unit 2: seawater

marine science

what do covalent bonds do?

connects together things within a water molecule

oxygen is ___

negative

hydrogen is ____

positive

what do hydrogen bonds do?

connect different water molecules to one another

positive hydrogen + negative oxygen =

hydrogen bond

what is waters most important property and what does it do?

polar; water can stick to other things

what does water’s polarity allow it to do?

be the universal solvent

what is water in a gas form?

water vapor

which phase of water is the LEAST dense?

least = ice

which phase of water is the MOST dense?

liquid

why is ice less dense than water?

water molecules spread out due to hydrogen bonds as water freezes

specific heat capacity

amount of heat needed to change the temp of something

how do oceans help regulate heat in coastal areas?

traps heat during day ——> cools land; releases at night ——> warms land. regulates the temp.

COhesion (**co = together)

water molecules stick together

ADhesion

water molecules stick to other substances

what is the equation for density

D = M/V

what is density measured in?

g/mL

salinity

amount of salt in a body of water

percentage of salt to fresh water on earth?

97% salt 3% fresh

where does most of earth’s fresh water come from?

glaciers and ice caps

how does water get salinity?

natural salts dissolve from land rocks

most abundant salt?

NaCl (sodium chloride)

what is the average salinity of the ocean?

35 ppt

osmoregulation

process of maintaining salt + water balance within body

how do marine mammals do osmoregulation (in case she asks for example)

they get water from food and then produce urine with high salt concentrate

why are surface waters extra salty?

evaporation. water evaporates and leaves salt behind

higher salinity =

higher density

halocline

where salinity rapidly changes with depth

what is surface tension?

ability of water to support small objects due to hydrogen bonds at the surface

how does latitude affect salinity?

salinity is LOWER near the EQUATOR because of high precipitation

where is the maximum salinity?

20 N and 20 S

thermocline

area where temp rapidly changes

how cold is the deep ocean?

~ 4 degrees celcius

average density of the ocean?

~ 1.02 - 1.05 g/cm³

density of pure H20?

1.0 g/cm³

buoyancy

upward force that keeps materials afloat in fluids

pycnocline

area where density rapidly changes with depth

LOWER temp =

HIGHER density

HIGHER salinity =

HIGHER density

what is the pressure at sea level? (atm=atmospheres)

1.0 atm

what are the most important nutrients in the ocean?

nitrates + phosphates

why are nitrates and phosphates called limited nutrients?

photosynthesis could not occur without them

where do phosphates + nitrates come from?

land rocks/nitrfication by bacteria

nutrients are ____ @ the surface because…

lower bc they are used up by photosynthetic animals

nutrients are ___ in the deep ocean because…

HIGHER bc no photosynthesis

where/what is the oxygen minimum layer

@ 1000m; oxygen is the lowest it will ever be here

what causes the oxygen minimum zone?

there is a bunch of bacteria breaking down dead matter, so they are using respiration. this uses up all off the oxygen

average depth of all oceans?

~4000 m

pelagic =

up in the water

benthic =

on the bottom (seafloor)

what are the two zones in the pelagic?

neritic + oceanic

neritic zone - (closer to land)

from low tide to the edge of cont. shelf

oceanic zone -

open water between edges of continental shelves

how does light attenuation change with depth? (red wavelengths are bigger)

blue/green penetrate furthest, red/orange is lost quickest

when can light not penetrate

nothing past 1000m

name the five ocean zones in order

epipelagic, mesopelagic, bathypelagic, abyssalpelagic, hadalpelagic

epipelagic (EUPHOTIC)

enough light for photosyntheis; “sunlight zone”

mesopelagic (DISPHOTIC)

a little bit of light; “twilight zone” no photosynthesis

what zone are the bathy, abysso, and hadal

aphotic

bathypelagic

“midnight zone”

abyssopelagic

“the abyss”

bioluminescence

emission of light by living organisms

what two zones are in the benthic zones?

littoral + sublittoral

what percentage of marine life is benthic?

98%

littoral =

near shore; between low and high tide

sublittoral

covers continental shelf from low tide to shelf break

how does sedimentary rock form?

formed when sediments are cemented

how does metamorphic rock form?

formed under immense heat/pressure

how does igneous rock form?

formed when lava/magma cools

sediments are

small pieces of material broken down by weathering

four types of sediment?

terrigenous, biogenous, hydrogenous, cosmogenous

terrigenous comes from ….

land rocks and has the HIGHEST volume

what makes terrigenous sediments? they are found where?

erosion of rock by water/wind/ice; near continents and islands

what are terrigenous (lithogenous) sediments made from?

quartz + clay

biogenous sediments are

from life; shells and hard skeletons

which two organisms contribute to calcium carbonate?

plankton + corals

what creates hydrogenous sediments (very rare)

from water; dissolved nutrients come out of solution

what creates cosmogenous sediments (very rare)

outer space cosmic dust