Since 2008, the Smith Lab has been conducting a wide range of coral reef research on the island of Maui, Hawaii. This work has primarily focused on understanding dynamics related to community ecology and human impacts on the environment, as well as monitoring oceanographic conditions and reef health.
Herbivore Communities (Emily Kelly; Levi Lewis; Samantha Clements; Jennifer Smith)
Coral reefs are dynamic systems with intense competition for space. In particular, constant competition between corals and algae plays a major role in shaping coral reef communities and the services they provide to the fish, invertebrates, and humans who rely on them. The balance between corals and algae is directly impacted by herbivores, which keep algal growth in check. Through a combination of observational and experimental methods, the Smith Lab has assessed the functional redundancy of coral reef herbivore communities, focusing specifically on the dietary preferences and grazing rates of reef fishes and sea urchins. Lab members have used a combination of caging experiments, grazing assays, and bite counts to determine herbivore behavior and stable isotopes to analyze their stomach contents. A subset of this research was conducted in collaboration with the Maui Ocean Center to determine the feeding preferences of herbivorous fish in captivity and the metabolic rates of sea urchins. By determining the ecological roles of different herbivores, this research has enabled us to better understand how many herbivores are needed to balance the growth of algae on a reef.
Environmental Issues (Emily Kelly; Ryota Nakajima; Jennifer Smith)
Coral reefs provide many important benefits to people, including food, coastal protection, revenue, opportunities for tourism and recreation, and natural beauty. However, human activities living in and around coral reefs can impact the underlying ecological dynamics and ultimately lower the capacity for the many ecosystem services which reefs can provide. Sedimentation and runoff from agriculture and coastal development are among the biggest local threats facing coral reefs on Maui. With funding from the US National Fish and Wildlife Foundation, the Smith Lab has worked to quantify changes in sedimentation using a combination of sediment traps and photo-mosaics. Lab members have also provided expertise in a number of applied conservation settings related to runoff, development, and associated environmental impacts. In addition, lab members have used a combination of methods described above to assess herbivore and benthic communities in and around the Kahekili Fisheries Management Area. By comparing herbivore biomass and abundance as well as reef condition across sites with variable levels of protection, this research has helped to better understand the ecological impacts of protected areas. The Smith Lab has also studied the presence of microplastics in marine sediments, both in Maui and across the Pacific Ocean.
Benthic Community Ecology (Christina Jayne; Orion McCarthy; Jennifer Smith)
Detailed time series are often necessary to understand how coral reefs change, respond, and recover to thermal stress and other large-scale disturbances. Since 2014, the Smith Lab has been monitoring the coral reef benthic community at more than 20 sites in Maui, tracking changes in the algal community, settlement of coral recruits, calcification, and bleaching response and recovery across the island. Using innovative imaging and data technologies to construct digital models of coral reefs, the Smith Lab and 100 Island Challenge team have amassed a multi-year photographic dataset capturing the state of coral reefs, including before and after imagery of the 2015-16 bleaching event that hit the Hawaiian Islands. Lab members have used these data to analyze algal community succession in response to the bleaching event and to quantify changes in structural complexity over time. The Smith Lab also assesses changes in the benthic communities over time with presence and absence of herbivore communities through caging experiments and through the placement of settlement tiles, or calcification accretion units (CAUs).