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Human emissions of CO2 and partial uptake by the oceans are causing an increase in surface seawater acidity and decreasing CaCO3 saturation states (W). Ocean acidification is a threat to organisms generating shells, tests or skeletons out of CaCO3, the most “famous” of which produce structures of aragonite (i.e., tropical corals and reefs). Computer simulations predict that conditions expected over the next 200 yrs with the BAU scenario will lead to an environment in which dissolution of carbonate sediments will exceed production and corals will have greater difficulty accreting. To date, in-situ studies of ocean acidification, calcification and especially carbonate dissolution, remain sparse on coral reefs or have not used the tools needed to elucidate how ecosystems respond to this threat. The understudied tropical estuaries and coral reefs represent a significant fraction of the global system and play a critical role in the global C cycle. Thus time-series data are necessary to quantify their contributions to air-sea exchange of CO2. Large fluctuations in DIC parameters on short time frames in Kaneohe Bay confirm that high-resolution time-series data are critical to characterize accurately net annual air-sea exchange of CO2. Furthermore, how coastal processes affect CO2 exchange remains poorly characterized at barrier reefs and it is therefore logical to shift the our emphasis to barrier reefs.
Mapping erosion hazards on Oahu and Kauai Coastal erosion is a growing global problem, and nowhere is the trouble felt more strongly than the coastal-focused and tourism-dependent culture of Hawai’i. Research proposed here will continue our multi-year effort to map the historical pattern of shoreline change on the islands of Maui, Oahu, and Kauai and provide the database to coastal managers for the purpose of improving policies and procedures. These data have been used in the past for new land-use policies on Maui and Kauai to shift from a static setback of 40 ft, to one that is calculated on the basis of annual erosion rate. It is our data that provide the scientific underpinning of these new policies.
High Resolution Temporal and Spacial Topographic Imaging of Beach Processes To advance our understanding of physical controls on beach morphology it is necessary to rapidly acquire high-resolution topographic information from the beaches themselves. In the past, this has been a time-intensive effort requiring many person hours, the advent of ground-based scanning laser technology (T-LiDAR, for ‘Tripod-LiDAR’), however, has radically altered our capability to acquire this topographic information. We propose to carry out high resolution temporal and spatial studies of beaches on Oahu using a combination of T-LiDAR surveys, digital photogrammetery, and in situ hydrodynamic measurements. The principal products of this research will be quantifiable measures of beach shape and volume change in response to natural or anthropogenic events.
Understanding Attitudes, Beliefs and Preparedness for Climate Change Impacts and Other Coastal Hazards in Hawaii The negative impacts of sea level rise accompanying climate change, increased wave run-up, inundation, and flooding, increased loss of beaches from coastal erosion, will be pronounced in island settings like Hawaii. Hawaii officially responded in 2007 by including a section dealing with climate change and sea level rise in the State Hazard Mitigation Plan. In contrast, little is known about the Hawaiian public’s perspective of these issues or if there is community desire to embrace adaptation and mitigation solutions. Public support for adaptation is a key factor in determining what policy decisions are viable. This social science proposal focuses on the Sea Grant focus area of Coastal Hazard Resiliency and is linked to the cross-cutting themes of Climate Change Impacts, Coastal and Ocean Literacy and Decision-Making Capacity, through a study of the factors that influence people’s ability to deal with sea level rise and climate change within 5 communities in Hawaii.
A better understanding of the ocean currents in Hawaii’s nearshore waters is critical for the economic, ecological, and cultural future of our coastal communities. A prime example is Hanauma Bay on the south shore of Oahu, where visitors come to enjoy the diverse and unique ecology of Hawaii’s first marine life conservation district. Wave-generated currents within the bay pose a significant hazard to swimmers and skin-divers. A variety of physical processes, including vigorous internal tides, is thought to control the transport of materials in and out of the bay, which strongly impacts the ecosystem as a whole.
 Copepod Recruitment in Kaneohe Bay Following Storm Events The coastal areas around the Hawaiian Islands include diverse and productive biological communities. At the base of this food chain are small planktonic organisms that graze phytoplankton (microscopic plants) and in turn provide food for invertebrate and vertebrate predators, in particular planktivorous reef fishes. Phytoplankton and zooplankton communities respond rapidly to environmental changes. Storm events create intense disturbances and have significant effects on species diversity and abundances. In order to investigate changes in species dominance, all developmental stages as well as recruitment to the population need to be assessed. During periods of rapid population growth, copepod communities are dominated by the early developmental stages (nauplii and copepodites). These stages are extremely difficult to distinguish visually, and are usually lumped in a single category).
Skeletal Growth Anomalies in Corals of genus Montipora: Physiological and Ecological Consequences and Correlations with Water Quality The health of corals is a key measure of coral reef ecosystems’ resilience against increasing numbers of environmental stressors. In Hawai`i, where 80% of coral reefs under US jurisdiction are found, corals have escaped mass scale bleaching or mortality to date. However, Montipora corals at Wai`opae in southeast Hawai`i Island are exhibiting a critically high prevalence (up to 67% in M. capitata) of skeletal growth anomalies (SGA). The etiology and pathology of coral SGA found in many coral species worldwide are virtually unknown. Given such an urgent situation, PI Takabayashi’s group has initiated multi-faced research on the outbreak of coral SGA on Hawai`i Island. The proposed Hawai`i Sea Grant aims to investigate two integral components of this: (1) Investigation of effects of SGA on photophysiology and ecology of Montipora corals; and (2) Correlation of SGA prevalence to water quality characteristics at sites around Hawai`i Island.
An Empirical Test of Ecosystem-based Management: How Density and Size Structure of ‘Opihi Affect Community Structure There is overwhelming consensus that human impacts on marine ecosystems have decreased individual abundance and altered the size structure of harvested species worldwide, but little consensus on how to resolve the issue. Given the diverse and multiplicative effects of harvesting and the failure of traditional single-species management to prevent collapse of many fisheries, new “Ecosystem-based Management” (EBM) practices have been heralded in recent years as a novel solution to fisheries problems. To date, we have been unable to locate a single published study that has tested empirically the differential effects of distinct fisheries regulations on community structure. We propose to fill this essential gap by experimentally manipulating the various interactive levels of size and density changes to simulate different fishing strategies, and quantifying the effects of these changes in a simple ecosystem as a model for how EBM may be applied in Hawaii.
Introduced Fish as a Vector for Invasive Parasites in Hawaii We propose to combine historical, ecological, and molecular data to determine the alien status of the parasitic nematode Spirocamallanus istiblenni in Hawaii. This parasite is thought to have hitchhiked to Hawaii with the introduced fish Lutjanus kasmira and is known in Hawaii to parasitize at least six species of native fishes. At high intensity (# of parasites per infected fish), it is known to cause severe damage to the intestinal tissue of L. kasmira but its effect on native fishes and the degree to which it has invaded native fish communities is unknown.
Quantifying Fluxes and Dissolved Loads of Submarine Groundwaters to Oahu’s Coastal Zone Submarine groundwater discharge (SGD) must be the only important source of new biologically-available nutrients to Hawaiian coastal environments, and high nutrient loading occurs even in areas that are not subject to anthropogenic pollution. Hydrological models show that nearly all groundwater is lost to the ocean as SGD, but we do not know how its magnitude is spatially distributed or controlled. Our studies have us now poised to robustly evaluate and quantify the locations, flow rates, and dissolved nutrient concentrations of Oahu’s SGD.
Abiotic and Biotic Changes Associated with Shifts in Canopy Structure: Impact of Invasive Species Invasive algae such as Gracilaria salicornia are structurally very different from the communities they may replace. One of the most striking differences between G. salicornia and native algae is the stiffness and density of the canopy that it forms in contrast to the native Gracilaria coronopifolia, and tall growing Sargassum obtusifolium. Differences in canopy density and flexibility have profound hydrodynamic, chemical and mechanical consequences within the canopy and the immediate area surrounding the communities. Shifts in hydrodynamics alter the nutrient dynamics within the canopy and sediments underlying the canopy impacting food web dynamics. In this study we will examine the impact of G. salicornia canopies on near bed hydrodynamics and nutrient exchange.
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