Oceanography: Exam Four

Buoyancy

one wat to resist sinking phytoplankton need light so evolved to have ability

surface areas

• bizarre attachments used to increase buoyancy especially in warm areas

• higher sa to v better resistance to sinking

streamlining

• important for larger organisms

• moves water out of water in front

• ex: flattened body, tapering back end

Broadcast Spawning

eggs and sperm released into seawater

• high viscosity allows egg and sperm to find each via buying time

stenothermal

organisms that can tolerate a narrow temperature range

eurythermal

organisms that can survive in wide temperature range

stenohaline

organisms withstand only small variation in salinity

euryhaline

organisms withstand large range of salinity

osmosis

water molecules pass from low salinty to high salinity

osmotic pressure

applied to higher salinity side to prevent water from entering

isotonic

organisms body fluid salinity same as ocean

hypertonic

seawater has lower salinity than organisms fluids

hypotonic

organisms fluid has lower salinity than ocean

Freshwater Fish

• hypertonic

• experience high osmotic pressure

• doesn’t drink

Saltwater Fish

• hypotonic

• experience low osmotic pressure

• drinks

Transparency

occurs in sunlit waters to avoid detection

countershading

organism dark on top and light on bottom so predators cannot see them

deep scattering layer

organisms migrate to deeper darker ocean layers during the day to dodge predators and return to feed at night

What allows sea creatures to adjust to buoyancy and pressure

collapsible rib cage, swim bladder

pelagic

open ocean

benthic

seafloor

Epipelagic

• zone to support photosynthesis

• dissolved oxygens decreased around 200 m

euphotic zone

from surface to where light disappears

mesopelagic

• organisms capable of bioluminescent common

• contain OML

Aphotic zone

all depth permanently in dark

primary productivity

rate at which energy is stored by organisms through formation of organic matter

phototrophy

process by which organisms produce food via light as source of energy

• nitrogen and phosphorous are necessary

respiration

process by which organism use organic materials as energy

• use oxygen make carbon dioxide and water

biomass

total mass of defined organism in entire water column per unit area of water

phytoplankton biomass

can be estimated via chlorophyll by capturingphytoplankton on filters and measuring the concentration of chlorophyll in the samples.

gross primary productivity

total amnt of organic carbon produced by photosynthesis per unit time in certain area

factors affecting primary productivity

• nutrient availability: productivity high along continental margins, comes from runoff

• solar radiation: high near surface

solar radiation

drives photosynthesis, only <1% penetrates below 100m in ocean, blue wavelength penetrates deepest

chemosynthesis

process by which bacteria or archaea synthesize organic molecules from inorganic nutrients using chemical energy released from the bonds of a chemical compound

• only occurs in aphotic zone

Anthophyta

• seed bearing plants

• only in shallow coastal waters

• grasses and mangroves

macroscopic algae

• seaweeds

• in middle latitudes and colder waters

• ex: sargassum and kelp

microscopic algae

• phytoplankton

• largest source of fixed carbon from photosynthesis

• ex: diatom, dinoflagellates

Prochlorococcus

smallest phytoplankton known discovered by Sallie Chisholm

• 20% of oxygen

• open ocean

Synechococcus

• parent to prochlorococcus

• coastal

• can use N and P as nutrients

biological pump

carbon dioxide is removed from euphotic zone to seafloor

• considered buried b/c it takes so long to be released again

biochemical cycling

recycling of nutrients through the ecosystem

How much energy is transferred between tropic levels

10%

Marine Fisheries

commercial fishing from seawater

• 20% of global protein

overfishing

fish stock harvested too rapidly, juveniles not sexually mature

• 90% of large fishes have been removed

• remaining stocks are smaller now

Bycatch

accidental fishing of marine organisms other than the species intentionally targeted

Fisheries Management

organized effort directed at regulating fishing activity with goal of sustaining long term fishery

How do organisms increase buoyancy

• rigid gas containers ex: cephalopods

• swim bladders ex: slow moving fish

foraminifera

• very small

• planktonic most abundant, benthic most diverse

copepods

• floating zooplankton

• shrimp like

• segmented bodies

• oceans zooplankton biomass

active swimming

swim by trapping water and expelling it or curving body from front to back like a wave

• squid do not have air chambers

• swim by blowing water out of a siphon

rounded fin

• slow

• maneuverable

• flexible

truncate fin

• fast

• ok maneuverability

forked fin

• fast

• OK maneuverability

lunate fin

• fast

• limited maneuvering

• rigid

heterocercal fin

• top heavy causes lift

• limited maneuvering

Lungers

wait for prey and pounce

ex: grouper

Cruisers

actively seek prey

ex: tuna

poikilothermic

body temperature nearly the same as their environment

ex: slow swimming fish, flounder

homeothermic

body temperature above sea water temperature

ex: fast moving, mako shark

bioluminescence

• photophores

• produce light glow in the dark

• adaptation to attract prey, patrol territory, communication, mating

Adaptations Of Deep-Water Nekton

• large sensitive eyes

• large sharp teeth

• expandable bodies

• hinged jaws

Schooling

• appear as a single larger unit

• schooling maneuvers confuse predator

• safety in numbers

Marine mammals

• warm blooded

• breathe air

• hair/fur

• bear live young

• milk

Carnivora

• canine teeth

• sea otter

• polar bears

• pinnipeds: walruses, seals, sea lions, fur seals

seals vs sea lion

seals: earless seals or true seals

distinct from sea lions: seals have no ear flaps, seals smaller flippers, different hip structure

sirenia

• herbivores- the only vegetarian marine mammal

• paddle like tails

• eat sea grasses

• ex Manatees and Dugongs

manatees

found in coastal of tropical Atlantic Ocean

dugongs

coastal areas of Indian and western pacific oceans

Cetacea

• whales, dolphins, porpoises

• elongated skull, blowholes on top of skull, few hairs, horizontal tail fin called a fluke

What allows Cetacea to deep diving

• muscles insensitive to buildup of carbon dioxide

• lots of alveoli

• efficient oxygen use

odontoceti

• suborder Cetacea

• toothed

• dolphins, porpoises, killer whale, sperm whale

• echolocation

echolocation

• good vision limited by ocean conditions

• dolphins/porpoises emit sounds blowhole

• sound passes through melon-organ on skull

vaquita - porpoise

• most endangered cetacean in the world

• tiniest

• only 8

Mysticeti

• suborder Cetacea

• fibrous plates of baleen sieve prey

• calls travel >50km

• ex Blue whale, finback whale, humpback

baleen

• parallel rows instead of teeth

• made of keratin

• used to filter food from water

gray whales

bottom feeders, 2-5 ventral grooves on lower jaw

rorquals

• balenopterids- longer slender bodies, flukes w/ smooth edges, minke, fin and blue whales

• megapterids- humpback whales, uneven trailing edge of fluke, tubercles with hair

corals

marine animals that live in colonies often forming reeds

• made up 100s to 1000s of polyps

• symbiotic relationships w/ microscopic organisms

zooxanthellae

• nonmotile

• algae

Dinoflagellates

• live in coral tissue

• provide coral with organic carbon

fringing reef

reef connected with shore of an island or continent w/o an open lagoon between reef and shore

barrier reef

reef separated from land parallel to a land mass with a lagoon between the reef and the shore.

atoll reef

ring shaped coral reef that grows upward from submerged island and encloses lagoon

shallow water corals

• <30m

• require access to light so zooxanthellae can photosynthesize

mesophotic corals

• 30-150 m

• adapted to lower light

• enough for photosynthesis but can consume plankton

deep sea corals

• >200 m

• no sunlight relies on plankton and detritus

• cold water gals

Why are coral reefs important

• essential habitat

• food source

• breeding grounds

• shelter

Threats to corals

• anchoring

• sunscreen: coral bleaching, dna damage, impaired growth

• climate change

coral bleaching

occurs when corals lose their symbiotic algae due to stress factors such as increased temperature or pollution, leading to a loss of color and essential nutrients.

Bleached corals can survive

• up to ten days

• need to reestablish symbiosis with zooxanthellae

• chances of survival is lower