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Total Categories: 6
Calcidiscus leptoporus is a species of archaea found in deep-sea hydrothermal vents.
Answer: False
Calcidiscus leptoporus is not an archaeon; it is a species of coccolithophore, a type of unicellular marine phytoplankton belonging to the phylum Haptophyta.
Calcidiscus leptoporus was first described in the 20th century by Erwin Kamptner.
Answer: False
Calcidiscus leptoporus was first described in 1898 by George Murray and Vernon H. Blackman. Erwin Kamptner reclassified it into the genus Calcidiscus in 1950.
The classification of Calcidiscus leptoporus has remained unchanged since its initial description in 1898.
Answer: False
The classification of Calcidiscus leptoporus has evolved significantly since its initial description, including reclassifications by Kamptner and ongoing discussions based on electron microscopy and genetic analyses.
Morphological variation within Calcidiscus leptoporus has simplified its taxonomic classification.
Answer: False
Significant morphological variation within Calcidiscus leptoporus has historically complicated, rather than simplified, its taxonomic classification, leading to debates about species and subspecies distinctions.
Genetic differences have provided evidence that C. leptoporus quadriperforatus might be a distinct species.
Answer: True
Genetic analyses, particularly of the 18S rRNA and tufA genes, published in 2003, suggested that C. leptoporus quadriperforatus could be genetically distinct enough to be considered its own species.
The NCBI taxonomy identifier for Calcidiscus leptoporus is 56426.
Answer: False
The correct NCBI taxonomy identifier for Calcidiscus leptoporus is 127549. The number 56426 is not associated with this species in the provided data.
What type of organism is Calcidiscus leptoporus?
Answer: A type of unicellular marine phytoplankton belonging to the phylum Haptophyta.
Calcidiscus leptoporus is classified as a unicellular marine phytoplankton within the phylum Haptophyta, commonly known as coccolithophores. These organisms are known for producing intricate calcium carbonate plates called coccoliths.
When was Calcidiscus leptoporus first described, and by whom?
Answer: 1898 by George Murray and Vernon H. Blackman
The species Calcidiscus leptoporus was initially described in 1898 by George Murray and Vernon H. Blackman, who named it Coccosphaera leptoporus.
Which scientist is credited with reclassifying the species into the genus Calcidiscus in 1950?
Answer: Erwin Kamptner
Erwin Kamptner is credited with reclassifying the species, originally named Coccosphaera leptoporus, into the genus Calcidiscus in 1950.
What has been a major challenge in the taxonomic classification of Calcidiscus leptoporus?
Answer: Significant morphological variation within the species.
The considerable morphological variation observed among individuals of Calcidiscus leptoporus has historically presented challenges for consistent taxonomic classification.
The binomial name Calcidiscus leptoporus (Murray & Blackman 1898) Loeblich & Tappan, 1978 indicates:
Answer: Murray and Blackman first described it, and Loeblich & Tappan later revised its classification.
The notation (Murray & Blackman 1898) indicates the original describers and year, while (Loeblich & Tappan, 1978) signifies their subsequent taxonomic revision or validation of the species name.
Coccoliths are organic molecules produced by coccolithophores for cell signaling.
Answer: False
Coccoliths are not organic molecules for cell signaling; they are intricate plates made of calcite (calcium carbonate) that form the coccosphere, providing structure and protection.
The coccoliths of Calcidiscus leptoporus typically measure between 5 and 8 micrometers in diameter.
Answer: False
While the intermediate morphotype falls within this range, the coccoliths of Calcidiscus leptoporus generally range from less than 5 micrometers to 8 micrometers or larger, encompassing small, intermediate, and large morphotypes.
The 'large' morphotype of Calcidiscus leptoporus has coccoliths less than 5 micrometers.
Answer: False
The 'large' morphotype of Calcidiscus leptoporus is characterized by coccoliths exceeding 8 micrometers in diameter, often with an infilled central area.
What are coccoliths primarily composed of?
Answer: Calcite (Calcium Carbonate)
Coccoliths, the characteristic plates of coccolithophores like Calcidiscus leptoporus, are primarily composed of calcite, a crystalline form of calcium carbonate.
What is the typical size range for the coccoliths of Calcidiscus leptoporus?
Answer: Less than 5 micrometers to 8 micrometers or larger
The coccoliths of Calcidiscus leptoporus exhibit variability, generally ranging from less than 5 micrometers (μm) up to 8 micrometers (μm) or more in diameter.
Which morphotype of Calcidiscus leptoporus is characterized by coccoliths exceeding 8 micrometers and having an infilled central area?
Answer: Large morphotype
The 'large' morphotype of Calcidiscus leptoporus is defined by its coccoliths, which are larger than 8 micrometers and possess an infilled central area.
Calcidiscus leptoporus exhibits a life cycle where it can only divide in its diploid phase.
Answer: False
Calcidiscus leptoporus exhibits a haplo-diplontic life cycle, meaning it can divide in both its haploid and diploid phases.
Holococcoliths are found in the diploid phase of Calcidiscus leptoporus, while heterococcoliths are found in the haploid phase.
Answer: False
The haploid phase of Calcidiscus leptoporus typically produces lightly calcified holococcoliths, while the diploid phase produces heavily calcified heterococcoliths.
High light availability and nutrient-rich conditions favor the diploid phase of Calcidiscus leptoporus.
Answer: False
The haploid phase, characterized by holococcoliths, is generally more tolerant of high light and nutrient-depleted conditions, while the diploid phase (heterococcoliths) is typically found in lower light environments.
The haploid phase of Calcidiscus leptoporus is characterized by heterococcoliths and a preference for low light conditions.
Answer: False
The haploid phase is characterized by holococcoliths and is more tolerant of high light and nutrient-depleted conditions, whereas the diploid phase bears heterococcoliths and is typically found in lower light.
What type of life cycle does Calcidiscus leptoporus exhibit?
Answer: Haplo-diplontic life cycle.
Calcidiscus leptoporus possesses a haplo-diplontic life cycle, characterized by the alternation between haploid and diploid phases, allowing for adaptation to varying environmental conditions.
How do the coccoliths produced during the haploid phase differ from those of the diploid phase?
Answer: Haploid phase produces lightly calcified holococcoliths; diploid phase produces heavily calcified heterococcoliths.
In the haploid phase, Calcidiscus leptoporus forms lightly calcified holococcoliths, whereas the diploid phase produces more robust, heavily calcified heterococcoliths.
What environmental factors are primary influences on the switch between haploid and diploid life stages?
Answer: Nutrient depletion and light availability.
The transition between the haploid and diploid life stages in Calcidiscus leptoporus is primarily regulated by environmental cues such as nutrient availability and light intensity.
Which of the following is NOT a characteristic of the haploid phase of Calcidiscus leptoporus?
Answer: Prefers nutrient-rich environments.
The haploid phase of Calcidiscus leptoporus, characterized by holococcoliths and a larger vacuole, is generally more tolerant of high light and nutrient-depleted conditions, not nutrient-rich environments.
In the Sargasso Sea, Calcidiscus leptoporus populations peak exclusively during the winter months.
Answer: False
In the Sargasso Sea, Calcidiscus leptoporus populations typically peak in late spring and summer, with a secondary, smaller peak observed in autumn and early winter.
Calcidiscus leptoporus populations in the Arabian Sea show peak concentrations during the spring monsoon season.
Answer: False
Calcidiscus leptoporus populations in the Arabian Sea exhibit peak concentrations during the fall, influenced by monsoon wind patterns, not the spring monsoon season.
The intermediate morphotype of Calcidiscus leptoporus is generally thought to prefer cold, nutrient-poor waters across all geographic locations.
Answer: False
Research suggests varying preferences for the intermediate morphotype; it is thought to prefer colder, nutrient-poor waters in some regions (e.g., North Atlantic) but warmer, nutrient-rich waters in others (e.g., South Atlantic).
Calcidiscus leptoporus is found globally, indicating a limited adaptability to different environmental conditions.
Answer: False
Its global distribution ('cosmopolitan') suggests Calcidiscus leptoporus possesses considerable adaptability to a wide range of environmental conditions, not limited adaptability.
What are the peak abundance periods for Calcidiscus leptoporus in the Sargasso Sea?
Answer: Late spring and summer.
In the Sargasso Sea, Calcidiscus leptoporus populations typically exhibit peak abundance during the late spring and summer months, with a secondary peak occurring in autumn/early winter.
Which geographic region shows the highest concentrations of Calcidiscus leptoporus in the fall, influenced by monsoon patterns?
Answer: Arabian Sea
The Arabian Sea is noted for its highest concentrations of Calcidiscus leptoporus during the fall, a pattern influenced by the region's monsoon wind patterns.
The 'large' morphotype of Calcidiscus leptoporus is generally associated with which environmental conditions?
Answer: Productive environments with higher temperatures and nutrients.
The 'large' morphotype of Calcidiscus leptoporus is generally associated with productive marine environments characterized by higher temperatures and nutrient availability.
Calcidiscus leptoporus plays a minor role in the ocean's calcium carbonate cycle due to its small size.
Answer: False
Despite its size, Calcidiscus leptoporus plays a significant role in the ocean's calcium carbonate cycle, particularly in carbonate export, due to the density and size of its calcite coccoliths.
Calcidiscus leptoporus is a minor contributor to carbonate export in the Great Calcite Belt compared to smaller species.
Answer: False
Calcidiscus leptoporus is disproportionately significant in carbonate export within the Great Calcite Belt, contributing substantially to the overall export despite potentially being less abundant than smaller species.
Calcidiscus leptoporus contributes less to ocean calcium carbonate export than Emiliania huxleyi because its coccoliths are smaller and less dense.
Answer: False
Calcidiscus leptoporus contributes more significantly to ocean calcium carbonate export than Emiliania huxleyi because it produces larger and denser calcified coccoliths, which enhance sinking rates.
In the Subantarctic Zone, Calcidiscus leptoporus accounts for approximately 10-20% of the annual carbonate export.
Answer: False
Sediment trap studies in the Subantarctic Zone indicate that Calcidiscus leptoporus contributes a significantly higher percentage, between 30% and 70%, of the annual carbonate export.
The dense coccoliths of Calcidiscus leptoporus hinder the efficiency of the biological pump by slowing down organic matter sinking.
Answer: False
The dense coccoliths of Calcidiscus leptoporus act as ballast, increasing the sinking velocity of organic material and thereby enhancing, not hindering, the efficiency of the biological pump.
How does Calcidiscus leptoporus contribute to sequestering atmospheric carbon dioxide?
Answer: By converting dissolved CO2 into calcium carbonate coccoliths that sink.
Calcidiscus leptoporus sequesters atmospheric carbon dioxide by utilizing dissolved inorganic carbon to precipitate calcium carbonate coccoliths, which then sink to the ocean floor, effectively removing carbon from surface waters.
What is the Great Calcite Belt (GCB)?
Answer: A circumpolar band in the Southern Ocean where coccolithophore blooms are common.
The Great Calcite Belt (GCB) is a circumpolar region in the Southern Ocean characterized by frequent and significant coccolithophore blooms, making it a key area for surface carbonate production.
Compared to Emiliania huxleyi, Calcidiscus leptoporus contributes more significantly to ocean carbon export because it produces:
Answer: Larger and denser calcified coccoliths.
Calcidiscus leptoporus contributes more significantly to ocean carbon export than Emiliania huxleyi due to its production of larger and denser calcified coccoliths, which enhance the sinking rate of organic matter.
What percentage range of annual carbonate export in the Subantarctic Zone is attributed to Calcidiscus leptoporus?
Answer: 30-70%
Studies in the Subantarctic Zone indicate that Calcidiscus leptoporus is responsible for a substantial portion of the annual carbonate export, ranging from 30% to 70%.
How does Calcidiscus leptoporus enhance the efficiency of the biological pump?
Answer: By increasing the sinking velocity of organic material with its dense coccoliths.
The dense coccoliths produced by Calcidiscus leptoporus act as ballast, accelerating the sinking rate of organic matter and thereby improving the efficiency of the biological pump for carbon sequestration.
Unfavorable environmental conditions, such as nutrient depletion, improve the coccolith morphology of Calcidiscus leptoporus.
Answer: False
Unfavorable environmental conditions, including nutrient depletion, tend to cause malformations in the coccoliths of Calcidiscus leptoporus and reduce their calcite production, rather than improve them.
Increased carbon dioxide concentrations have been shown to improve coccolith formation in Calcidiscus leptoporus.
Answer: False
Increased carbon dioxide concentrations, leading to ocean acidification, impair coccolith formation in Calcidiscus leptoporus, often resulting in malformed coccoliths.
The size of Calcidiscus leptoporus coccoliths can potentially be used as a paleo-proxy for reconstructing past ocean temperatures.
Answer: False
While coccolith size is studied as a paleo-proxy, it is primarily correlated with growth rate and used to infer past ocean productivity and environmental shifts, not specifically ocean temperatures.
How do unfavorable environmental conditions typically affect Calcidiscus leptoporus?
Answer: They lead to malformations in coccoliths and reduced calcite production.
Unfavorable environmental conditions, such as nutrient depletion, negatively impact Calcidiscus leptoporus by causing malformations in its coccoliths and reducing the overall production of calcite.
What effect does ocean acidification, specifically increased CO2, have on Calcidiscus leptoporus coccolith formation?
Answer: It leads to the formation of malformed coccoliths.
Elevated carbon dioxide concentrations, indicative of ocean acidification, negatively impact Calcidiscus leptoporus by promoting the formation of malformed coccoliths.
The size of Calcidiscus leptoporus coccoliths is proposed as a paleo-proxy for inferring past ocean:
Answer: Productivity and environmental shifts.
The size of Calcidiscus leptoporus coccoliths correlates with growth rates, making it a potential paleo-proxy for reconstructing past ocean productivity and identifying environmental shifts.
What potential impact might future ocean acidification have on Calcidiscus leptoporus's ecological role?
Answer: It may negatively impact its ability to form coccoliths and contribute to carbon export.
Future ocean acidification poses a risk to Calcidiscus leptoporus, potentially impairing its coccolith formation and thus diminishing its crucial role in marine carbon export.