scholarly journals A dynamic global model for planktonic foraminifera

2007 ◽  
Vol 4 (6) ◽  
pp. 4323-4384 ◽  
Author(s):  
I. Fraile ◽  
M. Schulz ◽  
S. Mulitza ◽  
M. Kucera
Keyword(s):  
Sediment Trap ◽  
Mixed Layer Depth ◽  
Planktonic Foraminifera ◽  
Temperature Tolerance ◽  
Biological Information ◽  
Food Type ◽  
Small Scale ◽  
Zooplankton Abundance ◽  
Polar Regions ◽  
White Variety

Abstract. Seasonal changes in the flux of planktonic foraminifera have to be understood to interpret corresponding proxy-based reconstructions. To study the seasonal cycle of planktonic foraminifera species we developed a numerical model of species concentration (PLAFOM). This model is forced with a global hydrographic dataset (e.g. temperature, mixed layer depth) and with biological information taken from an ecosystem model (e.g. "food type", zooplankton abundance) to predict monthly concentrations of the most common planktonic foraminifera species used for proxies: N. pachyderma (sinistral and dextral varieties), G. bulloides, G. ruber (white variety) and G. sacculifer. The sensitivity of each species with respect to temperature (optimal temperature and range of tolerance) is derived from sediment-trap studies. Overall, the spatial distribution patterns of most of the species are comparable to core-top data. N. pachyderma (sin.) is limited to polar regions, N. pachyderma (dex.) and G. bulloides are the most common species in high productivity zones like upwelling areas, while G. ruber and G. sacculifer are more abundant in tropical and subtropical oligotrophic waters. Modeled seasonal variation match well with sediment-trap records in most of the locations for N. pachyderma (sin), N. pachyderma (dex.) and G. bulloides. G. ruber and G. sacculifer show, in general, lower concentrations and less seasonal variability in all sites. The lower variability is reflected in the model output, but the small scale variations are not reproduced by the model in several locations. Due to the fact that the model is forced by climatological data, it can not capture interannual variations. The sensitivity experiments we carried out show that, inside the temperature tolerance range, food availability is the main parameter which controls the abundance of some species. The here presented model represents a powerful tool to explore the response of planktonic foraminifera to different boundary conditions, and to quantify the seasonal bias in foraminifera-based proxy records.

scholarly journals Predicting the global distribution of planktonic foraminifera using a dynamic ecosystem model

2008 ◽  
Vol 5 (3) ◽  
pp. 891-911 ◽  
Author(s):  
I. Fraile ◽  
M. Schulz ◽  
S. Mulitza ◽  
M. Kucera
Keyword(s):  
Sediment Trap ◽  
Planktonic Foraminifera ◽  
Ecosystem Model ◽  
Common Species ◽  
Temperature Tolerance ◽  
Biological Information ◽  
Global Ocean ◽  
Polar Regions ◽  
White Variety ◽  
Sensitivity Experiment

Abstract. We present a new planktonic foraminifera model developed for the global ocean mixed-layer. The main purpose of the model is to explore the response of planktonic foraminifera to different boundary conditions in the geological past, and to quantify the seasonal bias in foraminifera-based paleoceanographic proxy records. This model is forced with hydrographic data and with biological information taken from an ecosystem model to predict monthly concentrations of the most common planktonic foraminifera species used in paleoceanography: N. pachyderma (sinistral and dextral varieties), G. bulloides, G. ruber (white variety) and G. sacculifer. The sensitivity of each species with respect to temperature (optimal temperature and range of tolerance) is derived from previous sediment-trap studies. Overall, the spatial distribution patterns of most of the species are in agreement with core-top data. N. pachyderma (sin.) is limited to polar regions, N. pachyderma (dex.) and G. bulloides are the most common species in high productivity zones, while G. ruber and G. sacculifer are more abundant in tropical and subtropical oligotrophic waters. For N. pachyderma (sin) and N. pachyderma (dex.), the season of maximum production coincides with that observed in sediment-trap records. Model and sediment-trap data for G. ruber and G. sacculifer show, in general, lower concentrations and less seasonal variability at all sites. A sensitivity experiment suggest that, within the temperature-tolerance range of a species, food availability may be the main parameter controlling its abundance.

Stable isotopes in modern planktonic foraminifera: Sediment trap and plankton tow results from the South China Sea

2011 ◽  
Vol 79 (1-2) ◽  
pp. 15-23 ◽  
Author(s):  
Hui-Ling Lin ◽  
David Der-Duen Sheu ◽  
Yih Yang ◽  
Wen-Chen Chou ◽  
Guo-Wei Hung
Keyword(s):  
Stable Isotopes ◽  
South China Sea ◽  
South China ◽  
Sediment Trap ◽  
Planktonic Foraminifera ◽  
The South China Sea ◽  
The South ◽  
China Sea

scholarly journals Zooplankton in seagrass and adjacent non-seagrass habitats in Tun Mustapha Park, Sabah, Malaysia

2020 ◽  
Vol 4 (1) ◽  
pp. 6-13
Author(s):  
Sing Lui Lo ◽  
Tzuen Kiat Yap ◽  
Cheng Ann Chen ◽  
Teruaki Yoshida
Keyword(s):  
Environmental Variables ◽  
Statistical Difference ◽  
Structural Complexity ◽  
Zooplankton Community ◽  
Small Scale ◽  
Zooplankton Abundance ◽  
Seagrass Bed ◽  
Seagrass Meadows ◽  
Marine Park ◽  
Study Sites

A comparison of zooplankton abundance and community in the seagrass and non-seagrass areas of Limau-limauan and Bak- Bak waters within the newly established Tun Mustapha Marine Park was made during 15-17 May 2017. Samples were collected via horizontal tow of a 140 μm plankton net. Environmental variables (temperature, salinity, DO, pH, turbidity) showed no significant differences among the study sites. However, zooplankton showed increasing abundance from non-seagrass, seagrass edge, to seagrass areas at Limau-limauan, while abundance values were comparable among the stations at Bak-bak. Overall zooplankton abundance was significantly higher at the seagrass areas relative to the non-seagrass station at Limau-limauan (p < 0.005), while no statistical difference was found at Bak-Bak (p < 0.21). Mean canopy height was 3-fold higher (p < 0.001) at Limau-limauan than Bak-Bak, suggesting the importance of seagrass bed structural complexity in habitat preference for zooplankton. Cluster analysis revealed the zooplankton community from the seagrass area at Limau-limauan was different from that at seagrass edge and non-seagrass areas, which may be attributed to the influence of seagrass meadows in forming characteristic zooplankton compositions. Marked differences in zooplankton composition and abundance even in close vicinity of sites suggest the importance of local small-scale variations in seagrass habitats in shaping the zooplankton community.

Preliminary analysis and main problems of instrumental measurement complex at the Vernadsky Antarctic Station

2021 ◽  
Author(s):  
Denys Pishniak ◽  
Svitlana Krakovska ◽  
Anastasia Chyhareva ◽  
Sergii Razumnyi
Keyword(s):  
Measurement Data ◽  
Bias Reduction ◽  
Small Scale ◽  
High Temporal Resolution ◽  
Monthly Precipitation ◽  
Polar Regions ◽  
Indirect Methods ◽  
Precipitation Measurement ◽  
Precipitation Gauge ◽  
The Antarctic

&lt;p&gt;Measurements of precipitation has always had well known difficulties that caused inaccuracies. This is especially acute in Polar regions where prevailing solid precipitation is accomplished with strong winds. Alternatively some indirect methods of precipitation measurements still in development and numerous meteorological instruments have been created on their basis.&lt;/p&gt;&lt;p&gt;The Akademik Vernadsky station is located in the Antarctic Peninsula region with a large amount of precipitation and &amp;#160;the problem of its measuring has always been relevant here. Although the data of monthly precipitation have been found for Vernadsky (Faraday) station since 1964, the first standard Tretyakov precipitation gauge was set up there only in 1997. But in recent years, several new instruments for indirect precipitation measurement have been installed at the meteorological site. The consistency of their data are the subject for this study.&amp;#160;&lt;/p&gt;&lt;p&gt;Direct comparison of all measurement devices as well as investigation of their estimations dependencies from other meteorological parameters are analysed and will be presented for the period 2019-2020. Originally various instruments showed huge differences in precipitation estimates. Deep analysis and correction of the measurement results according to weather conditions is obviously needed for bias reduction. But the local features of the extremely heterogeneous underlying surface of the region affect the vertical component of the wind, and can cause the natural small scale precipitation variability.&amp;#160;&lt;/p&gt;&lt;p&gt;The advantages of indirect methods for precipitation measuring is a high sensitivity to registering even individual falling precipitation particles and, hence, the really high temporal resolution of the data. Therefore, it can be used for investigation of physical atmospheric processes. As an example, the case study of a cyclone with precipitation phase transition over Vernadsky station on December 5-6, 2020 is investigated and will be presented. A comparison of the measurement data of various devices (Tretyakov Precipitation Gauge, Snow Stick, Vaisala PWD22, Lufft WS100, METEK MRR-PRO) and the ERA-5 reanalysis was carried out. A vertical radar MRR-PRO is of special interest as a measuring instrument for polar regions because it can ignore surface snow transport and has proved reliability in the Antarctic environment recently. In Marine Antarctica this device can identify the height of precipitation melting and also show a number of other useful parameters. This complex of precipitation measurement instruments is planned to be used in the frames of the forthcoming YOPP-SH field campayne.&lt;/p&gt;

scholarly journals Modeling the Ocean in Climate Studies

1984 ◽  
Vol 5 ◽  
pp. 133-140 ◽  
Author(s):  
Albert J. Semtner
Keyword(s):  
Turbulent Mixing ◽  
Large Scale ◽  
Deep Convection ◽  
Vertical Mixing ◽  
Mesoscale Eddies ◽  
Small Scale ◽  
Polar Regions ◽  
Sea Ice Extent ◽  
Modeling Strategy ◽  
Climate Studies

A number of processes in the ocean must be modeled properly in order to produce valid estimates of oceanic heat transport, sea-surface temperature, and sea-ice extent in climate studies. These include: wind-driven turbulent mixing and water transport in the surface layer, internal vertical mixing due to several small-scale mechanisms, horizontal and vertical exchanges by mesoscale eddies, mixing along isopycnals, large-scale transport by currents, deep convection in polar regions, and boundary exchanges with atmosphere, ice, and land. Techniques to model these processes are described. Prospects are given for parameterizing the effects of phenomena that cannot be resolved in climate studies, particularly mesoscale eddies. Past simulations of the ocean in climate studies are reviewed. A modeling strategy is outlined for an improved treatment of the ocean, consistent with the computational power soon to be available.

Asymmetric geographic range expansion explains the latitudinal diversity gradients of four major taxa of marine plankton

Paleobiology ◽  
2017 ◽  
Vol 43 (2) ◽  
pp. 196-208 ◽  
Author(s):  
Matthew G. Powell ◽  
Douglas S. Glazier
Keyword(s):  
Range Expansion ◽  
Biological Diversity ◽  
Close Association ◽  
Planktonic Foraminifera ◽  
Geographic Range ◽  
Temperate Zone ◽  
Latitudinal Gradients ◽  
Polar Regions ◽  
Marine Plankton ◽  
Diversity Gradients

AbstractExtensive investigation of the close association between biological diversity and environmental temperature has not yet yielded a generally accepted, empirically validated mechanism to explain latitudinal gradients of species diversity, which occur in most taxa. Using the highly resolved late Cenozoic fossil records of four major taxa of marine plankton, we show that their gradients arise as a consequence of asymmetric geographic range expansion rather than latitudinal variation in diversification rate, as commonly believed. Neither per capita speciation nor extinction rates trend significantly with temperature or latitude for these marine plankton. Species of planktonic foraminifera and calcareous nannoplankton that originate in the temperate zone preferentially spread toward and arrive earlier in the tropics to produce a normal gradient with tropical diversity peaks; by contrast, temperate-zone originating species of diatoms and radiolarians preferentially spread toward and arrive earlier in polar regions to produce reversed gradients with high-latitude diversity peaks. Our results suggest that temperature affects latitudinal diversity gradients chiefly by its effect on species’ range limits rather than on probabilities of speciation and extinction. We show that this mechanism also appears to operate in various multicellular taxa, thus providing a widely applicable explanation for the origin of latitudinal diversity gradients.

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