The Coastal Observing Center was established in 2002 as part of NOAA’s Coastal Observation Technology System (COTS). It is now one of sixteen COTS projects. The UNH Center is working to develop and implement an observing system for monitoring the Western Gulf of Maine ecosystem. Our goal is to implement an end-to-end system with the capability to detect, model, and ultimately forecast changes in the ecosystem.

This Center is developing new and efficient methods to acquire, manage and distribute data. Data are analyzed and synthesized to generate new information, and information products are being designed to meet the needs of stakeholders. Two stakeholder communities identified in this region are those interested in water quality and in the fate and variability of the near-shore fisheries. A third stakeholder community are the formal and informal educators who help us translate knowledge about the coastal ocean to current and future generations. We are working closely with the Gulf of Maine Ocean Observing System (GoMOOS) and other partners in the northeast. Our collective goal is to establish a sustainable program of coastal ocean observations as part of the U.S. Integrated Ocean Observing System.

The Coastal Observing Center draws upon the talents of UNH scientists with expertise related to coastal observing and analysis. GoMOOS had established an array of 10 buoys in 2001 that provided real-time observations of the physical environment (currents, temperature, winds). While such measurements are essential to an ecosystem monitoring program, there was a need to develop new methodologies, models and analyses that pertain directly to the ecosystem.

Our focus is on a region centered on the Piscataqua River at Portsmouth Harbor, that extends north to the Kennebec River and south to Cape Cod (Fig. 1). This region includes Jeffrey’s Ledge, one of the most important fish habitats in the Gulf of Maine, now closed to ground fishing, and the adjacent deep waters of Wilkinson Basin. Like other coastal environments, this is a region of significant biological productivity and complex circulation. Central factors controlling the productivity are the seasonal cycles of water-column stratification and nutrient uptake, and year-to-year variability in the Maine coastal current. This east-coast site also represents a region where the surface waters interact with advected continental air that is often polluted. The effects of air-sea exchange of such trace chemicals on any coastal ecosystem are largely unknown. Two phenomena that are likely to have a measurable impact on our oceanic ecosystem are short-term episodic events, such as storms and strong freshwater pulses from land, and the long-term deposition of trace chemicals via the air or rivers. These issues are being examined by our ship-based measurement program whose goal is to provide both an ecosystem baseline and knowledge about its variability and controls. This knowledge will inform models that will be used to simulate what we observe, and to test hypotheses about the mechanisms controlling the marine ecosystem in this region.

Field measurements are made on monthly cruises along the two transects shown in figure 1. The Coastal Transect visits GoMOOS buoy B and waters of the Kennebec River Estuary, and the Wilkinson Basin Transect extends into one of the deep basins of the Gulf of Maine. The observations are made by teams responsible for different components of the ecosystem and its environmental controls. All teams participate in the cruises. Data from the cruises flow into WebCOAST, our data management system, and are being used to create models and to develop remote sensing algorithms for our region of interest.

While much can be learned from standard oceanographic measurements of temperature, salinity, nutrients, and biomass concentrations of phytoplankton and zooplankton, new technologies are being developed for observing the ecosystem. Measurements of the underwater light field are made with state-of-the-art instruments and used to calculate concentrations of phytoplankton biomass (as chlorophyll) as well as other forms of organic matter. A further step being taken is to connect our observations to satellite remote sensing of surface winds, ocean color and sea surface temperature to develop cost-effective means to extend such observations in time and space. Our long-term plan is to minimize the need for ship-based sampling by developing automated techniques deployed on buoys and by using remote sensing methods. However, the ability to sample and assess biological and ecological variables currently requires water sampling with analyses conducted in the laboratory.

An observing system for monitoring the ecosystem is approached by posing five questions: How is the ecosystem changing? What are the forcing factors causing it to change? How does the ecosystem respond to natural and human forcings? Can we predict future changes? and What are the consequences for stakeholders in our region?


How is the Ecosystem Changing and Why?

We know from historical records and from our own observations that the timing and magnitude of phytoplankton blooms vary significantly on interannual to decadal time scales (Fig. 2). In some years (e.g., 2002), the spring bloom of phytoplankton occurs in April, coinciding with vernal flowering on land, whereas in other years (e.g.,1999), the bloom occurs in February (Durbin et al. 2003).

Continuous Plankton Recorder (CPR) data reveal that this late-winter bloom was present throughout the 1990s but was, from all indications, absent during the 1980s. The CPR data have also shown dramatic shifts in the abundance of prominent zooplankton species over the past four decades (Pershing et al. submitted). Four of the smaller taxa were 1-3 orders of magnitude more abundant in the 1990s than in the 1980s, whereas adults of Calanus finmarchicus experienced a 1-2 order of magnitude decline in the 1990s.

Calanus finmarchicus is the major prey of forage and other species, including herring, mackerel, sand lance, and right whales. In the Gulf of Maine, Calanus finmarchicus is at the southern edge of its temperature range, and thus is vulnerable to climate-mediated changes in water temperature. During the plankton surveys conducted by Henry Bigelow in the early 1900s (Bigelow, 1926), Calanus finmarchicus was observed to dominate the zooplankton assemblages. However, in recent years, its abundance has declined in several areas within the Gulf of Maine. Such changes have been linked to reduced calving rates and migration patterns of right whales, and to the disappearance of hundreds of thousands of red-necked phalaropes (right) over the past decade in the Bay of Fundy.

Interannual variation in zooplankton species might be the result of changes in climate. The upward trend in northern hemisphere atmospheric temperature, attributed to the increase in atmospheric greenhouse gases, might result in a warming of Gulf of Maine surface waters. Recent warming trends have been seen in surface waters in Boothbay Harbor, for example, and in the long records from the dock at Woods Hole. Temperature change in itself may gradually or abruptly alter species distributions, as some species, such as herring and Calanus, are at the southern edge of their range. Another climate-related reason for interannual variation in the ecosystem might be the nature of water that enters the Gulf through the Northeast Channel. The North Atlantic Oscillation (NAO) is a climate-related phenomenon that affects Arctic wind patterns and water temperature in the coastal Northwest Atlantic, where it has been shown to affect the northern cod stock (Drinkwater 2002). The influence of the NAO on the Gulf of Maine is less clear, although there is evidence that in some states relatively cold and Calanus-poor Labrador shelf water flows southward across the Northeast Channel, where it makes its way into the deep water of the Gulf of Maine. Interannual to interdecadal variations in wind patterns, circulation and stratification also force ecosystem change in the Gulf of Maine.

Effects of Rivers on the Western Gulf of Maine Ecosystem. -- One of the ways that humans affect the marine ecosystem is through the rivers. Large rivers are major mechanisms for nutrient delivery to the ocean, and river water quality affects freshwater ecosystems and oceanic food webs. Three rivers are important to the Western Gulf of Maine Ecosystem. The Kennebec River estuary lies at the northern edge of our study area and has been a focus of our field work for the past two years. Discharge from this estuary mixes with the western Maine coastal current and is carried southward, thus potentially affecting water conditions throughout the region. The Kennebec River estuary is formed by the convergence of the Kennebec and Androscoggin rivers. The Androscoggin River was designated one of the ten most polluted rivers in America in the 1960s (Mitnik 2002), and both rivers have a history of water-quality problems. Numerous pulp and paper mills are located along the rivers, as well as municipal wastewater treatment facilities. Prior to the passage of the Clean Water Act in the mid-1970s, partially treated and untreated municipal and industrial wastewater was discharged directly into both rivers. Clean-up activities since that time have partially restored the Andro-scoggin, and both rivers now generally maintain fishable/swimmable status. The Androscoggin and Kennebec rivers have been implicated in the re-occurring blooms of “red tide” organisms, although the exact linkage remains unclear.

Two other rivers important to the Western Gulf of Maine region are the Piscataqua and Merrimack rivers. The Piscataqua River enters the Gulf of Maine at Portmouth Harbor, one of only two naturally deep harbors on the U.S. east coast. Together with Little Bay and Great Bay, it forms the Great Bay Estuary, a large, inland, tidally-dominated system that serves as a critical breeding and nursery ground for finfish, shellfish and invertebrates. Significant reductions in water quality and seagrass in this estuary have been linked to increased development since the 1970s (Short et al. 1991). The Merrimack River enters the Gulf at Ipswich Bay, Massachusetts. It has the most densely populated drainage basin in our domain. Many of New England’s former mill cities (Manchester, Lawrence, Lowell, Haverhill) are located along this river, which has a long history of pollution issues. Of this river Henry David Thoreau (1849) wrote“Salmon, shad and Alewives were formerly abundant here . . . until the dam, . . . and the factories at Lowell, put an end to their migrations hitherward. . . . Perchance, after a few thousands of years, if the fishes will be patient, and pass their summers elsewhere . . . nature will have levelled . . . the Lowell factories, and … River [will] run clear again.”


BENEFITS

An end-to-end system is being designed to deliver products tailored to benefit specific user communities: fisheries stakeholders, coastal resource managers, and educators. The benefits of to fisheries stakeholders are information, education and advanced warning to mitigate effects of ecosystem changes on harvesting of Gulf of Maine resources. Coastal resource managers include State planners, fish and game personnel, wetlands conservation staff, estuarine reserve managers and the like. Their role is to protect and restore natural resources in our estuarine and nearshore waters up to three miles offshore. They have expressed a need for better understanding of the spatial and temporal variability in water quality parameters currently monitored, and a better understanding of the coastal “system” of interacting riverine, estuarine, nearshore and offshore waters. Coupled physical-biological models being developed by our Center can be used to assess how representative the stations now being monitored are of the whole region, and to provide a systems-level understanding that should lead to a better sampling strategy for monitoring water quality. To benefit formal and informal educators, our Center has been demonstrating how to integrate ocean topics into the existing curriculum using ocean observing data. There is a pressing need to educate today’s citizens and future generations about the ocean to engender a sense of stewardship of both coastal and global ocean ecosystems.

Related Links

Coastal Ocean Technology System (COTS)

Gulf of Maine Ocean Observing System (GoMOOS)