to ecological activities data
Here is information
to help you
understand what makes the water off the coast of Peru so unique and valuable
to the fishing industry. There are only five places on Earth that have
a current system like this, but the Peruvian coast is the richest. Coastal
upwelling in the Peruvian Current System makes the coastal water nutrient-rich.
The mechanism to understand this is provided below.
most productive coastal upwelling region is the 300 x 33 miles off
the coast of Peru. In the seven-month fishing season of 1969-70,
11 million metric tons (mmt) of Peruvian anchoveta (Engraulis
ringens) were harvested in this region. Over 10 trillion anchoveta
are needed to make 11 mmt. Comparatively, the total U.S. harvest
for all species of fish and shellfish in 1969 was 2.5 mmt.
Current System is comprised of four distinct currents. The Peru
Coastal Current flows northward. It runs deep and hugs land
from about Valparaiso, Chile to Chimbote, Peru. The Peru Oceanic
Current also flows northward, but further out to sea. It runs
several hundred miles wide and 700 meters deep, and flows north
to a point opposite Gulf of Guayaquil before bending west.. The
Peru Coastal Countercurrent flow southward between these
two currents. And the Peru Undercurrent runs southward beneath
all three surface currents.
and southeast tradewinds blowing across the Andes Mountains
deflect surface water to the west (i.e. left) due to the Coriolis
effect. Deep ocean water rich with nutrients like N & P move
up to replace the displaced surface water. This constant renewal
of phosphates and nitrates stimulate phytoplankton growth totaling
from 45 to 200 mg of carbon fixed photosynthetically per cubic m
of water each day.
1973; Thompson, 1981)
upwelling fluctuates seasonally with its greatest intensity
and most disperse during winter, and weakest during summer. The
availability of nitrates and phosphates fluctuate accordingly. N
& P are most abundant and dispersed during the southern winter
(May, June, July, and August).
do you think the seasonal fluctuation of upwelling activity might
influence the phytoplankton population?
is the transport of nutrient-rich water from the deep ocean up to the surface.
This takes place at the equator (equatorial upwelling) and along the continental
slopes (coastal upwelling). For this reason, there is higher productivity
along coastal areas than the open ocean. It is the coastal upwelling driven
by the Peru, California, Benguela, Somalia, and
Canary Currents that produce the most nutrient-rich waters in the world.
Along the coasts of these currents primary production can fix up to 1 g
of carbon per m^2 of sea water a day.
DOES IT WORK?
- In the southern
hemisphere, the Coriolis effect deflects southward blowing longshore
wind to the left.
- This moves
the warm, nutrient-poor surface water offshore.
- Cold, nutrient-rich
bottom water moves to the surface along the continental slope to replace
the offshore moving surface water.
- It is the
transport of nitrogen and phosphorous nutrients from the ocean bottom
to the surface that makes upwelling such an important activity.
occurs more easily along narrow continental slopes, and usually along
the western coasts of continents in both the northern and southern hemispheres.
Its strength amount of upwelled nutrient varies seasonally. Off the Peruvian
coast, upwelling peaks in the summer. While these regions make up about
0.1% of the ocean's surface, they provide ~40% of all the commercial fish
is nitrogen and phosphorous so important?
do you think will happen if the amount of upwelled nutrients were to
increase or decrease?
upwelling is a large ecological activity. Can this be interrupted or
does coastal upwelling off the coast of Peru affect the abundance of
and Glantz, 2001)
to ecological activities data
site was created by Lynn Tran at the North Carolina State University, Department
of Mathematics, Science, and Technology Education on 7/12/03. Faculty advisor
Dr. David Eggleston, NCSU, Department of Marine, Earth, & Atmospheric Sciences.
December 29, 2003