Marine EcologyGroup 2:Bueno, RiomelCordeñera, DonnaFalcis, Mary Grace
Marine Ecology is the scientific study of marine-lifehabitat, populations, and interactions amongorganisms and the surrounding environmentincluding their abiotic (non-living physical andchemical factors that affect the ability of organismsto survive and reproduce) and biotic factors (livingthings or the materials that directly or indirectlyaffect an organism in its environment).Marine ecology is a subset of the study of marinebiology and includes observations at thebiochemical, cellular, individual, and communitylevels as well as the study of marine ecosystems andthe biosphere.
TROPHICSTRUCTURE TROPHIC LEVELSAll organisms in an ecosystemcan be placed in trophic levelsdepending on what energysource they rely upon and howthey provide energy for otherorganisms in the food web.With the exception of life nearhydrothermal vents in the deepocean, life is always dependentdirectly or indirectly on theenergy from the sun.
ENERGY FLOWThe food chain consists of trophic levels, or the levelswithin the food chain in which energy is transformed. Dueto basic principles of thermodynamics, energy is always lostto the environment any time an organism at one trophiclevel uses the energy from the trophic level below.
COMPONENTS OF AN ECOSYSTEMThere are four parts to every ecosystem: the abioticenvironment (e.g. geology or geography), producers (e.g.phytoplankton), consumers (e.g. shrimp) and decomposers(e.g. bacteria). Energy from the sun and abiotic nutrientssuch as carbon dioxide or minerals are taken in byproducers and transformed into usable energy throughphotosynthesis. Consumers, like herbivores, are dependenton producers to convert sunlight, water, and carbon dioxideinto glucose, which can be then be divided throughrespiration to recover the suns energy. Carnivores aresecondary consumers if they only prey on herbivores andtertiary consumers if they eat other carnivores.Decomposers, the organisms responsible for decomposingdead animal and plant matter, are able to break downorganic waste back into minerals that can be used byproducers.
BIOMASS When biomass is produced through photosynthesis, the amount can be measured in terms of primary production.
NUTRITIONAL GROUPS Organisms in the food chain are categorized into three basic nutritional groups in reference to what kind of carbon, energy, or electron source is utilized to make energy. Heterotrophic organisms use organic substrates and autotrophic organisms use inorganic substrates to obtain carbon. The reducing equivalent source is how organisms get electrons to reduce for biological processes. Lithotrophic organisms utilize inorganic compounds to get electrons and organotrophic organisms use organic compounds to get electrons necessary for biological processes. Phototrophic organisms use light energy and chemotrophic organisms, like those found near hydrothermal vents, use energy from chemical sources.
BIOTIC STRUCTUREBiotic structure describes theway organisms interact withinan ecosystem. The opposite ofbiotic is abiotic, which includesthe physical and chemicalfactors present in theenvironment. Every organism ina species has a limit oftolerance, zone of stress, andoptimum range for the abioticfactors present in itsenvironment. Ecosystems canbe simplified into three basicgroups of organisms:producers, consumers, anddecomposers. Some organismscan be in more than onecategory.
FOOD CHAINS AND FOOD WEBS Food webs illustrate the relationship between animals and what they feed on in the biotic community. Food webs also show how material and energy is transferred and lost within the ecosystem.
FOOD CHAINS A food chain is different from a food web because it illustrates only one energy and nutrient path in an ecosystem. Each platform is a trophic level with one organism that begins with one primary producer and ends with a secondary or tertiary consumer.
FOOD WEBS Food webs are more intricate than food chains and illustrate the feeding relationships between a numbers of organisms at different trophic levels in an ecosystem.
TROPHIC LEVELS Trophic levels are the platforms in the food chain that indicate a position for a particular organism. In a very basic way, a trophic level will indicate whether an organism is a foundation species, primary consumer, or secondary consumer. Information about whether the organism eats plants or animals can also be obtained. Most often trophic levels are used to determine how much energy is lost from the primary producers up to the tertiary consumers. For each trophic level in the food chain, energy is lost due to the laws of thermodynamics.
SYMBIOSIS Symbiosis is a term most often used to describe two organisms living in a close association that benefits both of their survival.
COMPETITION Species better adapted to their environment are able to survive and produce offspring. In biological terms, fitness refers to the number of offspring an organism is able to produce (versus the most well- known term indicating greater physical strength).
PREDATORS The common definition of a predator is one that hunts and kills other organisms for food. It could be claimed that herbivores are predators due to some similarities in their style of seeking and eating food.
THE STRUCTURES ANDADAPTATIONS TO MARINELIVING The ocean covers the majority of the planet, yet it remains a little understood realm as scientists are limited in the study of habitats that lack physical boundaries and can span thousands of miles. Each form of marine life has become adapted to a specific niche with a relatively narrow variation in salinity, temperature, and light. The high salt content found in the ocean can support the large bodies of giant squids and whales, which has allowed them to evolve without the use of strong limbs for support. Nevertheless, salt water exerts enormous pressure on the air spaces of marine animals at depth (fluids like blood are practically incompressible).
CHORDATE ORIGINS Animals in the Phylum Chordata include the vertebrates and some of the more primitive nonvertebrates like the protochordates, lancelets, acorn worms, tunicates, and the pterobranchs. The first vertebrates appearing in the fossil record during the Cambrian age were animals that resembled fishes and had respiratory gills formed by pharyngeal gill slits located in a set of pouches. The first purpose of the skeleton and scales were to protect the animal, to add support to the notochord, and to keep the brain protected. Later, a true backbone (rather than a notochord) evolved in marine animals.
REPTILES The reptiles came about as a novel group of terrestrial animals from the amphibians. Reptiles were extremely successful on land and quickly became the dominant animal for the next 150 million years. When mammals evolved, they took over the dominant position leaving the reptiles to crawl back into the ocean. The reptiles that survived include the snakes, turtles and lizards many of which have changed a little so they can live more successfully in salt-water environments.
MAMMALS Marine mammals include the Order Cetacea (porpoises and whales), the Order Carnivora (animals like seals), and the Order (dugongs, manatees and sea cows). Marine mammals are still warm-blooded and have to keep the temperature of their bodies above that of the ocean. Adaptations that have helped solve this problem include the reduction of surface area and the increase in internal volume, a fatty layer of blubber under very thick skin, and a reduction in the amount of blood going to areas in contact with the cold water. Unlike land animals, marine mammals are also able to dive very deep into the water without getting the bends because as they dive down deeper they exhale instead of inhale like we do.
ANIMALS WITH SHELLS About 500 million years ago, animals with hard-shells became prominent in the fossil record in the Phylum Molluska. The evolution of an impenetrable shell was obviously a very helpful trait for an animal to possess because now mollusks are found in almost every known environment. Animals with hard shells are protected from predation and drying out and some can even use their shell to float if necessary among other things.
EFFECTS OF POLLUTION ANDHUMAN ACTIVITIES ON THEMARINE LIFE Oceans constitute around 70% of the surface of earth and are an important part of the ecological cycle. Oceans are vast water resources and are home to millions of plants and organisms. Unabated human-activity has resulted in degradation of marine life and there are several species of organisms that are on the verge of extinction. The harmful and toxic substances that come out of industries are dumped into oceans, putting plants and animals to grave risks.
Causes of OceanPollutionMarine transportationand oil spills: Oil spills area major cause of oceanpollution. Oil is spilledmostly from oil containerswhich are being transportedfrom one place to anotheron ships. Oil spills can alsobe a result of leakage fromaircraft flying over theocean.
Garbage and sewage: Thegarbage and sewage that isdumped by shipsdeliberately into the oceansis one of the biggestcontributors to oceanpollution. Garbage andsewage contains toxicchemicals and these canstay in the ocean for a longtime.
Acid rain: Acid rain is nota natural phenomenon but aresult of industrial andautomobile pollution.Poisonous gases from thesesources are released in theenvironment which whencombined with rainwaterforms acid rain. Acid rainfacilitates the transfer ofharmful gases to oceans.
Impact of Ocean Pollution on Marine Life Like humans, marine organisms also need oxygen for their survival. Oxygen is present in the dissolved form in the oceans and the toxic substances have an ability to absorb this dissolved oxygen, thus resulting in decrease in the oxygen levels inside the oceans. Pollutants also stimulate the growth of certain organisms that are harmful for marine organisms. The contamination of ocean water with poisonous chemicals and toxins has already killed hundreds of thousands of marine organisms and many more are under the threat of extinction. The chemicals also have far-reaching effects as these interfere with the genetic make-up of organisms and cause various physiological changes. Because of this continuous exposure to chemicals and toxins, around two-thirds of marine life has been declared as threatened species.
ECONOMIC REGULATIONS Ecosystems are controlled by a multitude of factors, each influencing the other. Almost all living organisms rely on the energy from the sun. Organisms at the base of the food chain, such as phytoplankton and plants, use the suns energy directly. Organisms higher on the food chain receive energy from the sun indirectly. The only organisms on the planet capable of producing energy without the sun are microorganisms called chemoautotrophs that often live near deep sea vents and synthesize energy through a chemical process.
ENERGY There are thousands of species of primary producers in the ocean that convert inorganic carbon into organic compounds. phytoplankton’s are responsible for 95% of all primary production and use energy from the sun directly. These primary producers absorb energy from the sun through pigments inside the chloroplasts or through membranes in the cytoplasm of bacterial cells.
“There are things in life that areyet to be discovered, mysteries tobe solved and puzzles to be puttogether, but never forget totreasure what we have now andwhat we loved the most.”