| 1. |
- Filipsson, Helena L., 1973, et al.
(författare)
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A major change in the phytoplankton of a Swedish sill fjord - A consequence of engineering work?
- 2005
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Ingår i: Estuarine Coastal and Shelf Science. - : Elsevier BV. - 0272-7714. ; 63:4, s. 551-560
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Tidskriftsartikel (refereegranskat)abstract
- A major phytoplankton change occurred during the late 1930s and early 1940s in Koljo Fjord, a sill fjord on the Swedish west coast. Dinoflagellate cyst concentrations increased tenfold over a short period of time, front hundreds of cysts per gram sediment to thousands; and the species composition of both dinoflagellate cysts and diatoms changed markedly. These changes took place during a period of extensive engineering work at the entrance to the fjord from the Skagerrak. At this time, the entire passage was straightened, a new channel was built in a previously shallow area, and the old connection was closed. This study investigates whether this engineering work could have sufficiently altered the surface-water circulation to bring about the change in the phytoplankton composition. Several mechanisms are explored by which the construction could have influenced the phytoplankton in the fjord. The primary mechanism is probably increased efficiency of tidal-generated surface-water exchange in the fjord, resulting in a larger transport of surface water from the Skagerrak and consequently a changed surface-water environment. This Study highlights how engineering work can have a Substantial impact on the local and regional marine environment, a factor that must not be overlooked in environmental planning. (c) 2005 Elsevier Ltd. All rights reserved.
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| 2. |
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| 3. |
- Harland, Rex, et al.
(författare)
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A high-resolution dinoflagellate cyst record from latest Holocene sediments in Koljo Fjord, Sweden
- 2004
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Ingår i: Review of Palaeobotany and Palynology. - 0034-6667. ; 128:1-2, s. 119-141
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Tidskriftsartikel (refereegranskat)abstract
- A high-resolution dinoflagellate cyst record is detailed for the very latest Holocene sediments preserved in a silled fjord from western Sweden. Koljo Fjord is characterised by brackish water conditions together with intermittent deep-water renewal and oxygen depletion. The data provide information derived from the phytoplankton populations living in the surface waters, including possible changes to the nutrient availability and salinity regimes using an actualistic ecological approach. The cyst record provides evidence that the dinoflagellate populations within the surface waters of the fjord over the last 155 years or so have fluctuated markedly. The dinoflagellate cyst record from Core KG1A demonstrates a 10-fold increase in both total cyst numbers and Lingulodinium polyedrum since c. 1938, and a shift from assemblages with high Pentapharsodinium dalei to those with high L. polyedrum and Protoceratium reticulatum from about 1980. These fluctuations are singly and/or collectively indicative of possible cultural changes within the fjord; the effects of the North Atlantic Oscillation on both deep-water renewal and seasonality; nutrient enhancement (eutrophication?); and increased water column stability. (C) 2003 Elsevier B.V. All rights reserved.
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| 4. |
- Harland, Rex, et al.
(författare)
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A major change in the dinoflagellate cyst flora of Gullmar Fjord, Sweden, at around 1969/1970 and its possible explanation
- 2010
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Ingår i: Geological Society, London, Special Publications. - 0305-8719. ; 344, s. 75-82
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Tidskriftsartikel (refereegranskat)abstract
- An ultra high-resolution study of the latest Holocene dinoflagellate cysts from Gullmar Fjord, on the west coast of Sweden, provides evidence for the recognition of at least two major dinoflagellate communities within the fjord over the last 85 years. These communities may result from changes within the North Atlantic Oscillation (NAO) and hydrography of the fjord between the approximate years 1915 and 1999 and/or from the local pollution history. The dinoflagellate cyst populations were compared in detail with hydrographical parameters available from this fjord with its long historical instrumental records. The dinoflagellate cysts fail to demonstrate a convincing ongoing eutrophication for the fjord, although the reduction of Lingulodinium polyedrum partly coincides with the curtailment of activity at a sulphite pulp mill at Munkedal and canning activity at Lysekil, together with a cessation in the influx of untreated sewage from water closets. The significant change in the assemblage composition at about the late 1960s/early 1970s coincides with a change in the NAO from a negative phase to its present-day positive phase. The unravelling of local environmental effects from those associated with regional fluctuations is complex and needs to be approached with caution.
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| 5. |
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| 6. |
- Harland, Rex, et al.
(författare)
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A two-millennium dinoflagellate cyst record from Gullmar Fjord, a Swedish Skagerrak sill fjord
- 2013
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier BV. - 0031-0182. ; 392, s. 247-260
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Tidskriftsartikel (refereegranskat)abstract
- Gullmar Fjord, a sill fjord on the Skagerrak coast of western Sweden, contains a valuable sedimentary archive for the last 2500 years. This archive encompasses a temporal record from the Roman Warm Period, the Dark Ages, the Medieval Warm Period, the Little Ice Age and into the modern warm period. A high resolution dinoflagellate cyst analysis has been completed on this archive using material from two cores taken from the deepest part of the fjord, Alsbäck Deep. The recovered dinoflagellate cysts have provided a quantitative temporal record that has been used to construct a dinoflagellate cyst spectrum and has been subjected to both Q-mode cluster analysis and CABFAC factor analysis with varimax rotation. In addition the heterotrophic ratio and both the thermophilic and cryophilic ratios have been calculated to assist with the interpretation of the results. Well preserved and diverse dinoflagellate cyst assemblages have been recovered throughout the sedimentary sequence and have been used to explore surface water conditions within the fjord over this time interval. Although a clear link is observed between the cyst assemblages and the climate phases of the Subatlantic, established from previous stable isotope work, there was little change in the cyst populations and indeed they reflect the known modern cyst floras. However a major change was seen in the incoming of Gymnodinium nolleri during the Dark Age and its reduction to a relict species towards the end of the Little Ice Age. Comparisons to other published work confirm the regional nature of this dinoflagellate cyst event but its ecological preferences remain enigmatic. A second major change was also recognised around the late 1960s/early 1970s and was associated with differences in nutrient availability from either a diminution in upwelling, as the NAO changed from a negative phase to a positive, or from marine pollution or a combination of both. Otherwise the dinoflagellate cyst assemblages can be grouped, using the factor analysis, into F1 Protoperidinium spp. indet. (round, brown cysts); F2 Gymnodinium nolleri and F3 Lingulodinium polyedrum and Protoceratium reticulatum. The cluster analysis shows a similar subdivision into units closely associated with the recognised climate phases of the Subatlantic. Possible climate environments have been explored, but because of the relatively minor variations in the assemblages and the lack of autecological information, only relatively small scale changes were recognised except for the clear, but complex nature of the recent warm period.
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| 7. |
- Harland, Rex, et al.
(författare)
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Dinoflagellate cysts and hydrographical change in Gullmar Fjord, west coast of Sweden.
- 2006
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Ingår i: The Science of the total environment. - : Elsevier BV. - 0048-9697. ; 355:1-3, s. 204-31
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Tidskriftsartikel (refereegranskat)abstract
- This high-resolution study of the latest Holocene dinoflagellate cyst record from Gullmar Fjord, on the west coast of Sweden, provides evidence for the recognition of two major dinoflagellate communities within the fjord over the last 85 years. These communities may have their origins with the history of cultural eutrophication within the region, but are more likely to be associated with the wider phenomenon of the North Atlantic Oscillation and/or the complex hydrographical response of the fjord to various changing climatic environments between 1915 and 1999. The changing dinoflagellate cyst populations are compared in detail with the many hydrographical parameters available from this well studied fjord with its long instrumental records. Indeed the dinoflagellate cysts fail to demonstrate a convincing ongoing eutrophication record for the fjord but do show a major change in the cyst assemblages at about 1969/1970 at a time when the NAO was changing from a negative phase to the present-day positive phase. Gullmar Fjord is important in the history of dinoflagellate cyst studies, being the site of the 1954 study by Erdtman in which viable cysts, produced within the phytoplankton, were first documented within the water column.
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| 8. |
- Harland, Rex, et al.
(författare)
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Latest Holocene dinoflagellate cyst records from the west coast of Sweden and their impact on the interpretation of environmental change
- 2013
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Ingår i: Biological and Geological Perspectives of Dinoflagellates. - London : The Micropalaeontological Society, Geological Society. ; , s. 43-54
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Bokkapitel (refereegranskat)abstract
- The fjords along the west coast of Sweden have attracted attention for a number of unfortunate reasons, including the development of enhanced primary production and the presence of oxygen deficiency in bottom waters with its consequential benthic mortality. These difficulties have impacted local fisheries, mariculture and leisure activities along the coast. In the early 1990s a research programme, using the fjord sediments as an archive, was initiated to understand the various environmental processes at play. Included were studies on the foraminifera to access bottom water environments, and dinoflagellate cyst analysis for the interpretation of surface water conditions. In addition the sedimentary history within several of the fjords was constructed using 210Pb dating and a constant rate of supply model together with heavy metal analysis. Several fjords were analysed for their dinoflagellate cyst record including Koljo¨fjord, Gullmarsfjord and Havstensfjord. This contribution adds to the published information with the inclusion of Sanna¨sfjord and Dynekilen. All the dinoflagellate cyst records are consistent with modern cyst floras of the area, and include Lingulodinium polyedrum, Protoceratium reticulatum, Spiniferites bentorii and Pentapharsodinium dalei. It is however apparent that the temporal cyst record from Gullmarsfjord differs from the other fjords and is reacting differently to environmental change. Ultra-high-resolution dinoflagellate cyst analysis has a particular impact on the interpretation of environmental change within the marine realm.
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| 9. |
- Harland, Rex, et al.
(författare)
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The identification, occurrence and importance of microreticulate dinoflagellate cysts in the latest Holocene sediments of the Skagerrak and Kattegat, west coast of Sweden
- 2011
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Ingår i: Review of Palaeobotany and Palynology. ; 164, s. 84-92
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Tidskriftsartikel (refereegranskat)abstract
- Microreticulate dinoflagellate cysts are a major component of latest Holocene (Subatlantic) sediments from the Skagerrak and Kattegat, off the west coast of Sweden. They first appear about 4000 years BP, become more prominent from 2000 years BP to about 300 years BP, before they decline to their present minor occurrence in modern sediments. In particular they occur in at least two major pulses and one minor pulse, where their numbers exceed 5000 cysts per gram of sediment, seemingly correlating to times toward the end of the Roman Warm Period, to between the Roman and Medieval warm periods, and with the Little Ice Age. The minor pulse occurs within the Medieval Warm Period. Originally thought to be assignable to the species Gymnodinium catenatum Graham 1943 these cysts were interpreted as an indication of warmer waters, warmer climates and significant changes within the hydrology of the region. Opinion amongst palynologists and phycologists now favour assignment of these cysts to Gymnodinium nolleri Ellegaard and Moestrup 1999, based mainly upon their dimensions; this cautions against earlier environmental interpretations. Further study of microreticulate cysts from core material recovered in the Kattegat and Skagerrak (Gullmar Fjord) supports the identification of these cysts as G. nolleri and emphasises an environmental interpretation that does not solely depend upon possible temperature change but that other factors may be involved. This study also emphasises the importance of these microreticulate cysts to the biostratigraphy of the Subatlantic in offshore west coast Sweden.
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| 10. |
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| 11. |
- Harland, Rex, et al.
(författare)
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The seasonal occurrence of dinoflagellate cysts in surface sediments from Koljo Fjord, west coast of Sweden - a note
- 2004
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Ingår i: Review of Palaeobotany and Palynology. - 0034-6667. ; 128:1-2, s. 107-117
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Tidskriftsartikel (refereegranskat)abstract
- The opportunistic collection of the flocculent layer, over the spring to late summer seasons, has provided information on the seasonal dinoflagellate cyst sedimentation in Koljo Fjord, on the west coast of Sweden. The dinoflagellate cyst assemblages within the flocculent layer can be both diverse and contain many cysts. The cyst assemblages do not remain constant over time but demonstrate seasonality. Our very limited dataset of six samples suggests that the spring bloom is characterised by round, brown Protoperidinium cysts together with subsidiary Pentapharsodinium dalei and Protoperidinium conicum. The early summer assemblage differs in containing higher proportions of P. dalei with fewer round, brown Protoperidinium cysts together with relatively minor amounts of Lingulodinium polyedrum and Polykrikos schwartzii. The late summer cyst flora is co-dominated by Lingulodinium polyedrum and round, brown Protoperidinium cysts, together with minor amounts of P. dalei and Spiniferites spp. including Spiniferites bentorii. Cyst production within the different species occurs at times of the year when the surface water conditions within the fjord are suitable. This probably reflects, all or in part, the stability of the upper water column, the relative availability of nutrients and the overall phytoplankton productivity. (C) 2004 Elsevier B.V. All rights reserved.
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| 12. |
- Head, M. J., et al.
(författare)
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A history of the International Conferences on Modern and Fossil Dinoflagellates, 1978-2011
- 2013
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Ingår i: Biological and Geological Perspectives of Dinoflagellates. - London : The Micropalaeontological Society, Geological Society. ; , s. 1-21
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Bokkapitel (refereegranskat)abstract
- Abstract: The international conferences on modern and fossil dinoflagellates, held every 3–5 years, are an essential forum for all researchers of dinoflagellates. They bring together all aspects of this important group of protists, whether living or preserved as fossils. Dinoflagellates are an important component of the plankton, both as autotrophs and heterotrophs, but also include representatives that inhabit the cells of other organisms (including other dinoflagellates) as endosymbionts or parasites. The conferences were initiated in 1978 as a Penrose Conference of the Geological Society of America and have continued ever since. The latest conference, Dino 9, continues the tradition of bringing phycologists working as biologists, geneticists, ecologists and public health scientists together with palynologists working within the disciplines of earth science, geography and biology. The paramount impact of this series of conferences is the interdisciplinary cross-fertilization of ideas between these two otherwise disparate groups, and the spreading of their acquired specialist knowledge from one to the other. This series of conferences is set to extend into the future and to continue its important role of integrating and furthering the study of dinoflagellates and their cysts.
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| 13. |
- Howe, John A., et al.
(författare)
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Dinoflagellate cysts as proxies for palaeoceanographic conditions in Arctic fjords
- 2010
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Ingår i: Geological Society, London, Special Publication. - 0305-8719. ; 344, s. 61-74
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Tidskriftsartikel (refereegranskat)abstract
- The potential of using dinoflagellate cysts as proxies for palaeoceanographic conditions and as monitors of the dynamic marine environment of climatically sensitive Arctic fjords was investigated with sediment traps. Dinoflagellate cysts were analysed from three separate deployments in two high Arctic fjords in the Svalbard archipelago. Two deployments in Kongsfjorden on the west coast of Svalbard occurred during 2002 and 2006–2007 and a deployment in Rijpfjorden on the NE coast occurred during 2006–2007. The cyst production displayed peaks of abundance in the spring and late summer with distinct differences in cyst occurrence in different fjords and in different years. The recorded and identified cyst species were consistent both with the hydrography of the fjords and with changes in cyst composition that are comparable to the seasonal shifts in water mass characteristics. The presence of the heterotrophic species Protoperidinium conicum in Kongsfjorden during 2002 is of note and may reflect the availability of a particular food source possibly associated with the strong influx of Atlantic Water. Cysts recovered from Kongsfjorden during 2006–2007 were dominated by Islandinium minutum, an indicator of cold, polar to subpolar conditions. The temperature and salinity characteristics of the ambient hydrography in this period indicated less influence by Atlantic Water than in 2002, and the cyst production was consistent with regional cyst distribution patterns. In Rijpfjorden, cyst assemblages were dominated by Pentapharsodinium dalei, consistent with the fjord being dominated by full Arctic conditions during the mooring deployment and the possible occurrence of stratified water with high productivity during the spring phytoplankton bloom.
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| 14. |
- Howe, John A., et al.
(författare)
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Fjord systems and archives: a review
- 2010
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Ingår i: Geological Society, London, Special Publications. - 0305-8719. ; 344, s. 5-15
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Forskningsöversikt (refereegranskat)abstract
- Fjords are glacially over-deepened semi-enclosed marine basins, typically with entrance sills separating their deep waters from the adjacent coastal waters which restrict water circulation and thus oxygen renewal. The location of fjords is principally controlled by the occurrence of ice sheets, either modern or ancestral. Fjords are therefore geomorphological features that represent the transition from the terrestrial to the marine environment and, as such, have the potential to preserve evidence of environmental change. Typically, most fjords have been glaciated a number of times and some high-latitude fjords still possess a resident glacier. In most cases, glacial erosion through successive glacial/interglacial cycles has ensured the removal of sediment sequences within the fjord. Hence the stratigraphic record in fjords largely preserves a glacial-deglacial cycle of deposition over the last 18 ka or so. Sheltered water and high sedimentation rates have the potential to make fjords ideal depositional environments for preserving continuous records of climate and environmental change with high temporal resolution. In addition to acting as high-resolution environmental archives, fjords can also be thought of as mini-ocean sedimentary basin laboratories. Fjords remain an understudied and often neglected sedimentary realm. With predictions of warming climates, changing ocean circulation and rising sea levels, this volume is a timely look at these environmentally sensitive coastlines.
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| 15. |
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| 16. |
- Polovodova, Irina, 1980, et al.
(författare)
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Detailing the Little Ice Age on the Swedish west coast: a multi-proxy study of a sediment record from Gullmar Fjord
- 2014
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Ingår i: Marchant, M . & Hromic, T. (eds . ) 201 4 . Internation al Symposium on Foraminifera Forams 2014, Chile, 19 – 24 January 2014 , Abstract Volume . Grzybowski Foundation Special Publication, 20 , 124 pp.. - 9788388927355 ; , s. 38-39
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Gullmar Fjord, on the west coast of Sweden, represents a high-resolution environmental archive due to high sedimentation rates, low bioturbation and negligible tidal activity. In this study we attempt to detail the climatic and environmental changes in NE Europe during the last millennium by using a ca. 8-m long well dated sediment record from the deep fjord basin. According to the 14C-datings, the record includes the period of the late Holocene characterised by anomalously cold summers and well known as the Little Ice Age (LIA). Using a high-resolution stratigraphy of benthic foraminifera and dinoflagellate cysts along with lithology, bulk sediment geochemistry and foraminiferal δ13C we identify the timing of the cold period, reconstruct its various phases, and discuss the land-sea interactions occurring in the study area during that time. The onset of the LIA is indicated at ~1350 A.D by an increase in abundances of cold-water foraminifer Adercotryma glomerata and the cryophilic dinoflagellate cyst Islandinium cf. cezare. The first phase of the LIA was characterised by a stormy climate and higher productivity, as suggested by a foraminiferal assemblage of Nonionella iridea and Cassidulina laevigata. The hypothesis of higher productivity is supported by the isotopic and the dinoflagellate cyst records, which show a shift towards more negative δ13C values, and a marked increase in the microreticulate cysts of Gymnodinium nolleri at the onset of the LIA. The dinoflagellate species G. nolleri becomes relict towards the LIA termination and could be also associated with lower surface water temperatures at that time. It is likely that due to land use changes in the second part of the LIA there was an increased input of terrestrial organic matter to the fjord, which is indicated by lighter δ13C values and an increase of detritivorous and omnivorous foraminiferal species such as Textularia earlandi and Eggerelloides scaber. The climate deterioration during the climax of the LIA (1675-1704 A.D.) may have driven a decline in primary productivity, as suggested by the increase of agglutinated foraminiferal species, the presence of Hyalinea balthica, and a decline of N. iridea during that time.
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| 17. |
- Rochon, A., et al.
(författare)
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Dinoflagellates and their cysts: key foci for future research
- 2013
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Ingår i: Biological and Geological Perspectives of Dinoflagellates. - London : The Micropalaeontological Society, Geological Society. ; , s. 89-95
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Bokkapitel (refereegranskat)abstract
- The study of dinoflagellates and their cysts has been ongoing for the last c. 250 years following the pioneering work of the early, passionate researchers who first described them with rudimentary microscopes. The quality of modern microscopes and other laboratory equipment, coupled with enhanced computer capabilities, has extended the frontiers of research beyond what was thought possible even half a century ago. New research topics have emerged in accordance with today’s scientific and socio-economic priorities. Here we describe six of these research areas that have the most potential to advance our knowledge of dinoflagellate ecology and systematics.
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