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Study location and test species Subantarctic Macquarie Island lies in the Southern Ocean, just north of the Antarctic Convergence at 54 degrees 30' S, 158 degrees 57' E. Its climate is driven by oceanic processes, resulting in highly stable daily and inter-seasonal air and sea temperatures (Pendlebury and Barnes-Keoghan, 2007). Temperatures in intertidal rock pools (0.5 to 2 m deep) were logged with Thermochron ibuttons over two consecutive summers and averaged 6.5 (plus or minus 0.5) degrees C. The island is relatively pristine and in many areas there has been no past exposure to contamination. To confirm sites used for invertebrate collections were free from metal contamination, seawater samples were taken and analysed by inductively coupled plasma optical emission spectrometry (ICP-OES; Varian 720-ES; S1) The four invertebrate species used in this study were drawn from a range of taxa and ecological niches (Figure 1). The isopod Limnoria stephenseni was collected from floating fronds of the kelp Macrosystis pyrifera, which occurs several hundred meters offshore. The copepod Harpacticus sp. and bivalve Gaimardia trapesina were collected from algal species in the high energy shallow, subtidal zone. Finally, the flatworm Obrimoposthia ohlini was collected from the undersides of boulders throughout the intertidal zone. We hypothesised L. stephenseni would be particularly sensitive to changes in salinity and temperature due to its distribution in the deeper and relatively stable subtidal areas, while O. ohlini would be less sensitive due to its distribution high in the intertidal zone and exposure to naturally variable conditions. We reasoned that the remaining two species, G. trapesina, and Harpacticus sp. were intermediate in the conditions to which they are naturally exposed and hence would likely be intermediate in their response. Test procedure The combined effect of salinity, temperature and copper on biota was determined using a multi-factorial design. A range of copper concentrations were tested with each combination of temperatures and salinities, so that there were up to 9 copper toxicity tests simultaneously conducted per species (Table 1). Experiments on L. stephenseni and Harpacticus sp. were done on Macquarie Island within 2 to 3 days of collection, during which they were acclimated to laboratory conditions. While, G. trapesina and O. ohlini were transported by ship to Australia in a recirculating aquarium system and maintained in a recirculating aquarium at the Australian Antarctic Division in Hobart, both at 6 degreesC. These two taxa were used in experiments within 3 months of their collection. A limited number of G. trapesina and O. ohlini were available, resulting in fewer combinations of stressors tested. Controls for the temperature and salinity treatments were set at ambient levels of 35 plus or minus 0.1 ppt and 5.5 to 6 degreesC for all species. The lowered control temperature for the bivalve reflected the cooler seasonal temperatures at time of testing and lower position within the intertidal. Previous tests conducted under these ambient conditions provided information on the ranges of relevant copper concentrations, appropriate test durations, and water change regimes for each taxon (Holan et al., 2017, Holan et al., 2016b). From these previous studies, we determined that a test duration of 14 d was sometimes required with 7 d often being the best outcome for most species due to high control survival and sufficient response across concentrations. The bivalve G. trapesina was an exception to this due to unfavourable water quality after 3 days in previous work (Holan et al., 2016). For the other three species, this longer duration for acute tests, compared to tests with tropical and temperature species (24 to 96 h) was consistent with previous Antarctic studies that have required longer durations in order to elicit an acute response in biota (King and Riddle, 2001, Marcus Zamora et al., 2015, Sfiligoj et al., 2015). Experimental variables (volume of water, density of test organisms, copper concentrations, temperatures and salinities) differed for each experiment due to differences between each species (Table 1). The temperature increases that were tested (2 to 4 degreesC) reflected the increased sea and air temperatures predicted for the region tested by 2100 (Collins et al., 2013). Treatments were prepared 24 h prior to the addition of animals. Seawater was filtered to 0.45 microns and water quality was measured using a TPS 90-FL multimeter at the start and end of tests. Dissolved oxygen was greater than 80% saturation and pH was 8.1 to 8.3 at the start of tests. All experimental vials and glassware were washed with 10% nitric acid and rinsed with MilliQ water three times before use. Salinity of test solutions was prepared by dilution through the addition of MilliQ water. Copper treatments using the filtered seawater at altered salinities were prepared using 500mg/L CuSO4 (Analytical grade, Univar) in MilliQ water stock solution. Samples of test solutions for metal analysis by ICP-OES were taken at the start and end of tests (on days 0 and 14). Details of ICP-OES procedures are described in the Supplemental material (S4). Samples were taken using a 0.45 µm syringe filter that had been acid and Milli-Q rinsed. Samples were then acidified with 1% diluted ultra-pure nitric acid (65% Merck Suprapur). Measured concentrations at the start of tests were within 96% of nominal concentrations. In order to determine approximate exposure concentrations for each treatment, we averaged the 0 d and 14 d measured concentrations (Table 1). Tests were conducted in temperature controlled cabinets at a light intensity of 2360 lux. At the Macquarie Island station a light-dark regime of 16:8 h was used to mimic summer conditions. In the laboratories in Kingston, Australia, a 12:12 h regime was used to simulate Autum light conditions (as appropriate for the time of testing). Test individuals were slowly acclimated to treatment temperatures over 1 to 2 h before being added to treatments. Temperatures were monitored using Thermochron ibutton data loggers within the cabinets for the duration of the tests. Determination of mortality of individuals differed for each taxon. Mortality was recorded for Gaimardia trapesina when shells were open due to dysfunctional adductor muscles; for Obrimoposthia ohlini when individuals were inactive and covered in mucous; for Limnoria stephenseni when individuals were inactive after gentle stimulation with a stream of water from a pipette; and for Harpacticus sp. when urosomes were perpendicular to prosomes (as used in other studies with copepods; see Kwok and Leung, 2005). All dead individuals were removed from test vials.
Soil cores were collected from numerous locations across the Macquarie Island Isthmus. Replicate samples were collected from each location and a single sample was collected from 50cm depth below the surface. Soil cores were cylindrical, diameter 70 mm, depth 70 mm and included surface vegetation where present. Invertebrates were extracted from the soil core using a heat gradient process. Specimens were preserved in ethanol following extraction. Invertebrates were identified under microscope to the lowest practicable level, which was species level for most taxa. Mites (Acarina) were identified to morphotype. Column labels Sample - Unique numerical sample identifier Depth - Depth of collection: surface = 0 cm, depth = 50 cm below surface Location - Location identifier code Easting - easting (m) Northing - northing (m) Elevation (m) - Height above sea level (m) Parisotoma insularis - Abundance of Parisotoma insularis in core sample Folsotoma punctata - Abundance of Folsotoma punctata in core sample Tullbergia bisetosa - Abundance of Tullbergia bisetosa in core sample Ceratophysella denticulata - Abundance of Ceratophysella denticulata in core sample Hypogastrura viatica - Abundance of Hypogastrura viatica in core sample Hypogastrura purpurescens - Abundance of Hypogastrura purpurescens in core sample Cryptopygus antarcticus - Abundance of Cryptopygus antarcticus in core sample Cryptopygus caecus - Abundance of Cryptopygus caecus in core sample Cryptopygus lawrencii - Abundance of Cryptopygus lawrencii in core sample Cryptopygus tricuspus - Abundance of Cryptopygus tricuspus in core sample Polykatianna davidii - Abundance of Polykatianna davidii in core sample Lepidocyrtus sp. - Abundance of Lepidocyrtus sp. in core sample Megalothorax sp. - Abundance of Megalothorax sp. in core sample Acarina 1 - Abundance of Acarina 1 in core sample Acarina 2 - Abundance of Acarina 2 in core sample Acarina 3 - Abundance of Acarina 3 in core sample Acarina 4 - Abundance of Acarina 4 in core sample Acarina 5 - Abundance of Acarina 5 in core sample Acarina 6 - Abundance of Acarina 6 in core sample Acarina 7 - Abundance of Acarina 7 in core sample Acarina 8 - Abundance of Acarina 8 in core sample Big dark tick - Abundance of Big dark tick in core sample Spider - Abundance of Spider in core sample Microscolex macquariensis - Abundance of Microscolex macquariensis in core sample Enchytraeus albidus - Abundance of Enchytraeus albidus in core sample Nematode species - Abundance of Nematode species in core sample Styloniscus otakensis - Abundance of Styloniscus otakensis in core sample Harpacticoid - Abundance of Harpacticoid in core sample Puhuruhuru patersoni - Abundance of Puhuruhuru patersoni in core sample Stenomalium sp. - Abundance of Stenomalium sp. in core sample Thinophilus (fly) - Abundance of Thinophilus (fly) in core sample Australimyza - Abundance of Australimyza in core sample Grasshopper? - Abundance of Grasshopper? in core sample Slug sp. - Abundance of Slug sp. in core sample The easting, northing and elevation for each sample site was collected by Lauren Wise of the AAD and Josie van Dorst of the University of NSW using a Trimble differential GPS and the post processing was done by Dan Wilkins of the AAD. The elevations were derived using the global geoid model EGM96. To convert the eastings and northings of the sample sites to eastings and northings on the WGS84 datum of the Australian Antarctic Data Centre's GIS data representing the Macquarie Island station buildings and structures, add 1.40 metres to the eastings and 0.2 metres to the northings as given on page 3 of the survey report "Macquarie Island OSG Survey Campaign, Voyage 8 Round Trip, March 2002" by John VanderNiet and Nick Bowden of the Office of the Surveyor General, Tasmania.
Copied of a scanned document containing a check list from 1954 of known insect species from the Antarctic and sub-antarctic. Taken from the report: This check list contains all known records of insect species from the Antarctic and Subantarctic with the exception of the subantarctic islands of New Zealand (a list of the major references to their insect fauna appears at the end of this volume). The Antarctic region is most usefully defined as the area lying south of the Antarctic Convergence, the line along which the cold northward-moving antarctic surface water sinks beneath the warmer subantarctic water. Judged from this viewpoint, South Georgie, the South Orkney Islands, the South Shetland Islands, the South Sandwich Islands, Bouvet oya and Heard Island, all fall within the Antarctic region. The Falkland Islands, Iles de Kerguelen, Iles Crozet, the Prince Edward Islands and Macquarie Island lie between the Antarctic and Subtropical Convergences and are therefore subantarctic. Scientific exploration in these regions has proceeded unevenly and spasmodically. Some islands (Heard Island and Macquarie Island) where parties have been stationed for long periods have been thoroughly searched for insects, others (Iles Crozet, South Orkney Islands, South Shetland Islands) where parties have been landed during the brief visits of expedition ships have been partially searched, whilst others (Bouvet oya) offer an untouched field. Insects from Ile Amsterdam and Ile Saint Paul, and several species of Siphonaptera recorded from birds outside the geographical limits cited, have been included for a knowledge of them is essential in considering possible new subantarctic species. The Mallophaga as a group have been excluded from this list since their speciation and geographical distribution depends solely on that of their hosts and their inclusion would enlarge this list without adding greatly to its value. Orders, families and sub families are arranged according to current practice but genera and species are set out in alphabetical order within the various major groupings. Where a number of different Family names are in use one name may have been selected alternative names have been included in brackets. (Each case has been determined after considering the particular circumstances involved -- the terminology used in the most useful references to it, recent literature on its classification, etc). Where a cosmopolitan species has been recorded from Antarctic regions no attempt has been made to list all references to it and only the original description and the most important Antarctic records have been cited. As it is likely that some omissions have occurred in this check list the author would appreciate being notified of any which are detected. The author would also like to record his thanks to D.J. Lee, School of Public Health and Tropical Medicine, University of Sydney, for his help and advice in the preparation of this report. In a later paper it is hoped to discuss more fully the affinities, geographical and taxonomic, of the unique insect fauna of the Antarctic and subantarctic regions. The following analysis reveals the marked development of indigenous species in these unfavourable environments and shows the limited invasion from nearby continental areas. Of interest are the few cosmopolitan species that have succeeded in establishing themselves in the area. This paper lists 233 species and 9 varieties included in 143 different genera. In addition 7 insects are listed which have not been described, but merely recorded as either ? genus ? species or genus ? sp. Of the 233 species recorded, 26 have been introduced into the region since they have either a cosmopolitan or very extensive distribution. Of the insects recorded from the South American islands 23 are found on various parts of the South American Continent and the majority show very strong affinities with the fauna of Patagonia and South Chile. The insects of Iles de Kerguelen are for the most part indigenous and are in structure and habits archaic. Ile St. Paul has strong African affinities and Macquarie Island has a fauna similar to the subantarctic islands of New Zealand though more strongly modified.
Project Title: Survey of benthic and other marine invertebrates of the Prydz Bay region, Antarctica. Investigators: Dr W. Zeidler and Mrs K.L. Gowlett-Holmes, South Australian Museum, Adelaide. Project Aims: To collect marine invertebrate specimens from the bycatch of pelagic and marine trawls conducted by ANARE personnel. Results: A variety of marine invertebrates were collected from pelagic and benthic trawls, and incidentally by other means as follows:- 1) IYGPT net - 88 samples from 39 sites. Fauna consisted mainly of amphipods (see link below), medusae, pteropod molluscs, copepods and euphasids, with ostracods, mysids and carid prawns being less common. 2) Benthic trawls - 22 samples from 21 sites. Fauna consisted mainly of glass sponges, medusae, corals, echinoderms, anenomes and ascidians. 3) RMT net - 5 samples from 5 sites. A few polychaetes and amphipods. 4) From fish (from 1 and 2) - several species of parasitic copepods and leaches. 5) Drift net - site 29. Several pelagic polychaetes, amphipods and chaetognaths. 6) Mud grab - site 32. Several bryozoans and ophiuroids. 7) CTD winch wire - site 28. Several sea pens and ophiuroids. Most marine invertebrates were collected from the benthic trawls, often in large numbers. Frequently the best and greatest variety of specimens were caught in the wings of the net, and the co-operation of the crew in collecting these specimens is greatly appreciated. Several organisms, such as glass sponges, ascidians, sea pens, and echinoderms, were dominant in most trawls, with other groups present in varying quantities. Subtle changes in the fauna were noted in relation to the depth and geographic location of stations, but no pattern can be determined until the material collected is properly curated and identified. However, bottom trawls from shallower depths tended to be dominated by sponges, crinoids and ascidians. Comments on the fauna collected are as follows:- Sponges - about 3 or 4 glass sponges dominated most benthic trawls. Other species of sponges were less common. A large yellow species, which was common at Heard Island, was only collected on two occasions. Medusae - sometimes numerous, but usually too damaged for identification. Corals - one species of octocoral was very common in most trawls, as was a large species of sea pen. Soft corals and scleractinian corals were very rare. Bryozoans - relatively rare, although they appear to be common on rocks that came up in the net. Annelids - several polychaetes were found associated with sponges and octocorals. One large polynoid (scale worm), similar to the common Heard Island species, was present in small numbers in most benthic trawls. Two species of leach were found parasitic on icefish (mainly Chionodraco spp.), and a third species was found on skates (Bathyraja sp.). Spinunculans and Echiurans - present in most bottom trawls, but never very numerous. A good collection was obtained, and will be of special interest to Dr Stan Edmonds, who is an honourary researcher at the South Australian Museum. Echinoderms - starfish generally were common in most bottom trawls, as were holothurians. Crinoids were more common in bottom trawls from shallower depths. Echinoids were never numerous, but were present in most bottom trawls. One specimen, a stalked crinoid, is of special interest. Pycnogonoids - relatively common in most bottom trawls. A good collection of several species was obtained, and will hopefully form the basis of a research project. Molluscs (excluding cephalopods) - these were relatively rare, but several species of interest were obtained, mainly opisthobranchs, bivalves and chitons. Crustaceans - relatively rare except for pelagic amphipods (IGYPT trawls). Ascidians - common in most bottom trawls, dominated by 2-3 species. Others - several other animal groups were represented in the trawls, but they were rarely numerous, and often only occurred in a few trawls, e.g. nemerteans, hydroids, brachiopods etc. Concluding remarks: The aims of the project were achieved within the limits of the gear available, and no problems with gear, other than torn nets, were encountered. The variety of marine invertebrates collected was naturally limited by the gear used, and if future benthic surveys are envisaged then I would recommend the use of beam trawls and dredges to collect the smaller organisms. The benthic fauna of Prydz Bay is much more diverse and abundant than that found at Heard Island (Voyage 7.2 1990). The specimens collected will be curated and housed in the South Australian Museum, Adelaide, where they will be studied by resident curators and specialists interstate and overseas. A brief analysis of the specimens collected indicates that several may be of species new to science, and it is expected that several research papers will result once the specimens have been studied in detail. Ultimately, the material collected will form the basis of a reference collection for future research. The fields in this dataset are: notes site suborder family species numbers
Metadata record for data from AAS (ASAC) Project 2933. See the child records for access to the datasets. Public While it is generally thought that Antarctic organisms are highly sensitive to pollution, there is little data to support or disprove this. Such data is essential if realistic environmental guidelines, which take into account unique physical, biological and chemical characteristics of the Antarctic environment, are to be developed. Factors that modify bioavailability, and the effects of common contaminants on a range of Antarctic organisms from micro-algae to macro-invertebrates will be examined. Risk assessment techniques developed will provide the scientific basis for prioritising contaminated site remediation activities in marine environments, and will contribute to the development of guidelines specific to Antarctica. Project objectives: 1. Develop and use toxicity tests to characterise the responses of a range of Antarctic marine invertebrates, micro- and macro-algae to common inorganic and organic contaminants. 2. To examine factors controlling bioavailability and the influence of physical, chemical and biological properties unique to the Antarctic environment on the bioavailability and toxicity of contaminants to biota. 3. To compare the response of Antarctic biota to analogous species in Arctic, temperate and tropical environments in order to determine the applicability of using toxicity data and environmental guidelines developed in other regions of the world for use in the Antarctic. 4. Develop a suite of standard bioassay techniques using Antarctic species to assess the toxicity of mixtures of contaminants (aqueous and sediment-bound) including tip leachates, sewage effluents and contaminated sediments. 5. To establish risk assessment models to predict the potential hazards associated with contaminated sites in Antarctica to marine biota, and to develop Water and Sediment Quality Guidelines for Antarctica to set as targets for the remediation of contaminated marine environments. Taken from the 2008-2009 Progress Report: Progress against objectives: Due to logistical constraints, only a short field season (5 weeks) was conducted at Casey in 2008/09 and no berths were allocated solely to this project. A team of 6 scientists worked together on an intensive marine sampling program under TRENZ (AAS project 2948, CI Stark) in support of 5 different AAS projects, including this one. The lack of adequate personnel dedicated to this project and the limited time that we were allocated on station hindered progress and meant that no experiments on Antarctic organisms were able to be conducted in situ. The airlink was however successfully used to transport marine invertebrates collected at Casey and held in seawater at 0degC back to Hobart on 3 separate flights. These invertebrates are currently being maintained in the cold water ecotoxicology aquarium facilities at Kingston. Once they are sorted and where possible established in cultures, they will be used in toxicity tests. Progress against specific objects are: 1) Much effort and time has been put towards the husbandry and culture of the collected Antarctic marine invertebrates. Some species are now successfully breeding in the laboratory providing new generations and sensitive juvenile stages of invertebrates to work with in toxicity tests. This culturing capability, if able to be developed, will hugely extend opportunities for carrying out research for this project, by giving us access to live material over the winter months and during summer when berths to or space on station in Antarctica is limited. Toxicity tests using some of the common amphipods and gastropods collected in the 0809 season at Casey will commence shortly at Kingston. 2) Toxicity tests to commence shortly using invertebrates collected in the 0809 season now being maintained in the Ecotoxicology aquarium will focus on interactions and potentially synergistic effects of contaminants along with other environmental stressors including increases in temperature and decreases in salinity associated with predicted environmental changes in response to climate change. 3) A phD candidate has recently started on this project and is currently reviewing all available literature on the response of Antarctic species to contaminants and environmental stressors in comparison to related species from lower latitudes. 4) Invertebrates collected in the 0809 season that are being maintained in the Ecotoxicology aquarium will be screened in toxicity tests to commence shortly. Methods will then be developed using the most suitable and sensitive species to form the basis of standard bioassay procedures that can be used to test mixtures such as sewage effluents and tip leachates in the upcoming season. 5) The establishment of risk assessment models and Environmental Quality Guidelines for Antarctica is a long term goal of this project when data from the first 4 objectives can be synthesised and hence has not yet been addressed. Taken from the 2009-2010 Progress Report: Progress against objectives: Objectives 1 and 2: Metal effects on the behaviour and survival of three marine invertebrate species were investigated during the field season. Two replicate toxicity tests were conducted on the larvae of sea urchin Sterechinus neumayeri where combined effects of metal (copper and cadmium) and temperature (-1, 1 and 3 degrees Celsius) were to be investigated on developmental success. However, due to lower than optimal fertilisation success, both tests were terminated before any meaningful results could be derived. Four tests were conducted on the adult amphipod, Paramorea walkeri. Two replicate tests investigated combined metal (copper and cadmium) and temperature (-1, 1 and 3 degrees Celsius) effects, and two tests investigated the effects of copper, cadmium, lead, zinc and nickel exposure at ambient sea water temperature of -1 degrees Celsius. One test was conducted with the micro-gastropod Skenella paludionoides being exposed to copper, cadmium, lead, zinc and nickel at ambient sea water temperature. The larvae of bivalve Laternula sp. were also investigated as a potential test organism for metal toxicity. Strip spawning was conducted a number of times, however, this technique did not provide adequate levels of fertilisation success and as such, the toxicity tests on larval development were not completed. Objective 3: A phD candidate working on this project is in the process of compiling a review of all available date on the response of Antarctic species to contaminants and environmental stressors in comparison to related species from lower latitudes. This literature review will form a major component of her thesis' first chapter Objective 4: Methods for Standard bioassay procedures were developed using the most suitable and sensitive species, the amphipod Paramoera walkeri and the microgastropod Skenella paludionoides. These standard tests were then used to assess the toxicity of sewage effluent at Davis Station (in conjunction with project 3217). Objective 5: Toxicity tests on sewage effluent were conducted as part of a risk assessment to determine hazards associated with the current discharge. The determined toxicity of the sewage effluent will provide a basis for guideline recommendations on the required level of treatment and on what constitutes an adequate or 'safe' dilution factor for dispersal of the effluent discharge to the near shore marine environment.
Metadata record for data from AAS (ASAC) project 3022. Public The Vestfold Hills contains a suite of marine derived brackish to saline lakes that have simple food webs dominated by microorganisms, including dinoflagellates that are members of the phytoplankton. The lakes possess differing salinities that impact on other physical and chemical characteristics so that the original marine creatures have been subject to differing evolutionary pressures that have resulted in the evolution of distinct strains of dinoflagellate in each lake. We will look at the degree of speciation in dinoflagellates and their ability to colonise different lake environments. Taken from the 2008-2009 Progress Report: Project objectives: SPECIFIC OBJECTIVES The evolution and biogeography of macroorganisms has been investigated for more than two centuries. While for micro-organisms these issues have only recently received attention. Currently there is a heated debate as to whether free-living microbes are present in all environments that they can exploit (everything is everywhere - but the environment selects) or whether they exhibit biogeographic patterns due to geographical isolation, natural selection, or invasion sequence. We propose approaching this controversy by studying two of the fundamental mechanisms that are known to generate biogeographic patterns in macroorganisms: a) colonization and b) subsequent genetic divergence due to new environmental conditions (selection) and/or genetic isolation. As model organisms, we will use dinoflagellates, an ecologically and economically important group of phytoplankton. With their short generation time and ability to switch between asexual and sexual reproduction they are ideal for experimental evolution studies. We will work with strains of dinoflagellates from the suite of marine derived brackish to saline lakes in the Vestfold Hills. These lakes have simple microbially dominated food webs and offer us a unique natural laboratory in which to test a series of hypotheses outlined below: - Lake dinoflagellates have diverged rapidly among themselves and from their marine ancestors since the formation of the lakes in the last 10,000 years. Local adaptation to different lake conditions has driven the genetic and phenotypic divergence between populations, and between lake populations and their marine ancestors. - Lake populations out-compete marine strains, thereby preventing the re-colonisation of lakes by marine immigrants. - The populations from the different lakes are reproductively isolated among themselves and from their marine ancestors. Biogeography is the study of biodiversity over space and time and attempts to elucidate processes such as speciation, extinction, dispersal, and species interactions (Hughes Martiny et al. 2006). Although there is a consensus on the existence of biogeography in macroorganisms, the biogeography of microorganisms remains debated. Proponents of the 'everything is everywhere - but the environment selects' (Baas Becking 1934) argue that aquatic microorganisms are cosmopolitan, i.e., have no dispersal limitation and low global species diversity (Finlay 2002). They claim that due to the small size and huge abundance of unicellular organisms, there are no barriers for their dispersal and gene flow, and consequently no allopatric speciation (Fenchel 2005). However, recent studies dispute the idea that 'everything is everywhere'. Several reports using molecular techniques show unexpectedly high microorganism biodiversity (Fawley et al. 2004; Venter et al. 2004) and that they may exhibit biogeographic patterns (Pommier et al. 2005; Whitaker et al. 2003). Evidence from our research suggests that natural selection can give rise to speciation in phytoplankton in a very short time period (less than 10,000 years) (Logares et al. 2007). Within this proposal we will focus on some processes that shape biogeography in aquatic eukaryotic organisms. DINOFLAGELLATES AS MODEL ORGANISMS Dinoflagellates occur both in freshwater and marine ecosystems and can form intense blooms. They are important components of the planktonic food web, and are considered high food quality to predators. Toxic dinoflagellate blooms in marine habitats are a major environmental and economic problem worldwide e.g. (Hallegraeff 1993), and hence of major scientific interest. Dinoflagellates have a reproductive system of alternating asexual and sexual reproduction, and many species have a resistant and long-lived resting propagule (cyst) (Pfiester and Anderson 1987). Most important for this proposal, however, is that dinoflagellates are ideal for experimental evolution studies. They can be cultured, they have a short generation time ( BIOGEOGRAPHY AND THE SPECIES CONCEPT A central problem when debating microbial biodiversity is the lack of a definite and operational species concept and taxonomic unit. In unicellular organisms, the widely used biological species concept (BSC) is rarely applied, since many species reproduce asexually. Instead the morphological species concept, the 'morphospecies', prevails. The problem with the morphospecies concept is that similarity in appearance does not necessarily mean that they are evolutionarily closely related. Microorganisms (such as phytoplankton) simply have few morphological characteristics that are useful for species characterisation. For example, many phytoplankton are spherical and green, and are simply referred to as 'small round greens'. As a result, phytoplankton taxonomists and ecologists have lumped together things that look alike within one species. Thus, the relationship of lower species richness with decreasing size may or may not therefore be an artifact of taxonomic lumping. There is growing evidence that variation within a single algal morphospecies can be relatively large. Modern phylogenetic molecular studies on phytoplankton show that many morphospecies are in fact composed of several genetic lineages, also known as cryptic species (Montresor et al. 2003b). For instance, Coleman (2001) showed that there are at least 30 sexually isolated groups of the Pandorina/Volvulina species complex. Fawley et al. (2004) analogously did not detect so called cosmopolitan species in a big survey on green algae, but found several hundred new isolates with restricted distributions. Moreover, Kim et al. (2004) found that two dinoflagellate populations belonging to the same species, but with different physiological requirements were genetically distinct comparable to species level differences, despite being separated by only 400 m. Although the use of molecular markers has revolutionised the view on microbial diversity and phylogeny, the choice of markers must be done with caution. For instance, while no differences may be found in the small subunit (SSU) of the ribosomal DNA, large differences can be found within the less conserved ITS region (Cho and Tiedje 2000; Kim et al. 2004) For example two distinct morphospecies (Peridinium aciculiferum and Scrippsiella hangoei) present in different habitats (freshwater and Baltic Sea) were found to have identical ribosomal rRNA sequences (Logares et al. 2007). However, the two species could be separated based on cytochrome b mitochondrial DNA sequences and Amplified Fragment Length Polymorphism (AFLP) (which operates on the entire genome). This indicates a case of rapid adaptive evolution, but also emphasizes the need to use a combination of molecular markers. Drettman et al. (2003a) showed that a multilocus genealogical approach in the fungal genus Neurospora allowed to identify traditional biological species. Another important finding was that they could show that phylogenetic divergence could precede reproductive isolation (Drettman et al. 2003b). CAN PHYTOPLANKTON DISPERSE AND EASILY COLONISE NEW WATER BODIES? An assumption of the cosmopolitan view is that all microorganisms disperse easily and have a high environmental tolerance. The basis for this view is studies that show a huge number of microorganisms being transported in the air (Griffin et al. 2002) or water (e.g. Lindstrom et al. 2006). However, Hughes Martiny et al. (2006) found no clear correlation between body size and dispersal capacity and concluded that while some microbes disperse widely, others may have limited dispersal. Dispersal of planktonic protists and algae can occur through three major mechanisms; by water, air, or organisms (Kristiansen 1996). Coleman (1996), for instance, showed distinct genetic groups of a green alga, which showed patterns correlating to bird migratory patterns. Although many microorganisms undisputedly disperse far by birds, to date, there is no evidence on how many and which kinds of species actually survive dispersal by air or organisms. In a recent experiment, we were able to show that dinoflagellate vegetative cells were not able to survive the passage through a bird gut, while their resting cysts survived and germinated (Weissbach and Rengefors, unpubl). Another key concern with the cosmopolitan view is that it is assumed that dispersal leads to colonisation of new habitats. However, the findings of Maguire (1963) suggest that only a limited number of the small aquatic species being dispersed actually colonise new habitats. De Meester (2002) argues that despite high ability to disperse and rapid colonisation of some limnic zooplankton, it is very unlikely that it will also colonise the new habitat, since the endemic populations likely will have an adaptive advantage over the coloniser. De Meester refers to this as the Monopolisation Hypothesis. Further, the presence of a large resting propagule bank provides a buffer against newly invading genotypes enhancing the priority effect. Many phytoplankton species, including dinoflagellates, produce long-lived resting propagules, indicating that the Monopolisation Hypothesis may apply to phytoplankton as well. SPECIATION IN MICROORGANISMS The adherers of the cosmopolitanism view argue that because there are no geographic barriers to dispersal of microorganism, allopatric speciation is rare in unicellular organisms due to the homogenising action of gene flow. However, allopatric speciation is only one of the recognised speciation modes. We argue that genetic divergence and ultimately speciation in unicellular organisms, such as freshwater phytoplankton is more frequent and rapid than claimed. First of all, due to their shorter generation time, speciation can be quicker in microbes. Moreover, the large population sizes of microbes can harbour a very high genetic variability upon which natural selection can act, leading to a rapid adaptive divergence. Hairston et al. (1999) established that rapid evolution may occur within certain systems or species due to strong selection pressure. Likewise, Whitaker et al. (2003) showed recent divergence in microorganisms in geothermal spring. Secondly, many eukaryotic phytoplankton species, such as the dinoflagellates, have a life cycles promoting rapid genetic differentiation. These life cycles consist of alternating asexual and sexual reproduction. Speciation due to strong local adaptation is hypothesised to be more common in species with alternating sexual and asexual reproduction (De Meester et al. 2002). Due to the combination of sexual recombination generating genetic diversity, and clone formation propagating the entire genome, certain traits are more likely to become permanent in these species. Thirdly, limnic phytoplankton are especially interesting to study as lakes may function as ecological islands, i.e. isolated entities to which colonisation is restricted, at least if they have a long turnover time. Even when lakes are in close vicinity of each other, dispersal and colonisation can be effective barriers as argued above. Thus populations may become reproductively isolated, as reproductive isolation is considered (by some researchers) to be a prerequisite for maintaining species integrity in sexually reproducing species. PRELIMINARY RESULTS We have conducted preliminary work in the Vestfold Hills of Antarctica. This coastal ice-free area contains suites of freshwater and saline lakes. This suite of saline lakes has several characteristics that make them ideal for speciation studies: 1) The lakes formed as a result of isostatic rebound about 10, 000 years ago and consequently the dinoflagellate assemblage derives from relic marine populations. 2) The planktonic food web in these lakes is severely truncated, with few competitors and predators. 3) The lakes vary in salinity from brackish to hypersaline (10x seawater), and are ice-covered most of the year. 4) The area is remote from other limnic habitats (limited dispersal sources). In 2004/5 we collected and isolated dinoflagellate cells from Lake Abraxas and Ehko Lake. Several clonal cultures were established for two different species in each of the lakes sampled. Microscopic and preliminary sequence analyses of the SSU rDNA have allowed us to identify them as Polarella glacialis and a Scrippsiella sp. The former is a species with bi-polar distribution found both in the sea-ice and the water (Montresor et al. 2003a). The other is yet unidentified to the species level. Our first AFLP analyses of the different strains showed a promising pattern. Lake Polarellas were very different in their band pattern from strains isolated from the sea. Moreover, strains differed more among lakes than within lakes. We propose sampling and establishing cultures from a range of other lakes across a salinity spectrum (Highway, Pendant, Williams, Watts, Lebed, Ace) and establishing clonal cultures for return to our laboratories for further analysis. This will involve both molecular analysis at Lund and physiological investigations at the University of Tasmania. The dinoflagellates present in the Vestfold Hill lakes have undergone rapid divergence after the lakes became isolated from the sea. The selection pressures are very different in these lakes compared to the sea; i.e. a large relatively homogeneous habitat (the sea) in contrast to smaller habitats (lakes) with strong natural selection in different directions. Instead of thousands of dinoflagellate species competing as in the sea, these lakes contain only a handful of species. Predation pressure is likely much lower, with only one metazoan zooplankton and a few unicellular potential predators. Finally, the chemical composition (nutrients and salinity) and the light climate differ from the sea, being both more oligotrophic and ice covered to a higher extent. Nevertheless, cysts do disperse by wind from the sea and could potentially colonise these lakes continuously at times when they are ice-free (Downs, 2004 unpublished Ph.D.thesis). Progress against objectives: Please describe the progress you have made against each objective in the last twelve (12) months. The postdoctoral scientist at Davis has established a significant clonal collection of dinoflagellate cultures from a range of lakes and the sea. These will be returned to Lund University (Sweden) for molecular analysis. The download files contain an excel spreadsheet of data, a word document containing a table of data, as well as details on the methods used to collect the data, and a copy of the referenced publications with a manuscript (the latter is available to AAD staff only).
This project is very closely related to ASAC project 666 (ASAC_666). See that project for more details. A copy of the masters thesis arising from the project is attached to the record. Physical samples are stored at the University of Melbourne. Taken from the abstract of the attached thesis: Marine Plain covers an area of approximately 10 square kilometres, and is located 10 km southeast of Davis Station near the Vestfold Hills, East Antarctica. The sediments at Marine Plain are significantly older than other strata in the Vestfold Hills and unconformably overlie Precambrian gneiss. This thesis describes nine species of gastropods from five families and ten bivalves from eight families. Included within this study are descriptions of two new species of bivalve and one new bivalve genus; Ennucula sp. nov., Hiatellidae gen. nov. sp. nov. The gastropods include Parmophoridea cf. melvilli, Falsimargarita sp., Naticidae genus and species indeterminate A and Naticidae genus and species indeterminate B, Prolacuna sp., Taniella ? sp., Euspira sp., Chlanidota (Chlanidota) signeyana, and Trophon sp. Bivalves include Ennucula sp. nov., Neilo sp., Limopsis sp., LIssarca sp., "Chlamys" tuftensis, Austrochlamys anderssoni, Limatula (Antarctolima) cf. hodgsoni, Cyclocardia cf. asartoides, Hiatellidae gen. nov. sp. nov., and the Holocene aged Laternula elliptica. The molluscan assemblages at Marine Plain are found in two distinct horizons within the Sorsdal Formation. The only species common to both units is the bivalve "Chlamys" tuftensis. The Early Pliocene age of the sediments at Marine Plain is based on the presence "Chlamys" tuftensis in the sediments and diatom biostratigraphy. The highly lithified upper band of the Sorsdal Formation, the Graveyard Sandstone Member, is 30-50 centimetres thick. The fauna in the Graveyard Sandstsone Member is better preserved than that in the lower diamictite unit, with better shell preservation and larger numbers of articulated valves. Bivalves from five genera make up the total macrofossils present in the unit. The lower unit is diatomaceous sandstone, 1.4 metres thick. This unit has a high diversity of macrofossils, including archaeogastropods (and burrowing trails), echinoids, serpulid worms, algae and bryozoa (both sheet and stick). The Pliocene aged sediments at Marine Plain were deposited in a soft bottom, shallow marine environment. The ice cover in Antarctica was probably significantly reduced compared to present and the sea water temperature was possibly warmer. The molluscs however offer little evidence of this. The molluscs are a combination of both epifaunal and infaunal forms with varied modes of feeding including suspension and filter feeders and some gastropod carnivores. To date Marine Plain has yielded the best preserved and most diverse, available Pliocene fossils in Antarctica. Present day shelly marine communities in the vicinity of Davis station mainly consist of one species of Laternula, echinoids and pectinids, with ice rafted diatoms. The analysis of the Pliocene invertebrate fauna at Marine Plain provides a rare insight into the evolution of modern Antarctic marine communities and the Pliocene global warming debate. However, limited outcrop exposure, poor preservation and often severe distortion due to compaction hamper the utility of the macrofossils at Marine Plain.
Metadata record for data expected from ASAC Project 919. See the link below for public details on this project. The plankton dynamics of Ace Lake, a saline, meromictic basin in the Vestfold Hills, eastern Antarctica was studied between December 1995 and February 1997. The lake supported two distinct plankton communities; an aerobic microbial community in the upper oxygenated mixolimnion and an anaerobic microbial community in the lower anoxic monimolimnion. Phytoplankton development was limited by nitrogen availability. Soluble reactive phosphorus was never limiting. Chlorophyll a concentrations in the mixolimnion ranged between 0.3 and 4.4 micrograms per litre during the study period and a deep chlorophyll maximum persisted throughout the year below the chemo/oxycline. Bacterioplankton abundance showed considerable seasonal variation related to light and substrate availability. Autotrophic bacterial abundance ranged between 0.02 and 8.94 x 10 to the 8 per litre and heterotrophic bacterial abundance between 1.26 and 72.8 x 10 to the 8 per litre throughout the water column. the mixolimnion phtyoplankton was dominated by phytoflagellates, in particular Pyramimonas gledicola. P. geldicola remained active for most of the year by virtue of its mixotrophic behaviour. Photosynthetic dinoflagellates occurred during the austral summer, but the entire population encysted for the winter. Two communities of heterotrophic flagellates were apparent; a community living in the upper monimolimnion and a community living in the aerobic mixolimnion. Both exhibited different seasonal dynamics. The cliliate community was dominated by the autotroph Mesodinium rubrum. The abundance of M. rubrum peaked in summer. A proportion of the population encysted during winter. Only one other ciliate, Euplotes sp., occurred regularly. Two species of Metazoa occurred in the mixolimnion; a calanoid copepod (Paralabidocera antarctica) and a rotifer (Notholca sp.). However, there was no evidence of grazing pressure on the microbial community. In common with most other Antarctic lakes, Ace Lake appears to be driven by 'bottom-up' forces. The fields in this dataset are: Ace Lake Aerobic monimolimnion Ammonia Ammonium Ash free dry weight Autotrophic Bacteria Bacterial Production Leucine Bacterial Production Thymidine Biomass Carbon Cell Chlorophyll a Concentration Copepods Date Date Code Depth Diatoms Dinoflagellates Dissolved Organic Carbon Dissolved Oxygen Doubling Generation Time Heterotrophic Bacteria Heterotrophic Nanoflagellates Ice Thickness Intrinsic Growth Rate Julian Day Julian Month Mesodinium rubrum Mesodinium rubrum cysts Mixolimnion Monimolimnion Nauplii Nitrate Nitrite Notholca sp. Other Ciliates Oxygenated strata Paralabidocera antarctica copepodid Paralabidocera antarctica naupliar Particulate Organic Carbon Phosphate Phototrophic Nanoflagellates Salinity Season Soluble Reactive Phosphorus Total Ciliates Water Temperature
Metadata record for data from AAS (ASAC) Project 2933. See the child records for access to the datasets. Public While it is generally thought that Antarctic organisms are highly sensitive to pollution, there is little data to support or disprove this. Such data is essential if realistic environmental guidelines, which take into account unique physical, biological and chemical characteristics of the Antarctic environment, are to be developed. Factors that modify bioavailability, and the effects of common contaminants on a range of Antarctic organisms from micro-algae to macro-invertebrates will be examined. Risk assessment techniques developed will provide the scientific basis for prioritising contaminated site remediation activities in marine environments, and will contribute to the development of guidelines specific to Antarctica. Project objectives: 1. Develop and use toxicity tests to characterise the responses of a range of Antarctic marine invertebrates, micro- and macro-algae to common inorganic and organic contaminants. 2. To examine factors controlling bioavailability and the influence of physical, chemical and biological properties unique to the Antarctic environment on the bioavailability and toxicity of contaminants to biota. 3. To compare the response of Antarctic biota to analogous species in Arctic, temperate and tropical environments in order to determine the applicability of using toxicity data and environmental guidelines developed in other regions of the world for use in the Antarctic. 4. Develop a suite of standard bioassay techniques using Antarctic species to assess the toxicity of mixtures of contaminants (aqueous and sediment-bound) including tip leachates, sewage effluents and contaminated sediments. 5. To establish risk assessment models to predict the potential hazards associated with contaminated sites in Antarctica to marine biota, and to develop Water and Sediment Quality Guidelines for Antarctica to set as targets for the remediation of contaminated marine environments. Taken from the 2008-2009 Progress Report: Progress against objectives: Due to logistical constraints, only a short field season (5 weeks) was conducted at Casey in 2008/09 and no berths were allocated solely to this project. A team of 6 scientists worked together on an intensive marine sampling program under TRENZ (AAS project 2948, CI Stark) in support of 5 different AAS projects, including this one. The lack of adequate personnel dedicated to this project and the limited time that we were allocated on station hindered progress and meant that no experiments on Antarctic organisms were able to be conducted in situ. The airlink was however successfully used to transport marine invertebrates collected at Casey and held in seawater at 0degC back to Hobart on 3 separate flights. These invertebrates are currently being maintained in the cold water ecotoxicology aquarium facilities at Kingston. Once they are sorted and where possible established in cultures, they will be used in toxicity tests. Progress against specific objects are: 1) Much effort and time has been put towards the husbandry and culture of the collected Antarctic marine invertebrates. Some species are now successfully breeding in the laboratory providing new generations and sensitive juvenile stages of invertebrates to work with in toxicity tests. This culturing capability, if able to be developed, will hugely extend opportunities for carrying out research for this project, by giving us access to live material over the winter months and during summer when berths to or space on station in Antarctica is limited. Toxicity tests using some of the common amphipods and gastropods collected in the 0809 season at Casey will commence shortly at Kingston. 2) Toxicity tests to commence shortly using invertebrates collected in the 0809 season now being maintained in the Ecotoxicology aquarium will focus on interactions and potentially synergistic effects of contaminants along with other environmental stressors including increases in temperature and decreases in salinity associated with predicted environmental changes in response to climate change. 3) A phD candidate has recently started on this project and is currently reviewing all available literature on the response of Antarctic species to contaminants and environmental stressors in comparison to related species from lower latitudes. 4) Invertebrates collected in the 0809 season that are being maintained in the Ecotoxicology aquarium will be screened in toxicity tests to commence shortly. Methods will then be developed using the most suitable and sensitive species to form the basis of standard bioassay procedures that can be used to test mixtures such as sewage effluents and tip leachates in the upcoming season. 5) The establishment of risk assessment models and Environmental Quality Guidelines for Antarctica is a long term goal of this project when data from the first 4 objectives can be synthesised and hence has not yet been addressed. Taken from the 2009-2010 Progress Report: Progress against objectives: Objectives 1 and 2: Metal effects on the behaviour and survival of three marine invertebrate species were investigated during the field season. Two replicate toxicity tests were conducted on the larvae of sea urchin Sterechinus neumayeri where combined effects of metal (copper and cadmium) and temperature (-1, 1 and 3 degrees Celsius) were to be investigated on developmental success. However, due to lower than optimal fertilisation success, both tests were terminated before any meaningful results could be derived. Four tests were conducted on the adult amphipod, Paramorea walkeri. Two replicate tests investigated combined metal (copper and cadmium) and temperature (-1, 1 and 3 degrees Celsius) effects, and two tests investigated the effects of copper, cadmium, lead, zinc and nickel exposure at ambient sea water temperature of -1 degrees Celsius. One test was conducted with the micro-gastropod Skenella paludionoides being exposed to copper, cadmium, lead, zinc and nickel at ambient sea water temperature. The larvae of bivalve Laternula sp. were also investigated as a potential test organism for metal toxicity. Strip spawning was conducted a number of times, however, this technique did not provide adequate levels of fertilisation success and as such, the toxicity tests on larval development were not completed. Objective 3: A phD candidate working on this project is in the process of compiling a review of all available date on the response of Antarctic species to contaminants and environmental stressors in comparison to related species from lower latitudes. This literature review will form a major component of her thesis' first chapter Objective 4: Methods for Standard bioassay procedures were developed using the most suitable and sensitive species, the amphipod Paramoera walkeri and the microgastropod Skenella paludionoides. These standard tests were then used to assess the toxicity of sewage effluent at Davis Station (in conjunction with project 3217). Objective 5: Toxicity tests on sewage effluent were conducted as part of a risk assessment to determine hazards associated with the current discharge. The determined toxicity of the sewage effluent will provide a basis for guideline recommendations on the required level of treatment and on what constitutes an adequate or 'safe' dilution factor for dispersal of the effluent discharge to the near shore marine environment.