Plankton Collection Techniques and Dinoflagellates

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Questions and Answers

Which type of net is primarily designed to skim the surface and collect surface-living plankton?

Young fish trawls

Plankton nets

Nansen closing nets

Neuston nets (correct)

What method is used to prevent contamination of plankton samples when a net is being lowered or raised?

Using a buoyant frame

Using multiple sizes of nets

Closing the net with a noose (correct)

Employing a time-release mechanism

What is the primary function of young fish trawls in plankton collection?

To sample bottom-dwelling organisms

To catch microplastics

To filter floating debris

To collect larger macro-plankton (correct)

Which mechanism is NOT mentioned as a method for opening and closing nets during sampling?

Manual pulling Signup and view all the answers

What is the purpose of the messenger in the Nansen closing net?

To close the net at the desired depth Signup and view all the answers

During which period do dinoflagellates reach their greatest abundance?

Midsummer period Signup and view all the answers

What reproductive method do dinoflagellates predominantly use?

Asexual fission Signup and view all the answers

Which type of dinoflagellates is known to rely more on photosynthesis?

Thecate dinoflagellates Signup and view all the answers

At what point in their life cycle can diatoms begin sexual reproduction?

When they reach about a third of their original size Signup and view all the answers

What type of environments can dinoflagellates be found in?

Marine, freshwater and brackish water Signup and view all the answers

What type of gametes do 'centric' diatoms produce?

Motile sperm and large eggs Signup and view all the answers

What condition allows dinoflagellates to thrive despite low nutrient concentration?

Their capacity for photosynthesis Signup and view all the answers

How do daughter cells of thecate dinoflagellates form during reproduction?

They retain part of the old cell wall and secrete the other part Signup and view all the answers

What can diatom zygotes form during unfavorable conditions?

Auxospores Signup and view all the answers

What is a characteristic feature of dinoflagellates?

They possess two flagella Signup and view all the answers

Which organisms are commonly infected by parasitic dinoflagellates?

Various planktonic organisms including copepods and fish eggs Signup and view all the answers

Where is diatomaceous material particularly accumulated?

Beneath the Southern Ocean and northern part of the North Pacific Signup and view all the answers

What happens to the daughter cells after division in dinoflagellates?

They form a chain if not completely separated Signup and view all the answers

What helps diatom spores germinate after being enclosed in sea ice during winter?

Melting of the ice in spring Signup and view all the answers

What is one of the main environmental challenges faced by diatom zygotes during winter?

High salinity fluctuations Signup and view all the answers

What is a defining trait of dinoflagellates in terms of their classification?

Classified in the Infraphylum Dinoflagellata Signup and view all the answers

What method is NOT typically used to concentrate nanoplankton and ultraplankton from seawater samples?

Pumping seawater directly into a tank Signup and view all the answers

What key feature distinguishes high-speed plankton samplers from standard plankton nets?

Ability to operate at high speeds Signup and view all the answers

Who invented the first continuous plankton recorder (CPR)?

Sir Alister Hardy Signup and view all the answers

What is the purpose of the continuously moving bands of filter silk in the CPR?

To preserve captured plankton undisturbed Signup and view all the answers

What major change occurred in the CPR survey methodology in 1958?

Standardization of collection and analysis methods Signup and view all the answers

Which of the following is NOT a characteristic of the CPR instruments currently in use?

Collect into a 'cod end' container Signup and view all the answers

What additional information is provided by the electronic sensors in CPR instruments?

Depth, salinity, and temperature Signup and view all the answers

What happens when the blooms of Karenia brevis die off?

They release nitrogen, phosphorus, and iron. Signup and view all the answers

What is a significant benefit of using high-speed plankton samplers towed by merchant ships?

Reduced need for crew involvement Signup and view all the answers

Which of the following can result from a Karenia brevis bloom?

Massive fish kills. Signup and view all the answers

What is the primary toxin released by Karenia brevis during blooms?

Brevotoxin Signup and view all the answers

What environmental condition is commonly associated with red tides?

Nutrient-rich discharges in coastal areas. Signup and view all the answers

Which of the following locations is known for experiencing frequent red tides?

Gulf of Mexico. Signup and view all the answers

How do dinoflagellates affect marine mammals and seabirds?

They cause poisoning through toxic shellfish. Signup and view all the answers

What event in 1968 highlighted the dangers of dinoflagellates in the UK?

Human food poisoning due to mussels. Signup and view all the answers

Which dinoflagellate species was responsible for the death of humpback whales in 1987?

Alexandrium tamarense Signup and view all the answers

What primarily causes equatorial upwelling?

Divergences between equatorial currents Signup and view all the answers

How does the nutrient availability in the Southern Ocean during summer compare to the Arctic?

Nutrient availability is consistently high in the Southern Ocean Signup and view all the answers

Which aquatic area is most likely to be rich in marine life due to upwelling?

Localized divergences near seamounts Signup and view all the answers

Which group of microorganisms has a symbiotic relationship with marine invertebrates and plays a crucial role in marine ecology?

Photosynthetic dinoflagellates Signup and view all the answers

What is the main threat to coral reefs associated with zooxanthellae?

Coral bleaching due to stressors Signup and view all the answers

Why is phytoplankton growth likely limited in the Arctic during summer months?

Depletion of surface nutrients Signup and view all the answers

Which of the following marine animals is NOT likely to harbor zooxanthellae?

Jellyfish Signup and view all the answers

What role do zooxanthellae play in the survival of reef-forming corals?

Producing photosynthetic products Signup and view all the answers

What is the function of the transverse flagellum in dinoflagellates?

To vibrate gently and assist in movement Signup and view all the answers

Which feature distinguishes thecate dinoflagellates from nonthecate ones?

Strong wall made of interlocking cellulose plates Signup and view all the answers

In which type of environment are dinoflagellates most numerous?

Warmer parts of the ocean Signup and view all the answers

What does the sulcus in a dinoflagellate contain?

A whip-like longitudinal flagellum Signup and view all the answers

What is a unique characteristic of the shape variations among dinoflagellates?

Some possess multiple girdles and sulci Signup and view all the answers

What role do complex cellulose plates in thecate dinoflagellates potentially serve?

Assisting in flotation Signup and view all the answers

Which of the following statements about the pellicle of nonthecate dinoflagellates is true?

It covers the cytoplasm and is quite thin Signup and view all the answers

How do dinoflagellates generally move through the water?

By spiraling forward along a path Signup and view all the answers

Which group of organisms is primarily found in the hadal pelagic zone?

Crustaceans Signup and view all the answers

What is a primary ecological role of Benthocodon pedunculata in the BBL?

Prey for larger fish Signup and view all the answers

Which of the following challenges limits the study of planktonic animals in hadal zones?

Difficult sampling conditions Signup and view all the answers

Which species is recorded to inhabit depths of around 9500 m?

Archiconchoecilla maculata Signup and view all the answers

Which type of medusa is noted to be rare in the hadal pelagic zone?

Both types Signup and view all the answers

What is the depth range for the collected copepod species in hadal zones?

6000 to 8500 m Signup and view all the answers

Which of the following factors contributes to the nutrient enrichment of the BBL?

Decomposing organic matter Signup and view all the answers

What sampling method was used by Smith et al. (2020) to observe Benthocodon pedunculata?

Autonomous time-lapse camera system Signup and view all the answers

What term is used for organisms that spend their entire lifespan as plankton?

Holoplankton Signup and view all the answers

Which of the following terms describes plankton living in the surface layers of the ocean?

Epipelagic Signup and view all the answers

What differentiates meroplankton from holoplankton?

Meroplankton spend only part of their life in the planktonic stage. Signup and view all the answers

Which type of plankton includes organisms like jellyfish that have limited swimming ability?

Holoplankton Signup and view all the answers

What size category is commonly used for classifying plankton?

Microplankton Signup and view all the answers

What is the main ecological role of holoplankton in marine ecosystems?

They provide a source of food for various marine animals. Signup and view all the answers

Which organisms could be mistakenly classified as plankton due to their lifestyle?

Foraminiferans Signup and view all the answers

Which of the following terms describes organisms that live solely at the seabed?

Benthic organisms Signup and view all the answers

What is a common characteristic of true plant plankton in the kingdom Plantae?

They consist mainly of microalgae that may exhibit a motile phase. Signup and view all the answers

What is the primary form of reproduction observed in Halosphaera?

Asexual reproduction leading to swarmers. Signup and view all the answers

Which feature distinguishes Halosphaera from many other phytoplankton?

It can have up to eight nuclei in mature cells. Signup and view all the answers

Where is Halosphaera most commonly found?

Throughout the North Atlantic, especially in tropical areas. Signup and view all the answers

What role do bacterial plankton play in coastal waters?

They contribute significantly to the total biomass of plankton. Signup and view all the answers

What type of cell structure can be found in Halosphaera?

A tough elastic wall surrounding a central vacuole. Signup and view all the answers

Which factor most likely affects the distribution of bacterial plankton populations?

Nutrient availability in surface waters. Signup and view all the answers

What distinguishes true plant plankton from other phytoplankton types?

Their classification as part of the kingdom Plantae. Signup and view all the answers

What characteristic distinguishes centric diatoms from pennate diatoms?

Radially symmetrical and circular Signup and view all the answers

Which diatom shape is typically associated with being joined end to end to form stiff cylindrical chains?

Filamentous shapes Signup and view all the answers

Which type of diatom can be found forming chains connected by protoplasmic strands?

Thalassiosira Signup and view all the answers

In what primary shape do filamentous diatoms take when forming flexible ribbons?

Cylindrical Signup and view all the answers

Which type of shape represents diatoms that may have large spines or projections?

Branched shapes Signup and view all the answers

Which characteristic is typical for rod or needle-shaped diatoms?

Divided lengthwise Signup and view all the answers

What is the main grouping criterion for categorizing diatoms?

Symmetry and shape Signup and view all the answers

Which diatom shape is described as 'pillbox' shaped?

Centric Signup and view all the answers

What is the function of the haptonema in prymnesiophytes?

It helps in food gathering. Signup and view all the answers

In what phase do haploid individuals of prymnesiophytes primarily behave like gametes?

In the motile haploid phase. Signup and view all the answers

Why are nanoplankton considered important in marine ecosystems?

They contribute significantly to primary production. Signup and view all the answers

How does the contribution of nanoplankton to photosynthesis vary across different marine environments?

In tropics, they can account for over 80% of photosynthetic activity. Signup and view all the answers

What happens to the coccolith plates after prymnesiophytes die?

They sink down and contribute to deep-sea sediment. Signup and view all the answers

How do prymnesiophyte blooms affect the appearance of ocean water?

They turn the surface a milky white color. Signup and view all the answers

What characteristic is typical of the life history of prymnesiophytes?

They have complex life histories with multiple morphologically different phases. Signup and view all the answers

What distinguishes the shallow waters (epipelagic zones) in terms of nanoplankton presence?

They consist mainly of unicellular organisms with significant abundance. Signup and view all the answers

Study Notes

Open Water Lifestyles: Marine Plankton

Plankton are organisms that live suspended in the water column, drifting with tides and currents.
They can swim but not powerfully enough to go against the flow.
Plankton are mostly microscopic, although some can reach a few centimeters in length.
Nekton are larger, swimming animals, such as fish.
Plankton are important components of marine ecosystems and food webs.

Plankton Composition

Plankton include phytoplankton (photosynthetic organisms), zooplankton (animals), bacterioplankton (bacteria), and virioplankton (viruses).
Almost all marine phyla are represented in plankton, either permanently or temporarily.
Phytoplankton are responsible for most of the ocean's primary production, needed for life in the ocean.
Zooplankton feed on phytoplankton or each other, forming a crucial part of the marine food web.
Bacteria and viruses are also important components, playing roles in decomposition and nutrient cycles.

Plankton Types

Holoplankton are organisms whose entire lifecycles are in the plankton.
Meroplankton are organisms that only spend part of their lifecycles in the plankton, often during their larval stages. Larval stages of many benthic species form a key component of the meroplankton.

Size Classification of Plankton

Plankton is often classified by size, with smaller size categories (e.g., femto, pico, nano, micro, meso, macro, mega)
Size classification systems evolved over time, with the current widely-used system developed by Sieburth et al (1978).
The smaller sizes are sometimes called water bottle plankton as they can only be efficiently sampled by water bottles or specialized nets.
Size classifications are often used to segment plankton studies, and to understand the specific species and components of marine ecosystems.

Marine Phytoplankton

Phytoplankton includes microalgae and cyanobacteria.
These organisms are able to photosynthesize.
Different species of phytoplankton thrive in different parts of the ocean, (including diatoms, dinoflagellates, and prymnesiophytes), and vary according to the specific conditions (e.g., temperature, light, and nutrients).

Ecological Definitions

Plankton can be defined by size and habitat.
Holoplankton are organisms whose entire lifecycles are spent in the plankton, contrasted with meroplankton whose lifecycles are spent partly or entirely in the plankton.

Surface Living Plankton

Some plankton live at the very surface (neuston).
Some have ways to partially float submerged (e.g. hydrozoans, Porpita, Physalia).
Neuston and pleuston are also counted as surface organisms.
Surface plankton communities are ecologically significant, including species like jellyfish, that inhabit and float at the surface or in the upper layers.

Ecological Variations

Diatoms have unique cell walls made of silica, giving them a glassy quality.
Dinoflagellates can be both autotrophic and heterotrophic, performing photosynthesis or consuming other organisms.
Prymnesiophytes (coccolithophores) are characterized by tiny calcareous plates, or coccoliths. Many species have both free-living and colonial phases.
Dinoflagellates play an important role as producers and consumers in the ocean. Some species cause harmful algal blooms.
Phytoplankton blooms influence ecosystem dynamics, and serve as a primary food source for many organisms.

Bacterial Plankton

Bacteria are important in marine ecosystems as decomposers, saprophytes, and pathogens.

Plankton Blooms

Certain phytoplankton species can grow rapidly, forming blooms impacting water quality, often due to excess nutrients.
They can be a food source for other organisms but also pose threats to marine life, particularly when certain species die off. Harmful algal blooms (HABs) are especially dangerous.

Sampling Plankton

Plankton nets are frequently used to sample plankton.
High-speed plankton samplers used when studying plankton in large volumes of water.
Plankton can also be collected by underwater vehicles (like ROVs) or divers.
Specialized sampling strategies and methods are crucial in identifying and studying plankton.

Quantitative Plankton Studies

Measurements involve counting, determining density, or weights.
Volume of water filtered is crucial to estimations of numbers and densities.
Standard methods and specialist equipment (such as electronic instruments) are used in plankton counting and analysis..
Spatial and temporal variations in plankton abundance, alongside various environmental factors, can be evaluated for a comprehensive understanding.

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Description

This quiz explores various methods for collecting plankton, focusing on nets designed for surface collection and the role of young fish trawls. Additionally, it discusses the biology and reproductive methods of dinoflagellates, including their environmental preferences and survival strategies during adverse conditions.