Questions and Answers
What are Calanus finmarchicus and Calanus helgolandicus?
Types of copepods
Which of the following statements about Cyclopoida copepods is true?
What is Oithona similis known for?
Most abundant surface-dwelling copepod in the Arctic
Which of the following is true about Harpacticoida copepods?
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What do members of the Phylum Chaetognatha commonly refer to?
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Match the following classes of Subphylum Tunicata with their representatives:
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What is true about Class Thaliacea?
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Order Salpida consists of only solitary species.
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What distinguishes Salpa thompsonii?
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Which of the following is a characteristic of Order Doliolida?
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What is the role of mucous houses in Class Appendicularia?
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What are holoplankton?
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Which of the following features are characteristic of holoplankton?
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Which organism is classified as a heterotrophic flagellate?
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Name a feature of heterotrophic nanoflagellates (HNF).
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What is the primary role of ciliates?
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What is a common feature of radiolarians?
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What characterizes foraminifera?
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Which groups are included in the phylum Cnidaria holoplanktonic representatives?
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What feature do the Order Coronatae jellies have?
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What is the feeding strategy of Periphylla periphylla?
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What defines the Order Siphonophorae?
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All ctenophores are _______.
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What is a notable feature of Gymnosomata pteropods?
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Which crustacean group predominantly serves as a key link in the food web?
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What is a key characteristic of Calanoida copepods?
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Study Notes
Holoplankton
- Permanent plankton members spending entire life cycle in planktonic form.
- Low diversity with few phyla and classes compared to meroplankton.
- Significant contributors to global mesozooplankton biomass like copepods and euphausiids.
- Key in food web energetics; examples include copepods and chaetognaths.
- Found globally in open oceans, shelf seas, and estuaries.
Heterotrophic Flagellates and Ciliates
- Include heterotrophic nanoflagellates, ciliates, radiolarians, and foraminifera.
- Historically underrated due to small size; can dominate in oligotrophic regions.
- Ciliates, which include tintinnids and oligotrichs, feed by creating currents to sweep food into vacuoles.
Radiolarians
- Exclusive to marine environments, mainly oceanic.
- Characterized by mineral skeletons that provide fossil preservation.
- Feature needle-like pseudopodia for buoyancy and feeding.
Foraminifera
- Marine organisms ranging from 1 to 300 micrometers.
- Have calcium carbonate shells with numerous pores.
- Act as microbial climate proxies while mostly being benthic.
Cnidaria Representatives
- Holoplanktonic representatives include scyphozoans, hydrozoans, and siphonophores.
Coronate Jellyfish (Order Coronatae)
- Deep-sea hydrozoans with red coloration for camouflage.
- Exhibit direct development with larger eggs and diel vertical migration.
- Predate on copepods and euphausiids; bioluminescent for predator deterrence.
Siphonophores (Order Siphonophorae)
- Colonial cnidarians with specialized zooids for different functions.
- Feature a pneumatophore for buoyancy and long tentacles for food capture.
- Three main groups: physonectae, cystonectae, and calycophorae.
Pteropods (Phylum Mollusca)
- Include thecosomata (calcified shells) and gymnosomata (gelatinous bodies).
- Thecosomata feed using mucous and cilia; distributed globally.
- Gymnosomata, such as Clione limacina, are predatory and found in various ocean depths.
Crustacean Groups
- Holoplanktonic representatives include ostracods, cladocerans, amphipods, mysidaceans, and copepods.
- Ostracods have bivalved bodies and are primarily herbivorous filter feeders.
- Cladocerans, or water fleas, are mostly freshwater species, filter feeders, and reproduce through parthenogenesis.
Copepods (Class Copepoda)
- Most abundant zooplankton, critical for transferring energy in food webs.
- Exhibit diverse feeding habits and life cycle stages from nauplii to adult forms.
- Divided into calanoida (dominant class) and cyclopoida (mainly freshwater), with adaptations for various environments.
Arrow Worms (Phylum Chaetognatha)
- Transparent and typically planktonic; key marine predators.
- Possess bilateral symmetry and are effective swimmers equipped with grasping spines for capturing prey.
- Important food source for fish, found across varying depths in oceans.### Species Identification
- Species identified based on overall length, length of features, mouthparts, and fin positioning.
Subphylum Tunicata Holoplanktonic Representatives
- Consists of Class Thaliacea (orders Salpida and Doliolida) and Class Appendicularia.
Class Thaliacea
- Comprises pelagic tunicates: salps, doliolids, and pyrosomes.
- Features a simple transparent barrel with complex organs including stomach and muscles.
- Utilizes muscle bands for efficient filtration of phytoplankton, pumping water through the body.
- Reproduces as hermaphrodites with a metagenic life cycle, involving both asexual and sexual phases.
- Can be solitary or colonial, forming extensive blooms across ocean surfaces in various productivity zones.
Order Salpida
- Exhibits two body forms: solitary asexual ozooid and colonial sexual blastozooid.
- Incomplete muscle bands do not encircle the barrel; feeding occurs via swimming and muscle contraction.
- Example: Salpa thompsonii.
Salpa thompsonii
- Planktonic salp species with varying life cycles and depth distribution.
- Solitary stage lives at depth in winter; migrates to the surface in spring for phytoplankton blooms.
- Forms aggregates for sexual reproduction in spring and summer, returns to depth in autumn with developing embryos.
Order Doliolida
- Involves complex life cycles with alternating solitary and colonial zooids, including asexual production of trophozooids.
- Generally smaller than salps, features complete muscle bands and larval tails.
- Found cosmopolitan in tropical oceans, enjoys a ciliary feeding strategy similar to salps, creating currents for feeding.
Class Appendicularia
- Larvaceans like Oikopleura spp. have small trunks and long tails.
- Are protandrous hermaphrodites with direct development, managing reproduction and growth efficiently.
- Secretes mucous houses every three hours for filtering nanoplankton, which are consumed after being trapped.
- Abandons mucous houses when clogged; these structures are crucial for nutrient cycling and organic matter transport to the seafloor.
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Description
Test your knowledge on holoplankton and their characteristics. This quiz covers their life cycle, diversity, and ecological significance. Understand the role of holoplankton in marine ecosystems and food webs.
