Marine Ecology:

Physical Limiting

Factors.

Aileen Aponte Zayas

September 16, 2015

CIAM-6117

Loretta Roberson , Ph. D.

Content:

Basic concepts in marine ecology.

Marine habitats.

Marine lifestyles.

Physical limiting factors.

Basic Concepts:

Ecological community- It is a specific habitat

where different organisms interact.

Marine ecology study the relationships or

interactions between marine organisms and

their environment.

In general, it’s a study of marine organisms and

their population dynamics.

Marine habitats: Pelagic Zone:

Neritic zone: nearshore, over the continental or insular

shelf.

Oceanic zone: beyond the continental or insular shelf.

Benthic zone: on the substrate.

Littoral: “intertidal”.

Sublittoral: out to the edge of continental or insular shelf.

Bathyal: continental or insular slope.

Abyssal: abyssal plain.

Hadal: in deep sea trenches.

http://imgbuddy.com/ocean-life-zones-diagram.asp

Marine lifestyles: Planktonic: passive.

Phytoplankton

zooplankton

Nektonic: active swimmers.

Fishes.

Marine mammals.

Birds.

Benthic: live on the subtrate.

Epifaunal- live on the surface. Ex. Starfish, barnacles.

Infaunal- live within the substrate. Ex. Sea worm.

Physical limiting factors:

Light

Temperature

Salinity

Dissolved Nutrients

Gases

Depth(Pressure)

Geography

Light penetration:

Light has more penetration in coastal and superficial

areas of the ocean.

Also light penetrates better in clear water.

Sedimentation causes an increase in turbidity, and

therefore decreases the penetration of light in photic

zones.

Primary production is by photosynthesis process (upper

100-200 m), and turbidity affects this process.

Temperature:

Temperature can affect the metabolism rate of an

organism.

The rate of metabolism in an organism increases twice

every time the temperature rises 10° C in its body.

The majority of marine organism are ectothermic.

Some are endothermic.

Endotherms can tolerate a broader range of external

temperature than ectoderms. Endotherms need more

energy than ectothermic organisms.

Temperature affects organisms

activities:

http://www.asnailsodyssey.com/LEARNABOUT/SEASTAR/seasAcid.php

4

Temperature

affects activity• Barnacle cirri beat

faster at highertemperature

• Faster beat = moreefficient feeding

Temperaturesin the ocean

Extremophiles beyondthis range

- submarine hot springs

- in polar ice: antifreezeglycoproteins in blood

Limiting factors: salinity

• Normal marine salinity is 35‰

• Too high or too low is damaging– Low diversity in estuaries (low salinity)

– Low diversity in areas of high evaporation (high

salinity)

• Maintaining salt balance is critical -organisms do this by:

– Diffusion – passive movement from areas of high

concentration to low concentration

– Osmosis – diffusion of water through a membrane

– Active transport – active removal of substances

from an area of low concentration to high

concentration

Diffusion• Passive equalizing of concentrations

• Substance (or temperature) diffuses from high tolow concentration, equalizing them

• Examples: diffusion of gases into ocean, into cells;diffusion of nutrients into (and wastes out of)phytoplankton

Barnacle cirri beat faster at higher temperature,

increasing efficiency in feeding.

cirri

http://www.geo.arizona.edu/geo4xx/geos412/OcSci07.EcolIntro.pdf

Salinity:

Normal: 35 g of salt in each 1000 g of seawater.

Low salinity cause low diversity in estuaries.

High salinity cause low diversity in areas of high

evaporation.

Changes in salinity force the organisms to migrate

controlling their distribution.

To maintain salt levels, organisms do different

processes: Diffusion, Osmosis and Active transport.

Diffusion- high to low concentration.

High salinity affects the organisms equalizing process.

Osmosis- diffusion of water thought a membrane.

Higher salinity cause dehydration or cell rupture.

Active transport- active removal of substances from an

area of low concentration to high concentration.

Fishes use active transport to control water

concentration in their cells.

This allow to adapt to changes in salinity.

http://hyperphysics.phy-astr.gsu.edu/hbase/biology/actran.html

Dissolved Nutrients: Nutrients are required for photosynthesis.

There are limiting nutrients :

Phosphates.

Nitrates.

Phosphates and Nitrates are low in photic zones and

high in upwelling areas.

Fertilizers have nitrates and phosphates, and an excess

of them can cause uncontrolled growth of algae and

soon dead zones by hypoxia.

Oceanic dead zones around the world.

http://www.scientificamerican.com/media/inline/2008-08-15_bigMap.jpg

Gases: As atmospheric CO2 increase, the interaction with

ocean surface will change the chemistry of seawater

resulting in ocean acidification.

http://www.pmel.noaa.gov/co2/file/carbon+chemistry++

http://www.pmel.noaa.gov/co2/file/carbon+chemistry++

Depth (Pressure): We can find different communities of organisms in

depth with anatomical adaptations.

In the deep sea are organisms that have gas bladders

that they can adjust to different pressures.

Depth is related to the pressure, temperature and light.

Deeper= more pressure, less light and low temperature.

Global warming causes expansion. Shallower areas

may be more submerged affecting marine

communities.

ph

oto

syn

the

sis

http://www.windows2universe.org/earth/Water/temp.html

http://taxo4254.wikispaces.com/Avicennia+alba

Geography:

Refers to the physical environment in which marine

communities develop.

Each zone has its own characteristics according to the

geological processes that took place there.

There are areas with different depths and nutrients that

influence the productivity and the organisms that live in

this area.

The ocean has a variety of physical habitats.

http://www.ga.gov.au/ausgeonews/ausgeonews200706/marine.jsp

http://www.nmfs.noaa.gov/pr/species/invertebrates/elkhorncoral.htm

A Global Map of Human Impact on Marine Ecosystems

Discussion:

Is the human being altering the limiting factors that the

marine ecology have? How?

What human activities affect more the marine

ecosystems?

Are we complying with the regulations to protect the

marine environment?

Do we have efficient management plans to protect

marine ecosystems?

Do we give more priority to terrestrial ecosystems than

marine ecosystems?

Which zone or area of the marine ecosystem do you

think is the most affected?

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