Researchers at the Hawai‘i Institute of Marine Biology (HIMB), an organized research unit in the University of Hawai‘i at Mānoa’s School of Ocean and Earth Science and Technology have made a remarkable discovery.
Over 50% of the population in the United States and over 60% in the world live in coastal areas. Rapidly growing human populations near the ocean have massively altered coastal water ecosystems. One of the most extensive human stressors is the discharge of chemicals and pollutants into the ocean. In the Southern California Blight, more than 60 sewage and urban runoff sources discharge over 1 billion gallons of liquid on a dry day with the two largest sources of contaminants being sewage from municipal treatment plants and urban runoff from highly modified river basins. These discharges transport large loads of known and unknown contaminants including heavy metals, chlorinated hydrocarbons, petroleum hydrocarbons, nutrients, and bacteria, that have shown to be toxic to marine life, including both adult and larval (early development) stages. Most marine organisms such as sea stars (starfish) do not move among locations as adults; instead juveniles swim in the plankton before settling onto the sea floor and growing into a sedentary adult. Despite the known toxicity of terrestrial discharge, no one had investigated if it is limiting dispersal of marine larvae between populations along urban coastal areas.
Researchers at HIMB examined the genetic structure of a common, non-harvested sea star using a spatially explicit model to test whether the largest sewage discharge and urban runoff sources were affecting the genetic structure of this species. They found that these large pollution sources are not only increasing genetic differentiation between populations (presumably by limiting the dispersal of larvae between them) but also decreasing the genetic diversity of populations closest to them. In short, human beings are directly affecting the ecological and evolutionary trajectory of a species that is relatively free of any direct human impacts. PhD student Jon Puritz led the investigation, and when asked about the recent discovery said, “This study changes the scale at which we thought human beings can affect non-harvested marine species. These results have potential to change the way anthropogenic factors are incorporated into marine reserve design and ecosystem-based management.” Co-author Dr. Rob Toonen added, “This species was previously shown to have well-connected populations from Southern California to Southern Canada, but now we see that these urban runoff plumes in the Los Angeles area are more significant hurdle for the microscopic larvae to cross than the remainder of the pacific coast of the US.”
The online journal Nature Communications has published the full research report by Puritz and Toonen available at DOI: 10.1038/ncomms1238
The Hawai‘i Institute of Marine Biology, Papahānaumokuākea Marine National Monument, and NOAA Pacific Islands Fisheries Science Center will host the 4th Annual Northwestern Hawaiian Islands Research Symposium this Thursday and Friday at the East West Center.
Honolulu, HI – This week, managers and scientists from the Hawai‘i Institute of Marine Biology (HIMB), Papahānaumokuākea Marine National Monument, and NOAA Pacific Islands Fisheries Science Center will meet at the East West Center on the University of Hawai‘i at Mānoa campus to share the latest in marine science research in the Hawaiian Archipelago, specifically highlighting the Northwestern Hawaiian Islands, also known as the Papahānaumokuākea Marine National Monument. The purpose of this symposium is to help foster an understanding of Hawaiian reef ecosystems for management and planning in an effort to produce proactive responses to future social and ecological change. Special sessions regarding the future direction of marine science and management in the Hawaiian Archipelago and a tribute to the late Dr. Isabella Abbott’s life and career (one of the first scientists to explore the marine algae of the Northwestern Hawaiian Islands) will also be included.
This annual event provides a forum for managers and scientists from different agencies to share their research and encourage collaboration among agencies in Hawai‘i. With the recent inscription of Papahānaumokuākea Marine National Monument on the World Heritage list, the research taking place in the Monument is of great importance. 2010 also marked the 5th anniversary of the HIMB Northwestern Hawaiian Islands Research Partnership; since 2005, HIMB has been an integral part of Northwestern Hawaiian Islands decision-making process by providing ecosystem-based science to help inform the decisions of this unique ecosystem.
Now in its 6th year of partnership, both managers and HIMB scientists continue to work together offering research support and new scientific knowledge for ecosystem-based management. Scientists continue to characterize the marine resources in the Northwestern Hawaiian Islands, determining levels of coral health, and monitoring ecosystem threats such as climate change. Dr. Jo-Ann Leong, director of HIMB refers to the partnership as a, “highly dynamic partnership that has not only made huge advances in science, but demonstrates what can be accomplished when scientists and managers work together”. She also adds “we have been incredibly productive in the last five years, generating over a hundred peer-reviewed publications, ten science reports and hosting four large research symposia”.
The full press release is located here: NWHI Symposium press release
A Researcher at the Hawai‘i Institute of Marine Biology, an organized research unit in the University of Hawai‘i at Mānoa’s School of Ocean and Earth Science and Technology has come up with a new explanation for the effects of ocean acidification on coral reefs.
Since the beginning of the Industrial Revolution, the concentration of carbon dioxide in the atmosphere has been rising due to the burning of fossil fuels. Increased absorption of this carbon by the oceans is lowering the seawater pH (the scale which measures how acidic or basic a substance is) and aragonite saturation state in a process known as ocean acidification. Aragonite is the mineral form of calcium carbonate that is laid down by corals to build their hard skeleton. Researchers wanted to know how the declining saturation state of this important mineral would impact living coral populations.
Much of the previous research has been centered on the relationship between coral growth and aragonite levels in the surface waters of the sea. Numerous studies have shown a direct correlation between increased acidification, aragonite saturation, and declining coral growth, but the process is not well understood. Various experiments designed to evaluate the relative importance of this process have led to opposing conclusions. A recent reanalysis conducted by Dr. Paul Jokiel from the Hawaiʻi Institute of Marine Biology (HIMB), suggests that the primary effect of ocean acidification on coral growth is to interfere with the transfer of hydrogen ions between the water column and the coral tissue. Jokiel re-evaluated the relevant data in order to synthesize some of the conflicting results from previous ocean acidification studies. As a result, Jokiel came up with the “proton flux hypothesis” which offers an explanation for the reduction in calcification of corals caused by ocean acidification.
In the past, scientists have focused on processes at the coral tissues. The alternative provided by Jokiel’s “proton flux hypothesis” is that calcification of coral skeletons are dependent on the passage of hydrogen ions between the water column and the coral tissue. This process ultimately disrupts corals’ ability to create an aragonite skeleton. Lowered calcification rates are problematic for our coral reefs because it creates weakened coral skeletons leaving them susceptible to breakage, and decreasing protection.
Dr. Jokiel is excited about this work; he states that “this hypothesis provides new insights into the importance of ocean acidification and temperature on coral reefs. The model is a radical departure from previous thought, but is consistent with existing observations and warrants testing in future studies”. In general, this hypothesis does not change the general conclusions that increased ocean acidification is lowering coral growth throughout the world, but rather describes the mechanism involved.
Photos are available in the full PDF press release located here: Jokiel ocean acidification Press Release 08-11