Marine Biology Exam 2: Key Terms & Definitions for Success

rocky intertidal zones

beaches, estuaries, mangroves, tide pools

- important for viewing impacts of sea level rise, climate change

tidal influence on rocky intertidal zones

- caused by sun/moon

- affect organisms

1) water changes/air exposure

2) currents

3) varying salinity/dissolved compounds

Diversity controls

1) area hypothesis: tropical climates are older/larger = more diversification

2) time stability hypothesis: older the habitat, more diverse it is

3) intermediate disturbance hypothesis

4) predation: keystone predators minimize competition

community issues

- competition

- predation

- limited space

intertidal zonation

- occurrence of dominant species in distinct horizontal bands

- usually single sessile species

factors impacting zones:

1) water/tide/spray:

2) physical: wave shock, gas exchange, feeding time

3) biological: competition, predation (changes with tide)

4) oxygen: some cannot respire during low tide (will reduce metabolic rate)/physiological intolerance

upper vs lower zones

upper: controlled by physical factors

- limits where organisms live

lower: controlled by biological factors

- presence/absence of another organism

- predation may promote coexistence of competing prey species

Connell experiments/paine experiments

?

alternative stable states

- different communities develop in the same area under similar environmental conditions

- random effects of disturbance

ex) ice scouring: in winter ice scrapes away at rocks, either forming an algae or mussel dominated ecosystem

unified theory of diversity

dN/dt = rN (K-N)/K

N = # indiviudals

K = carrying capacity

- logistic growth

- N = K: no more growth (dN/dt = 0)

- N<

importance of predation

- as predation increases, competition decreases

- as predation increases, diversity increases then decreases

see graph

deep seafloor

- covers most of planet

- accounts for 60% of ocean

- stable (consistent for 8000 yrs), but extreme in:

1) temp

2) pressure

3) productivity

environmental factors

1) low flows: depositional, tidal to abyssal circulation

2) pressure: immense

- 1 atm every 10 m

3) light: none

4) temp: 2-4 degrees C (cold)

- vents are exception

5) salinity: very high

6) oxygen: plenty

- high at epifaundal

- can be depleted infaunal

deep sea sampling

- ROV, AUV

- nets, dredges, trawls, bottom grabbers, corers

- still a lot more species to be found

food sources

rain of detritus

- fecal pellets

- marine snow

- molts

- dead phytoplankton

- dead fish/whales

NO primary productivity

< 0.25% organic content

benthic connection to surface pp

- Responds to detritus from spring bloom

- benthic Biomass/growth correlates with surface pp

- benthic respiration occurs highest at equator (more material)

- biomass decreases exponentially w/ depth/distance from shore

Martin curve

F = F100 (z/100)^-b

- Z = trap depth

- F100 = POC flux at 100 m

- B = unitless parameter

Martin curve interpretation

- Large particles fall faster: dominate flux

- Flux declines exponentially with depth

- 1% or less OM in euphotic zone reaches deep sediment

vertebrates

benthic inverts classification

1) phylogeny

2) size

3) sediment location

4) feeding mode

size

Microfauna: <0.1 mm

Meiofauna: 0.1-1 mm

Macrofauna: > 1mm

Megafauna: >>> 1 mm

see notes table with scientific names

most abundant megafauna

echinoderms

- Usually penta-radially symmetrical

- Exclusively marine

- tube feed and water vascular system

- Complex life cycle w/ free swimming larval stages

sea urchins

- echinoderms

- Rigid, spherical body w/ movable spines

- Larvae are bilaterally symmetrical

- Develop into pentaradially symmetrical as adults

sea cucumbers

- echinoderms

- 2-200 cm

- 5 rows of tube feet: like seams on a football tentacles near oral end are specialized tube feet

most abundance macrofauna

polychaetes

- Segmented worms

- Benthic forms have reduced # of segments, not as pretty

2nd most abundant macrofauna?

crustaceans

1) isopods

- Exclusively benthic

- Broad range size

2) amphipods

- 1mm - 30 cm

- Detritivores, grazers

- Epibenthic

most important meiofauna

nematodes

- Very small <1 mm

- Detritus eaters = deposit feeders

other) Harpacticoid copepods

important meiofauna

- Ciliates

- Eat bacteria

- Bacteria do majority of metabolism (respiration) in benthic communities

shallow vs deep benthos (abundance and diversity)

Deep: open space, patchy, low abundance, high diversity

Shallow: crowded, zones/patches driven by physical factors, high abundance, relatively low diversity

rarefaction curve

- plotting the expected species richness against the number of individuals sampled

- inc # of individuals means increased number of species recovered (until a plateau)

area hypothesis

- large area promotes speciation and allows for more species to coexist

- Bigger habitat size = more species

- bc large habitats can have more niches, i.e more niche space for more species

Time Stability Hypothesis

- accommodation of species over time in a stable environment

- Long term stability = less die off

- Constant rate of invasion increases species

shallow benthos importance

- Food for many ground fish and birds

- Biogeochemical cycles

- Taxonomy, evolution, and phylogeny

2 benthos types

1) soft bottom

- organic rich, can sink

- Top layer: light brown, oxidized

- Lower layer: black, reduced

2) hard bottom

- rocky

why isn't there O2 below surface sediment?

- Supply of org. material is high to sediments bc the water is shallow or pp is high (or both)

- Supply of organic material and degradation of org material > diffusion of O2 into sediments

anaerobic metabolisms

- organisms in anoxic areas

- by bacteria, archaea, few protists

1) Fermentation: partial oxidation, release of organic material

2) Sulfate reduction: SO4 → H2S by bacteria and archaea

3) Methanogenesis: CO2 → CH4 only by archaea

sediment microzones

TOP

- aerobic bacteria

- fermenting bacteria

- sulfate reducing bacteria

- methanogenic bacteria

benthic invertebrates help...

- Break up detritus: creating more surface area for microbes

- Bioturbation: puts O2 into otherwise anoxic mud (allows O2 to get deep into sediments, changes what can live down there)

soft benthic organisms

1) Bacteria, archaea, protists

2) Benthic algae (if shallow enough for light to reach)

3) Many invert types

shallow benthic organisms classifications

1) phylogeny

2) size

3) lifestyle/location in sediment

4) feeding mechanism

benthic organism size

microfauna: Algae, copepods, crustaceans, ciliates, bacteria/archaea

meiofauna: Wormlike, interstitial meiobenthic animals, diverse phyla

macrofauna: Snails, worms, crustaceans

deposit feeding can be __ or __

1) Selective: individual food particles picked out of sediments

2) Non selective: ingest everything (sediments, detritus, microbes)

*choice depends on deposit feeder/detritus

symbiotic microbes help...

- Help in nutrition of benthic inverts

- Provide enzymes to hydrolyze polymers

- Chemolithotrophic bacteria provide carbon and energy: use inorg. compounds to make org. material from CO2

ex) tube worms sulfur oxidation

suspension feeding can be __ or __

1) Passive: go with the flow (sponges + corals)

2) Active: actively create currents (polychaetes, annelids, bivalve mollusks

- Particle not just caught by sieve or distance between cilia

- Cilia can retain particles much smaller than overall filtering unit size

- Need to be selective to avoid clogging

hydrothermal vents

- range 2000-8000 m

- found where new crust forms (spreading centers)

vent environmental factors

1) Low flows, tidal-abyssal circulation

2) Immense pressure

3) Little-no light

4) Cold temp

5) High salinity

6) Plenty of O2

food sources near vents

- POC raining detritus

- chemosynthetic bacteria?

vent plumbing steps

1) Inorganic compounds reduced by hot water (400 C)

2) Water sinks into sediment, heats up and becomes metal rich

3) Exits through vents, cools and metals precipitate out

4) Chimneys form (solid) as metal sulfides precipitates out at cool temps (up to 5 m tall)

tube worms

- first organisms at a new vent site

- up tp 37 cm

- heat resistant, live in super high hydrogen sulfide amounts

characteristics

1) No digestive tract: no mouth/anus

2) Trophosome tissue loaded with sulfur granules

other organisms: crabs

vent life supported by which process?

sulfide oxidation:

H2S +2O2 → SO42- + 2H+

- H2S = from vent

- 2O2 = from ocean

allows bacteria to gain a lot of energy (makes more biomass)

Chemoorganotrophy vs chemolithotrophy

chemoorganotrophy

- Aerobic respiration:

CH2O + O2 = CO2 + H2O

- CH2O is organic compound

chemolithotrophy:

- Replacing CH2O with H2X (another electron donor)

- usually sulfur

- O2 = e- acceptor

Where is the carbon coming from to build biomass?

CO2

unique vent site

The lost city

- 20 km west of mid atlantic ridge

- Metal poor, pH 9-11, >90 C water

- Dominated by carbonate towers 60 m tall

how to categorize organisms based on sources (carbon, energy, reducing power)

1) Source of carbon

- CO2 = autotroph

- Fixed organic C = heterotroph

2) Source of energy

- Sunlight = phototroph

- Preformed molecules = chemotroph

3) Source of reducing power

- From organic molecules: organotroph

- From inorganic molecules: lithotroph

Photosynthesis vs chemoautolithotrophy

1) Energy source

- Light vs chemical energy

2) Primary producers

- plants/algae vs chemolithotrophic bacteria

3) Carbon fixation pathway

- Same for both

vent symbionts

- Endosymbionts

- Live in tissue of larger organisms

- Require H2S, O2, CO2

vent symbionts benefits

Animals get:

- food from bacteria-release of organic material from living cells, dead cells

- Detoxification of H2S

Bacterial symbionts get:

- steady diet of H2S and O2

- protection from grazers

sulfate based vent communities

- Chemosynthetic bacteria are pp's (not phytoplankton)

- Source of energy: hydrogen sulfide (not light)

- Symbiotic bacteria are key

vent colonization

- planktonic larvae swim around and hope to get lucky

- Gene flow between sites is low

did life start at hydrothermal vents?

- First cell likely chemoautolithotroph

- Elements present in ancient enzymes abundant at vents

- Thermophiles/ hyperthermophiles (withstand very high temps) are at base of tree life

so yes?

mesopelagic zone

200-1000m

physical aspects of mesopelagic

1) Temp

- weak vertical mixing

- declining temps

2) Pressure

- increases 1 atm every 10 m

- fish/inverts vertically migrate

- enzymatic activity drops as pressure inc.

3) Light (quantity and quality)

light quantity

- Attenuated with depth

- diffuse attenuation coefficient: Kd (varies in diff areas)

light quality

- sunlight in zenith, snells window

- overall diffuse light field

- spectral composition

Coastal waters: greening

Open ocean: blueing

midwater biomass and biodiversity

biomass:

- very dilute compared to surface

- exponential decay as you move down

biodiversity:

- more stable than surface

- less decay as you move down

lost of archaea in deep water!

mesopelagic organisms

1. Crustaceans

- Amphipods

- Copepods, ostracods

- Decapods, euphausiids

2. Molluscs

- Pteropods

- Tereropods

- cephalopods

3. Ctenophores

4. Cnidarains

5. Echinoderms

6. Annelids

7. chordates

- Urochordates, vertebrates

mesopelagic adaptations

1. crypsis

2. bioluminescence

3. energy and metabolism

crypsis

- organisms are red/black

- makes them virtually invisible bc of lack of red light in water

- Can use mirrors to mimic background light: bouncing ambient light back to the predator at the correct angles

Bioluminescence

counterillumination

- emit blue light to match downwelling light field

- light output matches surrounding irradiance

uses for bioluminescence:

1. Avoiding predators

2. Catching prey

3. Finding mates

diverse organisms use common approaches: luciferins only slightly diffin each organism

energy and metabolism

need to

1) maximize energy input

2) minimize energy expenditure

maximizing energy input

1) predatory lifestyle

- Few filter feeders

- Eat whenever/whatever

- Adaptations: large upward looking eyes, large heads (cephalization), disarticulating jaw, teeth that trap, extensible stomach, long GI tract

2) Reduce density

- Store light ions

- Store lipids in tissues/swimbladder

- Reduce hard parts

- Sinking rates: counteracted by buoyancy

minimize energy expenditure

1) lower metabolic rate

- ex) pelagic animals w/ image-forming eyes: need to fuel locomotory activity for avoiding predators decreases as less light is available for visual predation

2) efficient growth

- Less metabolic demand = more energy for growth

- Less energy is required if tissues have more water

3) slow growth

- Life in cold/dark water generally slower

- Body mass increase of bathypelagic species = close to exponential

4) reproduction

- Difficult to find mates

- Solution: hermaphroditism

mesopelagic organisms generalizations

1. Slow: metabolism, growth

2. Efficient: vision, growth

3. Opportunistic: occasional big lunch

4. Flabby: watery tissue, weak bones

5. Bioluminescent: common

estuaries are

- salt+freshwater

- geologically young

- ephemeral: here for short period before modified

- impacted by sea level

define estuaries based on

1) morphology

- DE bay is a drowned river valley

2) geology

3) circulation

4) tides

estuary salinity

- PSU: practical salinity units

- ppt: parts per thousand

- no units

ex) east coast 30 ppt, full strength 35 ppt

estuary types

- salt wedge

- well mixed

- partially mixed!

- fjord

- reverse

Estuarine flow

- Low density freshwater at surface: flows toward ocean

- Denser more saline water: flows upriver

- Net flow: towards ocean

- Most estuaries are partially mixed

estuaries are __ rich, which causes __+__

nutrient rich

- high production + biomass but LOW diversity (intermediate salinities)

- nursery for organisms

blue crabs

callinectes sapidus

- range from argentina to nova scotia

- Support commercial/sport fisheries

blue crab life history

depends on estuary!

- Spawns in estuary in summer

- Larval develop on continental shelf

- Juvenile nursery in estuary

- Adults in estuary year round

blue crab transport

1) Spawn in estuary

2) Move southward in coastal ocean

3) Mixed offshore

4) Move northward in coastal ocean

5) Recruitment (juvenile-adult stages) to estuary

transport depends on..

wind direction/currents

- Northward: how larvae are transported back north

- Southward: how larvae are transported back into estuary

blue crab life cycle/

success dependent on...

1) Eggs

2) Zoea

3) Megalopa

4) Juvenile crabs

5) Adult crabs

depends on chance: many contestants, few survivors

important species DE estuary

- Blue crab: callinectes sapidus!

- Menhaden: brevoortia tyrannus

- Oysters: crassostrea virginica

- Shad: alosa sapidissima!

- Sturgeon: acipenser oxyrhynchus

Catadromous vs. Anadromous

- Catadromous = adults in river, spawn in saltwater sea

ex) American eel

- Anadromous = adult in sea, spawn in freshwater

ex) Salmon

shad

- Anadromous

(Return after 3-5 yr in ocean)

- extensive migrations

- stopped spawning bc of anoxic barrier south of PA

- O2 has increased, but fish still haven't gone back up

shad still not recovering bc of...

- Ocean fisheries catch adults

- Excessive predation + competition (Alternative stable state)

- Habitat destruction, not just pollution

oxygen is a good index of..

water quality

- Solubility of O2 decreases with temp + salinity (Warmer/saltier water holds less gas)

- Solubility of O2 increases with pressure

optimal O2 for fish

- general level: 3 mg/L

ex) Shad need 5 mg/L

ex) Mummichog can go down to 1 mg/L

- Saturation levels 8 mg/L

hypoxic areas are less than

2mg/L O2

Atlantic sturgeon

- Evolutionarily old

- live very old, be very big

- 6 yrs in estuary, move to ocean, return to spawn

- fished for caviar, overharvisting of flesh and eggs

- now only 250 returning to DE river

sturgeon not recovering bc of

- Fisheries bycatch mortality

- Boat + propeller strikes

- Water pollution/poor water quality

- Habitat loss, deepening/dredging

horshoe crabs

Limulus polyphemus

- related to arachnids

- Living fossils

- food for many fish/birds

red knots and horshoe crabs

- Distribution determined by horseshoe crab eggs

- Arrival to spring months when horseshoe crabs lay eggs

- Decline in red knots attributed to horseshoe crabs

horshoe crabs used for

- Fertilizer in 19th century

- Blood for detecting endotoxin

- Bait for fish (eel) and whelk