Citation:
Barry, J.P., Widdicombe, S., & Hall-Spencer, J.M. (2011) Effects of ocean acidification on marine biodiversity and ecosystem function. Ocean acidification, 192–209.

Purpose:
Barry, Widdicombe, and Hall-Spencer discussed the effects of ocean acidification on marine ecosystem functions and biodiversity, they focused far more on the large-scale issues and implications that controlled experiments cannot show in their limited scale. Large environmental changes can have broad effects on biodiversity, these effects can affect energy flow and other processes by the loss of keystone species who contribute to these processes. Other studies look at the survival of a single species and assumed that changes in the species effects the environment.

Methods:
The paper breaks up the topic into seven board categories and focus on how ocean acidification effects each.

Results:
Acidification of the ocean has effects that goes deeper than just a raise in ph of the water. It effects some of the earths most sensitive habitats. It also means that the servers that we rely on from the ocean will be affected negatively, from fishing to tourism. This problem is larger than most understand.

Significance for Palau:
As an island nation surrounded by the ocean and where fishing is a large part of the local’s life. During a lecture Dr. Rundell talked about how sea cucumbers are a large resource for the people of Palau. Along with the coral reefs many of the marine invertebrates are going to be directly affected by acidification. Any of the invertebrates who use calcium carbonate to make their skeletons it becomes harder for them to make their skeletons strong. This could lead to higher rates of predation and a reduction in prey populations.

Citation:
Golbuu, Y., Victor S., Wolanski, E., Richmond R.H. (2003) Trapping of fine sediment in a semi-enclosed bay, Palau, Micronesia. Estuarine, coastal and shelf science, 57, 941-949.

Purpose:
The purpose of this study was to collect data regarding the high sediment loading in Airai Bay that is smothering corals and creating a habitat shift from coral dominance to algae dominance. Airai Bay is semi-enclosed on the southeast coast of Palau, which is protected from tidal currents and the local winds are not strong enough to re-suspend the settled sediment. Environmental degradation like poor land use practices and destroying mangroves surrounding Airai Bay could be having a major impact of this coral reef system that is very ecologically and economically important.

Methods:
The researchers developed five stations that were used as testing sites in Airai Bay from the end of the Ngerikiil River to the mouth of the bay. They measured the vertical profile of the water column including salinity, temperature, and suspended sediment concentration at all the stations. At station one the mangrove swamp, they set up sediment traps on the river banks to determine how much sediment was being captured within the mangroves. Rainfall amounts were provided by the National Weather Service and during the time of the study two floods occurred.

Results:
At station 1 during river floods, the SSC (suspended sediment concentration) reading showed that the waters were very turbid as they exceeded the nephelometers saturation level. SSC was also higher at rising tide then during low runoff periods showing that sediment is being brought into the bay and settling in the mangroves. Following a river flood the river plume, freshwater exiting the estuary, could be traced though each stations readings. The readings at each station suggested that the sediment was being diluted, by lowering SSC and higher salinity levels. Based on the study’s results only about 2% of sediment is being exported out of the bay.

Significance for Palau:
Airai Bay is accumulating about 98% of the riverine sediment, which is an extremely high sediment loading. This is smothering corals and increasing turbidity which further stresses the system due to low light access and decreasing larval recruitment. These stressors are causing ecologically issues which is now effecting the local fisheries economy. In order for the ecosystem to restore itself the stressors would need to be lowered. The mangroves that are being cleared are exceptional at trapping sediment, lowering the sedimentation rate about 15-30% before the river plume continues throughout the bay. In order for the people of Palau to conserve this coral reef system, mangroves need to be stop being cleared and actually expanded. If the mangrove swamp had a higher land area, it would be able to trap more sediment. The next step in conservation efforts would be to educate and develop better land use practices. Perhaps during the nine-month period of heavy rainfall agricultural fields could be required to have a cover crop to prevent soil erosion. Lowering soil erosion without impacting the agricultural economy would be another important step to conservation and finding a balance between agriculture and fisheries.

Citation
Pusparini, Wulan, et al. “Rhinos in the Parks: An Island-Wide Survey of the Last Wild Population of the Sumatran Rhinoceros.” PLOS ONE, Public Library of Science, 16 Sept. 2015, journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0136643.
 
Purpose
The authors sought to asses the population size of the Sumatran rhinoceros, a critically endangered large mammal.  The population has dropped significantly in the last two hundred years since the species was first described by Fisher in 1814. The authors decided to conduct this survey in order to understand how best to conserve this rare species.
 
Methods
To get a solid idea of the rhinoceroses’ distribution and habitat the researchers searched for “signs” of the rhino’s presence, these “signs” includes rhino droppings, foot prints, and a few rare instances of actual sightings. After acquiring the data the researchers conducted statistical analyses of the populations by using PRESENCE var. 8.3 and R version 2.8.1 software.
 
Results
Despite this being the first systematic survey ever conducted on the species, the results were still inconclusive. This uncertainty in the data made the researchers conclude that immediate action must be taken to preserve the species in order to prevent a worst-case scenario.    
 
Relevance
This research is relevant to invertebrate conservation in Palau because it is an excellent example of population analysis of endemic species. Palau, being an archipelago, is home to countless endemic species, species that inhabit a small geographic range and are sometimes rare as a result. Palau is likely full of undescribed species, however just because they are undescribed does not mean they are safe from human impact. We can use this paper as a model to understand how we can more easily track rare and undescribed species in order to plan how we can save them.   

Citation:
Iwase, A., Sakai, K., Suzuki, A., & van Woesik, R. (2008) Phototropic adjustment of the foliaceous coral Echinopora lamellosa in Palau. Estuarine, coastal and shelf science, 77, 672–678. https://doi.org/10.1016/j.ecss.2007.10.022

Purpose:
Iwase et al. (2008) outline the concept of morphological adjustments by corals in response to wave action and light intensity. Many coral species have the ability to change their growth forms in response to light intensity while other coral species can only change their shape to a small extent. The coral species that express the latter for instance, may grow their branches toward the light or change the shape of their plates to maximize light intake. What previous studies didn’t focus on is the capacity of foliose corals (corals that can change shape to a small extent) in changing the shape of their plates to increase the number of tissue exposed to light.
 
Methods:
The researchers measure the angle of colonies of Echinopora lamellosa at various elevations of steep hills where light intensity is highest. They also produce a light model calculating both sun elevation and shade at any time and any location.
 
Results:
Foliose corals can change how much tissue on plates are exposed to light and E. lamellosa in particular can slightly change shape to look like it’s leaning with its plates taking on the shape of parabolic antennas. However, results show that sunlight intensity isn’t necessarily the only factor, suggesting that atmospheric diffusion or other factors may play an important role as well.
 
Significance for Palau:
Palau has a very rich diversity of coral communities because of its decent variety of reef habitats and lagoons. Reef flats around specific islands are quite notable for housing diverse coral communities even though the somewhat clear water limits visibility from the surface to between 10 and 12 meters. The diversity at these conditions shows the incredible adaptability of corals in limited sunlight. The paper by Iwase et al. may highlight the importance of morphological adjustments of corals in Palau and around the world when sea level increases with climate change and less sunlight reaches the corals underwater. Additionally, higher pollution levels in the air or from nutrient runoff may further diffuse sunlight intensity although corals may adapt very quickly and survive until conservation efforts are directed to coral reefs. 

Citation:
Evans, S.M., McKenna, C., Simpson, S.D., Tournois, J., & Genner, M.J. (2016) Patterns of species range evolution in Indo-Pacific reef assemblages reveal the Coral Triangle as a net source of transoceanic diversity. Biology letters, 12.
 
Purpose:
The authors began by discussing how it is crucial to understand the causes of spatial distributions of biodiversity when studying an ecosystem.  They applied this idea to study the species richness of the Coral Triangle, located in the Indo-Pacific region. The purpose of the study was to evaluate if the Coral Triangle is a net source of marine biodiversity.  The authors specifically hypothesized that if this location has acted as a net source, then the populations closest to the Coral Triangle have been the earliest establishments, therefore are older, and that as the distance from the region increased the relative age of the populations will decrease. 
 
Methods:
The authors used published population-level data from Genbank and yielded data from 45 different populations of reef-associated species with varying distances from the center of the Coral Triangle.  They statistically analyzed the data and created a regression line to fit the relationship between the distance from the center of the Coral Triangle and the relative time of the population’s establishment.     
 
Results:
The populations with the earliest establishment were found to be closer to the estimated center of the Coral Triangle than “younger” populations that have had more recent establishment.  The data supports the authors’ original hypothesis that the Coral Triangle has been a net source of reef-associated biodiversity, and they state that it’s achieved this by serving as a center of origin or survival for these species.         
 
Significance to Palau: 
The research and findings in the study described by this paper are significant because as coral reef species continue to face challenges such as habitat loss, ocean acidification and global climate change, regions that can act as a center for survival must be recognized and preserved.   
  
Palau is technically not located in the Coral triangle, however Koror, Palau is only about 8◦ 6’ N, 1◦ E of the estimated center of the Coral Triangle given in the paper.  Palau possesses an incredible diversity of marine organisms.  For example, it has been estimated by the Coral Reef Research Foundation that Palau has up to 425 species of stony corals and 137 species of sea squirts alone.  This paper may be of interest to those studying and practicing conservation of invertebrates in Palau because of the nation’s extensive coral reefs, marine biodiversity, and proximity to the Coral Triangle.  Understanding how populations in the waters around Palau relate to those studied in the paper could provide insight on the relative time of establishment of the populations.             

Citation:
Golbuu, Y., Victor, S., Penland, L., Idip, D., Emaurois, C., Okaji, K., . . . Woesik, R. V. (2007). Palau’s coral reefs show differential habitat recovery following the 1998-bleaching event. Coral Reefs,26(2), 319-332. doi:10.1007/s00338-007-0200-7


Purpose:
Golbuu et al. examine coral species variation, recruitment, and recovery rates in Palau, Micronesia following a dramatic bleaching event in 1998. Coral bleaching is a significant threat to coral diversity and is ultimately caused by rising ocean temperatures. The authors express that it is necessary to assess these Palauan reefs to make predictions on how corals can respond to climate change in the future.   


Methods:
The authors examined 13 permanent study sites of varying reef habitat types in 2001, 2002, and 2004 using digital-video analysis and random transect sampling to define the presence and abundance of coral recruits. Statistical tests were used to determine significant differences in coral recruitment and cover of common coral species over time and at different habitat types and depths.


Results:
The amount of coral present increased over time in the more sheltered bays (e.g. Nikko Bay), and they supported significantly different colonies of corals than the reefs being exposed to more wave action. The more exposed reefs had high levels of new colony formation (recruitment). Therefore, Palau’s coral reefs can recover rapidly from disturbance because they’re either protected from the disturbance itself or establishing new coral colonies from larvae that came from those protected reefs.   


Significance for Palau:
The authors of this study concluded that Palau’s coral reefs exhibited remarkable recovery rates after the bleaching event in 1998. In fact, several coral reefs in Palau have demonstrated an observable resistance to bleaching – either due to their toughness, their resilience, or their environment. Nikko Bay is an especially interesting reef in the context of coral bleaching resistance. Its waters are highly acidic due to a combination of coral respiration, coral skeleton formation, and lack of water movement. This extreme climate has made the corals better adapted to dramatic changes in environmental conditions. Furthermore, reefs off the rock islands can also effectively resist bleaching due to the shade given off from the islands themselves. This shading results in lower temperatures and can keep the coral alive. If these resistant reefs are protected from anthropogenic threats, they could be the key to preserving Palau’s coral species.