Science Wednesday: Protecting Ocean Meadows
Wednesday, September 30th, 2009
Each week we write about the science behind environmental protection. Previous Science Wednesdays.
“Amber waves of grain” conjures up images of vast expanses of grassland across middle America. In contrast, can you picture meadows of seagrasses covering broad areas of the seafloor?
Seagrasses are underwater marine flowering plants that have long, narrow leaves. Because they photosynthesize, seagrasses must grow in shallow water where light penetrates. Most of the light required for these plants disappears below 30 feet.
Florida alone has about a half-million acres of seagrass meadow.
Seagrasses provide essential “ecological services,” such as reducing erosion, improving water quality, and supplying refuge and food for aquatic animals. They are vital to commercial and recreational fisheries that are a major part of a coastal community’s economy.
Unfortunately, the health of seagrass meadows has been compromised in many places due to pollution from land-based activities. Excess nutrients from fertilizers and wastewater cause algal blooms which deprive seagrasses and aquatic organisms of essential oxygen. In addition, over-fishing, over-crabbing, and other harvesting practices change the ecological balance within seagrass meadows, leading to shifts in both plant and animal populations.
My PhD thesis brings me to the shallow waters off Bermuda where I am measuring the simultaneous effects of heavy grazing and excess nutrients on the overall health of seagrass pastures. Seagrasses here are being eaten (grazed) by green turtles and parrotfish while fertilizer runoff is also affecting them.
My main focus is to understand how grazers with different feeding strategies—where and how they feed—control the effects of nutrient pollution. I am working in both the laboratory and the field to manipulate and measure nutrient levels.
A conservationist at heart, I constantly seek to educate others about how human actions can either positively or negatively impact the physical environment. My research looking at the indirect effects of local fishing practices and wastewater treatment on seagrass ecosystems has pressing applications for coastal conservation and management worldwide.
About the author: Kim Holzer is a Ph.D. student in the Department of Environmental Sciences at the University of Virginia. Funding for her research is provided by a 2007 EPA Science to Achieve Results (STAR) Graduate Research Fellowship. Kim expects to graduate in the spring of 2011 and continue working as a scientist in environmental protection.

Starfish are mysterious creatures. Some people and articles I have read say they should be called sea stars because of their shape and their lack of relationship to fish. I had never taken an interest in them until recently when I visited Alaska and kayaked on the Tatoosh Islands. The Tatoosh are located north of Ketchikan and are part of the 
Dan has been working for Pyramid Lake Paiute Tribe (PLPT) since 1989. Dan recognized early the importance of bioassessments in detecting impairments from stressors on aquatic communities, and has applied his knowledge and expertise as an aquatic ecologist to the assessment of the condition of PLPT surface waters and biological resources. In his time at PLPT, Dan has worked to improve water quality and habitat for aquatic organisms and wildlife on the Pyramid Lake Reservation. Many of the concepts and programs Dan has established and managed at PLPT have been exported to other tribes. Dan has communicated his knowledgeable of ecology by teaching tribal members the benefits of establishing and sustaining a viable ecosystem using scientific evidence. The important component to understanding ecological function is to know tribal cultural practices, sacred sites and areas of natural vegetation cover present and past. Dan uses a practical approach in communicating these scientific concepts at the local level and to the scientific community.
Because the timber was thought to be the only remaining remnant of the fort extending into the river, dredge operators were instructed to avoid it, as well as a section of the river where the timber rested. However, unbeknownst to everyone, another timber was buried in the sediment underneath the exposed timber, and this timber extended past the exclusion zone and into the area approved for dredging by EPA. This second timber was 21 feet long. When the dredge operator came in contact with the buried timber and pulled it upward, it caused the other (exposed) timber to come free from the riverbank.
A flurry of archeological activity has been focused on the timbers and riverbank. Although experts need to determine the extent of contamination of the timbers, this incident now provides an excellent opportunity to carry out a detailed archaeological investigation of both the land area of the fort site, as well as the in-river areas adjacent to the site. The work will focus on defining the context and function of the timbers in question, as well as adding to the understanding of the activities carried out at the fort by controlled excavation and subsequent analysis of recovered artifacts. Of particular interest to the officials in the Town of Fort Edward is the opportunity for the public to observe the excavations.