Marine Ecology Exam 2

Define Salt Marsh

Transition zone from ocean to land, where saltwater and freshwater mix

Distribution of salt marshes (2)

• Middle to high latitudes

• Low energy coasts

Biogenic communities

Ecological communities that are created, modified, or maintained by living organisms 

Examples of animals living in salt marshes (6)

• Ribbed mussels

• Silversides

• Coffee bean snail

• Fiddler crabs

• Periwinkles

• Sesarma spp

Succession of salt marshes

Mudflat → grasses → rushes → shrubs

Bottom-up hypothesis

Physical forces (nutrients, physical factors, tides) mediated the energy flow at the bottom of the web

Major vegetation zones highlighting the relative roles of __________ and ___________ ________ in determining the zonation of marsh plants

• competition

• physiological stress

Foundation species

Those that create habitats and modify the environment with positive effects on the diversity, distribution, and abundance of associated organisms

Examples of foundation species (8)

• Reef-building corals

• Kelp

• Seagrasses

• Saltmarsh cordgrass

• Mangroves

• Oysters

• Hydrothermal vent tubeworms

• Sponges 

Services that foundation species provide (3)

• Substrate

• Reduced biotic & abiotic stress

• Increased food supply

Facilitation

Interactions between 2 or more species in which at least 1 species benefits, and non are negatively affected

Ecosystem engineers

Organisms that directly or indirectly modulate the availability of resources to other species by causing physical state changes in biotic or abiotic materials

Facilitation dominates under _______ stress

High

Competition dominates under ______ stress

Low

4 Fundamental Models of Ecology

• Fundamental vs Realized Niche

• Competition

• Invasion success

• IDH and species diversity 

Facilitation can…..

• Mitigate effects of niche-shrinking factors

• Expand the space/area of the fundamental niche

Phase shift

Large, abrupt, and persistent changes in the structure and function of an ecosystem, where it suddenly shifts from one community type to another

Phase shifts are caused by (3)

• Disturbances

• Human impacts

• Loss of key species

Threats to salt marshes (5)

• Trophic cascades & runaway grazing

• Invasive species

• Eutrophication

• Toxic pollutants

• Climate change - sea-level rise

Services Salt Marshes provide (4)

• Key nursery grounds for commercially/recreationally fished shellfish & finfish

• Buffer shorelines from storm damage & wave-driven erosion

• Sequester & store carbon

• Process nutrients that enter estuaries w/ terrestrial runoff

What order is kelp bed/forest in?

Laminariales

Define kelp forest

Large brown algae that form a floating surface canopies

Define kelp bed

Large brown algae that do not form a surface canopy

Examples of subtidal ecosystems? (3)

• Coral reefs

• Seagrass meadows

• Sand/mud seafloors

What do kelp blades do?

“Leaves” light capture, gas exchange, nutrient uptake, waste removal

What are pneumatocysts?

Gas-filled floats

What are stipes?

Long “stem” support, connecting structures

What are holdfasts?

Rootlike attachment to substrate

How many species of kelp are there?

30 species 

What is the range of subtidal/sublittoral zone?

Low tide to continental shelf break

What type of kelp is this?

Giant Kelp

What type of kelp is this?

Bull Kelp

Why is kelp brown?

Fucoxanthin

What is the function of Fucoxanthin?

Pigment that assists in light absorption for supporting photosynthesis

Distribution of kelp?

Temperate & subpolar regions

Resources needed for kelp (5)

• Hard substrate

• Temperature

• High Nutrients (N, P)

• Light 

• Wave motion

High temperature = _______ nutrients

low

What is a key limiting nutrient?

Nitrate

Most kelp forests are associated with ______ areas that deliver _______ to the surface.

• upwelling

• nutrients

Warm water impacts kelp __________ (3)

• Growth

• Tissue integrity

• Reproduction

What is consisted in the canopy layer of kelp forests?

Long stipes, often to surface

What is consisted in the understory layer of kelp forests?

Shorter stipes, often close to bottom

What is consisted in the substrate layer of kelp forests?

Encrusting, clumping ot filamentous algae

When is the lowest bottom temperature?

Spring

When is the warmest temperature on the surface?

Summer

Highest abundance & recruitment occurs during the __________

Spring

Lowest abundance occurs during the __________

late summer/fall

Kelp forests in SoCal have decline due to marine ____________

Heatwaves

Significance of Kelp Forests in Ecosystem (3)

• Foundation species/ecosystem engineers

• High productivity

• Support high diversity

Differences between kelp forests & terrestrial forests

• Kelp lasts fewer than 25 years

• Kelps are faster growing 

Kelp forests are _____ diverse in terms of animal phyla, _______ diverse in terms of animal species

• more

• less

What is “A”?

Canopy & frond assemblage

What is “B”?

Planktonic Assemblage

What is “C”?

Holdfast Assemblage

What is “D”?

Horizontal Substrate Assemblage

What is “E”?

Vertical wall assemblage

A large proportion of kelp forest productivity is _________

allochthonous = exported to other habitats

Define Functional Diversity

A diversity of species that form similar functions in an ecosystem 

Define functional redundancy

When more than one species performs a similar task or function in the ecosystem 

Biotic factors that influence kelp forests (3)

• competition

• grazing

• predation

Kelp forest competition types (2)

• Light

• Space

Kelp forest predators (2)

• Urchins

• Seastars

Range of the _______ zone is 200-1000m

Twilight

Range of the ______ zone is 0-200m

Photic

Range of the ______ zone is 200 to 8000m

Aphotic 

Only ___% of epipelagic food sinks to meopelagic

20%

Characteristics of mesopelagic fish (6)

• Small

• Big mouth

• Unspecialized diet

• No swim bladder

• Soft, weak bones

• Tubular eyes

Do deep-sea habitats have seasons?

No

Bioluminescence is used for (4)

• Prey attraction

• Communication

• Courtship

• Defense

Characteristics of deep-sea habitat (5)

• No sunlight

• Cold temperatures

• Slow currents

• High oxygen

• Low-food

• High pressure 

Only about ____% of the food produced in the photic zone makes it past the mesopelagic

5%

Deep sea fish are ____ and _____

Sluggish and sedentary

Much of the sinking organic matter is ______ before it reaches the seafloor

consumed

There is ____ organic content within sediment

low

Benthic fauna is dependent on organic matter from the __________

Euphotic zone

Given equivalent annual primary productivity, high-latitude regions have higher standing stocks than tropical regions. It’s more ________ with greater _______

• higher

• variable

• export

Some habitats within the deep-sea are (3):

• Hydrothermal vents

• Whale fall

• Cold seeps

What are the stages of whale fall? (4)

• Mobile scavenger 

• Enrichment opportunists

• Sulfophilic

• Reef 

Common reactions of chemosynthesis (2)

• Aerobic sulfide oxidation

• Anaerobic methanogenesis

Primary production done by chemosynthetic bacteria such as (3):

• Free-living bacteria

• Endosymbionts

• Ectosymbionts

Regions where cold, hydrocarbon rich water escapes from ocean floor

Cold seeps

Cold seeps are found in what regions of the earth?

Subduction zones

The gas in cold seeps comes from ______ ______ where organic matter has been buried for millions of years

Deep sediments

The anaerobic oxidation of methane by sulfate-reducing bacteria produces ___________

Bicarbonate

The bicarbonate reacts with calcium in seawater to form ________ ____________, creating biogenic carbonate rock around the seep.

Calcium carbonate

Examples of pattern of ecological succession (4)

• Bacterial mats

• Mussel colonies

• Tube worm assemblages

• Stony coral assemblages

What kind of gas is methane?

Greenhouse gas

Microbes consume most ______ before it reaches the ocean/atmosphere

Methane

Chemosynthetic communities incorporate methane into _______ and some _______ buried in sediments

• Biomass

• Carbon

Are cold seeps vulnerable to climate change?

Yes

Where do hydrothermal vents form?

Active seafloor spreading centers/mid-ocean ridges

Hydrothermal fluids between ____ °C and ____ °Cexit along the ridge axis of the spreading center

100-400°C

Hydrothermal vents are rich in (5):

• Hydrogen sulfide

• Manganeses

• Iron

• Methane

• Hydrogen

The division of limited resources by species to help avoid competition for an ecological niche is called

Resource partitioning

Environmental Gradients (4)

• Temperature

• Oxygen

• Toxic metals

• H2S

Resource partitioning

Division of limited resources by species to help avoid competition in an ecological niche

The sibogliniid tubeworms house symbiotic sulfide-oxidizing bacteria. in specialized structures called ___________

Trophosome

Mobile predators in hydrothermal vent communities (3)

• Vent eelpout

• Vent octopus

• Pacific White Skate