Chapter 12: Marine Life and the Marine Environment

3 domains

bacteria: simple life forms w/o nuclei

archaea: simple microscopic creatures

eukarya: complex multicellular

6 kingdoms

archaebacteria

eubacteria

protista

fungi

plantae

animalia

eubacteria

simplest organisms, single celled, no nuclei, cyanobacteria

archaebacteria

microscopic, bacterialike, includes methane producers and sulfur oxidizers of deep sea vents. most ancient life forms on earth

plantae

multicellular photosynthetic plants

surf, grass, eelgrass

animalia

multicellular animals, range from simple sponges to complex vertebrates

protista

single multicellular nucleus (algae, protozoa)

fungi

mold, lichen

carolus linnaeus

1758 came up with taxonomy, modern systematic classification

taxonomy

kingdom, phylum, class, order, family, genus, species

classification of marine organisms

plankton: floaters

nekton: swimmers

benthos: bottom dwellers

types of plankton

phytoplankton: autotrophic, can photosynthesize own food

zooplankton: heterotrophic, relies on food produced by others

bacterioplankton: very small, half of earth’s photosynthetic biomass. likely most abundant photosynthetic organism

meroplankton

part of lives as plankton, juvenile/larval stages

virioplankton

smaller than bacterioplankton

holoplankton

entire lives as plankton

macroplankton

large floaters such as jellyfish or sargassum

picoplankton

very small floaters such as bacterioplankton

nekton

independent swimmers

most adult fish and squid

marine mammals

marine reptiles

benthos

epifauna live on surface floor

infauna live buried in sediments

nektobenthos swim or crawl through water above seafloor

abundant in shallow water, many in perpetual dark, cold, still

hydrothermal vent communities

Abundant and large deep-ocean benthos \n Discovered in 1977 \n Associated with hot vents \n Bacteria-like archaeon produce food using heat and chemicals

how many marine species are there

228,445 out of 1.8 mill species

some not yet identified

2000 new marine and terrestrial discovered every year

more land than marine

what percentage of species is benthic vs pelagic

benthic: 98%

pelagic: 2%

protoplasm

substance of living matter

more than 80% is water

marine mammals don’t risk desiccation

adaptations of marine organisms

physical support (buoyancy)

surface area to volume ratio

streamlining

reproduction: broadcast spawning

why is ocean temp more stable than land

1. higher heat capacity of h20
2. ocean warming reduced by evap
3. solar radiation penetrates deeply into ocean layers
4. ocean mixing

cold vs warm species

floaters smaller in warm water

more appendages in warm

tropical organisms grow faster, live shorter

more diversity in warm

more biomass in cool, due to upwelling

stenothermal

organisms withstand variation with temp

eurythermal

organisms withstand large variation in temp

coastal waters

stenohaline

organisms withstand small change in salinity

\

euryhaline

organisms withstand large variation in salinity

salinity adaptations

diffusion, osmosis

isotonic

organism’s body fluid salinity same as ocean

hypertonic

seawater has lower salinity than organism’s fluids

hypotonic

organism’s fluids have lower salinity than ocean

camouflage

through color patterns

countershading

dark on top, light on bottom

DSL

daily migration of marine animals to deeper dark parts of ocean

dense \[ \] of organisms creates false bottom recorded on sonar readings

causes increased vertical mixing of ocean waters

crepuscular

An animal that is active during dawn and dusk is called ___________.

disruptive coloration

large bold patterns, contrasting colors make animal blend into background

h2o pressure

increases 1 atm every 10 m or 33 feet

many marine organisms have no inner air pockets

collapsible rib cage

water pressure

fish have swim bladder, can regulate depth

pelagic environment

open sea

divided into biozones:

neritic: from shore seaward, all water

benthic environment

sea floor

subneritic and suboceanic

epipelagic

only zone to support photosynthesis

dissolved O2 decreases around 200 m

mesopelagic

organisms capable of bioluminescence common

contains dissolved oxygen minimum layer (OML)

oceanic province

bathypelagic and abyssopelagic zones

75% of living space in oceanic province

where bioluminescence is common

detritus feeding shrimp

euphotic

surface where light supports photosynthesis

disphotic

small but measurable quantities of light

aphotic

no light

supralittoral

transition from land to sea floor above spring high tide line; spray zone

subneritic

spring high tide shoreline to 200 m about 1/2 continental shelf

littoral

intertidal zone

sublittoral

shallow subtidal zone

bathyal

continental slope

abyssal

more than 80% of benthic environment

hadal

below 6000 m, only deep trenches on continental margins