scholarly journals Species Composition and Distribution of Jellyfish in a Seasonally Hypoxic Estuary, Hood Canal, Washington

Diversity ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 53
Author(s):  
BethElLee Herrmann ◽  
Julie E. Keister
Keyword(s):  
Dissolved Oxygen ◽  
Low Oxygen ◽  
Marine Food Webs ◽  
Hood Canal ◽  
The North ◽  
Vertical Distributions ◽  
Northern Regions ◽  
Oxygen Conditions ◽  
Seasonal Hypoxia ◽  
Species Composition And Distribution

Seasonal hypoxia (≤2 mg dissolved oxygen L−1) can have detrimental effects on marine food webs. Recent studies indicate that some jellyfish can tolerate low oxygen and may have a competitive advantage over other zooplankton and fishes in those environments. We assessed community structure and distributions of cnidarian and ctenophore jellyfish in seasonally hypoxic Hood Canal, WA, USA, at four stations that differed in oxygen conditions. Jellyfish were collected in June through October 2012 and 2013 using full-water-column and discrete-depth net tows, concurrent with CTD casts to measure dissolved oxygen (DO). Overall, southern, more hypoxic, regions of Hood Canal had higher abundances and higher diversity than the northern regions, particularly during the warmer and more hypoxic year of 2013. Of fifteen species identified, the most abundant—the siphonophore Muggiaea atlantica and hydrozoan Aglantha digitale—reached peak densities > 1800 Ind m−3 and 38 Ind m−3, respectively. M. atlantica were much more abundant at the hypoxic stations, whereas A. digitale were also common in the north. Vertical distributions explored during hypoxia showed that jellyfish were mostly in the upper 10 m regardless of the oxycline depth. Moderate hypoxia seemed to have no detrimental effect on jellyfish in Hood Canal, and may have resulted in high population densities, which could influence essential fisheries and trophic energy flow.

scholarly journals Looking beyond stratification: a model-based analysis of the biological drivers of oxygen deficiency in the North Sea

2016 ◽  
Vol 13 (8) ◽  
pp. 2511-2535 ◽  
Author(s):  
Fabian Große ◽  
Naomi Greenwood ◽  
Markus Kreus ◽  
Hermann-Josef Lenhart ◽  
Detlev Machoczek ◽  
...  
Keyword(s):  
North Sea ◽  
Oxygen Deficiency ◽  
Low Oxygen ◽  
The North ◽  
Oxygen Conditions ◽  
Southern Central ◽  
The North Sea ◽  
Central North Sea ◽  
The Impact ◽  
Oxygen Dynamics

Abstract. Low oxygen conditions, often referred to as oxygen deficiency, occur regularly in the North Sea, a temperate European shelf sea. Stratification represents a major process regulating the seasonal dynamics of bottom oxygen, yet, lowest oxygen conditions in the North Sea do not occur in the regions of strongest stratification. This suggests that stratification is an important prerequisite for oxygen deficiency, but that the complex interaction between hydrodynamics and the biological processes drives its evolution. In this study we use the ecosystem model HAMSOM-ECOHAM to provide a general characterisation of the different zones of the North Sea with respect to oxygen, and to quantify the impact of the different physical and biological factors driving the oxygen dynamics inside the entire sub-thermocline volume and directly above the bottom. With respect to oxygen dynamics, the North Sea can be subdivided into three different zones: (1) a highly productive, non-stratified coastal zone, (2) a productive, seasonally stratified zone with a small sub-thermocline volume, and (3) a productive, seasonally stratified zone with a large sub-thermocline volume. Type 2 reveals the highest susceptibility to oxygen deficiency due to sufficiently long stratification periods (>  60 days) accompanied by high surface productivity resulting in high biological consumption, and a small sub-thermocline volume implying both a small initial oxygen inventory and a strong influence of the biological consumption on the oxygen concentration. Year-to-year variations in the oxygen conditions are caused by variations in primary production, while spatial differences can be attributed to differences in stratification and water depth. The large sub-thermocline volume dominates the oxygen dynamics in the northern central and northern North Sea and makes this region insusceptible to oxygen deficiency. In the southern North Sea the strong tidal mixing inhibits the development of seasonal stratification which protects this area from the evolution of low oxygen conditions. In contrast, the southern central North Sea is highly susceptible to low oxygen conditions (type 2). We furthermore show that benthic diagenetic processes represent the main oxygen consumers in the bottom layer, consistently accounting for more than 50 % of the overall consumption. Thus, primary production followed by remineralisation of organic matter under stratified conditions constitutes the main driver for the evolution of oxygen deficiency in the southern central North Sea. By providing these valuable insights, we show that ecosystem models can be a useful tool for the interpretation of observations and the estimation of the impact of anthropogenic drivers on the North Sea oxygen conditions.

Scaleable Production of Hematopoietic Cells Suitable for Transfusion from Human Embryonic Stem Cells in a Stirred Bioreactor System.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 728-728 ◽  
Author(s):  
Frances J. Harding ◽  
Charles M. Cameron ◽  
Wei-shou Hu ◽  
Dan S. Kaufman
Keyword(s):  
Stem Cells ◽  
Dissolved Oxygen ◽  
Blood Cells ◽  
Hematopoietic Cells ◽  
Embryonic Stem ◽  
Dissolved Oxygen Concentration ◽  
Low Oxygen ◽  
Hematopoietic Progenitors ◽  
Oxygen Conditions ◽  
Bioreactor System

Abstract Blood cell products, such as red blood cells and platelets suitable for transfusion, are attractive as a first generation human embryonic stem cell (hESC) derived therapy. Development of hESC-derived transfusion therapies will require a better understanding of how to control the differentiation of human ES cells into functional blood cells in sufficient quantities for clinical use. HESCs are known to produce mature hematopoietic cells during differentiation as embryoid bodies (EBs). Previously we have demonstrated development of both hematopoietic progenitor cells and more differentiated cell types of myeloid, lymphoid and erythroid lineages from hESC. A four-fold increase in total cell number was achieved when ESC-derived EBs were differentiated in stirred vessels compared to conventional static cultures. Spinner cultures generated EBs more uniform in size and density. Static- and spinner cultivated EBs produced equivalent percentages of hematopoietic progenitors when assayed by surface antigen expression (CD34+, CD31+ and CD45+) and colony forming potential. Hence, overall a greater yield of hematopoietic cells was generated in spinner cultures. Here we incorporate pH and oxygen control into the stirred vessel system in order to closely regulate environmental conditions at levels conducive to hematopoietic differentiation. Hematopoietic potential is compared under hypoxic and normoxic conditions. Hypoxic conditions were confirmed in the EB tissue mass by 2-nitroimidazole (hypoxyprobe) staining. We observed that the cellular response to hypoxia, monitored by the presence of HIF 1α protein, is transient. Peak levels of HIF 1α were detected within 48 hours of low oxygen culture, falling to baseline levels within 7 days. Under more severe conditions the kinetics of the hypoxic response were accelerated, HIF 1α expression peaking and subsiding earlier in cultures held at 1% dissolved oxygen compared to 5% dissolved oxygen. We show that by manipulating dissolved oxygen concentration we are able to influence the progress of differentiation. This can at least partly be attributed to the upregulation of hypoxia inducible genes, including VEGF-A and EPO, under low oxygen conditions. Expression levels of VEGF-A are dependent on dissolved oxygen concentration, being most highly expressed under 1% dissolved oxygen conditions. The transitory nature of the cellular hypoxic response suggests that short exposure to low oxygen conditions may be sufficient to gain the full beneficial impact of hypoxic signalling on hematopoietic cell generation without decreases in cell proliferation and increase in cell death associated with extended oxygen deprivation. We propose that control of culture parameters such as dissolved oxygen in conjunction with cytokines can specify the cellular microenvironment within EB to yield robust levels of hematopoietic progenitors. This work demonstrates proof-of-principle for hematopoietic cell production from human embryonic stem cells in a scaleable bioreactor system.

scholarly journals Vertical migration patterns of the different larval instars of Chaoborus flavicans and the influence of dissolved oxygen concentrations

2018 ◽  
Vol 75 (7) ◽  
pp. 1142-1150
Author(s):  
Manuel Weisser ◽  
Hilmar Hofmann ◽  
Jorge Encinas Fernández ◽  
Frank Peeters
Keyword(s):  
Dissolved Oxygen ◽  
Vertical Distribution ◽  
Vertical Migration ◽  
Low Oxygen ◽  
Migration Patterns ◽  
Larval Instars ◽  
Larval Stages ◽  
Chaoborus Flavicans ◽  
Anoxic Waters ◽  
Oxygen Conditions

Here we investigate the diel vertical migration (DVM) of the different larval stages of Chaoborus flavicans between spring and summer in two different lakes and three different years. Specific attention is given to the influence of the vertical distribution of dissolved oxygen (DO) on the DVM of the different larval instars. To our knowledge, this study is the first that combines continuous observations of DVM of C. flavicans with continuous measurements of DO distributions over several months, allowing the assessment of changes in DVM due to the development of hyperoxic conditions in the deep water of lakes. With ontogenetic development, C. flavicans larvae increase their sensitivity to changes in light intensity and their tolerance to low oxygen conditions. Our results suggest that the physiological changes of C. flavicans larvae are adaptations to seasonal changes in DO, improving migration abilities to enable utilization of hypoxic and anoxic waters to avoid predation. Interannual change in the abundance and vertical distribution of phytoplankton affecting DO concentrations was sufficient to alter DVM patterns of C. flavicans larvae between years.

scholarly journals The impacts of physical processes on oxygen variations in the North Sea-Baltic Sea transition zone

2011 ◽  
Vol 8 (4) ◽  
pp. 1723-1755 ◽  
Author(s):  
L. Jonasson ◽  
Z. Wan ◽  
J. H. S. Hansen ◽  
J. She
Keyword(s):  
Dissolved Oxygen ◽  
Baltic Sea ◽  
Transition Zone ◽  
North Sea ◽  
Late Summer ◽  
Physical Processes ◽  
The North ◽  
The North Sea ◽  
Seasonal Hypoxia ◽  
Benthic Ecosystems

Abstract. The bottom water of the North Sea-Baltic Sea transition zone suffers from seasonal hypoxia, usually during late summer and autumn. These hypoxic events are critical for the benthic ecosystems and the concentration of dissolved oxygen is an important measure of the water quality. However, to model the subsurface dissolved oxygen is a major challenge, especially in estuaries and coastal regions. In this study a simple oxygen consumption model is coupled to a 3-D hydrodynamical model in order to analyse oxygen variations in the transition zone. The benthic and pelagic consumption of oxygen is modelled as a function of water temperature and oxygen concentration. A quantitative assessment of the model demonstrates that the model is able to resolve both seasonal and interannual variations in dissolved oxygen. Results from several experimental simulations highlight the importance of physical processes in the regulation of dissolved oxygen. Advective oxygen transport and wind induced mixing are two key processes that control the extent of hypoxia in the transition zone.

scholarly journals Looking beyond stratification: a model-based analysis of the biological drivers of oxygen depletion in the North Sea

2015 ◽  
Vol 12 (15) ◽  
pp. 12543-12610
Author(s):  
F. Große ◽  
N. Greenwood ◽  
M. Kreus ◽  
H. J. Lenhart ◽  
D. Machoczek ◽  
...  
Keyword(s):  
North Sea ◽  
General Characteristic ◽  
Bottom Layer ◽  
Low Oxygen ◽  
The North ◽  
Oxygen Conditions ◽  
The North Sea ◽  
The Impact ◽  
Oxygen Dynamics ◽  
Stratified Regime

Abstract. The problem of low oxygen conditions, often referred to as hypoxia, occurs regularly in the North Sea, a temperate European shelf sea. Stratification represents a major process regulating the seasonal dynamics of bottom oxygen. However, lowest oxygen conditions in the North Sea do not occur in the regions of strongest stratification. This suggests that stratification is an important prerequisite for hypoxia, but that the complex interaction between hydrodynamics and the biological processes drives its development. In this study we use the ecosystem model HAMSOM-ECOHAM5 to provide a general characteristic of the different North Sea oxygen regimes, and to quantify the impact of the different physical and biological factors driving the oxygen dynamics below the thermocline and in the bottom layer. We show that the North Sea can be subdivided into three different regimes in terms of oxygen dynamics: (1) a highly productive, non-stratified coastal regime, (2) a productive, seasonally stratified regime with a small sub-thermocline volume, and (3) a productive, seasonally stratified regime with a large sub-thermocline volume, with regime 2 being highly susceptible to hypoxic conditions. Our analysis of the different processes driving the oxygen development reveals that inter-annual variations in the oxygen conditions are caused by variations in primary production, while spatial differences can be attributed to differences in stratification and water depth. In addition, we show that benthic bacteria represent the main oxygen consumers in the bottom layer, consistently accounting for more than 50 % of the overall consumption. By providing these valuable insights, we show that ecosystem models can be a useful tool for the interpretation of observations and the estimation of the impact of anthropogenic drivers on the North Sea oxygen conditions.

scholarly journals The impacts of physical processes on oxygen variations in the North Sea-Baltic Sea transition zone

Ocean Science ◽  
2012 ◽  
Vol 8 (1) ◽  
pp. 37-48 ◽  
Author(s):  
L. Jonasson ◽  
J. L. S. Hansen ◽  
Z. Wan ◽  
J. She
Keyword(s):  
Dissolved Oxygen ◽  
Baltic Sea ◽  
Transition Zone ◽  
North Sea ◽  
Late Summer ◽  
Physical Processes ◽  
The North ◽  
The North Sea ◽  
Seasonal Hypoxia ◽  
Benthic Ecosystems

Abstract. The bottom water of the North Sea–Baltic Sea transition zone suffers from seasonal hypoxia, usually during late summer and autumn. These hypoxic events are critical for the benthic ecosystems and the concentration of dissolved oxygen is an important measure of the water quality. However, to model the subsurface dissolved oxygen is a major challenge, especially in estuaries and coastal regions. In this study a simple oxygen consumption model is coupled to a 3-D hydrodynamical model in order to analyse oxygen variations in the transition zone. The benthic and pelagic consumption of oxygen is modelled as a function of water temperature and oxygen concentration. A quantitative assessment of the model demonstrates that the model is able to resolve both seasonal and interannual variations in dissolved oxygen. Results from several experimental simulations highlight the importance of physical processes in the regulation of dissolved oxygen. Advective oxygen transport and wind induced mixing are two key processes that control the extent of hypoxia in the transition zone.

scholarly journals Mn∕Ca intra- and inter-test variability in the benthic foraminifer <i>Ammonia tepida</i>

2018 ◽  
Vol 15 (1) ◽  
pp. 331-348 ◽  
Author(s):  
Jassin Petersen ◽  
Christine Barras ◽  
Antoine Bézos ◽  
Carole La ◽  
Lennart J. de Nooijer ◽  
...  
Keyword(s):  
Pore Water ◽  
Sediment Geochemistry ◽  
Reduced Form ◽  
Pore Waters ◽  
Low Oxygen ◽  
Oxygen Conditions ◽  
Vital Effects ◽  
Seasonal Hypoxia ◽  
Test Variability ◽  
Lake Grevelingen

Abstract. The adaptation of some benthic foraminiferal species to low-oxygen conditions provides the prospect of using the chemical composition of their tests as proxies for bottom water oxygenation. Manganese may be particularly suitable as such a geochemical proxy because this redox element is soluble in reduced form (Mn2+) and hence can be incorporated into benthic foraminiferal tests under low-oxygen conditions. Therefore, intra- and inter-test differences in foraminiferal Mn∕Ca ratios may hold important information about short-term variability in pore water Mn2+ concentrations and sediment redox conditions. Here, we studied Mn∕Ca intra- and inter-test variability in living individuals of the shallow infaunal foraminifer Ammonia tepida sampled in Lake Grevelingen (the Netherlands) in three different months of 2012. The deeper parts of this lake are characterized by seasonal hypoxia/anoxia with associated shifts in microbial activity and sediment geochemistry, leading to seasonal Mn2+ accumulation in the pore water. Earlier laboratory experiments with similar seawater Mn2+ concentrations as encountered in the pore waters of Lake Grevelingen suggest that intra-test variability due to ontogenetic trends (i.e. size-related effects) and/or other vital effects occurring during calcification in A. tepida (11–25 % relative SD, RSD) is responsible for part of the observed variability in Mn∕Ca. Our present results show that the seasonally highly dynamic environmental conditions in the study area lead to a strongly increased Mn∕Ca intra- and inter-test variability (average of 45 % RSD). Within single specimens, both increasing and decreasing trends in Mn∕Ca ratios with size are observed. Our results suggest that the variability in successive single-chamber Mn∕Ca ratios reflects the temporal variability in pore water Mn2+. Additionally, active or passive migration of the foraminifera in the surface sediment may explain part of the observed Mn∕Ca variability.

scholarly journals Mn / Ca intra-test variability in the benthic foraminifer <i>Ammonia tepida</i>

2017 ◽  
Author(s):  
Jassin Petersen ◽  
Christine Barras ◽  
Antoine Bézos ◽  
Carole La ◽  
Lennart J. de Nooijer ◽  
...  
Keyword(s):  
Pore Water ◽  
Sediment Geochemistry ◽  
Reduced Form ◽  
Pore Waters ◽  
Low Oxygen ◽  
Short Term ◽  
Oxygen Conditions ◽  
Seasonal Hypoxia ◽  
Test Variability ◽  
Lake Grevelingen

Abstract. The adaptation of some benthic foraminiferal species to low oxygen conditions provides the prospect of using the chemical composition of their tests as proxies for bottom water oxygenation. Manganese may be particularly suitable as such a geochemical proxy, because this redox element is soluble in reduced form (Mn2+), and hence can be incorporated into benthic foraminiferal tests under low oxygen conditions. Therefore, intra- and inter-test differences in foraminiferal Mn / Ca ratios may hold important information about short term variability in pore water Mn2+ concentrations and sediment redox conditions. Here, we studied Mn / Ca inter- and intra-test variability of living individuals of the shallow infaunal foraminifer Ammonia tepida sampled in Lake Grevelingen (The Netherlands) in three different months of 2012. The deeper parts of this lake are characterised by seasonal hypoxia/anoxia with associated shifts in microbial activity and sediment geochemistry, leading to seasonal Mn2+ accumulation in the pore water. Earlier laboratory experiments with similar seawater Mn2+ concentrations as encountered in the pore waters of Lake Grevelingen suggest that intrinsic intra-test variability in A. tepida (11–25 % RSD) is responsible for a considerable portion of the observed variability in Mn / Ca. Our results show that the seasonally highly dynamic environmental conditions in the study area lead to a strongly increased Mn / Ca intra- and inter-test variability (average of 45 % RSD). Within single specimens, both increasing and decreasing trends in Mn / Ca ratios with size are observed. Our results suggest that the variability of successive single chamber Mn / Ca ratios reflects the temporal variability of pore water Mn2+. Additionally, active or passive migration of the foraminifera in the surface sediment may explain part of the observed Mn / Ca variability.

MBAH HENDRO KUSUMO BIN SYECH AHMAD MUTAMAKKIN: JEJAK SYIAR ISLAM DI WILAYAH PATI

EMPIRISMA ◽  
2008 ◽  
Vol 27 (2) ◽  
Author(s):  
Fathimatuz Zahra Dan Abdul Azis
Keyword(s):  
Central Region ◽  
Marital Relationship ◽  
Southern Region ◽  
North Coast ◽  
The North ◽  
Trace Back ◽  
Northern Regions ◽  
The One

Pati is a region on the north coast, according to the hypothesis of the researcher, the region is divided into three categories. The northern regions are more religious, the central is more plural, while the southern region is in the middle. In the central region there are many relics of tombs believed to be the those of the Muslim proselytizers in the area of Pati. The one that attracts the researcher is a tomb in the Gambiran area, where there are five local Muslim saints buried, one of them belons to mbah Hendro Kusumo, the son of Syech Ahmad Mutamakkin. This article attempts to trace back the spreading of Islam in Pati based on the existence of thetomb of Mbah Hendro Kusumo. It wants to answer question of whethere the existence of his tomb is due to his studying there or marital relationship, and how it relates to the spreading of Islam.Keywords: Mbah Hendro Kusumo, Traces of Islamic Dakwah, Islam

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