By Mary Kerr (202) 225-6260
Statement of The Honorable James L. Oberstar
Port Huron, Michigan
May 12, 2008
Today, the Subcommittee on Water Resources and Environment meets to receive testimony on the impacts of nutrients on water quality in the Great Lakes.
Nutrients, such as nitrogen and phosphorous, in appropriate amounts, are essential to the health of aquatic systems. Excessive nutrients, however, can result in harmful or nuisance algal blooms, reduced spawning grounds and nursery habitat for fish, fish kills, the creation of hypoxic “dead” zones, and public health concerns related to impaired drinking water sources and increased exposure to toxic microbes.
Excessive nutrient problems can have significant impacts over large areas, and within entire watersheds. These problems can manifest themselves locally or much further downstream, leading to degraded estuaries, river systems, lakes, reservoirs, as well as to the creation of hypoxic “dead” zones where fish and aquatic life can no longer survive.
While the focus of this hearing is on the impacts of nutrient contamination in the Great Lakes, the issue of widespread nutrient contamination is a national issue, and one that deserves continued attention. Two leading examples of widespread nutrient pollution are in the Chesapeake Bay and in the Mississippi River system.
In the Chesapeake Bay, excessive nutrients have been identified as the primary cause of water quality degradation; yet, the difficulty in pinpointing all of the potential pollution sources, as well as implementing proper control mechanisms will force the Federal government and the States to miss their 2010 deadline for cleaning up the Bay.
Similarly, in the Mississippi River system, scientists have identified the likely causes for the creation of the Gulf of Mexico “dead zone;” however, because of the national scale of the problem, as well as a reluctance of individual states to take responsibility for controlling nutrient discharges into the river system, it is unlikely that the “dead zone” will be addressed anytime in the near future.
To some extent, the first national attention on nutrient contamination occurred here in the Great Lakes. In the 1960s, Lake Erie was famously declared “dead” when excessive nutrients in the Lake fostered excessive algae that became the dominant plant species, covering beaches in slimy moss and killing off native aquatic species by soaking up all of the oxygen.
Prior to the enactment of the Clean Water Act, pollution filled Lake Erie with far more nutrients than the Lake could handle, with phosphorous being the main culprit. Phosphorous induces plant and algal growth. Yet, at the time, phosphorous was also found in many commercial detergents. Plants and algal blooms began growing, dying and decomposing in Lake Erie, creating anoxia (severe deficiency of oxygen) at the bottom of the Lake and covering the surface with algal growth. This lack of oxygen killed fish and other aquatic species.
With the enactment of the Clean Water Act, and the signing of the Great Lakes Water Quality Agreement in 1972, a concerted effort was made to reduce the pollutant loadings into the Lakes, including a reduction in phosphorous. This effort has improved the overall health of the Lakes.
However, in recent years, there has been renewed attention to the problems of excessive nutrients. In fact, with the beginning of the new century, scientists have notices the reemergence of a “dead” zone within Lake Erie. According to EPA, the bottom waters in the central basin of Lake Erie are again becoming anoxic in the late summer, in part, due to a concern about continued excessive nutrient loadings to the Lakes.
Similarly, widespread outbreaks of harmful algal blooms have occurred throughout the Lakes, but most notably at Bear Lake, Michigan; Muskegon Lake, Michigan, Saginaw Bay, Michigan; and in Western Lake Erie. Although the controlling factors for growth of many harmful algal bloom species are not entirely understood, according to NOAA, harmful algal blooms are likely to over-enrichment of nutrients when runoff from lawns, roads, and farmland accumulate at a rate that "overfeeds" the algae that exist normally in the environment.
Finally, there is growing concern on a relationship between excessive nutrients in the Great Lakes and the presence of two aquatic invasive species – the zebra mussel and quagga mussels. NOAA’s Great Lakes Environmental Research Laboratory is currently studying this relationship.
NOAA has hypothesized this relationship, as follows. As nutrient laden waters flow into the Lakes, the near-shore microalgae flourish as they feed on the nutrients. The zebra and quagga mussels then feed on the abundance of microalgae, and deposit what they cannot digest or the byproducts of what they can on the bottom of the Lakes. This tends to concentrate nutrients in particular hotspots that often coincide where zebra and quagga mussels are found in abundance. These concentrations of nutrients, in turn, accelerate the growth of harmful algal blooms. In addition, because zebra and quagga mussels are filter feeders, they can quickly turn murky water into clear water, which allows sunlight to penetrate into deeper depths. This expands the depth of water in which algal blooms can grow.
Today’s hearing should start the debate on how best to take on the national problem of nutrient pollution in the Great Lakes and elsewhere. I am also hopeful that our witnesses can provide us with their insight on whether existing monitoring and control mechanisms are sufficient to address this issue. If they are not, I would hope that today’s witnesses can recommend suggestions on how we can improve Federal, State, and local efforts to address this troubling problem.
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