Interdependence in the Ocean Chapter 21

AIM To identify important nutrient cycles in the ocean environment To Explain Characteristics of ocean food chains and webs Discuss the importance of symbiotic relationships in the sea Describe how succession occurs in marine environments

Interdependence Is a relationship in which marine organisms interact in a mutually dependent way. Based on the need for food and or protection Example: Schooling bait fish, killer whale pods, or Nemo (clown fish) and sea anemones

Marine Ecology The study of the interactions of living things with each other and their ocean environment Biotic factors- living things in the ocean Abiotic factors- non-living components of the ocean environment (water, temp, light, minerals, dissolved gases

The interaction between biotic and abiotic factors within an environment make up an ecosystem Within ecosystems, many resources are recycled The most important include carbon, oxygen, nitrogen, sulfur, and phosphorus

Carbon Cycle All organic compounds contain carbon Photosynthesizing plants and algae take in carbon in the form of Co2, and produce carbohydrates (organic compounds) Animals take in carbon compounds when they eat the plants Animals give off Co2 through respiration or when they die

Thus making carbon available for plants once again In the marine environment dissolved carbon(carbon dioxide) is taken up by plants and animals and combined with calcium to produce calcium carbonate Which makes shells and body parts Calcium and carbon are again released into the marine environment when the organisms die and decay

Oxygen Cycle O2 is the crucial element needed for cellular respiration in both plants and animals Plants release oxygen into the atmosphere when they split water molecules during photosynthesis Carbon dioxide-oxygen cycle involves the interdependence between plants and animals

Oxygen in water Oxygen in air 21% Oxygen in water 0 - 15 Ppm (mg/l) Much less oxygen is available to aquatic organisms then there is available to terrestrial organisms Oxygen enters by: Photosynthesis of plants, algae, bacteria, protists Wave action, wind, currents, waterfalls

The solubility of oxygen varies with salinity. As salinity increases The solubility of oxygen decreases

The solubility of oxygen in water varies with temperature. As temperature increases Oxygen solubility decreases

Respiration removes oxygen from water The oxygen produced as a by product of photosynthesis may actually bubble out of aquatic environments during daylight hours on warm summer days because of its low solubility. Pollution may cause overgrowth of photosynthetic organisms Sewage - nitrates

Detergents - phosphates

Lawn fertilizer – both nitrates and phosphates

These blooms may produce tremendous amounts of oxygen during the day. At night they continue to respire without photosynthesizing They compete with the animal populations for oxygen.

The combined effect is to decrease the oxygen level below that in which the animals can survive - Causing fish kills Fish kills most frequently occur on very hot days. During the early morning. In areas of poor circulation To large groups of schooling fish

Fish Kills due to harmful algal blooms on the West coast of Florida Dinoflagellate – Gymnodinium breve

These blooms of organisms may color the water producing red stained water - red tides. Some red tide organisms produce toxins which may affect fish and other animal populations

Suspected toxic algae bloom leaves thousands of fish dead “Marine experts from the World Wildlife Fund have flown to Kenya to investigate the death of thousands of marine wildlife believed to be caused by toxic algae. Following what WWF called an apparent "freak, off season" bloom of toxic algae, huge numbers of dead fish, including manta rays, sharks and tuna have washed up on the Kenyan shore” http://www.ananova.com/news/story/sm_509252.html

Thirteen researchers who worked with dilute toxic cultures of Pfiesteria sustained mild to severe adverse health impacts through water contact or by inhaling toxic aerosols from laboratory cultures.

Intense local pollution was implicated in six events in 1999, accounting for approximately 15,000 fish mortalities. The largest single event in this category occurred December 29th after a discharge of #2 heating oil from a local elementary school killed approximately 12,000 fish in Spring Branch, Baltimore County.

Photo 4. The numbers and extent of hypoxic episodes are increasing, especially in areas important to commercial fishing. Concern is spreading as the media report the consequences of these events.

This type of plankton, Ceratium tripos, was responsible for a hypoxic event in the New York Bight in 1976.

Availability of Nutrients Coastal and shallow waters have a greater abundance of life-forms than does the open ocean Why do you think this is true?

Photosynthesis can only occur relatively close to the surface top 100 meters What is this area known as? Plants and algae need nutrients that are released by bacterial decay In the open ocean these nutrients sink to the bottom where there is no light

In shallow water almost all nutrients are available to plant life This plant life supports all other life Limited phytoplankton production limits the growth of all life-forms dependent on those plants

Two most important conditions Availability of nutrients to photosynthetic organisms and; In deep water upwelling of vital nutrients In either case without the availability of nutrients and light to support phytoplankton all other aspects of the food chain are affected

Food Relationships Producers, consumers, decomposers, carnivores, herbivores, omnivores, predators, and prey; parasites and hosts All of these components of the food chain are dependent upon the success of other parts of the chain

Food Chains When one type of living organisms serves as food for another organism which serves as food for the next organisms in the chain Example: Phytoplankton—zooplankton—shrimp—herring--?--?

Refer back to the food relationships which is the first in the food chain? Food chains vary in length but must have at least one producer and consumer

Primary consumer: first animal in the food chain (consumes the producer) (zooplankton) Secondary consumer: feeds on primary (shrimp) Tertiary consumer: feeds on secondary (fish or squid)

Each feeding level is called a trophic level Through each trophic level there is a transfer of chemical energy This chemical energy transfer begins with the producer and moves through the chain Eventually the chemical energy is re-introduced to be recycled

Omnivores- animals that consume both plants and animals Scavengers- organisms that eat the remains of already dead plants and animals Decomposers- break down already dead matter into smaller particles (microbes) Now thought to be up to 1/3 of biomass

Decomposer bacteria and fungi also known as Saprophytes Decomposers break down dead matter into organic molecules and simple compounds which are taken up by producers and recycles energy back into the food chain

Food Webs When food chains interconnect they form food webs These include predator/prey, omnivores relationships Predators can often withstand the loss of one food source However what are the impacts?

What happens to secondary consumers if its only food source is eliminated?

Food Pyramids In a food pyramid the population at each higher trophic level is smaller than the one below it Success of a food pyramid depends entirely on the decreasing population higher up the pyramid

Factoids Only about 10% of absorbed energy is transferred to the next trophic level In order for a shark to produce 10 kg of body tissue it must consume 100 kg of food which was produced as a result of the consumption of 1000 kg of food

Thus food pyramids demonstrate there is more energy available at the bottom of the pyramid Be sure to understand: succession in marine environments, ecological succession, various communities, and succession on islands

Symbiosis in the ocean Symbiosis: close relationship between different species, usually beneficial Mutualism: relationship in which BOTH species BENEFIT Commensalism: relationship in which one organism benefits and the other is not affected Parasitism: relationship in which one species benefits (parasite) while the other is harmed (host)