Plastic Ingestion in Mediterranean Sperm Whale

by Chloe Mayne

Marine debris has become an extensive problem in the oceans today. Plastics and other debris affect over 250 species of marine organisms by entanglement and ingestion. Current studies have shown large marine mammals to be affected by entanglement, but few studies exist on the affects of ingestion of plastic debris. There have been three recorded standings of sperm whales with large amounts of plastic and marine debris in their stomachs. In the Mediterranean Sea, the population of sperm whales is considered to be a separate species and has had a decline in population over the past 20 years. This decline has been attributed mostly to boat strikes and entanglement, with no knowledge of the affects of plastic ingestion. Stephanis et al. (2013) examined a stranded sperm whale in the Mediterranean Sea that had ingested a large amount of marine debris. They discuss the results in terms of the spatial distribution of sperm whales and the anthropogenic activities in the area. In the Mediterranean Sea, the species is found near Almería and the Strait of Gibraltar. This study found that the whales feed in an area with lots of debris from the greenhouse industry. In the sperm whale examined, the cause of death was determined to be gastric rupture from the build up of debris. Continue reading

Plastic Pollution and Associated Microorganisms in the North Pacific Gyre

by Chloe Mayne

Anthropogenic plastic pollution in the ocean has become extremely harmful to marine organisms and their environment. These problems include ingestion, entanglement, leaching of chemicals and adsorption of organic pollutants. The most common marine debris are small plastic fragments, which often are larger items that have been degraded. Microorganisms likely interfere with the degradation process as a result of biofilm formation on plastic surfaces. They may block plastic from UV radiation and photo-catalysis, which would increase plastic longevity. Inversely, microorganisms may accelerate degradation. Fouling microorganisms are extremely important to understanding the problems with plastic pollution, yet they have not been adequately studied. In this experiment, Carson et al. (2013) examine the abundance and diversity of microorganisms on plastics in the North Pacific Gyre. Continue reading

Plastic Debris in Predatory Pelagic Fishes of the North Pacific

by Chloe Mayne

The North Pacific subtropical gyre contains large patches of marine debris and plastic. Recently, there have been reports of marine debris ingestion by sea birds, marine mammals, and fishes. Plastic debris is harmful to marine life, resulting in entanglement and decreased mobility, decreased nutrition or suffocation. Plastic also allows harmful organic contaminants to enter the marine environment, but there have been few experiments conducted on plastic ingestion in large marine fishes. Choy and Drazen (2013) studied 7 species of large pelagic fish for evidence of anthropogenic debris ingestion. Nineteen percent of the specimen had marine debris, primarily plastic or fishing line. A large majority of these species are thought to be mesopelagic fish that don’t come close to surface waters where marine debris is usually found. Plastic in pelagic fish shows the possibility of plastic pollution making it’s way through the food webs. These results are key in understanding the widespread nature of debris and plastic pollution in the ocean. Continue reading

Garbage Patch in the South Pacific Subtropical Gyre

by Chloe Mayne

The marine environment contains a large amount of anthropogenic plastic pollution. While the Northern Hemisphere subtropical gyres (NHSG) have been found to contain plastics, there have been no data to suggest the existence of plastic pollution in the Southern Hemisphere subtropical gyres (SHSG). Recently, a large amount of plastic pollution has been found in the Southern Pacific Ocean and along the coastal shores. It has began to negatively impact fishing, tourism and navigation. In addition to the South Pacific, large amounts of plastic have also been found in the Southern Ocean and near Antarctica. In order to look at the presence of microplastics in the South Pacific subtropical gyre, Eriksen et al. (2013) surveyed a transect that crossed directly through the gyre and took 48 samples.  This transect was based on an accumulation zone created by currents and wind. The study found a greater amount of surface plastic pollution near the center of the transect than on the edges. These data prove… Continue reading

Record of Contaminant Exposure Found in Blue Whale Earplug

The blue whale is the largest animal on earth and an Endangered Species.  The blue whale population has not only been affected by whaling activities but also by anthropogenic activities such as fishing entanglement, boat strikes, climate change and chemical emissions. Many of the resulting contaminants of the latter are found to reside in blubber and other lipid rich layers. Blue whales, and other large baleen whales, accumulate layers of earwax, known as cerumen, throughout their lifetimes. This wax builds up over time and produces dark and light colored layers, or laminae, which represent periods of feeding or migration. While early earplug analysis was used to age whales, it was recently discovered that it is possible to reconstruct lifetime profiles of hormones, mercury, and other pollutants. in whales.  Similar to blubber, these contaminants build up in the whale’s earplug in large enough concentrations to quantify. Tumble et al. (2013) looked at the earplug of a male blue whale to examine lifetime contaminant and hormonal profiles. They found 24 different laminae and estimated the whale’s age to be 12 years ± 6 months. Looking at the hormone levels, they were able to age the whale’s sexual maturity. When the contaminants were examined, it was found that much of the contaminants came from mother during the first 12 months. The mercury profiles showed peaks as a result of environmental and anthropogenic mercury increase. —Chloe Mayne
Trumble, S., Robinson, E., Berman-Kowalewski, M., Potter, C., Usenko, S., 2013. Blue whale earplug reveals lifetime contaminant exposure and hormone profiles. PNAS published ahead of print September 16, 2013,doi:10.1073/pnas.1311418110.

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Marine Debris in Loggerhead Turtles: Bioindicator of the World’s Oceans

Plastic marine debris has been accumulating at a rapid rate around the world.  This debris, which comes from garbage, fishing, and ships, negatively affects marine environments and wildlife.  Marine organisms, especially turtles, are harmed when they accidentally ingest this litter. Loggerhead turtles, Caretta caretta, feed generally on invertebrates on the bottom of the ocean, but have a high range of diversity in their prey. This makes it easy for the loggerhead to mistake plastic for food. These plastics carry many chemicals and pollutants, which result in higher mortality and possible negative effects on the entire food chain. The Mediterranean loggerhead population is isolated and has distinctive characteristics such as the small size of the adult turtles. This is important in relation to maturation and the time to regain population numbers because the Mediterranean basin has a large number of turtles caught each year as by catch.  Campani et al. (2013) looked at the presence and abundance of marine debris in the gastrointestinal tract of the loggerhead sea turtles. They then worked to describe and quantify the types of plastic ingested by the turtles. Most of the turtles sampled had ingested marine debris, the most common type being user plastic, which is plastic used in everyday life .Chloe Mayne

Campani T., Baini M., Giannetti M., Cancelli, F., et al., 2013. Presence of plastic debris in
loggerhead turtle stranded along the Tuscany coasts of the Pelagos Sanctuary for Mediterranean Marine Mammals (Italy). Marine Pollution Bulletin 74, 22-230.

Campani et al. used data from 31 stranded loggerhead sea turtles that were collected along the Tuscany coast. A necropsy (dissection) was performed on each turtle to determine cause of death.  Each animal was weighed and measured and the most important organs were collected for chemical analysis.  Following a prior bird marine litter determination protocol, Campani et al. determined the marine litter present in the loggerhead turtles gastrointestinal tract. The three main parts (esophagus, intestine and stomach) were divided up and separately analyzed by removing the contents, rinsing them and placing them onto dishes to be examined and sorted under a microscope. The frequency that each type of debris occurred was recorded as well as each specific weight of the sample.  The results were then split into debris found in young, or juvenile, loggerhead sea turtles and adult loggerhead turtles.
This study found marine debris in 22 of the 31 sea turtles (71%) as there were a total of 438 pieces of marine debris. The majority of this was found in the turtles’ intestine with less in the stomach and only one item, a hook, in an esophagus. The most debris found in the loggerheads was user plastic in 91.7% of them.  One of the female loggerheads had the most marine debris of all the turtles with 90% being sheetlike user plastic.  The small and young turtles had an average of 19 pieces of marine debris while the older and larger sea turtles had an average of 27 pieces. The analysis that was performed showed a relationship between number of plastics and shell length, shell length and plastic weight, and animal weight and plastic weight.

The presence of marine debris in the gastrointestinal tract of loggerhead sea turtles was found to be high in the turtles that stranded on the Tuscany coast. The greatest amount of marine debris found in the turtles was sheetlike plastic, which is commonly found in the ocean as a result of worldwide use and its long decomposition rate. The loggerhead sea turtle is an effective bioindicator of the marine litter in the environment and the health of the oceans.

Sea Level Rise and the Uncertainty of Future Climate Conditions

Sea level rise (SLR) is one major consequence of global warming and the resulting climate change. Sea levels have already risen 1.8 cm/decade during the 20thcentury and this trend is expected to increase rapidly in the coming years. Sea level rise is mostly controlled by temperature and salinity changes in the oceans and continental ice sheet buildup and melting. As such, a rise in sea level is seen when there is warmer and less saline water as well as when continental ice melts.  Hu and Deser (2013) were able to analyze SLR rates for the future by using the Community Climate System Model Version 3 (CCSM3). This system was able to present 40 different climate change projections in order to understand the uncertainty that is related to the future climate variability.  The results of this experiment show the extreme uncertainty of the climate moving forward and that the SLR varies by a factor of 2 depending on global location with large increases in sea level in some areas and decreases in others. —Chloe Mayne

Hu, A. and Deser, C., 2013. Uncertainty in future regional sea level rise due to internal climate variability. Geophysical Research Letters 40, 2768—2772

Hu and Deser used the Community Climate System Version 3 (CCSM3) in order to model the rates of future sea level rise.  This system used 40 projections, called ensemble members, and began at the end of the 20th century. Each projection included similar levels of greenhouse gases, ozone, solar and aerosol over a period of 60 years from 2000—2006. In addition, the states of the ocean, sea ice, and land were also static. The differences in projections came from using atmospheric conditions found on days between December 1999 and February 2000. to encompass the variety of atmospheric conditions that are plausible over the next 60 years. It is, of course, impossible to predict future precisely, but this model is able to represent an array of future possibilities for sea level rise as greenhouse gas concentrations continue to rise and add to global warming.
The result of Hu and Deser’s study looked at the mean SLR over the last 20 years of the 60-year period. The global mean SLR was very similar for most cities at around 11+/- 0.2cm for the 20 year period.  On a more local scale, the regional SLR varied by a factor of 2. An example of the local scale SLR can be seen when looking at the large range for San Francisco, which was 4.3-9.6 cm.  Some of the ranges seen showed a peak in the distribution frequency (a large range for the SLR) while other cities showed no peak at all, with a constant rate of SLR.
The geographic distribution of the sea level projections was found to be positive across the globe, except for in the Southern Ocean. In the North Atlantic and Arctic the rate of SLR was projected to be around 5 cm/decade while only about 1-2 cm in the Pacific and 2-3 cm in the Atlantic. These numbers are due to the increase in the amount of heat that the ocean can store as less heat is being lost to the atmosphere. Most uncertainty is found in the high and middle latitudes around the Arctic Ocean, Southern Ocean, North Atlantic and North Pacific. Less uncertainty is found in areas that are tropical as well as in the North Indian Ocean.
Sea level rise is also associated with changes in ocean circulation, which are considered a dynamical component. These changes occur as a result of wind and buoyancy forcing.  Looking at two specific projections for SLR, it is possible to see the trends of sea level pressure, SLP, which is a measure of wind forcing. The results showed that SLP was weaker or stronger depending on which ocean basins were considered, probably resulting in different ocean circulation patterns and differences in sea level rise.  In addition to wind, buoyancy forcing, as a result of the Atlantic Meridional Overturning Circulation (AMOC), plays a large factor in ocean circulation. The AMOC moves warm waters north where they become cold and dense and sink deep down into the ocean. These waters then eventually move south and are cycled through the ocean conveyor belt. As GHG emissions continue to grow, it is expected that the AMOC will slow down and sea levels will increase in the Atlantic without the cold water in the north being forced deep into the ocean.

Disregarding ice melt, the primary increase in sea level rise was found to be expansion of seawater as the temperatures rise but it is clear from their study that there is a great amount of uncertainty as to future SLR.