Subscribe free to our newsletters via your
. 24/7 Space News .




WATER WORLD
Ocean-scale dataset allows broad view of human influence on Pacific reefs
by Staff Writers
Manoa HI (SPX) Apr 07, 2015


This image shows a school of bigeye trevally (Caranx sexfasciatus) and a NMFS PIFSC CRED diver conducting fish counts at Swains Island, American Samoa, as part of the Pacific Reef Assessment and Monitoring Program (Pacific RAMP). Image courtesy Ben Ruttenburg of NMFS SEFSC. For a larger version of this image please go here.

As man-made threats to coral reefs mount and interest in conserving reef ecosystems grows, scientists have turned to studying extremely remote and uninhabited reefs in an effort to understand what coral reefs would be like in the absence of humans. A number of islands and atolls in the Pacific Ocean remain virtually untouched by human influence, situated hundreds of kilometers from the nearest human populations.

A study published by scientists at the University of Hawai'i at Manoa (UHM) School of Ocean and Earth Science and Technology (SOEST), the National Oceanic and Atmospheric Administration (NOAA), and the University of Victoria in the journal PLOS ONE draws on data from nearly 40 islands and atolls across the central and western Pacific, including 25 unpopulated islands, to investigate the relative influence of environmental variation and human presence on reef fish assemblages. The resulting message is sobering.

After accounting for environmental variation among the reefs, the team of scientists estimates that human presence is associated with large reductions in reef fish biomass compared to projections for an uninhabited state - 20% to 78% depletion at reefs in the Main Hawaiian islands, up to 69% depletion in the Mariana Archipelago and up to 56% depletion in American Samoa.

At the core of the study is an extensive dataset of fish abundance across the Pacific, gathered by divers conducting visual surveys of reefs during more than 2,000 hours of underwater observation at reef sites spanning 39 U.S. Pacific islands and atolls.

The surveys were performed as part of NOAA's Pacific Reef Assessment and Monitoring Program, one of the world's largest coral reef monitoring efforts. The full dataset includes surveys of reef fish, coral habitat and satellite-derived measurements of oceanographic conditions at each reef location including sea surface temperature, wave energy, and oceanic productivity.

"The great strength of the Pacific Reef Assessment and Monitoring Program is that the data are extremely comparable because it is gathered at all locations using the exact same methods, survey design and by a core survey team. This continuity in a dataset across such a large scale is unparalleled and allows us to really focus on the causes of differences among those locations," notes lead author Ivor Williams of NOAA's Coral Reef Ecosystem Division.

The data on oceanographic conditions and human population at each reef location were combined in models to investigate the influence of both environmental and human variables on reef fish abundance.

Fish higher up in the food web, like grouper, appear most susceptible to the influence of human presence. The sharpest declines in fish abundance were associated with relatively low human population densities, with continuing but more gradual fish declines seen on highly populous islands such as Oahu and Guam.

The absence of humans from remote, uninhabited reef areas in the Pacific was not always associated with spectacular fish abundance. Reefs in the Northwest Hawaiian Islands, though extremely remote, had many fewer fish than uninhabited U.S. Line Islands situated close to the equator where regional and local upwelling bring nutrient-rich waters to the surface, enhancing phytoplankton production.

"The association between oceanic productivity and fish biomass that we document for Pacific reefs is an important reminder that not all coral reefs have the same capacity to sustain high fish biomass. There is natural variability among reefs that is unrelated to their history of human influence," said Kate Hanson, a postdoctoral fellow with the University of Hawai'i at Manoa and a co-author on the study.

"Natural variability in fish communities amongst reefs implies that there is no single target for what a healthy reef should look like," notes Julia Baum, Assistant Professor at the University of Victoria, Canada and a co-author on the study. "However, the consistent declines in fish abundance with even low levels of human presence suggest that fully protected no-take zones will be necessary to maintain coral reef fish communities in their natural state."

Ivor D. Williams, Julia K. Baum, Adel Heenan, Katharine M. Hanson, Marc O. Nadon, Russell E. Brainard (2015) Human, Oceanographic and Habitat Drivers of Central and Western Pacific Coral Reef Fish Assemblages. PLOS ONE, DOI: 10.1371/journal.pone.0120516.

.


Related Links
University of Hawaii at Manoa
Water News - Science, Technology and Politics






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





WATER WORLD
Bacteria plays key role in long term storage of carbon in the ocean
Munich, Germany (SPX) Apr 02, 2015
The ocean is a large reservoir of dissolved organic molecules, and many of these molecules are stable against microbial utilization for hundreds to thousands of years. They contain a similar amount of carbon as compared to carbon dioxide (CO2) in the atmosphere. Researchers at the Helmholtz Centre for Environmental Research (UFZ), the University of South Carolina and the Helmholtz Centre Munich ... read more


WATER WORLD
Extent of Moon's giant volcanic eruption is revealed

Yutu Changes Everything We Thought We Knew About Our Moon

Extent of moon's giant volcanic eruption is revealed

NASA's LRO Spacecraft Finds March 17, 2013 Impact Crater and More

WATER WORLD
Rover Amnesia Event Follows Latest Memory Reformatting

Ancient Martian lake system records 2 water-related events

Curiosity Rover Finds Biologically Useful Nitrogen on Mars

NASA's Opportunity Mars Rover Passes Marathon Distance

WATER WORLD
NASA Announces New Partnerships with Industry for Deep-Space Skills

A Year in Space

Russia to Consider Training First Guatemalan Cosmonaut

Russia, US to Jointly Prepare Mars, Moon Flight Road Map

WATER WORLD
Chinese scientists mull power station in space

China completes second test on new carrier rocket's power system

China's Yutu rover reveals Moon's "complex" geological history

China's Space Laboratory Still Cloaked

WATER WORLD
Cosmonauts Take Tablet Computer Into Space

Russia announces plan to build new space station with NASA

Soyuz spacecraft docks at ISS for year-long mission

One-Year Crew Set for Launch to Space Station

WATER WORLD
Soyuz Installed at Baikonur, Expected to Launch Wednesday

Soyuz ready March 27 flight to deploy two Galileo navsats

UAE Moves to Purchase Russian Spacecraft Launch Platform

Russia Launches Satan Missile With S Korean Kompsat 3A Satellite

WATER WORLD
Earthlike 'Star Wars' Tatooines may be common

Planets in the habitable zone around most stars, calculate researchers

Our Solar System May Have Once Harbored Super-Earths

SOFIA Finds Missing Link Between Supernovae and Planet Formation

WATER WORLD
Study reveals novel technique for handling molecules

Twisted nanofibers create structures tougher than bulletproof vests

A method to simplify pictures makes chemistry calculations a snap

Metals used in high-tech products face future supply risks




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.