scholarly journals Impact of large volcanic events on the marine environment recorded in marine cores

2021 ◽  
Author(s):  
◽  
Sophie Ellen Wilkinson
Keyword(s):  
Surface Temperature ◽  
Volcanic Eruptions ◽  
Sea Surface ◽  
Ocean Temperature ◽  
Planktic Foraminifera ◽  
Globigerinoides Ruber ◽  
Globigerina Bulloides ◽  
Volcanic Events ◽  
High Sedimentation ◽  
Silicic Volcanic

<p>Explosive silicic volcanic eruptions blanket widespread terrestrial and marine areas in ash, and have a profound effect on climate and local ecosystems. Short-term climate effects are caused by the dispersal of ash, but the injection of gas into the stratosphere, with sulphur being particularly important, drives a cooling of the climate that can last several years. These prolonged perturbations have been observed and recorded in recent decades, but despite the importance of the ocean in regulating global atmospheric climate, little is known about how and to what extent the climate signal produced by volcanic eruptions alters the oceanic environment. As the composition of foraminifera tests is highly sensitive to changes in the surrounding environment, a significant sea surface temperature decrease following a large silicic volcanic eruption may be recorded in the tests of live planktic foraminifera, now preserved in marine sediments. This study examines marine cores (and foraminifera within) that contain tephra units from three major volcanic events to determine if changes can be resolved in ocean temperature and/or foraminifera test morphology following large silicic eruptions.  The Holocene Taupo, Waimihia and Mamaku tephra units have been identified in a series of marine sediment cores collected from areas with high sedimentation rates off the east coast of North Island, New Zealand. The sources of these eruptions were from two calderas within the Taupo Volcanic Zone, one of the most active and important rhyolitic regions in the world. Sampling of sediment and foraminifera from these cores has been undertaken at 0.5 cm intervals above and below each tephra. This equates to varying sampling resolutions between cores of 5-30 years, with sufficient sampling taken to establish a stratigraphic record of >100 years either side of each tephra unit. A detailed stratigraphy was undertaken on the sediment surrounding all tephra units, including grain size and CaCO₃ analyses, to identify primary and secondary tephra deposits. One core, Tan0810-12 that contained solely Taupo tephra, was selected for foraminiferal analyses to determine changes in ocean temperature and foraminifera test morphology following this eruption. This core was selected based on the results of the stratigraphic analyses that identified the tephra as a primary deposit with minimal bioturbation above the ash layer and a very high sedimentation rate that enabled sub-decadal scale sampling.  Scanning electron microscope imaging was employed to identify the presence of surface contaminants on and within the foraminifera tests and allowed observations of test morphology and size. The morphologies of planktic foraminifera species Globigerinoides ruber and Globigerina bulloides showed no obvious change following the Taupo eruption. The Globigerinoides ruber test sizes distinctly decreased for a period after the eruption, while Globigerina bulloides tests slightly increased in size, correlating well with a decrease in sea surface temperature after the eruption as these species prefer warmer and colder temperatures, respectively. This suggests there is potential for test size to be employed as a proxy for temperature change in conjunction with geochemical analyses. Mg/Ca temperature analyses were conducted in situ using laser ablation inductively coupled plasma mass spectrometry. Both species indicated a decrease in sea surface temperatures when comparing results from tests collected below the tephra deposit to those above. Further results indicate ocean temperature may not have recovered for more than 65 years after the eruption. Such a rapid change in the oceanic environment not only has drastic implications for marine ecosystems but also atmospheric climate, and therefore, terrestrial ecosystems. To reduce the margin of error and determine a more exact value of temperature change following the eruption a greater population of foraminifera is needed. Nonetheless, this study highlights the potential of this method in determining how the oceans are impacted by volcanism and how further research is needed to determine the effects of volcanic eruptions on past and future climate.</p>

scholarly journals Impact of large volcanic events on the marine environment recorded in marine cores

2021 ◽  
Author(s):  
◽  
Sophie Ellen Wilkinson
Keyword(s):  
Surface Temperature ◽  
Volcanic Eruptions ◽  
Sea Surface ◽  
Ocean Temperature ◽  
Planktic Foraminifera ◽  
Globigerinoides Ruber ◽  
Globigerina Bulloides ◽  
Volcanic Events ◽  
High Sedimentation ◽  
Silicic Volcanic

<p>Explosive silicic volcanic eruptions blanket widespread terrestrial and marine areas in ash, and have a profound effect on climate and local ecosystems. Short-term climate effects are caused by the dispersal of ash, but the injection of gas into the stratosphere, with sulphur being particularly important, drives a cooling of the climate that can last several years. These prolonged perturbations have been observed and recorded in recent decades, but despite the importance of the ocean in regulating global atmospheric climate, little is known about how and to what extent the climate signal produced by volcanic eruptions alters the oceanic environment. As the composition of foraminifera tests is highly sensitive to changes in the surrounding environment, a significant sea surface temperature decrease following a large silicic volcanic eruption may be recorded in the tests of live planktic foraminifera, now preserved in marine sediments. This study examines marine cores (and foraminifera within) that contain tephra units from three major volcanic events to determine if changes can be resolved in ocean temperature and/or foraminifera test morphology following large silicic eruptions.  The Holocene Taupo, Waimihia and Mamaku tephra units have been identified in a series of marine sediment cores collected from areas with high sedimentation rates off the east coast of North Island, New Zealand. The sources of these eruptions were from two calderas within the Taupo Volcanic Zone, one of the most active and important rhyolitic regions in the world. Sampling of sediment and foraminifera from these cores has been undertaken at 0.5 cm intervals above and below each tephra. This equates to varying sampling resolutions between cores of 5-30 years, with sufficient sampling taken to establish a stratigraphic record of >100 years either side of each tephra unit. A detailed stratigraphy was undertaken on the sediment surrounding all tephra units, including grain size and CaCO₃ analyses, to identify primary and secondary tephra deposits. One core, Tan0810-12 that contained solely Taupo tephra, was selected for foraminiferal analyses to determine changes in ocean temperature and foraminifera test morphology following this eruption. This core was selected based on the results of the stratigraphic analyses that identified the tephra as a primary deposit with minimal bioturbation above the ash layer and a very high sedimentation rate that enabled sub-decadal scale sampling.  Scanning electron microscope imaging was employed to identify the presence of surface contaminants on and within the foraminifera tests and allowed observations of test morphology and size. The morphologies of planktic foraminifera species Globigerinoides ruber and Globigerina bulloides showed no obvious change following the Taupo eruption. The Globigerinoides ruber test sizes distinctly decreased for a period after the eruption, while Globigerina bulloides tests slightly increased in size, correlating well with a decrease in sea surface temperature after the eruption as these species prefer warmer and colder temperatures, respectively. This suggests there is potential for test size to be employed as a proxy for temperature change in conjunction with geochemical analyses. Mg/Ca temperature analyses were conducted in situ using laser ablation inductively coupled plasma mass spectrometry. Both species indicated a decrease in sea surface temperatures when comparing results from tests collected below the tephra deposit to those above. Further results indicate ocean temperature may not have recovered for more than 65 years after the eruption. Such a rapid change in the oceanic environment not only has drastic implications for marine ecosystems but also atmospheric climate, and therefore, terrestrial ecosystems. To reduce the margin of error and determine a more exact value of temperature change following the eruption a greater population of foraminifera is needed. Nonetheless, this study highlights the potential of this method in determining how the oceans are impacted by volcanism and how further research is needed to determine the effects of volcanic eruptions on past and future climate.</p>

scholarly journals Upper Ocean Thermal Responses to Sea Spray Mediated Turbulent Fluxes during Typhoon Passage

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Lianxin Zhang ◽  
Changlong Guan ◽  
Chunjian Sun ◽  
Siyu Gao ◽  
Shaomei Yu
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Kuroshio Extension ◽  
Turbulent Fluxes ◽  
Sea Surface ◽  
Sea Spray ◽  
Upper Ocean ◽  
Ocean Temperature ◽  
Turbulent Model ◽  
The Kuroshio

A one-dimensional turbulent model is used to investigate the effect of sea spray mediated turbulent fluxes on upper ocean temperature during the passage of typhoon Yagi over the Kuroshio Extension area in 2006. Both a macroscopical sea spray momentum flux algorithm and a microphysical heat and moisture flux algorithm are included in this turbulent model. Numerical results show that the model can well reproduce the upper ocean temperature, which is consistent with the data from the Kuroshio Extension Observatory. Besides, the sea surface temperature is decreased by about 0.5°C during the typhoon passage, which also agrees with the sea surface temperature dataset derived from Advanced Microwave Scanning Radiometer for the Earth Observing and Reynolds. Diagnostic analysis indicates that sea spray acts as an additional source of the air-sea turbulent fluxes and plays a key role in increasing the turbulent kinetic energy in the upper ocean, which enhances the temperature diffusion there. Therefore, sea spray is also an important factor in determining the upper mixed layer depth during the typhoon passage.

scholarly journals The Interdependency of the Morphological Variations of the Planktonic Foraminiferal Species Globigerina bulloides in Surface Sediments on the Environmental Parameters of the Southwestern Indian Ocean

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Abhijit Mazumder ◽  
Neloy Khare ◽  
Pawan Govil
Keyword(s):  
Indian Ocean ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Census Data ◽  
Planktonic Foraminifera ◽  
Morphological Characteristics ◽  
Sea Surface ◽  
Globigerina Bulloides ◽  
Foraminiferal Species ◽  
Ecological Parameters

18 surface sediment samples collected from a north-south transect along the Indian Ocean have been analyzed for planktonic Foraminifera content. Among the other planktonic foraminiferal faunas, Globigerina bulloides was present substantially in all samples. Census data of G. bulloides were measured for different parameters (average size, mean proloculus size, coiling direction, and number of chambers) and a Q-mode cluster analysis was applied on these data. Samples were segregated into two homogeneous clusters, each reflecting particular environmental conditions. Two clusters are as follows: (1) Cluster A, comprised of 6 samples and characterized by the highest range of foraminiferal and ecological parameters, except sea surface temperature and salinity which shows the lowest range, and (2) Cluster B, comprised of 12 samples and characterized by the lowest range of foraminiferal parameters and ecological parameters, except sea surface temperature and salinity which shows the highest range. The study suggests that the ecological parameters are the governing factors for the morphological characteristics of planktonic foraminiferal species G. bulloides.

scholarly journals Global Core Top Calibration ofδ18O in Planktic Foraminifera to Sea Surface Temperature

2019 ◽  
Vol 34 (8) ◽  
pp. 1292-1315 ◽  
Author(s):  
Steven B. Malevich ◽  
Lael Vetter ◽  
Jessica E. Tierney
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Sea Surface ◽  
Planktic Foraminifera

scholarly journals Zooplankters in an oligotrophic ocean: contrasts in the niches of the foraminifers Globigerinoides ruber and Trilobatus sacculifer in the tropical South Pacific

2020 ◽  
Author(s):  
George H. Scott
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Chlorophyll A ◽  
Environmental Variables ◽  
Planktonic Foraminifera ◽  
South Pacific ◽  
Sea Surface ◽  
Globigerinoides Ruber ◽  
Relative Abundances

AbstractThe distributions of two morphologically similar planktonic foraminifera (Globigerinoides ruber and Trilobus sacculifer) that are major taxa in the mixed layer of the tropical South Pacific Ocean are related to environmental variables (sea surface temperature, chlorophyll-a, nitrate, phosphate, salinity, oxygen) to determine the extent to which their niches overlap. Their distributions in ForCenS, a database of species in seafloor sediment are studied as a proxy for upper ocean data and are analysed as occurrences using MaxEnt, and as relative abundances via non-parametric regression (Random Forests). Their distributions are similar and their co-occurrences are high but relations between their abundances and the environmental variables are complex and non-linear. In the occurrence analysis sea surface temperature is the strongest predictor of niche suitability, followed by chlorophyll-a; environments between 0 – 20° S are mapped as the most suitable for both species. To the contrary, predicted species distributions are strongly differentiated by the abundance analysis. Nitrate and chlorophyll-a are primary variables in the map of predicted relative abundances of Globigerinoides ruber, with maxima in the hyper-oligotrophic zone of the subtropical gyre. In contrast, sea surface temperature and chlorophyll-a are primary variables in the map for Trilobatus sacculifer and predicted maxima are at the margins of the hyper-oligotrophic zone and near the West Pacific Warm Pool. The high relative abundance of Globigerinoides ruber in the hyper-oligotrophic zone is attributed to its close photosymbiotic relation with on-board dinoflagellates; this compensates for the low primary productivity in the zone. It is clearly identified as the best-adapted planktonic foraminifer in this huge marine ‘desert’ and might serve as a useful proxy. The photosymbiotic relation is less apparent in Trilobatus sacculifer which, as in vitro research suggests, primarily depends on particulate nutrition. The study shows the value of abundance over occurrence data for analysing the trophic resources of these zooplankters.

scholarly journals Immune-mediated hookworm clearance and survival of a marine mammal decrease with warmer ocean temperatures

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Mauricio Seguel ◽  
Felipe Montalva ◽  
Diego Perez-Venegas ◽  
Josefina Gutiérrez ◽  
Hector J Paves ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Marine Mammal ◽  
Marine Mammals ◽  
Mechanistic Explanation ◽  
Sea Surface ◽  
Positive Energy ◽  
Ocean Temperature ◽  
Attendance Patterns ◽  
Immune Mediated

Increases in ocean temperature are associated with changes in the distribution of fish stocks, and the foraging regimes and maternal attendance patterns of marine mammals. However, it is not well understood how these changes affect offspring health and survival. The maternal attendance patterns and immunity of South American fur seals were assessed in a rookery where hookworm disease is the main cause of pup mortality. Pups receiving higher levels of maternal attendance had a positive energy balance and a more reactive immune system. These pups were able to expel hookworms through a specific immune mediated mechanism and survived the infection. Maternal attendance was higher in years with low sea surface temperature, therefore, the mean hookworm burden and mortality increased with sea surface temperature over a 10-year period. We provide a mechanistic explanation regarding how changes in ocean temperature and maternal care affect infectious diseases dynamics in a marine mammal.

scholarly journals Increasing tropical cyclone intensity and potential intensity in the subtropical Atlantic around Bermuda from an ocean heat content perspective 1955- 2019

2021 ◽  
Author(s):  
Samantha Hallam ◽  
Mark Guishard ◽  
Simon Josey ◽  
Pat Hyder ◽  
Joel Hirschi
Keyword(s):  
Tropical Cyclone ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Mixed Layer Depth ◽  
Sea Surface ◽  
Environmental Research ◽  
Depth Range ◽  
Ocean Temperature ◽  
Tropical Cyclone Intensity ◽  
Cyclone Intensity

&lt;p&gt;Here we investigate tropical cyclone (TC) activity and intensity within a 100km radius of Bermuda between 1955 and 2019. Our results show a more easterly genesis over time and significant increasing trends in tropical cyclone intensity (maximum wind speed (Vmax)) with a decadal Vmax median value increase of 30kts from 33 to 63kts, together with significant increasing August, September, October (ASO) sea surface temperature (SST) of 1.1&amp;#176;C (0.17 &amp;#176;C per decade) &amp;#160;and ocean temperature between 0.5&amp;#8211;0.7&amp;#176;C (0.08-0.1&amp;#176;C per decade) &amp;#160;in the depth range 0-300m. The strongest correlation is found between TC intensity and ocean temperature averaged through the top 50m ocean layer (T&lt;sub&gt;50m&lt;/sub&gt;) r=0.37 (p&lt;0.01).&amp;#160;&lt;/p&gt;&lt;p&gt;We show how tropical cyclone potential intensity estimates are closer to actual intensity by using T&lt;sub&gt;50m&lt;/sub&gt; opposed to SST using the Bermuda Atlantic Timeseries Hydrostation S dataset. We modify the widely used sea surface temperature potential intensity index by using T&lt;sub&gt;50m&lt;/sub&gt;&amp;#160;to provide a closer estimate of the observed minimum sea level pressure (MSLP), and associated Vmax than by using SST, creating a T&lt;sub&gt;50m&amp;#160;&lt;/sub&gt;potential&amp;#160;intensity (T&lt;sub&gt;50m&lt;/sub&gt;_PI) index. The average MSLP difference is reduced by 12mb and proportional to the SST/ T&lt;sub&gt;50m &lt;/sub&gt;temperature difference. We also suggest the index could be used over a wider area of the subtropical/tropical Atlantic where there is a shallow mixed layer depth. Finally, we outline the TC wind-pressure relationship observed for the subtropical Atlantic around Bermuda, explaining 77% of the variance, which may prove useful for future prediction.&lt;/p&gt;&lt;p&gt;(Environmental Research Letters, 2020, in revision)&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

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