The Marine Environment How physical and chemical properties of water affect life in the sea The Marine Environment

The Marine Environment Salinity Seawater contains a variety of dissolved solids Open ocean salinity can range from 34 - 37 parts per thousand Salinity is measured: Conductivity of Cl- Refractometer The Marine Environment

How salinity affects marine organisms Most marine animals are adapted to a narrow salinity range Changes is salinity effect organisms through osmosis Hyperosmotic solution- water will flow into it across a semipermeable membrane Hypoosmotic solution - water will leave the solution The Marine Environment

The Marine Environment How to Cope Osmoconformers Allows its internal salt concentration to change with the salinity of the surrounding water Some molluscs & polychaete worms Osmoregulators Keeps its internal salt concentration constant regardless of the water salinity Many fishes & crabs More on this when we discuss Estuaries.. The Marine Environment

Temperature Regulation Homeotherms (Endothermic) - organisms which regulate their internal body temperature regardless of the environment Poikilotherms (Ectothermic) - organisms which have an internal body temperature that conforms to the environment The Marine Environment

Temperature Stratification Thermocline is an area in the water column of rapidly changing water temperature Thermoclines are most prominent during the warmer months due to solar radiation and weak mixing After the thermocline the water is an almost constant temperature The Marine Environment

Methods for Measuring Temp. Niskin Bottles Satellite Imagery The Marine Environment

The Marine Environment Dissolved Gases Dissolved Gases For living things the three most important dissolved gases are oxygen (O2), carbon dioxide (CO2) and nitrogen (N2) The amount of a given gas that can dissolve decreases with an increase in temperature The amount of oxygen in a body of water depends on: Mixing with the atmosphere Respiration Photosynthesis Sunlight + 6H20 + 6CO2 C6H12O6 (Glucose) + 6O2 The Marine Environment

The Marine Environment Oxygen Consumption Aerobic respiration Respiration in the presence of oxygen Anaerobic respiration Respiration in the absence of oxygen The Marine Environment

The Marine Environment Light Light is crucial for photosynthesis and is strongest in the surface waters Light attenuates with depth in an exponential fashion UV light can be damaging to the proteins and DNA of many surface organisms Effective light penetration can vary from 10-1,000m.) The Marine Environment

Turbidity and Light Penetration The amount of solid particles suspended in the water column Important since plants and algae need light for photosynthesis Increase turbidity can decrease the amount of light which effectively penetrates Large concentrations of phytoplankton can decrease light penetration (greenish tint) The Marine Environment

The Marine Environment Pressure Animals that live on land or sea level are at 1 ATM (14.7 psi) With an increase in depth of 10 meters (33 ft) pressure is increased by 1 ATM. Gas filled structures will shrink or collapse with depth At the ocean’s avg. depth (3,700 meters) pressure is 2.7 tons per square inch The Marine Environment

The Marine Environment Properties of Water Water is more dense and viscous than air Since it is a more supportive medium there is not a need for a strong supportive skeleton Also, an important consideration when we discuss sinking rates and movement through water Surface tension The Marine Environment

Ecological Principles Interactions among animals and the environment The Marine Environment

What is Ecology? A combination of biotic and abiotic factors Biotic Predator-prey interactions Symbiotic relationships Competition Species interactions Abiotic Salinity Temperature Pressure Non-biological factors In the real world these factors are not easily separated The Marine Environment

Ecological Principles Ecology: the interactions of animals with each other Habitat: the environment where an organism occurs Habitat can vary in temperature, salinity, tides, and currents The Marine Environment

The Marine Environment Key Ecology Terms Species: natural group of interbreeding individuals, which are reproductively isolated from other groups Population: all the species in a given area Community: several populations, which occur in an area Ecosystem: a series of communities and the surrounding environment The Marine Environment

The Marine Environment Competition Competition: refers to the interaction between organisms for a necessary and limiting resource Light, food, water, and space Barnacle and mussels compete for space The Marine Environment

The Results of Competition Natural selection: production of offspring by the best-adapted individuals in a population Evolution: a change in the genetic makeup of a population To be successful a species must find the right balance between specialization and generalization Niche: the role a species plays in the community The Marine Environment

The Marine Environment Predation Predation is the act of one animal eating another Coevolution - the predator evolving in response to adaptations of the prey, or vice versa The Marine Environment

The Marine Environment Living Together Symbiosis Commensalism Mutualism Parasitism Ectoparasites Endoparasites The Marine Environment

Ocean Ecosystem Components Autotrophic: organisms which capture energy to make organic matter Producers Heterotrophic: organisms that capture energy by eating Herbivores - eat strictly producers Carnivores or piscivores - eat meat or fish Omnivores - generalists Apex predators - top predators The Marine Environment