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