Nomination for a World Heritage Site 2009 - Phoenix Islands ...

Jamie Gove in Maragos et al (2008) provided a sketch of the equatorial current system in the
central Pacific shown in the figure below. The Phoenix Islands were in an area of unique
subsurface water currents. This may have great significance for dispersing larvae originating
from the Phoenix Islands.
Sketch of equatorial current system in the central Pacific Ocean (170 0 W) including the Equatorial Intermediate
Current (EIC), the North and South Subsurface Countercurrents (NSCC and SECC). (Source: Maragos et al
Coral Reefs of the USA, 2008). Cross-sectional sketch of the equatorial current system in the central Pacific
Ocean (170° W). Shown in crosshatch are the North and South Equatorial Countercurrent (NECC and SECC),
subsurface Equatorial Intermediate Current (EIC), North and South Subsurface Countercurrents (NSCC and
SSCC), and Equatorial Undercurrent (EUC ). Eastward flow is colored green or brown, and all westward flow is
white, including the North Equatorial Current (NEC) north of 5° N and the South Equatorial current (SEC )
south of 5° N and outside the EIC. Black numbers in italics were observations from January 1984 to June 1986
(latitude 165° E), and bold red numbers were observations from April 1979 to March 1980 (latitude 155° W),
with both representing transports in Sverdrups (Sv = 106 m3/s) (Modified from Tomczak and Godfrey (2003).
MARINE ECOSYSTEMS
The marine environment of the PIPA is extremely diverse. It varies from the spectacular
turquoise lagoons with huge coral heads and clams to pristine and colorful coral reefs that
form and surround the atoll, low reef islands and submerged reefs down the slopes of the
massive volcanoes to the ocean floor to over 6,000 meters deep. The marine environment of
the PIPA is known to support a number of globally endangered and endemic species and
hosts interesting and unique species assemblages not found elsewhere in the world.
From a marine science perspective the PIPA is extremely important because of the minimal
human impacts and hence it’s near pristine state. In addition PIPA is biogeographically
uniquely situated in the center of the equatorial Pacific. PIPA plays a significant role in
movements and dispersal of marine animals and larvae. Little is still known about the full
effect of these islands on the surrounding pelagic marine species and systems, which in turn
support internationally important seabird populations and numerous migratory birds.
Signs (prolific algae growth) of unusually high nutrient levels for oceanic atolls have been
observed in the Phoenix Islands. This effect could be caused by a combination of lagoon
enrichment, leaching of guano deposits or oceanic upwelling caused by deep currents striking
the massive seamounts underlying each of the Phoenix Islands. Pierce et al (2006) suggested
35