almost as prevalent as arthropods (80,000 species): clams, snails, octopuses, squid, chitons and bivalves are part of this group; they are bilaterally symmetric, have soft bodies and usually a shell
three groups of mollusks
gastropoda (means stomach-foot in latin), bivalvia (two doors), cephalopoda (head-foot in Latin)
snails; largest class of mollusks, inhabit relatively large shells, cannot attach to sand or mud, have an inner layer of CaCO3 to provide nonabrasive surroundings
clams, oysters and mussels; can't move but are well-protected; they have suspension feeding systems, they aren't predators
nautiluses, octopuses, cuttlefish, squid (largest invertebrate); most highly evolved mollusks, catch prey with stiff adhesion disks, intelligent and sophisticated with good eyesight
means "joint foot"; lobster, shrimp, crab, krill; occupy most variety of habitats, consume greatest quantities of food, exist in unimaginable numbers; bodies are clearly segmented; they are bilaterally symmetrical
what is the greatest biomass of any single species on earth?
krill (an arthropod)
3 evolutionary advances of arthropods
exoskeleton (strong, supportive, made of chitin), striated muscle (quick, lightweight, makes rapid movement possible), articulation (ability to bend appendages at points--full range of motion)
2 classes of arthropods
insecta (not a lot in the sea) and crustacea (having shell or ring---70% of all zooplankton)
"hedgehog skin" in latin; sea stars, sea urchins, sea cucumbers
3 common classes of echinoderms
asteroidea (sea stars, 5 or more arms), ophiuroidea (brittle stars, long slender arms, can evade capture with detachable arms), echinoidea (sea urchin)
most advanced animal phylum; have a notochord (tubular dorsal nervous system and gill slits behind the mouth)
what does the notochord do?
provides an internal mechanical foundation for skeletal and muscle development (about 5% of species lose the notochord after development; these are invertebrates; the other 95% are vertebrate chordates)
2 invertebrate chordates
tunicates (suspension feeders that look and function like sponges; they filter water with a mucous plankton; can trap microscopic food particles) and salps (act like mini jet engines, taking in water at one end and propelling it out at the other for movement)
what is an ectothermic organism?
"cold blooded", incapable of generating and maintaining a steady internal temp for metabolic heat (fish usually have same body temp as surrounding water)
freshwater v. saltwater
40% of fish live in freshwater at some point, 60% live exclusively in salt water
three classes of fish
agnatha (no jaws, are snake-like...lamprey and hagfish), chondrichthyes (cartilage skeleton...sharks, rays and skates) and osteichthyes (bony fish, hard lightweight gas bladders, most abundant and successful fish)
fish's resistance to movement
what determines drag?
frontal area, body contour and surface texture
why don't fish sink?
their weight is offset by propulsive forces or by buoyant gas in bladders
how swim bladders work
bladder fills with oxygen; fish has greater volume; provides buoyancy
where does gas in bladders come from?
controlled by secretion and absorption of gas from blood and by muscular contraction of bladder to compensate for changes in depth
what type of fish don't have swim bladders?
fast powerful fish like tuna, mackerel and swordfish
frogs, salamanders, toads; require flow-through water
what is the only marine reptile that doesn't need warm waters?
generation and regulation of metabolic heat to maintain a constant internal temperature that is generally higher than surroundings
toothed; have high brain weight to body weight ratio, they use sonar to find prey
eat krill, don't dive very deep
what is a community?
many populations of organisms that interact at a particular location (dependent on availability of energy, physical and biological characteristics)
where is the largest marine community?
between the sunlit surface and deep bottom of the ocean
what is a population?
a group of organisms of the same species occupying a specific area (populations exist within communities)
what is a habitat?
an organism's physical location in its community
what is a niche?
the organism's role int he community (its job)
the variety of species in a given area (i.e. biodiversity of a coral reef)
what is a limiting factor for organisms?
a limiting factor prevents the organism from feeding, growing or otherwise functioning correctly; an organism needs a proper balance of physical and biological factors
"narrow", used to describe organisms that have narrow tolerances for specific factors; they need environments where temperature, climate and salinity doesn't change much; they are sensitive organisms
"wide", used to describe organisms that have wide tolerances for specific factors; they are not very sensitive to environmental changes
the study of relationships of organisms and interactions with the environment
where are rocky intertidal communities located?
between the highest high-tide and lowest low-tide marks on a rocky shore (tide changes are an important physical factor for these organisms)
what is wave shock?
the powerful force of crashing waves
rocky intertidal community factors
rise and fall of tides, high wave energy, wave shock, rapid temp change, desiccation (drying)
rocky intertidal zones
spray zone (where waves break...highest high tide), intertidal zone (high tide has tides lower than spray zone, buckshot barnacles live here...middle tide has a lower tide than high tide but higher than low tide, hermit crabs live here...low tide is the lowest low tide, many species live in this zone)
what has been happening to coral reefs?
they've been dying over past 20 years and the food web within that community is affected, too
name the deep sea provinces
mesopelagic, bathypelagic, deep sea benthos
20% of the surface production 200-1000 meters deep, not enough light for photosynthesis, vertical migration for food
more than 1000 meters deep, always dark, 5% of surface production, low food, no vertical migration, hard to mate
deep sea benthos province
very dark, cold, high pressure, 4,000km average ocean depth, scarce food, diversity is high but population is low
methods for exploring deep sea
bathysphere, AUV, ROV
how does food get into the deep sea?
influx of organic matter from the photic zone to the deep sea bottom (fecal matter, plant detritus, zooplankton detritus, large carcasses)
why do mesopelagic fish have inward-curving teeth?
they have rare chances to consume prey, so they want to be sure they don't let go of it (seizing rare opportunities to eat)
examples of deep sea fish
deep sea anglerfish, gulper eel melanoceoetus johnsoni (male is smaller than female, attaches to female solely to inseminate her)
these fish are common; bioluminescence is a product of chemical reaction (they have organs to make light--oxidation of luciferin makes photons) ATP provides the energy to make luciferin, luciferin makes light
live on or are attached to sea floor, 98% of all marine species, they live long, they're diverse, they accept food well
benthic animals that live on surface attached to rocks at the bottom of the sea
benthic animals that live buried in sand, shells or mud
live on the bottom but move with ease through the water above the ocean floor
why is deep sea benthic animal diversity high but abundance is low?
because the food sources are patchy; there is uneven distribution of food to these organisms; microhabitats also foster high diversity
what are the two most valuable marine resources?
petroleum and gas
what is a physical resource?
results from deposition, precipitation or accumulation of useful substances in the ocean or seabed (NON renewable)
what is marine energy?
results from the extraction of energy directly from the heat of motion of ocean water (renewable)
what is a biological resource?
living animals and plants collected for human use and animal feed (renewable)
what is a non extractive resource?
uses of the ocean in place, transportation of people and commodities by sea, recreation and waste disposal (NON renewable)
what are hydrocarbon deposits?
petroleum, natural gas and methane hydrate (physical)
what are mineral deposits?
sand/gravel, magnesium and its compounds, salts, manganese modules, phosporites and metallic sulfides
where does petroleum come from?
from organic substances that was once marine
what is the largest well known reservoir of hydrocarbons on Earth?
what does methane-rich sediment look like?
what physical resource has the second highest dollar value behind oil and gas?
sand and gravel
what happened at Ocean City in the Bahamas?
extraction of aragonite sands (world's largest single mining operation)
what is the third most abundant element dissolved in seawater?
how much of magnesium worldwide comes from the ocean?
how much of the worlds table salt comes from the sea?
what are some examples of manganese nodules?
iron, copper nickel and cobalt (all very expensive)
the separation of pure water from seawater
distillation (boiling), freezing, reverse osmosis
what is the world's fastest growing power source?
wind (it will account for 12% of power by 2025)
what percentage of human protein intake do marine animals contribute?
what percentage of human protein intake do fish, crustaceans and mollusks contribute?
name the top 5 harvesters of seafood
China, Peru, U.S., Japan and India
why is there an increase in jellyfish?
overfishing; not enough fish left in the ocean to eat jellyfish
what is by-catch?
unintentional killing of organisms while collecting fish/animals from the sea (trawling the bottom kills benthic organisms)
60% of U.S. fish comes from where?
the Bering Sea
other than transportation and recreation, how else can the sea be of value in a non-extractive way?
real-estate values (sea views) and property tax on the shore is higher
by how much does demand exceed earth's natural replacement of raw materials?
by at least 20%
define marine pollution
introduction of substances or energy into the oceans (by humans) that changes the quality of the water or affects the physical, chemical or biological environment.
what are sources of marine pollution?
runoff and discharges from land, airborne emissions from land, shipping and accidental spills, ocean dumping, offshore mining/drilling
able to be broken down by natural processes into simpler compounds
what are chlorinated hydrocarbons (DDT)?
most abundant and dangerous halogenated hydrocarbons; as organisms consume DDT, it moves up the food chain; contamination starts at the bottom
what happened in Japan in the 1950s?
mercuric chloride was dumped into the sea (clams and oysters concentrated the mercury); led to kidney damage, birth defects, neuromuscular degradation, insanity, death; shellfish beds here will be unsustainable for generations
what is coastal eutrophication?
a set of physical, chemical and biological changes that take place when excessive nutrients are released into the water (toxic algal blooms form, causing hypoxia, choking gills of fish)
how much of the 120 metric tons of plastic produced annually ends up in the ocean?
how is waste heat a pollutant?
shoreside electrical plants use seawater to condense and cool the steam they produce. they put the water back into the ocean, but at a higher temp. Temp increase can be deadly to the environment.
drinks seawater, water loss by osmosis, salt excreted by gills
doesn't drink water (closed mouth), water is absorbed by osmosis, salt is absorbed by gills, urine removes excess water, internal fluids are saltier than outside water
protects us from harmful atmosphere on the other side O3= ozone
DDT increases as it moves up the food chain. it increases 10 million times between water and fish
the water is getting more acidic and pH is lowered because CO2 is broken down by the water
what is the average ocean pH
name the dinoflagellate phytoplankton living in symbiosis with coral
what happened on easter island?
overpopulation led to using up coastal organisms, sea birds and tress; complete depletion of the island
why is there no true marine amphibian?
osmosis would cause them to dehydrate. they can survive but not thrive in saltwater