Marine Ecology Terms• Ecology - study of

the relationships of living organisms (biota) to the environment (abiotic or non-living part)

• Major marine habitats are divided into 2 groups:

1. Pelagic Zone - photic zone containing plankton (floaters) and nekton (swimmers).a. neritic - coastal areasb. oceanic - open water

2. Benthic Zone - substrate on the margins or basins.a. aphotic - 90% dark area of open waterb. abyssal - deep bottom of the ocean floor.

These habitats are occupied by 5 levels of biota:

1. Individual - one plant or animal of a specie

a. plankton - organisms that can not make a forward motion against a current.• Phytoplankton -

photosynthetic producers• Zooplankton - primary

consumers

b. nekton: swimming animals ex: fish mammals,birds, reptiles

c. benthos - bottom dwellersb.Epifauna - live on

substrate. Ex: crabs

• Infauna - live in substrate. Ex: worms

d. demersal - hover or walk. Ex: lobsters

e. sessile - attached Ex: barnacles

2. Populations • 2 or more individuals of the same

species who must compete for mates, food, light, and space because they occupy the same niche and habitat.

• DNA studies are used to identify which individuals are part of a population.

• Population density is the number of individuals divided by the size of the habitat.

• Population density is effected by– Geography– Season factors– Pollution– Birth-death ratio based on the number

of adults

3. Communties• 2 or more populations occupying

different niches in the same habitat.

• Community living has an advantage by reducing competition, increasing variety and diversity.

The general niches are:a. Producers -

phytoplankton, start the food chains.

b. Consumers - herbivores, carnivores, omnivores - eat others

c. Decomposers - scavengers, break down organic compounds into nutrients for producers

Communities age in a process called biological succession.

a. Pioneer - first populations move into a habitat such as the polychaete worm.

b. Juvenile - young populations; simple food chainsc. Mature - older communities with complex food webs,

stable populations are those where natality = mortality

4. Ecosystems • have two or more

communities whose lifestyle is related to a unique habitat.

• Ex: coral reefs, polar seas

• Changes in the components will have unpredictable effects, but ecosystems have remarkable ways of restoration.

5. Biosphere• composed of

many ecosystems,• exhibiting great

diversity, that are related by the interdependence of living things.

Energy RelationshipsIn ecosystems, energy is

cycled through these niches:

• Autotrophs - produce food by photosynthesis

• Heterotrophs - consume autotrophs and other heterotrophs

• Decomposers - rearrange organic materials into nutrients for autotrophs

• The amount of energy available to support life is called the carrying capacity.

• Food chains represent the steps in transferring energy through the ecosystem. Complex and integrated food chains are called food webs.

• A keystone specie is the critical biomass in an ecosystem because the food web is built around that particular organism.

• Energy can be representations by trophic pyramids that compare the number of organisms in a population, or the weight (biomass) of organisms, or the productivity (energy calories).

Why does the amount of energy change if energy is never created or destroyed?

1. It can be converted into unusable forms such as heat or for organisms’ respiration, metabolism, and predation.

2. Not all parts of an organism have food value or provide calories. Ex: bones, scales

• The amount of energy available is calculated as net productivity or primary productivity.

• Primary productivity of the ocean is 22-28 billion tons of carbohydrates (mostly glucose)

• Gross productivity - respiration = net productivity given in units of g/m2/yr.

• Respiration is the amount of energy used at each level to maintain life (estimated at 90% of the available calories.

• If one trophic level has 100,000 calories available, only 10,000 can potentially be transferred to the next trophic level.

• The more levels in the ecosystem pyramid the less energy is available in a useable form at the next higher level.

• Shorter food chains are more efficient. The reason the ocean can support the tremendous expense of endothermic mammals is because they eat low on the food chain

Building Ecosystems• When competition is

fierce, communities form symbiotic relationships to improve survival odds and build healthy ecosystems.

• Symbiosis - closely associated life styles exhibited by more than half of all marine animals.

1. Parasitism– the most

common type of association

– One benefits, one is fatally harmed (+-)

– Ex: worms, bacteria

2. Mutualism• Both organisms benefit (++)• Ex: wrasses set up “cleaning stations” where they are allowed

to eat the parasites off larger reef fish. They get an easy meal and help reduce parasites on fish.

• Ex: coral is an animal that allows zooanthellae (algae) to live inside the protection of its hard skeleton. The algae makes food for the sessile animal.

3. Commensalism• One benefits, the other

not affected (+ o)• Ex: The remora fish is

allowed to attach itself to the chin of the shark, who is a very messy eater. The remora has someone to catch food for it. The shark is not affected.

Sea as a Resource• The UN Law of the Sea

Treaty (1982) establishes an Exclusive Economic Zone (EEZ) up to 200 nautical miles off shore.

• Coastal nations are given jurisdiction over 40% of the ocean’s resources, but they must share with land-locked countries.

• In return, they are responsible for pollution clean-up in the EEZ. Territorial waters have increased from 3 to 12 miles.

The primary resources to be exploited are:

1. Minerals - – primarily oil, – but also Mn, Mg, Cu, Al,

salt, sand, and many others

– Most are difficult to reach

2. Mariculture• The science of farming

the sea• It will not solve the

world hunger problem, but will certainly help.

• Farms must be located in coastal areas where pollution is often the highest

3. Fisheries• Commercial fishing is a $50

billion industry worldwide.• Of the thousands of species,

only 9 major groups are harvested and many are overfished.

• Finfish and shellfish provide 10% of the animal protein worldwide. Not all of this is for human consumption

• The maximum sustainable yield is the largest number of fish that can be harvested and still allow the species to continue.

Destroying Ecosystems• In the past “dilution was the

solution to pollution”.• Today we realize that “we all live

downstream”.• Pollution is generally divided into

2 classes:a. point source - where the

source can be identified, regulated & prosecuted

b. non-point - where no single entity is responsible, such as runoff from over-fertilized yards or oil stained highways and parking lots.

Types of Pollution:1. Sewage • greatest single source of

ocean pollution• It is most harmful because

it often contains mixtures of all the other types of pollution.

• High bacteria counts, particularly E.coli (also called fecal coliform) points to serious pollution and potential health hazards.

2. Oil • Sources are oil tanker

accidents (Exxon Valdez), offshore drilling (BP), runoff, and eco-terrorism

• Oil mats marine bird’s feathers so they can’t fly, catch food or keep warm.

• When marine mammals ingest it, the result is liver damage and hypothermia.

• Oil also coats benthic organisms, larvae and eggs. It prevents evaporation and gas exchange at the surface, resulting in suffocation.

3. Thermal • Sources are

discharges from industries using water for cooling which raises the temperature an average of 12 degrees.

• Most organisms can only tolerate 3-5 degree increase.

4. Chemical• Sources are industry,

pesticides, runoff into storm drains

• Biomagnification is a process by which organisms concentrate toxins in the exchange of energy in food webs.

• Notable examples such as Minimata Bay (Japan) and Chernobyl (Russia) produced birth defects and cancers in humans.

• Birds developed reproductive disorders like soft shelled and crossed bills.

• There may be many hidden connections linking chemicals in our food, water, and air to a variety of disorders and disease.

• High phosphate and nitrates cause algae blooms that block sunlight and gas exchange. Bacteria decomposing organic material further reduce oxygen levels.

5. Garbage & Dumping

• Sources may be individuals, industry or the government

• Activities such as dredging, fisheries, and ships dumping million/tons/yr of trash increases the problem.

• Animals become entangled in pop-tops, six-pack rings or mistake non-biodegradable substances and plastics for food.

• It may later cause suffocation, strangulation or digestive blockages

6. Acid rain• Created by emissions from industry, cars, and space

shuttle launches.• When pH is altered, enzymes for metabolism are

affected and limits for tolerance of other tissues may be exceeded.

• Acid rain is formed when sulfur and nitrogen oxide are emitted into the air from burning of fossil fuels.

• As precipitation (rain, dew, snow) falls, it combines pollutants with oxygen and water to form carbonic, sulfuric, and nitric acids.

• Acids restrict the formation of shells and prevents enzyme activity.

7. Greenhouse Effect• Results in atmospheric heating• It is caused by an increase in carbon dioxide

levels that prevent infrared light from escaping the atmosphere.

• This results in world-wide temperature increases

• With warmer temperatures, the sea level could rise as glacial ice melts.

• Salinity, density, and coastlines would change. However, scientists do not agree on many of these issues.