significantly larger (p=0.000) number of adventitious roots than Miscanthidium. Nitrifying bacteria attached to papyrus (2.15 x 10(6)+/-1.53 x 10(5) MPN/g DW) and Miscanthidium roots (1.30 x 10(4)+/-8.83 x 10(2) MPN/g DW) and the corresponding nitrification activities were consistent with this finding. Epiphytic nitrifiers appeared more important for total nitrification than those in peat or suspended in water. Papyrus root structures provided more microbial attachment sites, sufficient wastewater residence time, trapping and settlement of suspended particles, surface area for pollutant adsorption, uptake, assimilation in plant tissues and oxygen for organic and inorganic matter oxidation in the rhizosphere, accounting for its high treatment efficiency.

Biodegradation, Environmental↗
PubMed2004

A comparison of the carbon balances of a natural lake (L. Orträsket) and a hydroelectric reservoir (L. Skinnmuddselet) in northern Sweden.

Carbon balances were calculated for the summer stratification period of 2001 for the hydroelectric reservoir L. Skinnmuddselet (created in 1989) and the natural L. Orträsket, and estimated on annual basis for both lakes. The reservoir and the lake have similar chemical characteristics and are located in adjacent catchments in the northern part of Sweden. Our main hypothesis was that the CO(2) production and emissions from the reservoir, L. Skinnmuddselet, would be greater than in the natural L. Orträsket, due to the decomposition of flooded vegetation and peat. The carbon balances showed that the total production of CO(2) per unit lake surface area during the summer was very similar in the natural lake and the reservoir (31.3 g Cm(-2) in L. Orträsket and 25.3 g Cm(-2) in L. Skinnmuddselet). The sediments were the major CO(2) source in the reservoir, while most of the mineralization in the natural lake occurred in the water column. On annual basis the natural L. Orträsket produced and emitted more CO(2) per unit of lake surface area than the reservoir L. Skinnmuddselet since mineralization proceeded during winter when L. Skinnmuddselet was emptied for electricity production. Therefore, the potential for CO(2) emission was not greater in the reservoir than in the natural lake.

Carbon↗
PubMed2004

Multi-component adsorption of Ag(I), Cd(II) and Cu(II) by natural carbonaceous materials.

Adsorption of silver, cadmium and copper from aqueous solutions by natural carbonaceous materials was investigated. The studied series of natural materials (spruce wood, pine bark, cork, peat, fusinite, lignite, oxidised lignite, bituminous coal and anthracite) was extended to include industrial carbon-rich materials: coke, activated carbon F-400 and Multisorb 100. Adsorption was tested on a single-component system and on the binary and ternary mixtures. All the materials used differ in their ability to adsorb selected metals. The adsorption of metals is significantly affected by the presence of other ions in solution. Total metal uptake was considerably higher in a mixture than single-ion adsorption. Chemical reactions, such as precipitation and reduction of metallic silver, play a role in metal uptake by bituminous coal, coke and activated carbon.

Adsorption↗
PubMed1990

Coinhibition of viral interferon induction by benzo[a]pyrene in association with occupation-related particles.

Benzo[a]pyrene (B[a]P) in combination with coal, asbestos, or metal particles was studied for its inhibitory effects on interferon-alpha/beta induction by influenza virus in rhesus monkey kidney (LLC-MK2) cell monolayers. B[a]P per se had no adverse effect on the induction process. However, when cell cultures were pretreated with B[a]P that was bioactivated by rat liver S9 homogenate, from 52 to 65% inhibition of interferon induction occurred. Significantly greater (P less than 0.05) depression (coinhibition) of viral interferon induction (greater than 83%) resulted when bioactivated B[a]P was incorporated with coal particles representative of coal rank (anthracite, bituminous, lignite, peat). Coinhibition affected by bioactivated B[a]P was coal rank-independent but any interferon inhibitory activity affected by coal particles per se was coal rank-dependent. When metals (aluminum, aluminum oxide, ferric oxide, nickel, or chromium) or asbestos fibers (chrysotile, crocidolite, anthophyllite, or amosite) were individually mixed with bioactivated B[a]P, coinhibition of cellular interferon synthesis also resulted which was significantly greater (P less than 0.05) than that manifested by bioactivated B[a]P or particles per se. Coinhibition of interferon induction by silicates (Min-U-Sil, DQ-12, hypersthene, or wollastonite) and the bioactivated hydrocarbon was not in evidence although some silicates alone partially inhibited the induction process. Viral interferon induction was inhibited in a dose-response manner by B[a]P (+/- S9) in combination with selected particles. The adsorption of B[a]P to all types of particles was no more than 5.98 micrograms B[a]P/mg of particles and, moreover, less than 0.5% by weight. These findings provide further evidence that bioactivated B[a]P and occupation-related particles act together to coinhibit a biological defense mechanism, the interferon induction phase of the interferon system.

Animals↗
PubMed1996

Assisted reproductive technology in the United States and Canada: 1994 results generated from the American Society for Reproductive Medicine/Society for Assisted Reproductive Technology Registry.

OBJECTIVE: To summarize the procedures and outcomes of assisted reproductive technology (ART) initiated in the United States in 1994. DESIGN: Data were collected on the Society for Assisted Reproductive Technology (SART) Database program and submitted to KMPG Peat Marwick, who served as the 1994 collection center for the American Society for Reproductive Medicine/Society for Assisted Reproductive Technology Registry. PARTICIPANT(S): Two hundred forty-nine programs submitted data on procedures performed in 1994. Data were collected after October 1995 so that outcome of all pregnancies established would be known. MAIN OUTCOME MEASURE(S): The outcomes measured included clinical pregnancy, ectopic pregnancy, abortion, stillbirth, delivery, and congenital abnormality. RESULT(S): Programs reported initiations of 39,390 cycles of ART treatment, excluding frozen embryo and donor oocyte cycles. Of these, 33,700 cycles initiated were IVF (standard, with micromanipulation, and for host uterus transfer) with 20.7% deliveries per retrieval; 4,214 were cycles of GIFT with 28.4% deliveries per retrieval; 926 were cycles of zygote intrafallopian transfer with 29.1% deliveries per retrieval; and 550 were combination cycles, combining IVF and one of the tubal transfer techniques, resulting in 29.7% deliveries per retrieval. In addition to these cycles initiated in 1994, 7,046 frozen ET procedures were reported, either as separate procedures or in combination with another ART procedure with 15.4% deliveries per procedure, and 3,119 donor oocyte cycles were initiated with an overall success of 46.8% deliveries per retrieval. As a result of all procedures, a total of 9,573 deliveries were reported. CONCLUSION(S): In 1994, there were fewer programs reporting a similar number of treatment cycles of ART as in 1993. Overall average success rates (deliveries per procedures) exhibited only a small increase compared with previously reported summaries.

Adult↗
PubMed2001

Microwave assisted solvent extraction and coupled-column reversed-phase liquid chromatography with UV detection use of an analytical restricted-access-medium column for the efficient multi-residue analysis of acidic pesticides in soils.

A screening method has been developed for the determination of acidic pesticides in various types of soils. Methodology is based on the use of microwave assisted solvent extraction (MASE) for fast and efficient extraction of the analytes from the soils and coupled-column reversed-phase liquid chromatography (LC-LC) with UV detection at 228 nm for the instrumental analysis of uncleaned extracts. Four types of soils, including sand, clay and peat, with a range in organic matter content of 0.3-13% and ten acidic pesticides of different chemical families (bentazone, bromoxynil, metsulfuron-methyl, 2,4-D, MCPA, MCPP, 2,4-DP, 2,4,5-T, 2,4-DB and MCPB) were selected as matrices and analytes, respectively. The method developed included the selection of suitable MASE and LC-LC conditions. The latter consisted of the selection of a 5-microm GFF-II internal surface reversed-phase (ISRP, Pinkerton) analytical column (50 x 4.6 mm, I.D.) as the first column in the RAM-C18 configuration in combination with an optimised linear gradient elution including on-line cleanup of sample extracts and reconditioning of the columns. The method was validated with the analysis of freshly spiked samples and samples with aged residues (120 days). The four types of soils were spiked with the ten acidic pesticides at levels between 20 and 200 microg/kg. Weighted regression of the recovery data showed for most analyte-matrix combinations, including freshly spiked samples and aged residues, that the method provides overall recoveries between 60 and 90% with relative standard deviations of the intra-laboratory reproducibility's between 5 and 25%; LODs were obtained between 5 and 50 microg/kg. Evaluation of the data set with principal component analysis revealed that the parameters (i) increase of organic matter content of the soil samples and (ii) aged residues negatively effect the recovery of the analytes.

Chromatography, Liquid↗
PubMed1991

Liquid chromatographic determination of carbendazim in the presence of some normal soil constituents with photodiode-array detection.

A reversed-phase high-performance liquid chromatographic method was developed for the determination of carbendazim in the presence of some normal soil constituents (kaolinite, montmorillonite and peat). Spiked aqueous soil samples were injected after centrifugation and filtration. Quantitative recoveries were observed and good precision was obtained. The concentration range studied, 1.6716-8.3580 mg/l, is the most suitable for adsorption-desorption studies of carbendazim on soil and soil constituents.

Benzimidazoles↗
PubMed2003

Novel stepwise gradient reversed-phase liquid chromatography separations of humic substances, air particulate humic-like substances and lignins.

RP-HPLC using stepwise gradients of dimethylformamide (DMF) in buffered aqueous mobile phase and a wide-pore (30 nm) octadecylsilica column has been applied to the analysis of soil, peat and air particulate humic and humic-like substances (HSs), as well as lignin, in order to demonstrate the usefulness of the approach for their characterization even at trace concentration level. Tandem combination of spectrophotometric (DAD) and fluorimetric detection was used to get more detailed information on chromatographic behaviour of HSs. The results showed that ten-step gradient can induce distinct features of HSs and lignins. Combination of very good DMF solvating and disaggregating properties for HSs and lignins together with wide pore RP sorbent improves surface interactions of the analytes and suppresses influence of size exclusion effects. Thus it provides reproducibility of characterisation profiles and robustness of the method. Very good reproducibility of retention times (from +/-0.12 to +/-0.36% RSD), of peaks enforced by the step gradient shape supports well defined characterization and/or fractionation of HSs. Evaluated limit of quantitation (S/N = 10) of selected soil humic acid working standard using fluorimetric detection (ex.470 nm/em.530 nm) was 9.7 microg/ml. This corresponds to 0.5 microg of the humic acid per injection. Calculated limit of detection (S/N = 3) was 3.3 microg/ml, what corresponds to 0.15 microg of the humic acid per injection and enabled determination of 0.1% (m/m) humic-like substances in 20 mg of air particulates under defined rules and conditions.

Air↗
PubMed2003

Molecular weight fractionation of humic substances by adsorption onto minerals.

Molecular weight (MW) fractionation of Suwannee River fulvic acid (SRFA) and purified Aldrich humic acid (PAHA) by adsorption onto kaolinite and hematite was investigated in equilibrium and rate experiments with a size-exclusion chromatography system using ultraviolet (UV) light detection. The extent of adsorptive fractionation based on UV detection was positively correlated with the percent carbon adsorption for both humic substances (HS), although the specific fractionation pattern observed depended on the particular HS and mineral used. Higher MW fractions of SRFA, an aquatic HS, were preferentially adsorbed to both kaolinite and hematite whereas the fractionation trends for PAHA, a terrestrial peat HS, differed for the two minerals. The contrasting fractionation patterns for SRFA versus PAHA can be explained reasonably well by the different structural trends that occur in their respective MW fractions and the underlying adsorption processes. Rate studies of adsorptive fractionation revealed an initial rapid uptake of smaller HS molecules by the mineral surfaces, followed by their replacement at the surface by a much slower uptake of the larger HS molecules present in aqueous solution.

Journal Article↗
PubMed2003

Regional and habitat differences in 7-methyljuglone content of Finnish Drosera rotundifolia.

The concentration of 7-methyljuglone was studied in the round-leaved sundew Drosera rotundifolia L. collected from different regions in Northern Finland. Samples for analysis were collected from peat bogs and sandpit habitats. The mean concentration of 7-methyljuglone varied from 1.0 to 2.3% of dry weight. Variation between years in the amount of 7-methyljuglone was significant in plants growing on sand, and in the northernmost region studied. Overall, the variation in the production of 7-methyljuglone among different populations of round-leaved sundew in Northern Finland was rather low. The variation between years in the production of 7-methyljuglone was more significant.

Drosera↗
PubMed2001

An unusual, structurally preserved ovule from the Permian of Antarctica.

Anatomically preserved ovules are described from silicified peat of Late Permian age collected from Skaar Ridge in the central Transantarctic Mountains, Antarctica. The small ovules are significant in possessing fleshy apical appendages and a funnel-shaped micropylar extension formed by the sarcotestal layer of the integument, by which they differ from all other Permian ovules described to date. The apical modifications may have functioned in pollination and/or seed dispersal. Similarity with the apical organization of earlier Paleozoic ovules is shown to be superficial, since the analogous structures are developmentally derived from different tissues. Although the ovules occur in rocks in which glossopterids are the only gymnosperms represented, there is insufficient evidence to assign them to a taxonomic group. These ovules are of particular importance because there are so few anatomically preserved gymnosperm reproductive structures known from the Permian and thus provide new data on the diversity of late Paleozoic gymnosperms.

Journal Article↗