Marine Biology: Deep-Sea Ecosystems Quiz

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Questions and Answers

What primary source of nourishment do many bottom-dwelling animals rely on?

Gathering falling food particles (correct)

Hunting larger prey

Active predation on schools of fish

Seeking shelter to avoid predators

What is a major feature of the marine environment that supports a diverse range of habitats for organisms?

Shallow coastal waters

Deep-sea trenches

Open water columns

The seabed (correct)

How do sediment deposits benefit certain marine creatures?

They give concealment and protection for burrowing creatures. (correct)

They promote rapid growth of coral reefs.

They enhance photosynthesis in algae.

They provide a food source for filter feeders.

What has been the impact of modern exploration techniques on our understanding of deep-sea biodiversity?

They have rapidly increased knowledge of deep-sea benthos. Signup and view all the answers

Which of the following statements is true about biomass in relation to ocean depth?

Biomass generally decreases with depth. Signup and view all the answers

What role do hydrothermal vent communities play in deep-sea ecosystems?

They exhibit unique ecosystems due to extreme conditions. Signup and view all the answers

What determines the depth range at which benthic communities receive primary production?

Water clarity Signup and view all the answers

What is one of the main reasons for the greater diversity of the benthic population compared to the pelagic population?

Availability of hard surfaces and shelter Signup and view all the answers

Which organism is identified as an obligate commensal living alongside the hermit crab?

Neanthes fucata Signup and view all the answers

What role does the barnacle Peltogaster paguri play in the hermit crab's ecosystem?

It acts as a parasite on the hermit crab. Signup and view all the answers

Which animal uses the shell of the hermit crab as a substitute habitat rather than for protection?

Porcellana platycheles Signup and view all the answers

What impact do environmental changes have on species within the community?

They impact recruitment and mortality rates differently among species. Signup and view all the answers

Which organism is capable of boring into the shell of the hermit crab?

Polydora ciliata Signup and view all the answers

What type of relationship does the hermit crab have with the polychaete worm N. fucata?

Commensal Signup and view all the answers

What helps maintain the dynamic equilibrium within a community?

Increased predation and competition among species. Signup and view all the answers

Which of these organisms typically uses the shell of a whelk for habitat?

Pseudione spp. Signup and view all the answers

What is the primary method by which deep-living species obtain nutrients in the water column?

Saprophytic feeding on dead materials Signup and view all the answers

Which of the following is associated with the production of marine snow?

Aggregation of organic and inorganic particles Signup and view all the answers

What role do polysaccharides play in the formation of marine snow?

They enhance the cohesion of particles. Signup and view all the answers

Which of the following is considered a primary producer in deep-sea ecosystems?

Chemosynthetic bacteria Signup and view all the answers

How fast can aggregated marine snow particles sink through the water column?

Up to 200 m per day Signup and view all the answers

What provides the basis for carbon fixation by chemosynthetic bacteria in abyssal sediments?

Reduced inorganic metal compounds Signup and view all the answers

What is the significance of marine snow for deeper marine ecosystems?

It serves as a food source for a variety of organisms. Signup and view all the answers

Which of the following organisms are known to benefit from the presence of marine snow?

Microorganisms in the water column Signup and view all the answers

What is marine snow primarily linked to?

Surface phytoplankton blooms Signup and view all the answers

What is a significant implication of marine snow for climate change?

It facilitates the transfer of CO2 to deeper ocean levels. Signup and view all the answers

What term is used for a whale carcass that has reached the deep-sea floor?

Whale fall Signup and view all the answers

Which organisms are primarily responsible for breaking down whale bones?

Osedax worms Signup and view all the answers

How do scavengers benefit from whale falls?

They obtain a concentrated food source. Signup and view all the answers

What type of bacteria utilizes sulfides released from decaying whale bones?

Chemosynthetic bacteria Signup and view all the answers

Which of the following animals is NOT mentioned as a scavenger of whale falls?

Eels Signup and view all the answers

How long can a large whale fall sustain a community of organisms?

Many years Signup and view all the answers

What is the primary function of the tangled root-like lower body of the worms?

To penetrate bone and dissolve it through acid secretion Signup and view all the answers

What role do symbiotic bacteria play in the nutrition of the worms?

They transfer nutrients directly to the worms Signup and view all the answers

Which deep-sea invertebrates have been reported to utilize dissolved organic matter (DOM) directly?

Deep-sea starfish and polychaetes Signup and view all the answers

How much of the energy required by the deep water starfish Plutonaster and the polychaete Tharyx is estimated to come from dissolved organic carbon?

30% Signup and view all the answers

Which of the following factors increases the capacity of invertebrates to absorb DOM?

A soft body and high surface area to volume ratio Signup and view all the answers

What is an important source of food for deep-sea benthic animals?

Dissolved organic matter (DOM) Signup and view all the answers

Where is considerable DOM held in deep-sea sediments?

In interstitial water Signup and view all the answers

Which marine invertebrate is specifically mentioned as utilizing symbiotic chemosynthetic bacteria?

Giant tubeworms such as Riftia Signup and view all the answers

What is the primary function of sediment traps in marine research?

To collect data on biogenic particle rain Signup and view all the answers

Which component of deep water sediment traps allows for the automatic collection of samples?

Rotary collector with sampling bottles Signup and view all the answers

What characteristic makes kelp forests particularly significant as ecosystems?

They provide a biologically generated habitat. Signup and view all the answers

What is the approximate height that Giant Kelp can reach?

30 - 40 meters Signup and view all the answers

When were modern sediment traps first tested in deep water?

1978 Signup and view all the answers

What is one method used alongside sediment traps in marine studies?

Using time-lapse photography Signup and view all the answers

In which era were kelp forests recognized for their high productivity and biodiversity?

Modern environmental research Signup and view all the answers

What design feature is used to prevent large objects from contaminating sediment traps?

A baffle to keep large objects out Signup and view all the answers

In which zone do animal growths predominate while foliose algae are restricted to scattered patches due to low light levels?

Upper circalittoral Signup and view all the answers

What ecological role does the bottom current play in benthic communities?

It aids in the settlement of pelagic larvae on the seabed. Signup and view all the answers

Which factor is considered most crucial for community differences at abyssal depths?

Hydrostatic pressure Signup and view all the answers

What is a potential effect of strong wave action on benthic communities?

It can damage or displace animal growths. Signup and view all the answers

Which feature is essential for the richest benthic communities in the sublittoral zone?

Moderate tidal water flow Signup and view all the answers

What significant challenge do bivalve molluscs face in sediment communities?

Filtering out food from silt-laden water Signup and view all the answers

Which type of algae is often found at depths with little shading from kelp?

Foliose algae Signup and view all the answers

What describes the composition of the community at greater depths beyond 20 meters?

A mix of calcareous encrusting algae and animal growths Signup and view all the answers

What factor primarily influences the settlement behavior of Ophelia bicornis larvae?

Type of sediment and organic coating Signup and view all the answers

What happens to the larvae of Ophelia bicornis when they encounter repellent sand?

They swim away and search for new substrates Signup and view all the answers

What effect does washing sand samples with hot concentrated sulfuric acid have on Ophelia bicornis larvae behavior?

Makes the sand neutral, losing attractive qualities Signup and view all the answers

Which sensory cue is NOT mentioned as a settling cue for larval organisms?

Ability to detect sound Signup and view all the answers

What is a common characteristic of species that settle on substrates with high organic matter content?

Increased chemical sensitivity to diffusing substances Signup and view all the answers

How long after being produced do Ophelia bicornis larvae begin to enter the deposit for metamorphosis?

5 days Signup and view all the answers

What behavior do Ophelia bicornis larvae exhibit when exploring deposits?

They engage in repeated exploration until finding suitable sand Signup and view all the answers

What type of larvae are attracted to organic substrates like wood?

Pelagic larvae Signup and view all the answers

What are sediment traps primarily used for in marine research?

Measuring biogenic particles falling throughout the year Signup and view all the answers

What is the main feature of modern sediment traps that allows for sample collection?

A rotating carousel with automatic sealing mechanism Signup and view all the answers

Which group of organisms is primarily responsible for creating the physical framework of kelp forests?

Kelp, specifically large brown seaweeds Signup and view all the answers

How deep can Giant Kelp grow, reaching heights similar to certain tropical trees?

30-40 m Signup and view all the answers

What was a significant study that made use of sediment traps in the 1990s?

The Joint Global Ocean Flux Study Signup and view all the answers

What design feature is included in deep-water sediment traps to prevent contamination by large objects?

A baffle system Signup and view all the answers

In which year were modern sediment traps first tested in deep water?

1978 Signup and view all the answers

What type of ecosystems do kelp forests exemplify in terms of productivity and biodiversity?

Highly productive and biodiverse systems Signup and view all the answers

What aspect of the marine habitat classification for Britain and Ireland is emphasized in its compatibility?

It is integrated with the EUNIS system. Signup and view all the answers

Which of the following communities did Petersen distinguish in his studies of marine benthic communities?

Venus communities Signup and view all the answers

What was a significant limitation of the methods used by Thorson in classifying marine communities?

Certain prominent organisms could appear in different ecological contexts. Signup and view all the answers

What are some of the key environmental factors that affect species distribution in marine communities, according to Thorson's observations?

Temperature and salinity Signup and view all the answers

What type of sampling method did Petersen utilize in his investigations of marine benthic communities?

Grab sampling Signup and view all the answers

In the context of marine benthic communities, what is a characteristic feature of the Venus community as identified by Petersen?

It predominates in shallow sandy bottoms. Signup and view all the answers

What does the classification approach used by Thorson primarily emphasize in relation to community composition?

The most prominent genera rather than species Signup and view all the answers

What factor complicates the classification of marine communities based on prominent species, as noted in the content?

Certain species can exist in multiple habitats. Signup and view all the answers

What defines the size of meiofauna within marine ecosystems?

Typically smaller than 0.5 mm Signup and view all the answers

Which organisms are considered prominent members of meiobenthos?

Nematodes and harpacticoid copepods Signup and view all the answers

What role does meiofauna play in marine food webs?

They serve as a vital early trophic link. Signup and view all the answers

What defines the microbenthos community in shallow waters?

Small organisms living in algae and sediment. Signup and view all the answers

Which statement accurately represents the size range of meiofauna?

From 0.063 mm to approximately 0.5 mm Signup and view all the answers

Where are permanent residents of the meiofauna typically found?

In sediment from intertidal zones to deep ocean Signup and view all the answers

How do some meiofaunal species contribute to the overall ecosystem?

By providing a link between bacteria and larger organisms Signup and view all the answers

What is the significance of sediment particle sizes for benthic communities in the deep sea?

They influence the composition and biomass of animal communities. Signup and view all the answers

What is a key factor that influences the classification of benthic communities?

Physical and chemical parameters Signup and view all the answers

Which parameter did Jones use to define shelf communities in the northeast Atlantic?

Multiple factors including depth and salinity Signup and view all the answers

What aspect limits the effectiveness of classification systems for benthic communities?

Species have fluctuating distributions and overlapping zones Signup and view all the answers

What modern advancement has contributed to the classification of benthic habitats?

Computer technology enabling comprehensive data integration Signup and view all the answers

In benthic community classifications, what is typically abstracted from studies of overlapping distributions?

Community composition Signup and view all the answers

How does the distribution of benthic species usually behave in relation to habitat changes?

There are corresponding adjustments in species assemblage Signup and view all the answers

What aspect of deep-sea benthic communities is often characterized by transitional zones?

Continuous changes in habitat characteristics Signup and view all the answers

What does the modern classification system for benthic habitats combine?

Physical habitat and species approaches Signup and view all the answers

Study Notes

Benthic Organisms

Benthic organisms live on or in the seabed, from the seashore to abyssal depths, covering a vast range of habitats.
Sublittoral communities are found on continental shelves, up to 200m deep.
Bathybenthic communities extend down the continental slope to about 4000 m.
Abyssobenthic communities are in the deepest parts of the ocean.

Substratum

The seabed substratum's type heavily influences benthic distributions.
Hard, rocky seabeds support epifauna (surface-dwelling) and epiflora.
Sediment-covered areas have infauna dwelling within the sediments.
Diverse habitats in rocky areas lead to more species diversity compared to sediment areas where conditions are usually more uniform, as local conditions are more consistent.

Physical Factors

Light penetration is limited at depth, decreasing to less than 1% at 200 meters.
Light is essentially absent below around 1000 m.
Wave action impacts seabed habitats, affecting depths up to about 150-300 meters depending on wavelength.
Water currents influence sediment particle size, nutrient content, and dispersal of pelagic larvae, transporting food particles and affecting oxygen content.
Temperature and salinity variations are less significant below 500m.

Benthic Communities

Different parts of the seafloor are inhabited by different communities, with distinctive organisms in specific geographic and environmental areas.
Differences result from water and substratum characteristics, including various sediment types, currents, and light penetration.

Physical Factors Affecting Benthic Communities

Temperature
Water composition
Water movement
Pressure
Light
These factors affect species distribution and community makeup, particularly in terms of stability and resilience.

Selective Settlement of Larvae

Larval settlement is not random, influenced by selection of habitats.
Biotic and abiotic factors influence larval choice, including roughness, slope, texture, chemical nature, and often color of the substratum.
Biofilms on surfaces, either attracting or deterring settling larvae, are an important factor.

Competition and Predation

Species compete for space and resources, leading to dominance relationships.
Predators impact community composition and abundance. This can lead to shifts in distribution and abundance of species.

Coral Reefs

Coral reefs are highly productive and biodiverse, creating complex food webs and shelter.
Dominated by one dominant species (kelp), forming a structural habitat framework.
Kelp forests have an understory of algae.
Kelp Forests are found in temperate, cold areas, with temperature and water clarity affecting growth.
Reefs have various zonation patterns, each with specific species associations, depending on depth, water exposure, and other factors.
Reefs vary in complexity, stability, and resilience depending on physical factors, such as wave action, currents, and temperature.

Hydrothermal Vents and Cold Seeps

These communities are not dependent on sunlight.
Chemosynthetic bacteria form the base of the food web.
Vent communities are often rich with large, unique animals.
High diversity of specialized species is found. These communities are located at unique geological features, such as mid-ocean ridges and in areas with significant hydrothermal activity.

Sampling and Collecting Benthos

Various methods are employed for sampling in different niches.
Trawls and dredges are large nets dragged along the seabed.
Corers also take sediment samples.
Specialized instruments, like ROVs and submersibles are used for sampling deep-sea communities.
Various methods are crucial for understanding benthic ecosystems, including accurate measurements of sample locations.

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Description

Test your knowledge about deep-sea ecosystems and the unique adaptations of bottom-dwelling animals. This quiz covers various aspects including food sources, habitat diversity, and the roles of different marine species. Dive into the complexities of ocean biodiversity and the impact of human exploration techniques.