Carina Lange | Universidad de Concepción (original) (raw)
Papers by Carina Lange
Marine Micropaleontology, 2001
In an effort to understand the relationship between surface water processes and sea¯oor sediment ... more In an effort to understand the relationship between surface water processes and sea¯oor sediment characteristics in the Southern California Bight, opal concentrations, organic carbon weight percent measurements, diatom abundances and assemblages, and living benthic foraminiferal abundances were examined in surface sediments from two sites along the continental margin of Southern California. Although opal and organic carbon weight percentages in the top 1 cm of surface sediments re¯ect spatial changes in productivity between sites, our results indicate that they are not sensitive indicators of seasonal changes in surface water productivity at either site. The close correspondence between seasonal diatom¯ux in the adjacent Santa Barbara Basin (SBB), abundances of diatoms indicative of upwelling conditions, and opportunistic benthic foraminifera indicate that there is a rapid, (weeks to months) opportunistic response of the benthic species, Nonionella fragilis, to input from changes in surface water characteristics. These results highlight the close association of surface water conditions and preservable microfauna and¯ora, and con®rm the in¯uence of surface characteristics on sea¯oor ecosystems in bathyal environments on the California margin. Additional information on these associations will further improve our ability to discern seasonal and spatial changes in paleoproductivity from the geologic record. q
Science, 2001
Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coa... more Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including pollution, degradation of water quality, and anthropogenic climate change. Historical abundances of large consumer species were fantastically large in comparison with recent observations. Paleoecological, archaeological, and historical data show that time lags of decades to centuries occurred between the onset of overfishing and consequent changes in ecological communities, because unfished species of similar trophic level assumed the ecological roles of overfished species until they too were overfished or died of epidemic diseases related to overcrowding. Retrospective data not only help to clarify underlying causes and rates of ecological change, but they also demonstrate achievable goals for restoration and management of coastal ecosystems that could not even be contemplated based on the limited perspective of recent observations alone.
Estuarine, Coastal and Shelf Science, 2005
Here we present the first reconstruction of changes in surface primary production during the last... more Here we present the first reconstruction of changes in surface primary production during the last century from the Puyuhuapi fjord in southern Chile, using a variety of parameters (diatoms, biogenic silica, total organic carbon, chlorins, and proteins) as productivity proxies. Two sediment cores from the head and the center of the fjord were analyzed and compared to gain insights on past changes in productivity in these two different depositional environments. Higher sedimentation rates found at the head of the fjord result from the combination of a shallower water column and a restricted circulation by the occurrence of a sill. Additionally, sediment mixing depths estimated from 210 Pb data suggest that suboxic conditions may dominate the bottom water and the sediment-water interface in this location.
Progress in Oceanography, 2007
We compared the signals of several water column properties (upwelling intensity, sea level anomal... more We compared the signals of several water column properties (upwelling intensity, sea level anomaly, temperature, nutrients, dissolved oxygen, chlorophyll-a, and surface sediments) of the continental shelf off Concepció n (36°S) during the 1997-1998 El Niñ o with those of a normal year (2002)(2003). We found that the primary hydrographic effect of El Niñ o 1997-1998 was a reduction in the input of nutrient-rich, oxygen-poor Equatorial Subsurface Water over the shelf. This affected the biology of the water column, as evidenced by the reduced phytoplankton biomass. Surface sediment properties (biogenic opal, organic carbon, bulk d 15 N) observed during El Niñ o 1997-1998 reflected a reduced export production and the sediments failed to show the water column seasonality that occurs under normal conditions. In addition, weakened denitrification and/or upper water column fertilization could be inferred from the sedimentary d 15 N. Although diminished, export production was preserved in the surface sediments, revealing less degraded organic matter in the upwelling period of the El Niñ o year than in the normal year. We suggest that the fresher organic material on the seafloor was probably associated with a severe reduction in the polychaete Parapronospio pinnata, which is considered to be the most important metazoan remineralizer of organic carbon at the sediment-water interface in the study area.
Estuarine, Coastal and Shelf Science, 2005
Here we present the first reconstruction of changes in surface primary production during the last... more Here we present the first reconstruction of changes in surface primary production during the last century from the Puyuhuapi fjord in southern Chile, using a variety of parameters (diatoms, biogenic silica, total organic carbon, chlorins, and proteins) as productivity proxies. Two sediment cores from the head and the center of the fjord were analyzed and compared to gain insights on past changes in productivity in these two different depositional environments. Higher sedimentation rates found at the head of the fjord result from the combination of a shallower water column and a restricted circulation by the occurrence of a sill. Additionally, sediment mixing depths estimated from 210 Pb data suggest that suboxic conditions may dominate the bottom water and the sediment-water interface in this location.
Estuarine Coastal and Shelf Science, 2005
Here we present the first reconstruction of changes in surface primary production during the last... more Here we present the first reconstruction of changes in surface primary production during the last century from the Puyuhuapi fjord in southern Chile, using a variety of parameters (diatoms, biogenic silica, total organic carbon, chlorins, and proteins) as productivity proxies. Two sediment cores from the head and the center of the fjord were analyzed and compared to gain insights on past changes in productivity in these two different depositional environments. Higher sedimentation rates found at the head of the fjord result from the combination of a shallower water column and a restricted circulation by the occurrence of a sill. Additionally, sediment mixing depths estimated from 210Pb data suggest that suboxic conditions may dominate the bottom water and the sediment–water interface in this location.Productivity of the Puyuhuapi fjord during the last century was characterized by a constant increase from the late 19th century to the early 1980s, then decreased until the late 1990s, and then rose again to present-day values. The influence of rainfall on productivity was most noticeable during periods of low rainfall, which coincided with decreased overall productivity within the Puyuhuapi fjord. Simultaneous variations in productivity and rainfall in the study area suggest that marine productivity could respond to atmospheric–oceanic interactions at a local scale. At a regional scale, marine productivity of the area may be related to other large-scale processes such as the El Niño Southern Oscillation.
Quaternary Research, 2009
A high-resolution multi-proxy study including the elemental and isotopic composition of bulk orga... more A high-resolution multi-proxy study including the elemental and isotopic composition of bulk organic matter, land plant-derived biomarkers, and alkenone-based sea-surface temperature (SST) from a marine sedimentary record obtained from the Jacaf Fjord in northern Chilean Patagonia (∼44°20′S) provided a detailed reconstruction of continental runoff, precipitation, and summer SST spanning the last 1750 yr. We observed two different regimes of climate variability in our record: a relatively dry/warm period before 900 cal yr BP (lower runoff and average SST 1°C warmer than present day) and a wet/cold period after 750 cal yr BP (higher runoff and average SST 1°C colder than present day). Relatively colder SSTs were found during 750–600 and 450–250 cal yr BP, where the latter period roughly corresponds to the interval defined for the Little Ice Age (LIA). Similar climatic swings have been observed previously in continental and marine archives of the last two millennia from central and southern Chile, suggesting a strong latitudinal sensitivity to changes in the Southern Westerly Winds, the main source of precipitation in southern Chile, and validating the regional nature of the LIA. Our results reveal the importance of the Chilean fjord system for recording climate changes of regional and global significance.
Quaternary Research, 2009
J. Sepúlveda). Phone: +1 617 18 324 3954; Fax: + +1 617 253 8630 19 20 ABSTRACT 24 A high-resolut... more J. Sepúlveda). Phone: +1 617 18 324 3954; Fax: + +1 617 253 8630 19 20 ABSTRACT 24 A high-resolution multi-proxy study including the elemental and isotopic 25 composition of bulk organic matter, land plant-derived biomarkers, and alkenone-based sea 26
Quaternary Research, 2009
J. Sepúlveda). Phone: +1 617 18 324 3954; Fax: + +1 617 253 8630 19 20 ABSTRACT 24 A high-resolut... more J. Sepúlveda). Phone: +1 617 18 324 3954; Fax: + +1 617 253 8630 19 20 ABSTRACT 24 A high-resolution multi-proxy study including the elemental and isotopic 25 composition of bulk organic matter, land plant-derived biomarkers, and alkenone-based sea 26
Biogeosciences Discussions, 2015
ABSTRACT We reconstructed oxygenation changes in the Oxygen Minimum Zone of the upwelling ecosyst... more ABSTRACT We reconstructed oxygenation changes in the Oxygen Minimum Zone of the upwelling ecosystem off Concepción (36° S), Chile, using inorganic and organic proxies in a sediment core covering the last ca. 110 years of sedimentation in this area. Authigenic enrichments of Mo, U and Cd were observed between ca. 1935–1971 CE indicating a prolonged period of more reduced conditions in bottom waters and surface sediments. Significant positive correlations (p < 0.05; Spearman) between redox sensitive metals, algal sterols, biomarkers of anaerobic microorganisms, and archaeal glycerol dialkyl glycerol tetraether indicated a coupling among bottom water oxygen depletion, and increased primary and export production, suggesting that the period with low O2 of ca. 35 years, follows low frequency inter-decadal variation of the Pacific Decadal Oscillation, which may have resulted in O2 depletion over the entire continental shelf off Concepción. Taken together with the concurrent increase in sedimentary molecular indicators of anaerobic microbes allow us to suggest that the prokaryote community has been influenced by changes in oxygenation of the water column.
Gayana. Botánica, 2011
Quistes de resistencia del dinofl agelado potencialmente tóxico Lingulodinium polyedrum (Stein) D... more Quistes de resistencia del dinofl agelado potencialmente tóxico Lingulodinium polyedrum (Stein) Dodge son registrados por primera vez en sedimentos costeros del Mar Interior de Chiloé. Se entrega información de abundancia, distribución, descripción y fotomicrografías de la especie. Se confi rma la presencia de L. polyedrum en aguas costeras del sur de Chile.
We examined the effects of bottom oxygen conditions and organic matter availability on the vertic... more We examined the effects of bottom oxygen conditions and organic matter availability on the vertical distribution of living (Rose Bengal-stained) benthic foraminifera (>180 mm fraction) within 10-cm sedimentary columns from three stations along a bathymetric transect off Concepción, Chile (Sta. 18 = 88 m, Sta. 26 = 120 m, and Sta. 40 = 1030 m water depth) that includes sites within and below the Oxygen Minimum Zone. Calcareous foraminifera dominated the three stations. Onshore-offshore pattern revealed overall highest foraminiferal densities within the shelf Stas. 18 and 26 where bottom water dissolved oxygen was lowest (<1 ml L-1) and sediment labile organic matter was greatest. Within the sediment column, maximum abundances (50 and 60%) of living organisms were found in the first centimeters at o rganic-rich and oxygen-poor shelf stations 18 and 26 (average living depth = 1.08 cm and 1.86 cm, respectively), in contrast to the well-oxygenated slope station 40, where 70% of liv...
The Salton Sea, 2002
Hydrobiologia 473: 179201, 2002. DA Barnum, JF Elder, D. Stephens &amp; M. Friend (eds),... more Hydrobiologia 473: 179201, 2002. DA Barnum, JF Elder, D. Stephens &amp; M. Friend (eds), The Salton Sea. © 2002 Kluwer Academic Publishers. Printed in the Netherlands. ... The diatom flora of the Salton Sea, California ... Carina B. Lange1 &amp; Mary Ann Tiffany2,∗ ...
Revista chilena de historia natural, 2008
Revista chilena de historia natural, 2008
Phycologia, 2002
... Fig. 30. Tabularia investiens attached to the mucilage pad connecting two cells of Terpsinoe ... more ... Fig. 30. Tabularia investiens attached to the mucilage pad connecting two cells of Terpsinoe musica. Figs 31, 32. Pleurosira laevis. Fig. 31. ... delicatulum on the valve face and girdle of Pleurosira laevis. Page 8. Tiffany &amp; Lange: Diatom epiphytes on diatoms 123 Figs 34-39. ...
J Plankton Res, 2007
ABSTRACT We have examined the species composition of 127 sediment trap samples collected sequenti... more ABSTRACT We have examined the species composition of 127 sediment trap samples collected sequentially from the Santa Barbara Basin, USA, during a 7-year period. The sampling period included two warm-water periods (El Ninos) and two cold-water periods (one La Nina and one more local). We examined changes in total species composition and changes in subsets of species accompanying extreme environmental conditions, as well as changes in flux composition associated with periods of anomalous flux. Our goal was to improve the scale and precision of hindcasting past conditions from the sedimentary record and, hence, prediction of the biological consequences of environmental change. Although large-scale climate events were accompanied by changes in the flux composition, there was little similarity in composition during environmentally similar periods, precluding generalization. Eighty-four percent of the flux (number of cells m(-2) d(-1)) and 89% of its variability were due to changes in the flux of four dominant species. Anomalous flux events were due to changes in flux of these species rather than introduction of new flora. Rare species showed the same patterns as the flora as a whole: there were changes in composition associated with extreme environmental temperatures but little redundancy of species between similar periods. Our data indicate that, at present, we can predict only that the specific composition of flux will change in response to extreme environmental conditions. It is premature to generalize about the specific composition of that response. Knowledge about mechanisms linking flux with ocean environment is currently insufficient to permit the precision of hindcast and prediction that we were seeking from our data. Nevertheless, species composition remains a potentially important tool for interpreting past environmental conditions on both the regional and the local scales.
Quaternary Research, Nov 1, 2009
A high-resolution multi-proxy study including the elemental and isotopic composition of bulk orga... more A high-resolution multi-proxy study including the elemental and isotopic composition of bulk organic matter, land plant-derived biomarkers, and alkenone-based sea-surface temperature (SST) from a marine sedimentary record obtained from the Jacaf Fjord in northern Chilean Patagonia (˜44°20'S) provided a detailed reconstruction of continental runoff, precipitation, and summer SST spanning the last 1750 yr. We observed two different regimes of climate variability in our record: a relatively dry/warm period before 900 cal yr BP (lower runoff and average SST 1°C warmer than present day) and a wet/cold period after 750 cal yr BP (higher runoff and average SST 1°C colder than present day). Relatively colder SSTs were found during 750-600 and 450-250 cal yr BP, where the latter period roughly corresponds to the interval defined for the Little Ice Age (LIA). Similar climatic swings have been observed previously in continental and marine archives of the last two millennia from central and southern Chile, suggesting a strong latitudinal sensitivity to changes in the Southern Westerly Winds, the main source of precipitation in southern Chile, and validating the regional nature of the LIA. Our results reveal the importance of the Chilean fjord system for recording climate changes of regional and global significance.
Laminated sediments in the Shaban Deep, a brinefilled basin in the northern Red Sea, were analyze... more Laminated sediments in the Shaban Deep, a brinefilled basin in the northern Red Sea, were analyzed with backscattered electron imagery. Here we present possible mechanisms involved in the formation of laminae of various types and homogenous intervals arising from the detailed investigation of multicore GeoB 7805-1 (26 • 13.9 N and 35 • 22.6 E; water depth 1447 m) and gravity core GeoB 5836-2 (26 • 12.61 N, 35 • 21.56 E; water depth 1475 m). Sediment makeup includes six types: a) a laminated structure with alternating light (mainly coccoliths) and dark (diatom frustules) layers, where the diatom component is indicative of the intra-annual variability between stratification and mixing events; b) a pocket-like structure attributed to the sinking of particles within fecal pellets and aggregates; c) a matrix of tightly packed diatoms that relates to extended stratification/mixing periods of the water column; d) homogenous intervals that result from turbidity deposition; e) silt accumulations which origin may lie in agglutinated foraminifers; and f) pyrite layers with pyrite formation initiated at the seawaterbrine interface.
Marine Micropaleontology, 2001
In an effort to understand the relationship between surface water processes and sea¯oor sediment ... more In an effort to understand the relationship between surface water processes and sea¯oor sediment characteristics in the Southern California Bight, opal concentrations, organic carbon weight percent measurements, diatom abundances and assemblages, and living benthic foraminiferal abundances were examined in surface sediments from two sites along the continental margin of Southern California. Although opal and organic carbon weight percentages in the top 1 cm of surface sediments re¯ect spatial changes in productivity between sites, our results indicate that they are not sensitive indicators of seasonal changes in surface water productivity at either site. The close correspondence between seasonal diatom¯ux in the adjacent Santa Barbara Basin (SBB), abundances of diatoms indicative of upwelling conditions, and opportunistic benthic foraminifera indicate that there is a rapid, (weeks to months) opportunistic response of the benthic species, Nonionella fragilis, to input from changes in surface water characteristics. These results highlight the close association of surface water conditions and preservable microfauna and¯ora, and con®rm the in¯uence of surface characteristics on sea¯oor ecosystems in bathyal environments on the California margin. Additional information on these associations will further improve our ability to discern seasonal and spatial changes in paleoproductivity from the geologic record. q
Science, 2001
Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coa... more Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including pollution, degradation of water quality, and anthropogenic climate change. Historical abundances of large consumer species were fantastically large in comparison with recent observations. Paleoecological, archaeological, and historical data show that time lags of decades to centuries occurred between the onset of overfishing and consequent changes in ecological communities, because unfished species of similar trophic level assumed the ecological roles of overfished species until they too were overfished or died of epidemic diseases related to overcrowding. Retrospective data not only help to clarify underlying causes and rates of ecological change, but they also demonstrate achievable goals for restoration and management of coastal ecosystems that could not even be contemplated based on the limited perspective of recent observations alone.
Estuarine, Coastal and Shelf Science, 2005
Here we present the first reconstruction of changes in surface primary production during the last... more Here we present the first reconstruction of changes in surface primary production during the last century from the Puyuhuapi fjord in southern Chile, using a variety of parameters (diatoms, biogenic silica, total organic carbon, chlorins, and proteins) as productivity proxies. Two sediment cores from the head and the center of the fjord were analyzed and compared to gain insights on past changes in productivity in these two different depositional environments. Higher sedimentation rates found at the head of the fjord result from the combination of a shallower water column and a restricted circulation by the occurrence of a sill. Additionally, sediment mixing depths estimated from 210 Pb data suggest that suboxic conditions may dominate the bottom water and the sediment-water interface in this location.
Progress in Oceanography, 2007
We compared the signals of several water column properties (upwelling intensity, sea level anomal... more We compared the signals of several water column properties (upwelling intensity, sea level anomaly, temperature, nutrients, dissolved oxygen, chlorophyll-a, and surface sediments) of the continental shelf off Concepció n (36°S) during the 1997-1998 El Niñ o with those of a normal year (2002)(2003). We found that the primary hydrographic effect of El Niñ o 1997-1998 was a reduction in the input of nutrient-rich, oxygen-poor Equatorial Subsurface Water over the shelf. This affected the biology of the water column, as evidenced by the reduced phytoplankton biomass. Surface sediment properties (biogenic opal, organic carbon, bulk d 15 N) observed during El Niñ o 1997-1998 reflected a reduced export production and the sediments failed to show the water column seasonality that occurs under normal conditions. In addition, weakened denitrification and/or upper water column fertilization could be inferred from the sedimentary d 15 N. Although diminished, export production was preserved in the surface sediments, revealing less degraded organic matter in the upwelling period of the El Niñ o year than in the normal year. We suggest that the fresher organic material on the seafloor was probably associated with a severe reduction in the polychaete Parapronospio pinnata, which is considered to be the most important metazoan remineralizer of organic carbon at the sediment-water interface in the study area.
Estuarine, Coastal and Shelf Science, 2005
Here we present the first reconstruction of changes in surface primary production during the last... more Here we present the first reconstruction of changes in surface primary production during the last century from the Puyuhuapi fjord in southern Chile, using a variety of parameters (diatoms, biogenic silica, total organic carbon, chlorins, and proteins) as productivity proxies. Two sediment cores from the head and the center of the fjord were analyzed and compared to gain insights on past changes in productivity in these two different depositional environments. Higher sedimentation rates found at the head of the fjord result from the combination of a shallower water column and a restricted circulation by the occurrence of a sill. Additionally, sediment mixing depths estimated from 210 Pb data suggest that suboxic conditions may dominate the bottom water and the sediment-water interface in this location.
Estuarine Coastal and Shelf Science, 2005
Here we present the first reconstruction of changes in surface primary production during the last... more Here we present the first reconstruction of changes in surface primary production during the last century from the Puyuhuapi fjord in southern Chile, using a variety of parameters (diatoms, biogenic silica, total organic carbon, chlorins, and proteins) as productivity proxies. Two sediment cores from the head and the center of the fjord were analyzed and compared to gain insights on past changes in productivity in these two different depositional environments. Higher sedimentation rates found at the head of the fjord result from the combination of a shallower water column and a restricted circulation by the occurrence of a sill. Additionally, sediment mixing depths estimated from 210Pb data suggest that suboxic conditions may dominate the bottom water and the sediment–water interface in this location.Productivity of the Puyuhuapi fjord during the last century was characterized by a constant increase from the late 19th century to the early 1980s, then decreased until the late 1990s, and then rose again to present-day values. The influence of rainfall on productivity was most noticeable during periods of low rainfall, which coincided with decreased overall productivity within the Puyuhuapi fjord. Simultaneous variations in productivity and rainfall in the study area suggest that marine productivity could respond to atmospheric–oceanic interactions at a local scale. At a regional scale, marine productivity of the area may be related to other large-scale processes such as the El Niño Southern Oscillation.
Quaternary Research, 2009
A high-resolution multi-proxy study including the elemental and isotopic composition of bulk orga... more A high-resolution multi-proxy study including the elemental and isotopic composition of bulk organic matter, land plant-derived biomarkers, and alkenone-based sea-surface temperature (SST) from a marine sedimentary record obtained from the Jacaf Fjord in northern Chilean Patagonia (∼44°20′S) provided a detailed reconstruction of continental runoff, precipitation, and summer SST spanning the last 1750 yr. We observed two different regimes of climate variability in our record: a relatively dry/warm period before 900 cal yr BP (lower runoff and average SST 1°C warmer than present day) and a wet/cold period after 750 cal yr BP (higher runoff and average SST 1°C colder than present day). Relatively colder SSTs were found during 750–600 and 450–250 cal yr BP, where the latter period roughly corresponds to the interval defined for the Little Ice Age (LIA). Similar climatic swings have been observed previously in continental and marine archives of the last two millennia from central and southern Chile, suggesting a strong latitudinal sensitivity to changes in the Southern Westerly Winds, the main source of precipitation in southern Chile, and validating the regional nature of the LIA. Our results reveal the importance of the Chilean fjord system for recording climate changes of regional and global significance.
Quaternary Research, 2009
J. Sepúlveda). Phone: +1 617 18 324 3954; Fax: + +1 617 253 8630 19 20 ABSTRACT 24 A high-resolut... more J. Sepúlveda). Phone: +1 617 18 324 3954; Fax: + +1 617 253 8630 19 20 ABSTRACT 24 A high-resolution multi-proxy study including the elemental and isotopic 25 composition of bulk organic matter, land plant-derived biomarkers, and alkenone-based sea 26
Quaternary Research, 2009
J. Sepúlveda). Phone: +1 617 18 324 3954; Fax: + +1 617 253 8630 19 20 ABSTRACT 24 A high-resolut... more J. Sepúlveda). Phone: +1 617 18 324 3954; Fax: + +1 617 253 8630 19 20 ABSTRACT 24 A high-resolution multi-proxy study including the elemental and isotopic 25 composition of bulk organic matter, land plant-derived biomarkers, and alkenone-based sea 26
Biogeosciences Discussions, 2015
ABSTRACT We reconstructed oxygenation changes in the Oxygen Minimum Zone of the upwelling ecosyst... more ABSTRACT We reconstructed oxygenation changes in the Oxygen Minimum Zone of the upwelling ecosystem off Concepción (36° S), Chile, using inorganic and organic proxies in a sediment core covering the last ca. 110 years of sedimentation in this area. Authigenic enrichments of Mo, U and Cd were observed between ca. 1935–1971 CE indicating a prolonged period of more reduced conditions in bottom waters and surface sediments. Significant positive correlations (p < 0.05; Spearman) between redox sensitive metals, algal sterols, biomarkers of anaerobic microorganisms, and archaeal glycerol dialkyl glycerol tetraether indicated a coupling among bottom water oxygen depletion, and increased primary and export production, suggesting that the period with low O2 of ca. 35 years, follows low frequency inter-decadal variation of the Pacific Decadal Oscillation, which may have resulted in O2 depletion over the entire continental shelf off Concepción. Taken together with the concurrent increase in sedimentary molecular indicators of anaerobic microbes allow us to suggest that the prokaryote community has been influenced by changes in oxygenation of the water column.
Gayana. Botánica, 2011
Quistes de resistencia del dinofl agelado potencialmente tóxico Lingulodinium polyedrum (Stein) D... more Quistes de resistencia del dinofl agelado potencialmente tóxico Lingulodinium polyedrum (Stein) Dodge son registrados por primera vez en sedimentos costeros del Mar Interior de Chiloé. Se entrega información de abundancia, distribución, descripción y fotomicrografías de la especie. Se confi rma la presencia de L. polyedrum en aguas costeras del sur de Chile.
We examined the effects of bottom oxygen conditions and organic matter availability on the vertic... more We examined the effects of bottom oxygen conditions and organic matter availability on the vertical distribution of living (Rose Bengal-stained) benthic foraminifera (>180 mm fraction) within 10-cm sedimentary columns from three stations along a bathymetric transect off Concepción, Chile (Sta. 18 = 88 m, Sta. 26 = 120 m, and Sta. 40 = 1030 m water depth) that includes sites within and below the Oxygen Minimum Zone. Calcareous foraminifera dominated the three stations. Onshore-offshore pattern revealed overall highest foraminiferal densities within the shelf Stas. 18 and 26 where bottom water dissolved oxygen was lowest (<1 ml L-1) and sediment labile organic matter was greatest. Within the sediment column, maximum abundances (50 and 60%) of living organisms were found in the first centimeters at o rganic-rich and oxygen-poor shelf stations 18 and 26 (average living depth = 1.08 cm and 1.86 cm, respectively), in contrast to the well-oxygenated slope station 40, where 70% of liv...
The Salton Sea, 2002
Hydrobiologia 473: 179201, 2002. DA Barnum, JF Elder, D. Stephens &amp; M. Friend (eds),... more Hydrobiologia 473: 179201, 2002. DA Barnum, JF Elder, D. Stephens &amp; M. Friend (eds), The Salton Sea. © 2002 Kluwer Academic Publishers. Printed in the Netherlands. ... The diatom flora of the Salton Sea, California ... Carina B. Lange1 &amp; Mary Ann Tiffany2,∗ ...
Revista chilena de historia natural, 2008
Revista chilena de historia natural, 2008
Phycologia, 2002
... Fig. 30. Tabularia investiens attached to the mucilage pad connecting two cells of Terpsinoe ... more ... Fig. 30. Tabularia investiens attached to the mucilage pad connecting two cells of Terpsinoe musica. Figs 31, 32. Pleurosira laevis. Fig. 31. ... delicatulum on the valve face and girdle of Pleurosira laevis. Page 8. Tiffany &amp; Lange: Diatom epiphytes on diatoms 123 Figs 34-39. ...
J Plankton Res, 2007
ABSTRACT We have examined the species composition of 127 sediment trap samples collected sequenti... more ABSTRACT We have examined the species composition of 127 sediment trap samples collected sequentially from the Santa Barbara Basin, USA, during a 7-year period. The sampling period included two warm-water periods (El Ninos) and two cold-water periods (one La Nina and one more local). We examined changes in total species composition and changes in subsets of species accompanying extreme environmental conditions, as well as changes in flux composition associated with periods of anomalous flux. Our goal was to improve the scale and precision of hindcasting past conditions from the sedimentary record and, hence, prediction of the biological consequences of environmental change. Although large-scale climate events were accompanied by changes in the flux composition, there was little similarity in composition during environmentally similar periods, precluding generalization. Eighty-four percent of the flux (number of cells m(-2) d(-1)) and 89% of its variability were due to changes in the flux of four dominant species. Anomalous flux events were due to changes in flux of these species rather than introduction of new flora. Rare species showed the same patterns as the flora as a whole: there were changes in composition associated with extreme environmental temperatures but little redundancy of species between similar periods. Our data indicate that, at present, we can predict only that the specific composition of flux will change in response to extreme environmental conditions. It is premature to generalize about the specific composition of that response. Knowledge about mechanisms linking flux with ocean environment is currently insufficient to permit the precision of hindcast and prediction that we were seeking from our data. Nevertheless, species composition remains a potentially important tool for interpreting past environmental conditions on both the regional and the local scales.
Quaternary Research, Nov 1, 2009
A high-resolution multi-proxy study including the elemental and isotopic composition of bulk orga... more A high-resolution multi-proxy study including the elemental and isotopic composition of bulk organic matter, land plant-derived biomarkers, and alkenone-based sea-surface temperature (SST) from a marine sedimentary record obtained from the Jacaf Fjord in northern Chilean Patagonia (˜44°20'S) provided a detailed reconstruction of continental runoff, precipitation, and summer SST spanning the last 1750 yr. We observed two different regimes of climate variability in our record: a relatively dry/warm period before 900 cal yr BP (lower runoff and average SST 1°C warmer than present day) and a wet/cold period after 750 cal yr BP (higher runoff and average SST 1°C colder than present day). Relatively colder SSTs were found during 750-600 and 450-250 cal yr BP, where the latter period roughly corresponds to the interval defined for the Little Ice Age (LIA). Similar climatic swings have been observed previously in continental and marine archives of the last two millennia from central and southern Chile, suggesting a strong latitudinal sensitivity to changes in the Southern Westerly Winds, the main source of precipitation in southern Chile, and validating the regional nature of the LIA. Our results reveal the importance of the Chilean fjord system for recording climate changes of regional and global significance.
Laminated sediments in the Shaban Deep, a brinefilled basin in the northern Red Sea, were analyze... more Laminated sediments in the Shaban Deep, a brinefilled basin in the northern Red Sea, were analyzed with backscattered electron imagery. Here we present possible mechanisms involved in the formation of laminae of various types and homogenous intervals arising from the detailed investigation of multicore GeoB 7805-1 (26 • 13.9 N and 35 • 22.6 E; water depth 1447 m) and gravity core GeoB 5836-2 (26 • 12.61 N, 35 • 21.56 E; water depth 1475 m). Sediment makeup includes six types: a) a laminated structure with alternating light (mainly coccoliths) and dark (diatom frustules) layers, where the diatom component is indicative of the intra-annual variability between stratification and mixing events; b) a pocket-like structure attributed to the sinking of particles within fecal pellets and aggregates; c) a matrix of tightly packed diatoms that relates to extended stratification/mixing periods of the water column; d) homogenous intervals that result from turbidity deposition; e) silt accumulations which origin may lie in agglutinated foraminifers; and f) pyrite layers with pyrite formation initiated at the seawaterbrine interface.