The Ocean’s primary Productivity

Marine Biomass

Phytoplankton bloom

Environment Ecosystem – composed of living

organisms and their nonliving environment

Biotic – living organisms Abiotic – physical characteristics

Habitat An organisms habitat is where it lives

Niche: An organism’s environmental role

An organisms niche is the role the organism plays in its community An organisms niche is determined by a

variety of biotic and abiotic factors acting together on the organism.

Environmental Factors Maintaining Homeostasis

An organisms ability to maintain a stable internal environment regardless of the external environment

Homeostasis and the distribution of marine organisms

Optimal range allows for an organism to thrive and reproduce (sunlight, nutrients)

Zones of stress are areas above or below the optimal range

The organism expends more energy maintaining homeostasis

Less energy is available for reproduction Zones of intolerance are areas beyond the optimal

range where the organism cannot survive

Environmental factors continued

Physical environment Sunlight Temperature Salinity Pressure Metabolic requirements Metabolic wastes

Sunlight Sunlight penetration

less than 1 meter in coastal waters as much as 200 meters in tropical waters

Photosynthesis directly or indirectly provides energy to nearly all forms of life on earth Phytoplankton – the largest group of

photosynthetic organisms in marine environments

Phytoplankton are the primary sources of nutrients and energy for marine animals

Temperature Temperature influences the distribution of

organisms Ectotherms – obtain body heat from

surroundings Endotherms – maintains a constant body

temperature Most organisms can tolerate only a

specific range of environmental factors Temperatures above or below the critical range

disrupt metabolism resulting in: Decreased ability to reproduce, injury, or death

Salinity Salinity is a measure of the concentration

of dissolved inorganic salts in the water In order to maintain homeostasis all

organisms must maintain a proper balance of water and solutes in their bodies

The process of osmosis is vital to cells If a cell loses too much water it will become

dehydrated and die If a cell takes in too much water it will swell

and burst

Pressure The pressure of the water affects

organisms that inhabit the deep regions of the seas Some animals must have special

adaptations that allow them to survive at great depths to avoid compression (diving) and decompression (surfacing)

Metabolic Requirements The availability of nutrients

influences the distribution of organisms in the marine environment Nutrient – all of the organic and

inorganic materials that an organism needs to reproduce

Metabolic requirements continued

Limiting nutrients (ex. nitrogen, phosphorus)

Anaerobic organisms – survive in the absence of oxygen

Aerobic organisms – require oxygen Eutrophication –nutrient enrichment Algal bloom – population explosion of

photosynthetic plankton

Metabolic wastes Waste products are usually removed

from the environment by organisms or broken down by bacteria

Waste products can accumulate to toxic levels and prohibit growth

Environmental factors continued

Biological Environment Biological environment - all of the

different species and the interactions an organism comes in contact with

Relationships Competition Predator-Prey relationships Symbiosis: Living together

Competition Two or more species in the same habitat

that have the same requirements for resources that are limited in supply are in competition

Predator-prey relationships Keystone predator (keystone species)

– An animal in a community that makes it possible for other species to live there

Ochre seastar REMOVAL OF A CERTAIN SPECIES OF

STARFISH CAUSED A RAPID GROWTH IN THE NUMBERS AND BIOMASS OF THE MUSSEL UPON WHICH THE SEASTAR FED

Symbiosis: Living together Symbiosis – any prolonged association or

living together of two or more organisms of different species

Mutualism Both organisms benefit

Commensalism One organism benefits, the other is neither

harmed nor benefited Parasitism

One organism benefits, the other is harmed

Distribution of Marine Communities

Pelagic Division – the water column Benthic Division – the ocean bottom

Ecosystems: Basic units of the Biosphere

Producers – organisms that contain pigments like chlorophyll that capture the sun’s energy

Photosynthesis – the process by which energy of sunlight is used to form glucose

Chemosynthesis – the process by which energy from chemical reactions is used to construct organic glucose

Producers Autotrophs – organisms able to

produce their own food Chemoautotrophs – organisms that

use energy from inorganic chemicals to produce their own food

Measuring Primary Productivity

Grams of carbon per square meter of surface area per year

gC/m2/yr

Ecosystems: Basic units of the Biosphere continued

Trophic Levels

Primary Producers(Phytoplankton)

Primary Consumers(Zooplankton)

Secondary Consumers

HumansCarnivores

Only about 10%of the energy is

transferred (Filter Feeders)