Marine Biology:Introduction to Marine Environment

Marine Environment

• Properties of water

• Basic oceanography

• Ecological principles

• Larval ecology

• Terrestrial vs. Marine ecosystems

• Divisions of marine environment

Oceans: seawater

• 71% surface

• 3.8 km depth

• 1.370 x 106 km3 volume

• Presence of all phyla

Water property

Solvent actions of water

Water property

• Surface tension

• Conduct of heat

• Viscosity

• Latent heat of evaporation

• Heat capacity

• Density (Temp, Salinity, Pressure)

• Dissolving ability

Seawater property

• 96.5% water + 3.5% dissolved compounds (salt)

• Salinity: 34-37 psu

• ppt• %o

• PSU (practical salinity unit)

(Evaporation – Precipitation)

Equator

Seawater constituents: Principle of constant proportions

• Major (99.28%):

Cl (55.04%); Na (30.61%); SO4-2; Mg; Ca; K

• Minor (0.71%):

HCO3; Br; HBO3; Sr (Strontium)

• The remaining 0.01%: (not constant)

Nitrate; phosphate; SiO2; trace metals; organic compounds; gases (O2 and CO2)

Basic oceanography

• Oceans: 4 divisions + marginal seas

Basic oceanography

• Oceans: 4 divisions + marginal seas

• Continental shelf, slope, rise, & abyssal plain

• Seamount & trench

Basic oceanography

• Oceans: 4 divisions + marginal seas

• Continental shelf, slope, rise, & abyssal plain

• Seamount & trench

Basic oceanography

• Oceans: 4 divisions + marginal seas

• Continental shelf, slope, rise, & abyssal plain

• Seamount & trench

• Tectonic plates (板塊 )

Plate Tectonics

• Continental drift

• Seafloor spreading

Plate Tectonics

• Continental drift

• Seafloor spreading

• Subduction

• Hydrothermal vents

Temperature and vertical stratification

• Metabolism: Q10

• Preference & tolerance

• Poikilothermic or ectothermic vs. homeothermic or endothermic

• Thermocline (50-300m)

• Picnocline

• Surface water temperature: SST

T-S diagram: Sigma-t (t) = (density – 1) x 1000

Light: solar radiation

• Photosynthetic Active Radiation

• Euphotic, disphotic, aphotic

• Light extinction coefficientK = (ln I0 – ln Id) / depth (m)

Wave

• Wind wave height: wind speed, distance wind blows, duration wind blows

• Wavelength

Current

• Predominant wind

• Ekman spiral: Corioris effect

Upwelling

• Coastal upwelling

• Equatorial upwelling

Circulation of seawater

• Antarctic convergence: cooling of saline water from equator >>> intermediate water masses

• Antarctic circumpolar: freezing causes cold and saline water sink >>>Antarctic bottom

Atlantic

Pacific

Indian ocean

Ocean conveyor belt

• Thermohaline circulation

• Slowing or shut-down: cooling of Europe

Internal wave

• Flow over tough topography

• Propagate along the picnocline

• Weak surface slick

• Mix deep water in thermocline

• Luzon channel

Ecological principles

• Ecology, Species, community, ecosystem

• Ecosystem components: autotrophic vs. heterotrophic; trophic structure, trophic level, food web vs. food chain

Biomass pyramid

Energy pyramid

Biogeochemical cycles

• Carbon cycle

• Phosphorus cycle

• Nitrogen cycle

Carbon cycle

Phosphorus cycle

Nitrogen cycle

Ecosystem structure

• Niche: fundamental & realized niches

• Habitat

• Dominant

• Species richness, diversity:

species richness not equal to stable environment

• Liebig’s law od the minimum: limiting factor

Ecological control• Competition: competitive exclusion principle

• Predation: predator vs. prey

• Grazing

• Keystone species or key industry species

Benthic invertebrates: distribution & abundance

• Recruitment

• Migration

• Asexual reproduction

• Mortality

Larval types

• Planktotrophic larvae:

mostly in tropics, shallow water

• Lecithotrophic:

more towards polar regions and the deep sea

• Non pelagic (no free-swimming larvae):

as lecithotrophic larvae

Planktotrophic Lecithotrophic

Nonpelagic

Factors affecting larval settlement

K Selection vs. r selection

Opportunistic vs. equilibrium species

• life-history strategy

• Higher frequency of disturbances favors r selective species

• Unequal distribution of disturbance allows coexistence

Terrestrial vs. marine ecosystems

• Carbohydrates vs. proteins

• Vertical distribution

• Large vs. small primary producer

• Carnivores common in marine environment

• More productive on land; more efficient in energy transfer in marine food chains ay lower levels

• Marine food chains much more complicated