Full Oceanography Exam 2

Melting sea ice does not raise sea level because it already floats in the ocean

Does melting sea ice raise sea level?

Main causes: melting continental glaciers and thermal expansion of seawater

What causes sea level rising?

Satellite data show about 3 mm per year

how much does sea level rise?

Has risen about 10–25 cm over the past 100 years

how much has sea level risen in the past 100 years?

Dissolved CO₂ forms carbonic acid, Lower pH makes shell secretion harder, Dissolves coral, Harms larvae and fish reproduction

What are some side effects of increased acidification?

Arctic sea-ice area has been decreasing, Antarctic ice shelves are shrinking

What are some effects of climate change on sea ice?

Freshwater from melting glaciers lowers salinity and density at the surface, which can

inhibit downwelling and alter deep-water circulation.

what happens when glaciers melt?

Ocean absorbs about 93% of trapped heat

How much heat does the ocean absorb?

Ocean absorbs about 25% of CO₂ added to the atmosphere

How much CO2 does the ocean absorb?

Increasing ocean temperature, Changes in deep-water circulation, Changes in sea ice, Seawater acidification, Rising sea level

What are 5 ocean changes due to climate change?

CO₂, CH₄, H₂O vapor

What are key greenhouse gases?

Earth absorbs shortwave solar radiation, Earth re-emits longwave infrared radiation, Greenhouse gases absorb some of that infrared energy and warm the atmosphere

What is the greenhouse gas effect?

The lecture links increasing atmospheric CO₂ since the Industrial Revolution to a stronger greenhouse effect and atmospheric warming.

What is the effect of the Industrial Revolution?

The oceanic biological pump moves carbon from the atmosphere through the ocean and into seafloor sediments by photosynthesis, shell-making, feeding, and death. This makes the ocean a sink for CO₂.

What is the oceanic biological pump?

Amplify change = positive feedback, Reduce change = negative feedback

What can feedback loops do?

Hydrosphere, Lithosphere, Atmosphere, Biosphere, Cryosphere

What are spheres in the Earth’s climate conditions?

Climate involves long-term atmospheric conditions and the ocean is the largest part of Earth’s climate system

How does the climate relate to the ocean?

Biological pollution includes non-native/invasive species that outcompete native species. Examples from the lecture include zebra mussels, lionfish, and Caulerpa taxifolia

What is biological pollution?

Nurdles = pre-production plastic pellets, Microbeads = tiny plastic particles 1–5 mm, Plastic is transported by rivers and then redistributed by surface currents, helping form garbage patches.

What are some things to know about plastic?

Plastic is the main form of solid marine debris: Floats, Degrades slowly, Entangles organisms, Is mistaken for food, Can absorb toxic substances like DDT and PCB

What are some more plastic facts?

Bacteria convert elemental mercury into methyl mercury, which is highly toxic. The lecture uses Minamata Bay as the major case study and links mercury poisoning to neurological disease.

What is mercury’s effect?

Bioaccumulation = pollutant concentration builds up in one organism, Biomagnification = concentration increases up the food chain

What are some terms for pollution?

Both highly toxic, DDT caused thin eggshells in birds, PCBs are carcinogenic, Both were banned in the 1970s, They are persistent organic pollutants that remain in seawater and sediments for a

long time

DDT and PCB effects

habitat and mobility

marine organisms can be grouped by

drifters

plankton

active swimmers

nekton

bottom dwellers

benthos

autotrophic, photosynthetic plankton

phytoplankton

heterotrophic, animal plankton

zooplankton

drifting bacteria

bacterioplankton

drifting viruses

virioplankton

plankton for their entire life

holoplankton

plankton only during juvenile/larval stages

meroplankton

2-20 cm

macroplankton

.2-2 um

picoplankton

pelagic and benthic environments

ocean is divided into

water column

pelagic environment

seafloor

benthic environment

surface to 200 m

epipelagic

200-1000 m

mesopelagic

1000-4000 m

bathypelagic

below 4000 m

abyssopelagic

euphotic, disphotic, aphotic

what are the light zones?

enough light for photosynthesis, roughly surface to ~100 m

euphotic

dim light

disphotic

no sunlight

aphotic

support

what do buoyancy and friction provide?

rises, drops

viscosity increases as salinity _____ and temperature ___

high, sinking

small organisms have ____ surface area-to-volume ratio, helping them resist ____

streamlining

larger swimmers benefit from

broadcast

reproduction often includes _____ spawning

osmosis

salinity affects organisms through ____

internal salinity equal seawater

isotonic

internal fluids saltier than seawater

hypertonic

internal fluids less salty than seawater

hypotonic

isotonic

most marine invertebrates are _____

hypotonic, seawater, salts

saltwater fish are _____, so they drink ____ and expel ____ through their gills

the rate at which organisms store energy by forming organic matter from inorganic carbon

primary productivity

directly, indirectly, photosynthesis

nearly all ocean biomass depends ____ or ____ on _____

autotrophs

produces are ____ such as plants, algae, bacteria, and phytoplankton

heterotrophs

consumers are ____

nutrients and sunlight

what are the key limits on productivity?

nitrogen, phosphorus, iron, calcium, carbon, and silica

what are some important nutrients for productivity?

nutrients, because overall coastal areas can be productive even when water is less clear

are nutrients or sunlight the main limiting factor for productivity? why?

depth below which photosynthesis is no longer possible

compensation depth

productive surface layer, about 100 m in the open ocean

euphotic zone

ocean margins, estuaries, upwelling zones, continental shelves, and algae beds and coral reefs

highest productivity occurs in

open, tropics, sunlight, nutrients

low productivity occurs in much of the ____ ocean and ____, where ____ is available but ____ are scarce

low, thermocline, nutrients

in low productivity zones, tropical productivity is ___ because a _____ inhibits mixing and keeps deep ____ from reaching the surface

large summer bloom, strong seasonality

what are the regional patterns in polar oceans

spring and autumn blooms

what are the regional patterns for mid-latitudes

steady but low productivity, except where upwelling occurs

what are the regional patterns for tropics

seed-bearing plants, macroscopic algae, microscopic algae, photosynthetic bacteria, including Prochloroccus

photosynthetic groups

green, red, brown

types of macroscopic algae

diatoms, coccolithophores, dinoflagellates

types of microscopic alage

SiO2

Diatoms use ____

CaCO3

Coccolithophores use ___

red

Dinoflagellates can cause ___ tides

a bloom of dinoflagellates that can create harmful algal blooms. these blooms may reduce oxygen through decomposition and may also release toxins harmful to fish, shellfish, mammals, and humans

what is a red tide

nutrient enrichment, often from fertilizer, sewage, or animal waste runoff. it can trigger blooms and produce dead zones, where oxygen becomes too low for many organisms. benthic organisms are often hit hardest because they cannot easily leave

what is eutrophication

unidirectional

energy flow in marine ecosystems is _____

sunlight —- producers ——- consumers ——- heat

Arrows

cycled, producers, consumers, decomposers

nutrients are ____, not lost. ____ take them up, ____ transfter them, and ____ return them to usable forms

herbivores, carnivores, omnivores, bacteriovores, decomposes

feeding categories (know them!)

carnivory, filter/suspension feeding, deposit feeding

feeding strategies (know them!)

feeding stages in the food web

trophic levels

10, 2, sunlight, phytoplankton

only about ___% of energy typically transfers to the next trophic level, and only about ___% of ______ is converted into chemical energy by _______

gas or fluid filled buoyancy structures, swimming, oils or fats in some zooplankton

pelagic animals avoid sinking by

cephalopods, gas

_____ may use rigid ___ containers

swim bladders

many fish use ____ ____ to avoid sinking

SiO2 tests with spikes

zooplankton group: radiolarians

CaCO3 tests

zooplankton group:foraminifers

major zooplankton biomass

zooplankton group: copepods

important macroscopic zooplankton, especially in the Southern Ocean

zooplankton group: krill

Portuguese man-of-war, jellyfish

zooplankton group: cnidarians

thrust

caudal fin gives ____

stabilize

vertical fins ___

steer, balance

pectoral and pelvic fins ____ and ____

pressure

lateral line detects ______ changes