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An integrated nutrient observatory is being developed within the Northeastern Regional Association of Coastal Ocean Observing Systems (NERACOOS), capable of monitoring nutrient dynamics year-round at temporal and spatial scales necessary to address critical needs of stakeholders throughout the Northeast region. Nutrient levels and fluxes drive total biological productivity throughout the region, from phytoplankton to commercially exploited fish stocks. Nitrate sensors (Satlantic SUNAs) are being installed on existing mooring assets in western Long Island Sound, Narragansett Bay (Prudence Island), Great Bay in New Hampshire, Massachusetts Bay, three sites along the coastal shelf of the Gulf of Maine (GOM), at five depths in Jordan Basin in the interior GOM, and at two depths in the GOM Northeast Channel. Phosphate and ammonium sensors (WET Labs Cycle-PO4 and Cycle-NH4) are also being deployed at the three nearshore sites. The measurements from these sensors will extend the current sparse, long-term records of nutrients from discretely collected samples in the Northeast region and will dramatically improve temporal resolution and continuity of the data for use in studying potential impacts of climate change. Nearshore measurements will be used by NERACOOS stakeholders to help assess, regulate, and mitigate the adverse impacts on water quality associated with excessive pollutant loadings. Measurements throughout the GOM will be used to assess basin-wide nutrient variability and to initialize harmful algal bloom (Alexandrium fundyense) forecast models.

We used a coupled biophysical model to investigate larval transport and connectivity patterns in the Gulf of Maine lobster (Homarus americanus) population. Biological ‘particles’ were released at over 21 000 locations every 10 days over a 4-month hatching period, and were followed from hatching through late postlarval stage. In addition to circulation and dispersion, model calculations included spatial patterns of egg production, temporal patterns of hatching, temperature-dependent development, vertical distribution and mortality. We ran the model for three larval production seasons using the same hatching patterns and individual-based modeling parameters but different flow patterns in the coastal current system. Model results gave distribution and abundance patterns of competent postlarvae that closely resembled observed, alongshore patterns of lobster settlement density. We evaluated the relative contribution of all source regions to the total number of competent postlarvae in a series of medium-size zones along the coastal shelf, many of which are used in lobster management. Connectivity depended on many factors, including patterns of egg production and transport, and the location and size of the receiving zones. Self recruitment ranged from a few percent to >90% of competent postlarvae. Although it was common for postlarvae to come from many, often distant, sources, most of the competent postlarvae in a zone originated within one to two zones in the prevailing ‘up-stream’ direction, forming shorter connections along the coast than the energetic currents might otherwise suggest. Inshore migrations during summer hatching may contribute to these shorter patterns of connectivity. Transport in the prevailing ‘upstream’ direction was also indicated.

The Gulf of Maine Ocean Observing System (GoMOOS) was established in the summer of 2001 as a prototype real-time observing system that now includes eleven solar powered buoys with physical and optical sensors, four shore-based long-range HF radar systems for surface current measurement, operational circulation and wave models, satellite observations, inshore nutrient monitoring, and hourly web delivery of data. The observing system in the Gulf of Maine (GoM) is one of the most comprehensive and operational of the Integrated Ocean Observing Systems (IOOS) systems that have been established in the United States to date. It has also been a very successful system, with data returns routinely in the 85-95% range.The Gulf of Maine is a harsh operational environment. Winter storms pose severe challenges, including high waves and the build-up of sea ice on buoy sensors, superstructure, and solar panels, and in summer its productive waters present severe biofouling problems that can affect the optical sensors. The periods of most difficult field operations often coincide with periods of greatest data value in terms of marine safety, search and rescue, and monitoring biological productivity.The challenges of the Gulf of Maine physical environment were paired with the unexpected challenges of the funding environment that have been the hallmark of the turn of this century. Funding for the system has been chronically short and subject to the unpredictable fluctuations of the congressional appropriations process. The inadequacy and variability of funding has substantially hampered the operations of many of the Integrated Ocean Observing Systems, including GoMOOS, and has hindered technological advancements and maintenance measures. As a result, the design of the GoMOOS infrastructure is little improved from that developed almost a decade ago, and it has deteriorated with age, usage, and suboptimal replacement schedules. In the absence of an adequate and reliable funding stream, the system is fast approaching the end of its expected operational lifetime. Unless this trend is reversed, the system will no longer well serve the many citizens, organizations, and agencies that have come to rely on the data it provides.In this article, we present lessons learned by the scientific and technical groups that have been responsible for the data acquisition of GoMOOS. We believe that these lessons are generic, rather than peculiar to the GoMOOS system, and that they have value for others who are embarking on similar endeavors. However, it is important to make clear that these lessons are from the perspective of the scientists, and that the views of others involved in complementary aspects of GoMOOS, including public outreach, fundraising, and providing data and products to the more general user community, are not represented here.

The remarkable increase of Homarus Americanus (lobster) abundance in recent years has resulted in record landings throughout the states and provinces along the perimeter of the Gulf of Maine. A considerable amount of data on various life stages of lobsters has been collected for research, management and conservation purposes over the past 15 years. We have used these data sets to develop models that simulate lobster populations from newly hatched larval stage through settlement and recruitment to the fishery. This paper presents a part of the synthesis study that focuses on the early life history of lobsters. A coupled biophysical individual based model was developed that considers patterns of egg production (abundance, distribution and timing of hatch), temperature-dependent larval growth, stage-explicit vertical distributions of larvae, and mortality. The biophysical model was embedded in the realistic simulations of the physical environment (current and temperature) from the Gulf of Maine Nowcast/Forecast System. The predominant direction of larval movement follows the cyclonic Gulf of Maine Coastal Current (GMCC). Results show relatively low accumulation of planktonic stages along the eastern Maine coast and high accumulation along the western Maine coast. In years when the eastern branch of the GMCC turns offshore southeast of Penobscot Bay, more particles accumulate downstream of the branch point. Interannual variability is also apparent in development times that vary as a function of year-to-year water temperature variation. The larval stages tend to remain relatively near shore, but the final planktonic stage (the postlarva) resides near the sea surface, and the prevailing southwesterly winds in summer cause eastward and offshore drift of postlarvae. Thus, more settlement might take place earlier in the potentially long postlarval stage, and the timing and strength of the southwesterly winds are important in determining the population of potential settlers.

Exchange of water between eastern Casco Bay and the adjacent Gulf of Maine shelf is examined to assess the circulation processes that impact the distribution and occurrence of a toxic dinoflagellate, Alexandrium fundyense, in eastern Casco Bay. Over the inner shelf adjacent to the bay, tidal variance is weak, and the across-shelf current is highly coherent and in phase with the along-shelf wind stress. Although tidal current variance increases as one advances into the bay, non-tidal currents account for 30–40% of the across-shelf current variance at the bay entrance. Between the shelf and the bay interior is a transition region, where the circulation response to wind forcing changes as the wind adjusts to the changing orientation of the shoreline. Far from shore, the overall large-scale coastline orientation dominates the wind-driven response, but within a few internal Rossby radii, the local coastline clearly dominates the flow patterns and across-shelf wind becomes locally shore-parallel inside the bay. Within the bay interior, the across-shelf wind is highly coherent and in phase with the near-surface subtidal across-shelf current. The Kennebec River north of the study area supplies freshwater to eastern Casco Bay in all seasons. A pool of low-density, relatively fresh water at the entrance to the bay sets up an across-shelf density gradient that is reversed from a typical estuary, and likely contributes to the mean surface on-shelf transport in this region. Surface-drifter trajectories observed over the course of the study suggest that both the across-shelf wind and the across-shelf density gradient are important in driving surface up-bay transport and in the retention of surface-dwelling organisms in eastern Casco Bay.

Cold surface temperatures, reflecting Scotian Shelf origins and local tidal mixing, serve as a tracer of the Eastern Maine Coastal Current and its offshore extensions, which appear episodically as cold plumes erupting from the eastern Maine shelf. A cold water plume emanating from the Eastern Maine Coastal Current in May 1994 was investigated using advanced very high resolution radiometer (AVHRR) imagery, shipboard surveys of physical and biochemical properties, and satellite-tracked drifters. Evidence is presented that suggests that some of the plume waters were entrained within the cyclonic circulation over Jordan Basin, while the major portion participated in an anticyclonic eddy at the distal end of the plume. Calculations of the nitrate transported offshore by the plume show that this feature can episodically export significant quantities of nutrients from the Eastern Maine Coastal Current to offshore regions that are generally nutrient depleted during spring-summer. A series of AVHRR images is used to document the seasonal along-shelf progression of the coastal plume separation point. We speculate on potential causes and consequences of plume separation from the coastal current and suggest that this feature may be an important factor influencing the patterns and overall biological productivity of the eastern Gulf of Maine.

Covering more than two-thirds of the Earth’s surface, the oceans are a central component of the global climate system. The oceans help to control the timing and regional distribution of the Earth’s response to climate change, primarily through their absorption of carbon dioxide (CO2) and heat. Changes to the physical and chemical properties of the oceans are already being observed. Sea surface temperatures are warming, sea level rise is accelerating, the oceans are becoming increasingly acidic, and the rate of sea ice melt is steadily increasing. The International Panel on Climate Change (IPCC) assessment released in 2007 projects that, due to the persistence of greenhouse gases in the atmosphere, it is highly likely that the oceans will continue to warm and the impacts will be felt for centuries (IPCC, 2007a). This section focuses on the physical and chemical changes currently being observed in the Earth’s oceans, including changes in temperature, stratification, salinity, sea ice, climate regimes, ocean circulation, and ocean acidification. Knowledge gaps and research needs will be discussed throughout. The aim is to assess the current state of knowledge related to how climate change may be interacting with, and in some cases, driving, the observed physical and chemical changes in the Earth’s oceans, and what that means for the U.S.

The hydrography and distributions of cod larvae on Georges Bank were surveyed during two research cruises in April and May 1993 in order to relate larval drift between cruises to the vernal intensification of the frontal component of the residual circulation. We observed the transport of two patches of cod larvae. One patch, which had maximum larval cod densities of 45 larvae 100 m −3 in April, appeared to have been advected south about 75 km between surveys, while the other, which had maximum larval cod densities of 20 larvae 100 m −3 in April, appeared to have been advected north-northeast about 25 km. Maximum larval densities in each patch sampled during the second cruise in May were 15 and 18 larvae 100 m −3 , respectively, and mean growth in total length for larvae in the two patches was approximately 5.5 mm and 4.5 mm, respectively, between the two cruises. During the April cruise there was a large volume of anomalous cold, fresh water, of Scotian Shelf origin, which occupied much of the eastern third of Georges Bank. During May, relatively cold, fresh water appeared in a band from the Northeast Peak along the Southern Flank, between Georges Bank water on the top of the Bank, and upper Slope Water offshore. The distribution of cold, fresh water suggests its participation in the general clockwise circulation around the Bank. The transport of cod larvae comprising the first patch appeared to become organized within, and move along, the frontal boundary established by the Scotian Shelf-like water mass, while larvae in the second patch, which we assumed to have moved to the north, may have been transported northward in an on-Bank flow of warmer and saltier upper Slope Water, which may have originated from a Gulf Stream Ring. Based upon observed transport of the first patch of larvae in relation to the frontal boundary, we present a conceptual model of frontal mixing currents on Georges Bank, where current velocities may reach 5 cm s −1 at the depth of the pycnocline. We suggest that this frontal component of the residual circulation, which is in addition to that resulting from tidal rectification, may be important in the transport of fish larvae, and that interannual variability in the degree of intrusion of extrinsic water masses may contribute to variable larval cod drift patterns, to variable larval cod retention on the Bank, and ultimately, to variable larval fish recruitment to the early juvenile stage.

The Gulf of Maine ocean observing system (GoMOOS) was established in the summer of 2001 as a prototype real-time observing system that now includes eleven solar- powered buoys with physical and optical sensors, four shore- based long-range HF radar surface current systems, circulation and wave models, satellite observations, and hourly web delivery of data. The Gulf of Maine (GoM) is a harsh operational environment. Its winter storms pose severe challenges that include waves exceeding 10 m in height, and the build up of sea ice on buoy superstructure, solar panels, and sensors. In summer the productive waters of the GoM present severe biofouling problems that can affect the optical sensors. These periods of most difficult operations correspond to the periods of greatest data value, in terms of marine safety, search and rescue, and monitoring biological productivity.

The Gulf of Maine Ocean Observing System (GoMOOS) was established in the summer of 2001 as a prototype real-time observing system that now includes eleven solar-powered buoys with physical and optical sensors, four shore-based long-range HF radar surface current systems, circulation and wave models, satellite observations, and hourly web delivery of data. The Gulf of Maine is a harsh operational environment. Its winter storms pose severe challenges including the build up of sea ice on buoy sensors, superstructure, and solar panels, and in summer its productive waters present severe biofouling problems that can affect the optical sensors. The periods of most difficult operations often coincide with periods of greatest data value in terms of marine safety, search and rescue, and monitoring biological productivity. GoMOOS scientists and engineers continue to refine system designs and operational procedures to moderate the environmental stresses on the sensors and systems.

The Gulf of Maine Ocean Observing System (GoMOOS) is a comprehensive prototype integrated coastal ocean observing system that was established in the summer of 2001. Its current configuration includes eleven solar-powered buoy-monitored locations with physical and optical sensors, four shore-based long-range HF radar systems for surface current measurement, operational circulation and wave models, satellite observations, inshore nutrient monitoring, and hourly web-delivery of data. It serves a broad array of real-time oceanographic and marine meteorological data and data products to scientists, state and federal regulators, the National Weather Service, both the US and Canadian Coast Guards, the National Data Buoy Center, educators, regional natural- resource managers, the Gulf of Maine fishing and maritime industries, local airports and airlines, sailors, and the general public. The ocean observing system that can be thought of as consisting of four major subsystems: the data acquisition subsystem; the data handling, processing, and archiving subsystem; the system of numerical nowcast and forecast models; and a web-based data distribution/presentation subsystem. The Gulf of Maine is a harsh operational environment. Winter storms pose severe challenges including the build up of sea ice on buoy, its solar panels, and its meteorological sensors. In summer the productive waters of the gulf can present severe biofouling problems that affect the operation of optical sensors. Thus, the periods of most difficult field operations coincide with the periods of greatest data value in terms of marine safety, search and rescue, and the monitoring biological productivity. Never-the-less, the data returns for the GoMOOS ocean sensor array has averaged approximately 90% over the first seven years of operation. This unusually high rate of data return is due in large part to our operational six-month duty/maintenance cycle on all equipment. We have 22 buoys for 11 locations, and 22 complete sets of instrumentation that are rotated in and out of service on a six month schedule. The challenges of the Gulf of Maine physical environment were largely understood a priori, and were incorporated into the system design criteria and the blueprints for the service and maintenance protocols. However, there were unanticipated challenges in the funding process that have caused the greatest difficulties, and which continue to pose a serious threat to continued operation and success of this ocean observing system, as well as others observing systems in the United States. Funding for the system has been chronically short and subject to the unpredictable fluctuations of a US congressional appropriations process. The inadequacy and variability of funding has substantially hampered the operations of many of the Integrated Ocean Observing Systems (IOOS), including GoMOOS, and has hindered technological improvements. The funding crisis has deepened to the point that, unless this trend is quickly reversed, the number of monitoring stations will be substantially reduced and system will no longer be able to serve many of citizens, organizations, and agencies that have come to rely upon the data it currently provides. Ocean sensors, ocean platform technologies, and modeling and visualization techniques are in a period of rapid technical development. If stable funding can be achieved, the capabilities of operational ocean observing systems could increase dramatically over the next decade. Autonomous vehicles could become the fast response survey fleet of the IOOS, as well as taking on routine, sustained marine survey functions that are already prohibitively expensive to perform using ships, and will become even more costly as energy costs rise in the future. Practical autonomous vehicles will likely expand beyond gliders and AUVs to include surface sail vessels and energy-efficient autonomous aerial drones. The combination of time series measurements from profiling packages on buoy arrays with the repeatedly spatial surveys of the autonomous fleets will provide a new look at our coastal oceans that could transform coastal ocean science and management. Coupled with these new platform advances will be significant growth in the areas of real-time biochemical sensors, sensor miniaturization, high-speed data telemetry technologies, increases in onboard data processing capabilities, routine two-way communications with submerged sensors, and advances in data visualization techniques that will amount to virtual presence. The single greatest enabling factor of these broad improvements to ocean observing operations and science appears, at present, to be the establishment of an adequate, stable, and predictable funding process.

The Gulf of Maine Ocean Observing System (GoMOOS) was established in the summer of 2001 as a real-time pilot integrated observing system that includes a comprehensive array of moored physical and optical sensors, shore based long-range HF radar systems, circulation and wave modeling, satellite observations, and Web delivery of data and data products. The system is automated and operational. The GoMOOS moored buoy array presently consists of 10 solar-powered, automated buoy systems that telemeter data hourly via cellular/iridium phone and GOES satellite transmitters. The operational protocol is that 20 buoys and instrument suites are rotated through the 10 locations on a six-month cycle. Current measurements are made at 2 m depth using Aanderaa RCM9 in situ Doppler current meters, and subsurface currents are made with downward-looking RIM Doppler profilers. In addition, near-surface currents in the Gulf of Maine are being measured using a 5-megahertz long-range HF radar system manufactured by CODAR Ocean Systems Inc. Comparisons of the three current measurement systems are presented, and the operational logistics of current monitoring using these technologies in the challenging Gulf of Maine environment is discussed.

A turbidity maximum has been observed in the Kennebec estuary during mode rate and low flow conditions near the upstream limit of salinity intrusion. Hydrographic, ADCP, and transmissometer data were collected at different river flow levels and seasons during 1995–1998. The location of the tip of the salt intrusion changes dramatically and during high runoff may be flushed from the channel of the estuary along with the accumulated particles in the turbidity maximum. It is hypothesized that the estuarine turbidity maximum (ETM) was absent 18% of the time with occurrences in all seasons during 1993–1999 based on river flow volumes from the Kennebec and Androscoggin Rivers throughout the study period. When the flow is moderate and low, which occurred 73% of the time on average, a region of high turbidity can be found as far as 40 km upstream of the mouth. Suspended particulate loads are low in the ETM, on the order of tens of mg l−1 and may vary with the length of time that the ETM has been present.

Somes Sound has been described as the only example of a fjord on the east coast of the United States. On a small scale, and from a morpho? logical point of view, the Sound has key features normally associated with fjords, including pronounced subaerial topographic relief, submarine sills, and the U-shaped cross-section typical of glacially-carved troughs. However, based on its salinity distribution, which is related to the mixing and circulation processes used to characterize estuarine types from an oceanographic point of view, Somes Sound is a vertically well-mixed estuary that does not exhibit the strong stratification typical of fjords. While its geomorphology is unique, the oceanographic processes operating in the embayment are essentially the same as those in other shallow Maine estuaries with low fresh water input. In these estuaries, as well as in Somes Sound, tidal mixing is dominant over freshwater inflow in determining the circulation and the vertical stratification of the water column. Somes Sound, a narrow cut that nearly divides Mount Desert Island in two (Fig. 1), is morphologically unique among coastal embayments and estuaries along the eastern seaboard of the United States. The coastal embayments of Maine were altered by glacial erosion of the Pleistocene ice sheets and postglacial changes in sea level creating the typical low rolling relief best characterized as a fjard or firth coastline (Belknap et al. 1986; Kjerfve 1989). On the other hand, topographic relief in the Mount Desert region is decidedly more pronounced, and the eastern shore of Somes Sound rises at one point to more than 250 m above sea level. In addition to the spectacular subaerial relief, the submarine topogra? phy of the Sound displays the U-shaped channel cross-section and shallow terminal sill that characterize glacially-carved and deepened valleys. Based on these and other geological characteristics, Johnson (1925) concluded that Somes Sound represents the only "possible ex? ception to the statement that the term fjord cannot be properly applied to the coast of Maine." * Department of Oceanography, University of Maine, Orono, ME 04469-5741; ** Bigelow Laboratory for Ocean Sciences, West Boothbay Harbor, ME 04575 This content downloaded from 157.55.39.178 on Fri, 05 Aug 2016 04:51:03 UTC All use subject to http://about.jstor.org/terms 36 Northeastern Naturalist Vol. 4, No. 1 Figure 1. Mt. Desert Island

Observations of wave crest elevation, wave trough elevation, and wave celerity have been made in the surf zone on a natural beach. A series of 22 wave poles having vertical gradations of 7 cm (near shore) and 11 cm (off shore) were placed across the surf zone from outside the break point to the swash zone. Movements of 10 individual waves all having a break point within one wave pole spacing of each other have been photographed, and the data on wave height changes and wave speed changes have been analyzed. Wave celerity within the surf zone, given as a ratio M to solitary wave celerity, shows a systematic increase of wave speeds near the break point to a peak of M ≃ 1.2, thence a decrease farther shoreward to M ≃ 0.8, and finally a second increase where M > 1. Wave height decay after breaking follows the theory of turbulent dissipation recently presented by Sawaragi and Iwata (1974). The wave height to water depth ratio within the surf zone is a function of distance from the break point and ranges from 2.0 to 0.6. The results indicate that the use of linear and nonlinear nonviscous wave theories to quantify surf zone wave characteristics is misleading insofar as quantitative prediction is concerned.

The Nantucket Shoals Flux Experiment (NSFE) was a collaborative effort to measure the alongshelf transport of mass, heat, salt and nutrients from March 1979 through April 1980 with a dense army consisting of moored current, temperature and bottom pressure instruments in an across-shelf and upper-slope transect south of Nantucket Island. The pressure component of that experiment is described here. Bottom pressure recorders were deployed at stations N1 (46 m), N2 (66 m), N4 (105 m), and N5 (196 m) during two half-year periods. spring–summer 1979 (SUMMER) and fall–winter 1979/80 (WINTER). A synthetic subsurface pressure (SSP) record was formed from atmospheric pressure and sea level observations at Nantucket Island. The low-pass filtered (periods > 36 h) or subtidal pressures were used for the subsequent analysis. It was found that Nantucket SSP and BP are very nearly equivalent for fluctuation periods less than about 50 days if steric changes in sea level, due to density changes above the seasonal ...

The NEFC participation was supported by the NMFS Marine Resources Monitoring, Assessment, and Prediction (MARt-1AP) Program. The U.S. Bureau of Land Management (BLM) supported the USGS field and analysis component under t~emoranda of Understanding M550-MU6-79, M551-MU8- 24, M551-MU9-4, and M551-MU0-18. The WHO! and UNH field programs were supported by the National Science Foundation under Grants OCE 78-19513 and OCE 78-26229.

A bottom-mounted Doppler Acoustic Profiling Current Meter (DAPCM) has been developed and tested in 133 m of water on the northern California continental shelf during the Coastal Ocean Dynamics Experiment (CODE). The prototype DAPCM is a self-contained, battery-powered instrument consisting of an acoustic Doppler profiler and a microprocessor-controlled data logger. The instrument measures vertical profiles of ocean currents with an acoustic range of approximately 150 m and vertical resolution which can be varied from 1 to 32 m. Results of a 90-day comparision between the DAPCM and 8 mechanical current meters (VMCM and VACM) show striking agreement between the two measurement techniques. Mean differences between corresponding acoustic and conventional current measurements were generally less than 0.5 cm/sec and rms differences were approximately 2 cm/sec. Vector correlation coefficients exceeded 0.97 except within 10 m of the sea surface.

The Gibraltar Pilot Experiment was carried out in June 1984 in order to obtain preliminary moored current measurements in the vicinity of the sill in the Strait of Gibraltar. Bottom-mounted Doppler current measurements and moored temperature measurements from this experiment show directly the westward transport of Western Mediterranean Deep Water (WMDW) over the sill. The net westward transport of WMDW over the sill is roughly estimated to be 0.2×106 m3 s−1.