Bio 3202 (Marine Biology/Ecology) PDF

# Bio 3202 (Marine Biology/Ecology) ## Textbook: Introduction to Marine Biology * by: George Karleskint ## Introduction ### 1. The Importance of Oceans and Marine Organisms * Oceans are the most important physical feature of our planet * Cover nearly 71% of the earth's surface * Represent...

# Bio 3202 (Marine Biology/Ecology) ## Textbook: Introduction to Marine Biology * by: George Karleskint ## Introduction ### 1. The Importance of Oceans and Marine Organisms * Oceans are the most important physical feature of our planet * Cover nearly 71% of the earth's surface * Represent the last great expanse on this planet to be charted and explored * Physical characteristics of these great bodies of water directly affect our everyday lives * Living organisms that inhabit the oceans are an important source of food and natural products. * Ocean productivity - (a) the amount of food marine organisms can produce and (b) the number of organisms the oceans can support is an important area of research in marine biology. * Marine organisms play an important role in scientific research. Species inhabiting the sea and seashores are ideally suited to the study of such varied fields as ecology, physiology, biochemistry, biogeography, behavior, genetics, and evolution. ### 2. The Study of the Sea and its Inhabitants * Oceanography - is the study of the oceans and their phenomena such as waves, current, and tides * The science of oceanography draws from many different disciplines including: * Chemistry * Physics * Geology * Geography * Meteorology * Biology * Marine biology - the study of the living organisms that inhabit the seas and their interaction with each other and their environment. * Oceanography and Marine biology - these two areas of study are not completely distinct from each other and they frequently overlap. It is necessary to combine elements from both fields in order to form a complete picture of the oceans and their inhabitants. ## History of Marine Biology * Human interest in the sea probably dates back to the time we first set eyes on it, fished its waters, and sailed across it. * Early attempts to study the sea creatures can be traced back to the ancient Greeks and Romans. * **Aristotle** - a Greek philosopher * An accomplished naturalist * First to develop a scheme of classification which he called the "ladder of life" * Writings contain descriptions of over 500 species of which almost 1/3 are marine * **Charles Darwin** - HMS Beagle Expedition (December 1831) * Father of the theory of evolution by natural selection * An early marine biologist * Able to observe marine life first hand and collected many specimens of marine organisms * Proposed an explanation of coral atoll development in the Pacific * Atolls - ring-shaped coral reefs that enclose a lagoon * 1859, published his landmark work "Origin of Species by means of Natural Selection" * **Challenger expedition** - (HMS challenger, 1876), 3 1/2 years * Gave birth to modern sciences of marine biology and oceanography * **Charles Wyville Thomson** - chief scientist of challenger expedition * Collected microscopic organisms that were floating in the water (suspend/drift) * 1887, Victor Henson coined the term "plankton" * **Alexander Agassiz (1887)** - an American naturalist * Began the first of several expeditions * Collected samples of animals from hundred locations * Dredged animals from depths of 180 to 4,240 meters * **Louis Agassiz** - Alexander's father * Founded the Museum of Comparative Zoology at Harvard University * Founded the first Marine Laboratory in the U.S.A. in July 1873 * Penikese Island off the Massachusetts coast * Called the Anderson Summer School of Natural History * Aimed to help teachers at all levels to improve their methods of teaching natural history to their students * Agassiz school was the inspiration and predecessor of the Marine Biological Laboratory at Woods Hole, Massachusetts which was founded in 1888. ## 1922 - the Woods Hole Oceanographic Institute was constructed down the street from the Marine Biological Laboratory. Their proximity allowed for a great interchange between the two institutions. * Later in this century, other important institutions were founded such as: * Scripps Institute of Oceanography in California * The University of Miami's Rosentiel School of Marine and Atmospheric science in Florida * Friday Harbor Laboratories of the University of Washington * Duke University Marine Laboratory in North Carolina, to name a few ## Earlier in this century – expeditions were mounted to study the Arctic and Antarctic seas * Two scientists who led expeditions that collected information and organisms from these two areas * **Fridtjof Nansen (Norwegian)** – was interested in reaching the magnetic North Pole and charting the waters around the pole * **Sir Alistair Hardy (British)** – was interested in the biology of whales ## Geography and Geomorphology of the Oceans /Seas ### Zones of the Marine Environment #### Two Major Divisions * **Pelagic division** - composed of ocean waters (water column) * **Benthic division** - composed of ocean bottom #### These divisions can be subdivided into zones on the basis of three characteristics: * Distance from the land * Light availability * Depth ### Pelagic division is subdivided into: * **Neritic zone** - composed of water that overlies the continental shelves * **Oceanic zone** - larger, consists of the water that cover the deep ocean basins ### Pelagic division can also be subdivided into: * **Photic zone** - where sunlight is present to support photosynthesis * **Aphotic zone** - where sunlight is absent #### Organisms that inhabit the pelagic division consist of: * **Plankton** (drifters) * **Nekton** (swimmers) ### Benthic division – begins at the shore with the intertidal zone #### Subdivisions: * **Intertidal zone** – region of ocean bottom covered with water during high tide and exposed during low tide * **Shelf zone** - extends from the line of lowest tide to the edge of continental shelf * **Bathyal zone** - from the edge of continental shelf to a depth of 4,000 meters (13,000 ft) * **Abyssal zone** - extends from 4,000 – 6,000 meters * **Hadal zone** - a bottom deeper than 6,000 meters (19,800 ft) #### Benthic organisms live primarily in or on the bottom sediments * **Epifauna** - benthic animals that live on the bottom sediments * **Infauna** - benthic animals that live in the bottom sediments ## Temperature and Vertical Stratification * On the basis of surface ocean temperatures and overall organism distribution, four biogeographical zones may be established. ### Temperature * Is a measure of the energy of molecular motion * In the world oceans – it varies horizontally with changes in latitude and vertically with depth * Important factor in governing life processes and distribution of organisms * Vital processes - function in relatively narrow temperature 0° – 40°C * **Poikilothermic/ectothermic** - Except for marine birds and mammals * Meaning their body temperatures vary with that of surrounding water * **Homiothermic/endothermic** – birds and mammals have the ability to regulate their own internal temperature, regardless of the temperature of the water mass. * Temperature in the oceans has a marked variation with depth. Surface water in tropical regions are very warm all year round, 20-30°C. In temperate regions, surface water is warm during summer. Below the warm surface water, temperature begins to fall and from 50-300 meters deep, it undergoes rapid decline. * **Thermocline** – depth zone with rapid temperature decline ## The Marine Environment ### The Special Properties of Water * All organisms contain a large proportion of water * **Specific heat is high** – for a given input of heat, little change in temperature * Hold more heat with less change of temperatures than most substances * **Pure water is taken as the standard** * **1 calorie (=4.17 joules)** – raises the temperature of 1 gram of water by 1°C * **Specific heat = 4.17 J g-1 °C-1** * Therefore, water forms a valuable buffer against changing environmental temperature both for H2O within organisms and for aquatic environment * **Density** - maximum density of 1000 kg m-3 * It reaches at this density (1000 kg m-3) at temperature close to 4°C * 4°C – H2O warmed above this temperature * **Freezing point = 0°C** * **Salt content** – depresses the freezing point of water * For sea water – Ex. Salt content is 35 ppt – the freezing point is -1.91 °C * Therefore, temperature of maximum density is also changed * **Viscosity** – water has a high viscosity than air means that there is an increased frictional resistance to the movement of organisms through it * Viscosity decreases as temperature increases * Ex. At 10°C – the frictional resistance to an organism moving thru water is about 100 times what it would be for that organism in air ## Major and Minor Constituents of 34.8 ppt Sea Water ### Ion % by weight #### **Major** * Chloride (Cl-) 55.4 * Sodium (Na+) 30.61 * Sulfate (SO42-) 7.68 * Magnesium (Mg2+) 3.69 * Calcium (Ca2+) 1.16 * Potassium (K+) 1.10 #### **Minor** * Bicarbonate (HCO3-) 0.41 * Bromide (Br-) 0.19 * Boric Acid (H3BO3) 0.07 * Strontium (Sr2+) 0.04 * 99.99 ## Physical Properties of Water 1. Boiling point – 100°C 2. Freezing point – 0°C 3. Heat capacity – 1 cal g-1°C-1 4. Density (at 4°C) – 1 g cm-3 or 1000 kg m-3 5. Latent heat of fusion – 80 cal 6. Latent heat of vaporization – 540 cal ## Features of the sea which are of major ecological interest 1. The sea is big, it covers 70 percent of earth's surface 2. The sea is deep, and life extends to all its depths. Although apparently there are no abiotic zones in the ocean, life is much denser around the margins of continents and islands. 3. The sea is continuous, not separated as are land and fresh water habitats. All the oceans are connected. Temperature, salinity, and depth are the chief barriers to free movement of marine organism. 4. The sea is in continuous circulation. Air temperature differences between poles and equator set up strong winds such as the trade winds (blowing steadily in the same direction the year round) which together with rotation of the earth, create definite currents. In addition to the wind-driven currents on the surface, deeper currents results from variations in temperature and salinity, which create differences in density. So, effective in the circulation that oxygen depletion and “stagnation" such as often occurs in fresh water lakes. Is comparatively rare in the ocean depths. ## Important Processes * **Upwelling** – occurs when winds consistently move surface water away from precipitous coastal slopes, bringing to the surface, cold water rich in nutrients which have been accumulating in the depths * **Outwelling** – occurs when nutrients rich estuarine waters move out to sea * **The sea is dominated by waves of many kinds and by tides produced by the pull of moon and sun** * **Tides** - important in the shoreward zones where marine life is often especially varied and dense. * Chiefly responsible for the marked periodicities in marine life communities and entrain the "lunar day" biological clocks (Photoperiodicity) * Periodicity of about 12 1/2 hrs * **High tide** occurs in most localities twice daily, being about 50 minutes later on successive days * **Spring tide** occurs every two weeks when sun and moon are working together, the amplitude of tides is increased * **Neap tide** – midway in the fortnightly periods where the range between low and high tide is smallest * Occurs when the sun and moon tend to cancel one another * **The sea is salty.** The average salinity or salt content is 35 parts by weight per 1000 parts of water, or 3.5% (35 ppt). About 27% is sodium chloride (NaCl) and most of the rest consist of magnesium (Mg), calcium (Ca), and potassium (K) salts. Sea water is strongly buffered (resistant to pH change). The electrical dissociation force of cations exceeds that of the anions which accounts for the alkaline nature of sea water (normally pH = 8.2). **Chemistry of the Sea (% grams per kilograms)** * Positive Ions (Cations) * Sodium 10.7 * Magnesium 1.3 * Calcium 0.4 * Potassium 0.4 * Negative Ions (Anions) * Chloride 19.3 * Sulfate 2.7 * Bicarbonate 0.1 * Carbonate 0.007 * Bromide 0.07 * **The concentration of dissolved nutrients is low and constitute an important limiting factor in determining the size of marine populations.** Concentration of NaCl and other salts are measured in ppt (parts per thousand) while nitrates, phosphates and other nutrients are so diluted that they are measured in ppb (parts per billion). Their residence time is very much shorter. The concentration of these vital biogenic salts varies greatly from one place to place and from season to season. * **Paradoxically, the ocean and some groups of organism that live in it are older than the ocean floor, which is consistently being altered and renewed by tectonic and sedimentary processes.** The sea floor is apparently slowly spreading outward from mid-ocean ridges, pushing continents apart as it progresses. In addition to marginal spreading, the level of the ocean has varied considerably as glaciers have waxed and waned. ## Environmental Factors That Affect The Distribution of Marine Organisms ### 1. Maintaining homeostasis * Maintain a stable internal environment – one of the greatest challenges faced by living organisms, whether they are microscopic and consist of single cell or large or multicellular #### Factors such as: * Temperature * The amount of water * The amount of salts * The amount of nutrients * Level of waste products * All of these have to be maintained within narrow limits for an organism to survive. When these factors changes, the organism must make proper adjustment to reestablish a balanced state or homeostasis #### Factor - Maintaining homeostasis * For every species, there is an optimal range for each environmental factor that affects its life * As long as the factors remain within the optimal range, organism should be able to survive and reproduce. * When one or more of the environmental factors is outside of the optimal range, an organism's chances of survival are decreased #### Zones of stress - are regions above or below the optimal range of an environmental variable * Organism may be able to exist in a stress zone if the stress is not too great * If the stress is high, the organism may have to expend so much energy maintaining the homeostasis * **Zones of Intolerance** - zones where an environmental variable is so far from the optimum range. * Organism cannot survive * Found beyond the stress zone ### 2. Sunlight * Plays an important role in the marine environment * It powers the process of photosynthesis * Directly or indirectly provides energy to nearly all forms of life on earth #### Phytoplankton - the most important organisms in marine environment * Tiny plant-like organisms and bacteria that float in the ocean currents * Are the primary source of food for marine animals (including seaweeds and seagrasses) * Their distribution is determined by the available sunlight #### Factor - Sunlight * Light is necessary for vision * Many animals rely on their vision to: * Capture prey * Avoid predation * Communicate with each other * Excessive sunlight can be a problem * Organisms that live in the intertidal zone are subject to the intense heat of the sun * Dessication (drying out) – results from exposure to sunlight * Many algae suffer pigment destruction when exposed to intense sunlight – limiting their ability to photosynthesize ### 3. Temperature * **Ectotherms** - majority of marine animals * They obtain most of their body heat from their surroundings * Becomes sluggish when temperature drops * Becomes more active when temperature rises * **Endotherms** - marine mammals and birds * Can maintain a constant body temperature because its metabolism (chemical reactions within its cells) generates heat internally * Animals maintain temperatures are usually higher than their surroundings #### Factor - Temperature * Temperature - influences the distribution of organisms in shallow water in the intertidal zone/regions that are covered during high tide and exposed during low tide * Temperature – changes dramatically for short periods as a result of hot summer sun or freezing nights * Larger bodies of water like the oceans do not change temperature rapidly #### Factor- Temperature * Most organisms can tolerate only a specific range of environmental temperatures * Temperature above or below this critical range disrupt metabolism resulting in: * Decrease ability to reproduce * Injury * Even death ### 4. Salinity * **Salinity** – a measure of the concentration of dissolved organic salts in the water * All organisms must maintain a proper balance of water and solutes in their bodies (maintain homeostasis) in order to keep their cells alive * When solute cannot move across the cell membrane to reach a balanced state on both sides (equilibrium) water moves instead to achieve the balances #### Solutes - substances dissolved in water #### Factor - Salinity * **Osmosis** - movement of water across a membrane in response to differences in solute concentration * The process of osmosis is vital to life of a cell * If the cell loses too much water, it will become dehydrated and die * **Isotonic** - equal concentration of solute inside and outside of the cell * **Hypertonic** – low solute concentration inside the cell, high solute outside (cell shrinks) * **Hypotonic** – high solute concentration inside the cell and low outside the cell (cell swells and bursts) * Osmosis – water tends to move from areas of lower solute concentration to areas of higher concentration ### 5. Pressure * 760 mmHg - pressure at sea level * Equal 1 atmosphere (14.7 lbs per inch2) * Water is so much denser than air * For every 10 meters (33 ft) below sea level in the ocean the pressure increases by 1 atmosphere * 370 atmospheres = 2.7 tons per inch2 * The pressure at an average ocean depth of 3,700 meters * Ex. A styrofoam cup lowered to a depth of 1,000 meters where pressure is 100 atmospheres is compressed to about one third (1/3) of its original size * Whales and other deep sea fishes possess specialized adaptations that allow them to survive at great depths ### 6. Metabolic Requirement * **Availability of nutrients** – is another factor that influences the distribution of organisms in the marine environment * **Nutrients** – refer not just to food but to all the organic and inorganic materials that an organism needs in order to: * Metabolize * Grow * Reproduce * Ex. Nitrogen and phosphorous – are those needed by phytoplankton, seaweeds and other marine plants. * Chemical composition of seawater – supplies many of the mineral needs of marine organisms * Ex. Mineral calcium – important for the synthesis of: * Mollusk shell * Coral skeletons * Exoskeleton of crustaceans #### Factor – Metabolic Requirement * **Oxygen** - important requirement for metabolism (cellular respiration) * By product of photosynthesis performed by phytoplankton seaweeds and plants (seagrasses) * Not all organisms require oxygen - some bacteria are anaerobic ### 7. Metabolic Wastes * All organisms produce waste products * Most living organisms release carbon dioxide as product of respiration * Animals excrete nitrogen-rich waste products * Plants release oxygen when they photosynthesize * Most of the time, waste products of metabolism are: * Either removed from the environment * Or broken down and recycled by a variety of organisms, especially the bacteria * In some environments, waste products can accumulate to toxic levels and prohibit the growth of all but the hardiest organisms ## The biota of marine habitats ### A. The pelagic community of the open water #### Components: * Those close to neutral buoyancy, suspended (free floating), relatively, passively in the water * Ex. Zoo - and phytoplankton #### Types of plankton * **Megaplankton** – organism above 2.0 mm – captured in standard plankton nets * **Macroplankton** – 0.2 to 2.0 mm also captured in standard plankton nets * **Microplankton** – 20 µm to 0.2 mm * **Nanoplankton** – 2.0 µm to 20 µm * **Ultraplankton** – less than 2 µm – the smallest plankton #### Biota-Marine habitats * **Nanoplankton and ultraplankton** * Cannot be captured in plankton nets * Captured by centrifuge or filter paper (Millipore filter) * **Holoplankton** – organisms that spend their entire lives in the plankton * **Meroplankton** – those species that spend but a part of their lives in the plankton * **Nekton** – swimming organisms * Able to navigate at will * Ex. Fish, amphibians, large swimming insects #### Biota - Marine habitats * Those larger, actively swimming animals (nekton) ### B. The benthic community living on or in the bottom deposits – Benthos * Ex. Attached algae (seaweeds) * **Fringing community** * Where water is shallow * Abundance of rooted aquatic plants * Ex. Seagrasses, mangroves ## Fundamentals of Marine Ecology ### Ecology * Deals with the interactions of marine organisms with each other and their environment * Is the study of relationships among marine organisms and the interactions of marine organisms with their environment ### Marine ecosystem * As cells are parts of living organisms, marine organisms are part of marine ecosystems ### A. Characteristics of the marine environment * An organism's environment consists of all the external factors acting upon that organism * Factors can be either: * Physical * Biological #### Physical or abiotic environment – consists of the non-living aspect of an organism's surroundings * In marine organisms includes: * Temperature * Salinity * pH * Amount of sunlight * Ocean currents * Wave action * Type and size of sediment particles #### Characteristics of the environment * **Living or Biotic environment** * Consists of living organisms * The ways in which they interact with each other * Ex. 1. Some organisms serve as food/prey * Some are predators * Others are parasites * Although biotic and abiotic environments are separate aspects of an organism's surrounding, in reality the two are difficult to separate ### B. Habitat and Niche * **Habitat** - where an organism lives * The specific place in the environment where an organism is found #### Types of Habitat * Estuaries (areas where rivers meet the sea) * Rocky shores * Sandy beaches * Coral reefs * Open ocean * Deep water #### Marine Habitats * Are characterized primarily by their abiotic features, the physical and chemical characteristics of the environment * Each habitat can be divided into smaller subdivisions called microhabitats * Ex. Sandy beach habitat – contains several different microhabitats for microscopic organism in the space between the sand granules * As a general rule, the more complex the habitat the more microhabitats it contains * Ex. Coral reef #### Habitat and Niche * **Niche** * An organism's environmental role * What an organism does in its environment (in a sense, its occupation) * Ex. 1. Mussels stick to rocks and filter water for food * Crabs - scavenge * Worms - burrow into the bottom sediments to extract organic material #### I. Biological factors that describe a niche * Predator-prey relationships * Parasitism * Competition for the same resources * Organisms that provide shelter for other organism #### II. Behavioral Factors * An organism's behavior plays an important role in defining its niche * **Behavioral Factors:** * When and where an organism feeds * How it mates * Where it bears its young * **III. Social Behavior** * Social behavior influences an organism's niche * Ex. Two very similar species that require the same kind of food can coexist if one feeds at night and the other during the day; provided the amount of available food will support both organisms. ## Marine Biota and Productivity ### A. Estuary * **Components of estuarine communities** * A mixture of endemic species – species restricted to the estuarine zone * Those which come from the sea * Very few species with the osmoregulatory capabilities for penetrating to from fresh water environment #### Example of mixed endemic and marine species * Seafood populations – spotted sea trout (Cynoscion nubulosus) * Commercial species – oysters and crabs * Commercially important shrimps – larval stage in the estuaries, adult spawn in the offshore * Coastal nekton – use estuary as nursery ground. Young growth stages (larval stage) take advantage of protection and abundant food. * Anadromous fishes (salmons and eels) – depend on the estuary where they reside for considerable lengths of time during their migration from salt water to fresh water. #### Most Productive and Most Important Part of the Nursery Ground * Intertidal * Adjacent shallow water zones * They are the first to suffer from ill-planned encroachment by man #### Naturally Productive Ecosystems * Estuary = Tropical Rainforest = Coral Reefs #### Reasons for High Productivity in Estuary * An estuary is a nutrient trap * Partly physical * Partly biological * Ex. Coral reefs * Retention and rapid recycling of nutrient by the benthos * Rapid formation of organic aggregates and detritus * Rapid recovery of nutrients from deep sediments by microbial activity * Deeply penetrating roots or burrowing animals create a sort of "self enriching" system * Natural tendency and toward eutrophication makes estuaries vulnerable to pollution since pollutants get "trapped " like nutrients * Red Tide - organic pollutants * Inorganic pollutants #### Reasons for high productivity in estuary * Estuary benefits from a diversity of producers types "programmed" for virtually year round photosynthesis #### Three types of producers * **Macrophytes** * Seaweeds/macroalgae * Seagrasses- support large population of * Epiphytic algae(Aufwuchs) or periphyton * Small fauna * Marsh grasses * **Benthic microphytes** * **Phytoplankton** * Aufwuchs * Periphyton Important food for grazing fish and other nekton * Small fauna #### Reasons for high productivity in estuary * The importance of tidal action in creating a "subsidized” fluctuating water level ecosystem * The higher the tidal amplitude – the greater the production potential provided that the ensuing currents are not too abrasive * Back and forth movement of water does a great deal of "work" * Removing wastes * Transporting food and nutrients * Coastal waters – capable of supporting intensive fisheries probably benefit from either: * Outwelling from shallow water production zones or * Upwelling from nutrient-rich bottom waters ## Concept of Productivity * **Primary productivity of an ecosystem community** * The rate at which radiant energy is stored by photosynthetic and chemosynthetic activity of producer organism (chiefly the green plants) in the form of organic substances which can be used as food materials. #### Four successive steps in the production process: * **Gross Primary productivity** * Total rate of photosynthesis, including the organic matter used up in respiration during the measurement period. * Also known as total photosynthesis or total assimilation * **Net Primary Productivity** * Rate of storage of organic matter in plant tissues in excess of the respiratory utilization by the plants during the period of measurement * Also called apparent photosynthesis or net assimilation * **Net community productivity** * Rate of storage of organic matter not used by heterotrophs during the period usually on growing season * Net primary production minus heterotrophic consumption * **Secondary Productivities** * Rates of energy storage at consumers levels ## Measurement of Primary Productivity * **Harvest method** * Usual situation in regard to cultivated crops that involve species to prevent insects and other animals from removing material * Rate of production starts from zero at the time of planting seeds * Rate of production reaches a maximum at the time of harvest * **Oxygen measurement** * In most situations, animals and bacteria, as well as plants themselves are rapidly using up oxygen * Light and dark bottle method of measuring oxygen production in aquatic situations * Sum of the oxygen produced in the light bottle is the total oxygen production, thus providing an estimate of primary production * Dissolved oxygen is measured titrametrically by Winkler method * Combination of light and dark bottles measure gross primary productivity * Light bottle measures net community production * **Carbon Dioxide method** * CO2 uptake to measure photosynthesis in leaves or single plant * Community is enclosed in a transparent chamber * Ex. A large bell jar or a plastic box or tent is placed over a community. Air is drawn through the enclosure. CO2 concentration in incoming and outgoing air is measured with an infrared gas analyzer. * **The pH Method** * In aquatic ecosystems, the pH of the water is a function of the dissolved CO2 content * To use pH as an index of productivity, the investigator must prepare a calibration curve for the water in particular system * **Disappearance of Raw Materials** * Nitrogen or Phosphorous are not being supplied steadily perhaps once a year. The rate at which their concentration decreases becomes a very good measure of productivity. * **Productivity Determinations with Radioactive Materials** * For measuring aquatic plants production: * 14C absorption in dark bottle – done in bottles with radioactive carbon (14C) added as carbonate. After a short period of time, the plankton or other plants are filtered from water, dried and placed in counting device. * **Chlorophyll Method** * Chlorophyll or green pigment content of whole natural communities provide an index of productivity. * Amount of chlorophyll is expressed in per square meter (m2). ## Marine Fauna ### Marine Mammals * A Marine mammal is a mammal that has adapted to aquatic life and relies on the ocean to maintain a healthy, livable existence. * These amazing animals can be found living in all of the world's major oceans from the tropical environments in and around the equator to the northern and southern polar hemispheres in and around the Arctic and Antarctic oceans. * Marine mammals share several characteristics that are common among all mammals such as the need to breathe air, being warm-blooded, having mammary glands which produce milk to feed their young, giving birth to live young (pregnancy/gestation periods) and in some cases having hair. #### Common characteristics found in marine mammals * **Marine mammals breathe air** – Although marine mammals live in and around the water they must come to the surface to breathe otherwise they'll drown. * **Marine mammals are warm-blooded** – In order to maintain their body heat marine mammals consume large quantities of calories and develop a thick layer of fat or blubber to keep their vital organs from freezing in cold environments. * **Marine mammals give birth to their offspring** – Unlike fish and other aquatic animals whales do not lay eggs; instead they carry their children in their womb until they are born. * **Marine mammals produce milk** – Marine mammals have mammary glands that produce milk which they use to feed their children. The milk is often full of fat and nutrients to help the child develop. ## THE DISTINCT TYPES OF MARINE MAMMALS * In terms of the various marine mammal species there are several distinct groups of marine mammals; sirenians (manatees and dugongs) cetaceans (whales, dolphins and porpoises), fissipeds, sea otters, pinnipeds (seals, fur seals, sea lions and walruses) and (as considered by some researchers and biologists) polar bears. * Both cetaceans and sirenians live in the ocean while polar bears, pinnipeds and fissipeds are land dwellers, but rely on the ocean to supply them with food and water. * As a whole there are over 125 recorded species of marine mammal inhibiting the ocean and native aquatic environments of the world. #### List of the of individual sub groups within the marine mammal family: * Cetaceans (whales, dolphins and porpoises) * Fissipeds * Pinnipeds (seals, fur seals, sea lions and walruses) * Ursidae (polar bears) * Sea otters * Sirenians (manatees and dugongs) * Although these animals can be found throughout the world the highest concentration of marine mammals (about 40%) are found at or around 40° both north and south of the equator. * Seacow/Dugong * Polar Bear * Sea Otter ## Marine Fishes ### Ideal Water Conditions * Fish and aquatic animals are directly influenced by the chemical, biological, and physical characteristics of their aquatic environment. In natural environments such as a coral reef in the ocean, the water is chemically, biologically and physically stable because of the large volume of water and the presence of currents. An aquarium, on the other hand, is subject to quick and possibly large changes in water conditions. Compared to a lake or an ocean, aquariums have relatively small water volumes, which are more easily affected by the potential fluctuations of the ideal water parameters. Aside from physical water conditions, changes in the aquatic environment are the result of various biochemical processes and the metabolic activities of all things living in the aquarium which includes fish, invertebrates, algae, and bacteria to name a few. If these chemicals are allowed to accumulate to levels above what aquarium inhabitants can tolerate, death can occur. Also, toxicity of some of these chemicals can be lethal in very low concentrations, so constant attention must be given to the ideal water conditions. ### Temperature * Temperature is a physical characteristic of water that greatly influences the organisms living in it. Since fish and invertebrates are cold-blooded species, they are directly affected by temperature, which affects their activity, feeding habits, immune system, and other metabolic functions. Marine fish and invertebrates in particular are very sensitive to rapid temperature fluctuations, so maintaining the right consistent temperature range is very important. At higher water temperatures, fish metabolism increases, thus the greater need for food. But at the same time, this increases metabolic wastes, which can quickly reach toxic levels. Also, O2 dissolves more readily in cooler water. For example, twice as much O2 can be dissolved in water at 32° F versus water at 86° F. ### pH * pH is a measure of the acidity or alkalinity of water. pH ranges from 0 to 14 with 7 being neutral. Marine water acceptable ranges between 8.0 to 8.3. Freshwater pH can range 6.5 to 8.5 depending on the species of fish. Therefore, not all freshwater fish are compatible in the same aquarium based on this one factor. The general trend of water in an aquarium is the pH to lower, that is, it becomes more acidic. The biological processes that occur in the aquarium are the reason for this trend. Buffers are chemicals that occur naturally and stabilize fluctuations in pH. Buffers are widely available and can be added to the water to keep the water at the desired pH. Having the correct pH for the livestock in your aquarium is extremely important to their survival. The pH of water affects vital biological chemical processes. If the pH is not right vital biological chemical process cannot occur and life cannot be sustained. * **Ammonia: NH3, Nh4+** * Ammonia is the most toxic product in the water that is formed naturally from the biological processes in the aquarium. Ammonia exists in two forms in the water: NH3 (un-ionized) and NH4+ (ionized). The sum of both forms of ammonia is known as total ammonia. Both forms exist in water, but the proportion of each form is dependent on pH, temperature and other factors. The un-ionized form, NH3, is extremely toxic and the higher the pH (more alkaline), the higher the concentration of the NH3. Ammonia is naturally broken down into Nitrite and then Nitrate by beneficial bacteria. * **Nitrite: NO2-** * As part of the Nitrogen Cycle, Ammonia is converted into Nitrite by the beneficial bacteria, Nitrosomonas. Nitrite is the intermediate step of the conversion of Ammonia into Nitrate. Once beneficial bacteria have been established, Nitrite detection is often impossible. Though, Nitrite is less toxic than Ammonia, it is still somewhat toxic to animals because it binds with red blood cells which prevent the uptake of dissolved oxygen. Nitrite buildup is mainly a concern during the set up or cycling of a new aquarium. * **Nitrate: NO