Uptake and metabolism of arsenate by anexic cultures of the microalgae Dunaliella tertiolecta and Phaeodactylum tricornutum     

Simon Foster  Danielle Thomson  William Maher   《Marine Chemistry》2008,108(3-4):172-183

Axenic cultures of the microalgae species, Dunaliella tertiolecta and Phaeodactylum tricornutum were grown at arsenic (As) concentrations typically found in uncontaminated marine environments ( 2 µg L^− 1) under different phosphorus concentrations. D. tertiolecta accumulated higher arsenic concentrations (mean: 13.7 ± 0.7 µg g^− 1 dry mass) than P. tricornutum (mean: 1.9 ± 0.2 µg g−1 dry mass). Media phosphorus concentrations (0.6–3 mg/L) had little influence on microalgae growth rates or arsenic accumulation. Arsenic was present as lipid bound (29–38%; 4.2–9.5%), water-soluble (20–29%; 26–34%) and residue bound (41–45%; 57–69%) arsenic species in D. tertiolecta and P. tricornutum respectively. Hydrolysed lipids contained mostly glycerol arsenoribose (OH- ribose), dimethylarsinate (DMA) and inorganic arsenic (As(V)) moieties. Water-soluble species of microalgae were very different. D. tertiolecta contained inorganic arsenic (54–86%) with variable amounts of DMA (7.4–20%), arsenoriboses (5–25%) and traces of methylarsonate (MA) ( 1%). P. tricornutum contained mostly DMA (32–56%) and phosphate arsenoribose (PO₄-ribose, 23–49%) and small amounts of OH-ribose (3.8–6.5%) and As(V) (9–16%). Both microalgae contained an unknown cationic arsenic species. The residue fractions of both microalgae contained predominately inorganic arsenic (99–100%). These results show that at natural seawater arsenic concentrations, both algae take up substantial amounts of inorganic arsenic that is complexed with structural elements or sequestered in vacuoles as stable complexes. A significant portion is also incorporated into lipids. Arsenic is metabolised to simple methylated species and arsenoriboses.  相似文献   

Dr Donald S McLusky – an appreciation and thanks from ECSS     

Eric Wolanski Ivan Valiela  Mike Elliott 《Estuarine, Coastal and Shelf Science》2010

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Managed realignment as compensation for the loss of intertidal mudflat: A short term solution to a long term problem?     

Krysia Mazik  Will Musk  Oliver Dawes  Katya Solyanko  Sue Brown  Lucas Mander  Mike Elliott 《Estuarine, Coastal and Shelf Science》2010

Intertidal mudflats are critical to the functional ecology of estuaries yet large areas are being lost as a result of land claim, erosion and coastal squeeze. This study examines whether managed realignment (at Paull Holme Strays, Humber estuary) can realistically achieve compensation for the loss of intertidal mudflat in the long term. Typical estuarine species quickly colonised the site with the total number of species recorded from the site as a whole being almost equal to that in the reference area within one year. Comparable biomass between the two areas was achieved after 2 years. However, organism abundance remains an order of magnitude lower within the realignment site compared to outside. Community structure within the realignment has changed from one characterised by terrestrial/freshwater organisms and early colonising species to one composed of typically estuarine species. However, the developing benthic communities only represent those typical of the estuary in areas of low elevation and high inundation frequency. Rapid accretion has favoured saltmarsh colonisation in much of the realignment site and this is expected to increase as accretion proceeds with invertebrate colonisation being inhibited by increasing elevation. Hence, realignment to restore intertidal mudflats can only be a short term solution in sites of high tidal elevation and in a dynamic and turbid estuary with high natural accretion rates, such as the Humber.  相似文献   

Contemporary initiatives on the future of the International Whaling Commission     

Mike Iliff 《Marine Policy》2010

In his term as Chairman of the International Whaling Commission between 2006 and 2009, Dr BillHogarth championed a process for finding a way forward for the IWC. In parallel with, and in places intertwined with the Hogarth Initiative, a number of other initiatives attempting to move the IWC forward have been proposed by a range of stakeholders; both governments and NGOs. This paper traces the more important suggestions, commenting on their likelihood of success.  相似文献   

Geochemistry of surface sediments in an acid stream estuary     

P. Foster  D.T.E. Hunt 《Marine Geology》1975,18(1):M13-M21

Selective chemical attack has been used to separate recent surface marine sediments into organic, non-detrital and detrital components, and the concentrations of iron, manganese, copper and zinc in each fraction determined. The non-detrital fraction controlled the overall elemental concentrations and relationships apparent in the bulk sediment, particularly in the cases of copper, manganese and zinc. Copper was found associated with the organic fraction. The predominant processes of primary deposition are precipitation of hydrated ferric oxide and adsorption of copper and zinc onto this material.  相似文献   

Understanding sediment in river systems—Building on a 50-year contribution     

Bruce W. Webb  Ian D. L. Foster  James P. McNamara 《水文研究》2023,37(1):e14792

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Ethnohistoric and Geoarchaeological Landscape Chronology at Kawaihae,Leeward Hawai‘i Island     

Mike T. Carson 《Geoarchaeology》2012,27(5):385-409

The royal court of the Kamehameha Dynasty in Kawaihae, Hawai‘i Island, presents an unequalled opportunity to examine the ethnohistoric rendering of a cultural landscape, in comparison to the geoarchaeological record of physical transformation of this same landscape. Beneath the surface, earlier occupation layers predate the historic royal precinct of the A.D. 1790s through 1820s. Drawing on results of 19 controlled excavations, point‐specific cultural activities are situated within the last several centuries of natural terrain formation, beginning A.D. 1200–1400 and ending A.D. 1830–present. Geoarchaeological excavations provide the means to place the stratified cultural deposits, occupational horizons, and activity areas in the context of depositional history, environmental transformation, and changing social circumstances in a continuous sequence. The material‐based geoarchaeological landscape chronology and the ethnohistorically defined cultural landscape are combined for a more holistic view than either one could provide independently.  相似文献   

Dietary niche separation of three Late Pleistocene bear species from Vancouver Island,on the Pacific Northwest Coast of North America     

Cara Kubiak  Vaughan Grimes  Geert Van Biesen  Grant Keddie  Mike Buckley  Reba Macdonald  M. P. Richards 《第四纪科学杂志》2023,38(1):8-20

Competition between taxa related to climate changes has been proposed as a possible factor in Pleistocene megafaunal extinctions, and here we present isotope evidence of the diets of three co-existing bear species [black bear (Ursus americanus), brown bear (Ursus arctos), and the now extinct short-faced bear (Arctodus simus)] from a locale in western North America dating to the Late (Terminal) Pleistocene (~14.5–11.7 ka). The three bear species were found at several sites on Vancouver Island, on the western coast of Canada. To examine the chronological overlap and niche partitioning between these species of bear, we used direct radiocarbon dating, stable isotope analysis and ZooMS proteomic identification methods. Here we present new radiocarbon evidence from Terminal Pleistocene U. americanus, U. arctos and A. simus from several sites on the island, along with both bulk collagen and compound-specific isotope data for these species. Radiocarbon dates confirm the chronological overlap of Arctodus and both Ursus species in the montane regions of the island at the end of the Pleistocene. Stable isotope data reveal niche differentiation between these species, with U. americanus occupying a distinctly lower trophic position than the other two taxa.  相似文献   

Correlation of environmental and cultural chronology in New Caledonia     

Mike T. Carson 《Geoarchaeology》2008,23(5):695-714

A case study in New Caledonia explores the changes in the natural and cultural setting at the end of the Lapita period in the first millennium B.C. After the mid‐Holocene highstand, sea level fell about 1.5 m, thereby enlarging coastal plains, altering previous mangrove and marshy settings, and transforming nearshore marine environments. Many of these changes occurred gradually over several centuries, but the termination of finely decorated Lapita pottery coincided with the first signs of loss of coastal habitat optimal for marine‐based horticulturalists in the first millennium B.C. Organized village compounds and extensively cultivated landscapes emerged much later, in the first millennium A.D. The results suggest that, although the Lapita phenomenon represents the founding ancestry of Oceanic societies, it also represents the end of an era and way of life that eventually could not be maintained in a changing world. © 2008 Wiley Periodicals, Inc.  相似文献