Oceanography Test 3 Notes

define coastal waters

shallow areas of the ocean over the continental shelf directly influenced by freshwater runoff, winds, and tides

define the open ocean

beyond the continental shelf where conditions are more stable and uniform

what’s an estuary?

a partially enclosed coastal body of water where freshwater runoff from rivers mixes with salty ocean water

what is the head of an estuary?

where freshwater enters

what is the mouth of an estuary?

area open to the ocean

how are estuaries classified?

by geologic origin

how are coastal plain (drowned river) estuaries formed?

rising sea levels flood an old river valley

how are fjord estuaries formed?

sea level floods a glacially carved valley, common in high latitudes

how are bar built estuaries formed?

sandbars or barrier islands create a lagoon as sea level rises

how are tectonic estuaries formed?

tectonic movements creates a down dropped coastal basin that floods with sea water

what are positive estuaries?

where river inflow exceeds evaporation; there are 4 mixing patterns

what are negative estuaries?

there is high evaporation and low river inflow; occurs in arid regions; surface salinity increases toward mouth as evaporation leaves behind salts, dense, saline water sinks

what are the characteristics of vertically mixed estuaries?

shallow, low freshwater input; salinity is uniform from top to bottom, increasing toward the mouth

what are the characteristics of slightly stratified estuaries?

two layers. a fresher surface layer flowing seaward and a saltier bottom layer flowing landward; weak halocline

what are the characteristics of highly stratified estuaries?

deep estuaries with strong layering; the surface layer’s salinity increases toward the mouth and the bottom layer stays constant

what are the characteristics of salt wedge estuaries?

high volume rivers; freshwater completely overlays the salty water, forming a wedge of seawater underneath

how is the Chesapeake bay classified?

coastal plain; slightly stratified

how is the Delaware bay classified?

coastal plain; vertically mixed

how is the Pamlico sound classified?

bar built; vertically mixed

how is the San Francisco bay classified?

tectonic; slightly stratified

how is the Columbia River estuary classified?

drowned river valley; salt wedge

how is the laguna madre classified?

bar built; negative estuary

what type of wetlands border estuaries?

salt marshes and mangrove forests

what are the characteristics of salt marshes?

found in mid latitudes; dominated by salt tolerant grasses like cordgrass; zoned by tidal submergence and serve as nutrient rich, dynamic ecosystems

what are the characteristics of mangrove forests/mangals?

found in low latitudes, composed of salt tolerant trees with prop roots; they support diverse wildlife and stabilize coastal sediment

why are estuaries and bordering wetlands valuable?

provide nursery habitats for over half of commercially important fish species, filter pollutants, buffer coastlines against erosion and storm surge, support recreation and tourism, mangrove forests provide timber

what are the four ways biologists classify living organisms?

taxonomy, behavioral, habitat, and functional

explain taxonomy

a hierarchical system for classifying life; organisms are grouped by similarities in physical and genetic trains into domain, kingdom, phylum, class, order, family, genus, and species

explain behavioral classifications of organisms

groups organisms by how they act; example feeding or movement strategies

explain habitat classifications of organisms

groups organisms by where they live; example plankton (drifters), nekton (swimmers), an benthos (bottom dwellers)

explain functional classification of organisms

groups organisms by their role in the ecosystem or trophic level; like primary producers, grazers, and predators

what is the three domain system?

classifies all life into the 3 broad domains of bacteria, archaea, and eukarya; system replaced the older five-kingdom model as genetic research developed

what are the characteristics of bacteria?

simple, single celled organisms without a nucleus

what are the characteristics of archaea?

microscopic organisms similar to bacteria, often found in extreme environments like hydrothermal vents

what are the characteristics of eukarya?

complex organisms with a nucleus; includes plants, animals, fungi, and protists

how do species abundance and diversity compare between land and ocean?

about 86% of specifies like on land while 14% live in the ocean; land environments are more variable, leading to more specialization and diversity; marine conditions are stable meaning there’s less need for diversity; 98% of species live on seafloor

how do the physical/abiotic environments differ between land and ocean?

ocean environment more stable than land; water has high heat capacity while land experiences rapid temperature fluctuations, seasonal changes, and variable humidity; light, salinity, pressure, and viscosity play larger roles in shaping life in the ocean

what 5 adaptations help ocean organisms cope with sinking, light limits, temperature, salinity, and gas exchange?

buoyancy and sinking, light, temperature, salinity and water balance, gas exchange

what are the characteristics of buoyancy and sinking adaptations?

organisms increase surface area to volume ratio or use appendages, oil droplets, or gas bladders to stay afloat; streamlined swimmers (tuna and sea turtles) reduce drag and turbulence

what are the characteristics of light adaptations?

accessory pigments help photosynthetic organisms absorb light of different wavelengths; red coloration in deep sea animals makes them invisible in low light

what are the characteristics of temperature adaptations?

stenothermal species tolerate small temp ranges, eurythermal species tolerate wide ranges; some fish use rete mirabile to keep muscles warm

what are examples of stenothermal species?

deep ocean and coral reef species

what are examples of eurythermal species?

coastal and migratory species

what is rete mirabile?

countercurrent heat exchange used to keep the muscles warm

what are the characteristics of salinity and water balance adaptations?

marine fish drink seawater and excrete excess salt through gills; sharks retain urea to match seawater salinity without drinking; marine plants excrete or exclude salts and store them in sacrificial leaves

what are the characteristics of  gas exchange adaptations?

diffusion across membranes in single celled organisms; gills, branchiae, and respiratory trees in invertebrates; fish gills use countercurrent exchange to maximize oxygen uptake

explain broadcast spawning reproduction

releasing eggs and sperm into the water for external fertilization; corals

explain internal fertilization reproduction

fertilization occurs inside the organisms with eggs often laid or brooded

explain brooding reproduction

parents protect developing offspring; seahorses brood in a pouch, some fish brood eggs in their mouths

what 2 main strategies do marine organisms use to evade predation?

physical and coloration adaptations and behavior adaptations

explain physical and coloration adaptations to evade predation

camouflage (blending in), transparency (plankton and jellyfish), disruptive coloration (confusing predators), countershading (dark on top, light on bottom to conceal)

explain behavioral adaptations to avoid predation

schooling, symbiosis (mutualism, commensalism, and parasitism), vertical migration (zooplankton move deeper during the day to avoid predators and rise at night to eat)

what is primary productivity?

measures the rate at which energy is stored in organic matter, usually expressed as how much carbon is fixed per area or volume per unit of time; represents the energy available to all other organisms in the ecosystem

what is primary production?

the process by which organisms store energy in carbon bonds, forming the base of the food web

what are the two types of primary productivity in the ocean?

photosynthesis and chemosynthesis

how do the two types of primary productivity in the ocean differ?

photosynthesis uses solar energy while chemosynthesis uses chemical energy to create food

explain photosynthesis

used by most marine producers to convert sunlight, water, and carbon dioxide into sugar and oxygen; process supports 99.% of all life in ocean

explain chemosynthesis

used by specialized bacteria near hydrothermal vents; uses chemical energy from inorganic compounds to produce organic material

what are the global trends in oceanic primary production?

high productivity in coastal waters and upwelling zones where nutrients are abundant; lowest productivity in open ocean (especially subtropical gyres) where nutrients are scarce; polar regions have abundant nutrients but limited, seasonal sunlight

what two main methods do oceanographers use to measure ocean productivity?

gaarder and gran bottle method and satellite methods

explain the gaarder and gran bottle method of the 1920s

seawater samples are placed in light and dark bottles, oxygen levels are measured before and after incubation, light bottom measures NPP while dark bottom measures respiration only, both values are added to get gross production, radioactive carbon is sometimes used to measure productivity more precisely

explain satellite methods to measure ocean productivity

measures chlorophyll concentrations, algorithms convert chlorophyll data into estimates of primary productivity, satellite images show highest chlorophyll levels in coastal, polar, and upwelling regions

what are the 4 main groups of photosynthetic organisms found in the ocean?

anthophytes, macroscopic algae, microscopic algae, photosynthetic bacteria 

what are the characteristics of anthophytes?

flowering lants found in shallow coastal waters; include seagrasses, mangroves, and salt marsh grasses

what are the characteristics of macroscopic algae?

seaweeds that include brown (phaeophytes) like kelp, red (rhodophytes), and green (chlorophytes) algae; common in coastal and shallow regions

what are the characteristics of microscopic algae?

phytoplankton like diatoms, coccolithophores, and dinoflagellates (that can cause red tides); perform most oceanic photosynthesis

what are the characteristics of photosynthetic bacteria?

includes cyanobacteria, green and purple sulfur, and non-sulfur bacteria; mat makeup half of the total photosynthetic biomass in the ocean

what are the characteristics of primary productivity in polar regions?

in winter there is no sunlight or photosynthesis, in spring sunlight returns causing nutrient abundance and a huge phytoplankton bloom, summer and fall brings grazing and nutrient depletion reducing productivity, short but intense growing season

what are the characteristics of primary productivity in temperate regions?

winter has limited light but high nutrients, spring has increasing light and nutrients resulting in a major bloom, summer brings stratification which isolates surface and decreases nutrients and productivity, cooling and storms remix nutrients in fall resulting in smaller bloom, two peaks per year in spring and fall

what are the characteristics of primary productivity in tropical regions?

year round sunlight but strong thermocline prevents nutrient mixing, low productivity except where upwelling occurs, coral reefs are local productivity hotspots due too symbiotic algae

what are the 4 main feeding strategies common among marine organisms?

deposit, filter/suspension, predation, decomposition/detritivory

what are the characteristics of deposit feeding?

animals feed on organic material that settles on the seafloor, often by ingesting sediment and extracting nutrients (sea cucumbers)

what are the characteristics of filter/suspension feeding?

animal filter small food particles or plankton from the water using specialized structures like gills, baleen, or mucous nets (clams, sponges, baleen whales)

what are the characteristics of predation feeding?

active hunters capture and consume other living organisms

what are the characteristics of decomposition/detritivory feeding?

organisms feed on decaying organic material or waste (bacteria, worms, crabs)

how does energy flow through marine communities?

via trophic levels (producers, primary consumers, secondary, tertiary, top predators) where 10% of energy moves up trophic levels

what’s the difference between a food chain and a food web?

a food chain is a linear sequence showing one path of energy flow while a food web is a complex, interconnected network of food chains

what is the microbial loop?

the recycling pathway of energy and nutrients in the ocean; primary producers leak dissolved organic material into water, bacteria and other microbes eat it, the microbes are then eaten by protozoans which are eaten by zooplankton; allows energy to return to main food web; 50% of all primary production goes through it

what are examples of detrital food webs in the ocean?

wetland ecosystems (salt marshes and mangroves) and kelp forests

what are the characteristics of wetland ecosystems in terms of detrital food webs?

vascular plant material decomposes slowly because its hard to digest, microbes break down the material making nutrients available, deposit and suspension feeders eat detritus and microbes

what are the characteristics of kelp forests in terms of detrital food webs?

dead and decaying kelp forms detritus pool, filter and suspension feeders consume detrital material in water column, ensures energy continues to flow from primary producers to higher trophic levels

what trends occur in the number of individuals at successive trophic levels?

decreases; fewer predators than prey because energy availiablity declines at each level

what trends occur in total biomass at successive trophic levels?

decreases; most energy is lost so less mass is supported at higher levels

what trends occur in organism size at successive trophic levels?

increases; higher trophic levels typically consist of larger organisms

how can you identify a marine food chain and determine the trophic level of each organism within it?

what are examples of marine food chains based on phytoplankton?

what are examples of marine food chains based on macroalgae?

what is one adaptation a marine organism has evolved to avoid predation?

what is one adaptation a marine organism has evolved to help it find or catch prey?

how do marine organisms time their reproductive cycles to coincide with the spring bloom?

how do reproductive adaptations improve their chances of survival and reproductive success?

how are benthic organisms and habitats distributed geographically?

over 98% of known marine species live in or on the seafloor; majority is found on the continental margins, below the most productive surface waters; extend from the intertidal zone along shorelines to the deep ocean floor

what is the benthos?

the seafloor

where do infauna live?

within the sediment

where do epifauna live?

on top of the seafloor

what is the physical environment like in intertidal (littoral) ecosystem zones?

between high and low tide marks; organisms experience alternating exposure to air and water, wave energy, temp fluctuations, and salinity changes from rain and runoff; adaptations are needed for desiccation prevention, attachment, and heat balance

what is the physical environment like in shallow subtidal ecosystem zones?

always submerged and usually sunlit allowing photosynthesis; found along the continental shelf with soft sediments or rocky bottoms; includes kelp forests and coral reefs

what is the physical environment like in deep sea ecosystems?

completely dark; no photosynthesis; food comes from marine snow or chemosynthesis; found at hydrothermal vents, cold seeps, and trenches, where microbes use chemical energy to produce food

what biological adaptations help benthic organisms survive in their environments?

intertidal, subtidal, and deep sea

what are the benefits of intertidal adaptations?

prevents drying (shells, thick skin, mucous coatings, or hiding in cracks/pools), wave resistance (barnacles cement themselves, mussels use byssal threads), heat regulation (shell color affects heat absorption; dark=cold light=hot)