I was able to attend a poster presentation on Capuchin monkeys. There is very little research on these monkeys because their numbers are low and they live in very remote locations (in Eastern Brazil). Previous research shows that buff-headed capuchins avoid human influence and spend more than 80% of their day in food-related activities. As a result, scientists tend to study their close relatives instead, as it’s the only way to gather more information on them. Capuchin monkeys are further threatened by habitat loss. The natives of the jungle also hunt the monkeys for food.

This project proposes that researchers should tag and track buff-headed capuchins in order to determine the relationship between movement and foraging. Such a program will allow researchers to observe the habits of Capuchin monkeys remotely. With the new information gathered by this covert surveyance, researchers will be able to designate better habitats for the monkeys, thus increasing their chances at survival. Capuchin monkeys must be conserved for being close evolutionary relatives of humans and for their important role in their ecosystems.

In the article “Biomass Energy: The Scale of The Potential Resource”, Chris Field and his colleagues discuss how Biomass for energy is very useful in offsetting the use of fossil fuels, but may threaten conservation areas, pollute water resources, and decrease food security

They found that the areas most suitable for biomass energy were those that had been previously used for agriculture or pasture but had been abandoned and left in its original condition. Field believes that the there is an extremely large potential for biomass energy production, but not enough to significantly replace a large portion of fossil fuel usage. If biomass energy is over utilized, Field concluded that food security would be reduced, and the speed of global climate change dramatically increased.

The most significant geological sinks of carbon dioxide produced by fossil-fuel combustion are terrestrial and marine environments, taking up about half of the current man-made production. Therefore, an intimate knowledge of the exchanges between the atmosphere, land, and oceans over time is integral to an understanding of how global climate change is affecting carbon storage in different ecosystem types, and also of the rate at which these effects are occurring. So far, carbon uptake by terrestrial and marine sinks is limiting the severity of climate change – in fact, the terrestrial biosphere showed no net carbon exchange in the 1980s, but became a net sink in the 1990s as global atmospheric carbon levels increased, buffering the climatic repercussions of greenhouse gas emissions (this from atmospheric CO2 and O2 data). Eurasian and North American extra-tropical areas were largely responsible for this increased carbon sink function, while tropical areas showed approximately no net carbon exchange due to the canceling effects of copious and rich vegetation and emissions due to tropical deforestation. The phenomenon of terrestrial ecosystems acting as carbon sinks probably evolved due to land use changes over time, like regrowing on abandoned agricultural land, fire prevention, warmer and therefore longer growing/photosynthetic seasons, and fertilization by carbon and nitrogen. More research is needed to more specifically identify the magnitude of the sink in different regions.

Schimel, DS; Field, CB; et al. 2001. Recent patterns and mechanisms of carbon exchange by terrestrial ecosystems. Nature 414, 169-172.

Annual global temperatures have been increasing recently due to various reasons.   Since 1980, the average global temperature have increase by approximately 0.4 degrees.    This temperature change has noticeably affected the yields of crops.

Lobell and Field examined the effect of climate change on the yields of the six most widely grown crops in the world: wheat, rice, maize, soybeans, barley, and sorghum.   They obtained average global yields from the Food and Agriculture Organization while climate data was taken from the Climate Research Unit.   By applying a regressing model to observed trends in climate and yields, they found that recent climate trends towards global warming have negatively impacted global production of the six most widely grown crops.

These negative impacts were likely mitigated by the effects of increased CO2 levels as well as technological advancements in crop production such that yield losses were not noticeable.   However, it is clear that as the climate continues to warm, crop yields will continue to be impacted on a global scale.

Environ. Res. Lett. 2 (March 2007) 014002
doi:10.1088/1748-9326/2/1/014002

The authors of this study set out to determine a way to avoid 1. acceleration of climate change and 2. decreased food security in using abandoned agricultural lands for sources of bioenergy. They employed the History Database of the Global Environment, the Center for Sustainability and the Global Environment, and the International Geosphere Biosphere Programme DIScover databases, and a MODIS satellite map of land cover to approximate the land area globally that is made up of abandoned agricultural fields. The Carnegie-Ames-Stanford Approach ecosystem model was utilized to determine the natural aboveground biomass on all lands. They found that the United States, Brazil and Australia had the highest potential for bioenergy, and although this energy source would represent only a small part of the energy economy in use, the authors determined that this is a very important fraction of global primary energy consumption that should be taken advantage of once the necessary research to do so has been completed.

Campbell, J. E. and D. B. Lobell. R. C. Genova, C. B. Field. 2008. The Global Potential of Bioenergy on Abandoned Agriculture Lands. Environmental Science and Technology 42:5791–5794.

In a publication entitled “Estimation of the carbon dioxide (CO2) fertilization effect using growth rate anomalies of CO2 and crop yields since 1961,” Chris Field and David Lobell analyze the impacts of elevated carbon dioxide levels on crop yields as a way to assess climate change impacts and adaptations. Measurements of carbon dioxide levels (more than a 1 ppm increase) were taken over the years from many countries since 1961. The authors stated that “because the gradual increase in CO2 is highly correlated with major changes in technology, management, and other yield controlling factors, we focused on the differences of CO2 and yield time series” (page 1). However, this study was more focused on what models and large amounts of data can tell scientists, instead of finding actual numerical values. Their reasons for doing so are because CO2 measurements are far from precise and the fact that “there is limited availability of experimental data on CO2 responses for crops grown under typical field conditions” (page 1). They conclude by saying that getting more data and reliable field records “may result in empirical estimates with useful levels of uncertainty to complement estimates from experimental studies.”

Lobell, D. B. and C. B. Field. 2008. Estimation of the carbon dioxide (CO2) fertilization effect using growth rate anomalies of CO2 and crop yields since 1961. Global Change Biology 14:39-45.

As temperatures rise, organisms will need to adapt or move their habitat range.  Scott Loarie of the Carnegie Institution for Science and colleagues developed a metric of the velocity of temperature change (km yr^-1), which is derived from spatial thermal gradients and projected warming rates.  They compared different biomes and found that montane landscapes including sub-tropical coniferous forests have the lowest temperature change velocities at 0.08 km yr^-1 while flooded grasslands have the highest velocities at 1.26 km yr^-1.  Projected velocities depend on carbon emission scenarios and the time period for which the temporal gradient is calculated (2000-2050 or 2000-2100), but velocities were similar across scenarios.  Reduced greenhouse gas emissions, expanded protected areas, or managed relocation of vulnerable species may be needed to protect ecosystems in regions of high velocity of temperature change.

Nature doi:10.1038/nature08649 (2009)

In Hollie Putnam’s article, “The physiological response of reef corals to diel fluctuations in seawater temperature”, she studies how the fluctuations in temperature of the scleractinian corals when significant warming was found in Moorea, French Polynesia.

Her statistical analysis used a randomized block ANOVA, with factors of treatment, species, and trial.

Symbiodinium density F = 79.26, df = 1, P < 0.0001; F_V/F_M F = 4.39, df = 1, P < 0.05; chl-a F = 32.72, df = 1, P < 0.0001; and growth F = 8.04, df = 1, P < 0.01

Data from each trial were analyzed separately. MANOVA was used in each in each trial to test for the effectiveness of treatments using the four measures of coral condition response variables. They completed multivariate test of treatment effects protected from Type 1 errors. The statistics were then examined through graphical analysis using JMP 7.0 software.

Although I did not have access to the statistics done by Stahle et al in the NC tree ring study, I was able to find another very similar paper using identical climate change indices and methodology in examining Sabina tibetica tree rings in Northern Tibet, China. The time frame is not the same as in the previous study (this one measured the long-term history of drought over the past 500 years), but the findings also allowed researchers to determine patterns in dry and wet conditions (showing abrupt changes and century-long dry or wet trends).

The methods used to determine whether tree rings indicated a wet or dry period of time were primarily correlation analysis of temperature and the reconstructed Palmer Drought Severity Index (PDSI), response function analysis to make a fitting model, and a simple linear regression between the predictor (tree ring indices) and predictand (PDSI), including statistics determining the significance of differences and a goodness of fit analysis. Finally, more complex statistics were applied to investigate the periodicity of drought over time using wavelet analysis, the Mann-Kendall test, and the moving t-test.

A total sample size of 106 trees were used, and statistics on the tree rings themselves were gathered by measuring ring widths and correlating them with the chronological date. Then at each site (of 3 general ones differing by elevation) the climate-growth response patterns were determined. For example, “The chronology of Sogxian was positively correlated with May precipitation, June humidity and January minimum temperature of the growth year and November maximum temperature of the previous year, and was negatively correlated with May and June mean temperature and June maximum temperature of the growth year.” Overall there was, as one might predict, a positive correlation between summer temperature and wetness and tree growth. Doing this long term allowed researchers to see overall trends over hundreds of years.

Wang, X, et al. 2007. A tree ring record of 500 year dry-wet changes in Northern Tibet, China. The Holocene 2008 18: 579.

Tyler and McGlathery conducted research to examine the relationship between benthic and pelagic algae in shallow waters such as coastal lagoons.  They demonstrated that benthic algae were inportant in controling the dissolved inorganic as well as organic nitrogen fluxes between the sediments and the water column.  They took measurements of nitrogen and oxygen in sediment cores from virginina and calculated the flux based on the change in water column concertration over time.

They measured the influence of algae on sediment fluxes across all sites and dates by using one-way analysis of variance (ANOVA) using data on biomass and nutrient uptake.  Differences between sites and dates were then analyzed using two-way ANOVA.  They also used the Pearson correlation analysis to identify relationships between sediment flux rates and benthic microalgae and macroalgae as well as relationships between algal uptake rates and algal tissue N levels.

They found that, despite the large amount of variation in the data, there was a clear pattern of benthic algae controlling the flux of nitrogen into the water column.  They also found that macroalgae (kelp) played a significant role in intercepting and influencing the release of N from sediments into the water column.