Many field campaigns in coastal and oceanic waters have attempted to set biological investigations in the context of physical studies, but few of these have been at the cutting edge of modern physical oceanography. The opportunity to embed an inquiry regarding the regulation of coastal system biological production into a physical study as sophisticated as ASCOT-01 is unprecedented.

The physical dimensions of Massachusetts Bay allow for an interdisciplinary endeavor with a comprehensiveness that would be unattainable in a larger domain. Transient conditions, such as vertical displacement of plankton in strong light gradients due to the formation of internal wave packets in late summer; coastal wind-driven upwelling and subsequent advection of nutrients and organisms; and re-suspension of bottom sediments and nutrients via wind and tidal mixing in shallow waters, etc. can be forecast with models. These physical processes have potential to strongly influence the rates and fates of biological productivity in Massachusetts Bay. The response of biological processes to pulses of upwelling or tidal mixing may be brief, perhaps only a day or two (the generation time for the phytoplankton). Given typical rates of biological activity and advective and diffusive dissipation, a local record of the primary features of such events, e.g. the elevation of nutrients, may be significantly diminished only a few days after the event.

After an initial survey, physical, biological, and chemical data will be assimilated to guide adaptive sampling each day, which will maintain a bay-wide scale synoptic assessment (with sub-mesoscale resolution) and will facilitate the siting of subsequent sampling observations in dynamically interesting places. Guided by and armed with these tools, strategic sampling for the assessment of key biogeochemical-ecological processes can be efficiently deployed.

The survey aspect of this project will lend itself to data assimilation and forecast methodologies with a level of sophistication that has never before been attained in ecosystem studies. The more nimble strategic sampling effort will enable assessment of near instantaneous response of biological systems to stimulating and enhancing perturbations at an equally unprecedented level.

This draft description of a biological module has been prepared by Jim McCarthy, Allan Robinson and Wayne Leslie after discussions with scientists from: UMass.-Boston, UMass-Dartmouth, MIT, Massachusetts Water Resources Authority and SACLANTCEN. A planning meeting will be held at Harvard University on 21 December 2000 and a final draft of this document will result. Participants will include: Wendell Brown (UMass.-Dartmouth), Bob Chen (UMass.-Boston), Bernie Gardner (UMass.-Boston), Carlton Hunt (Battelle), Wayne Leslie (Harvard), Jim McCarthy (Harvard), Mike Mickelson (MWRA), Allan Robinson (Harvard), Henrik Schmidt (MIT), Rich Signell (USGS/SACLANTCEN), Jeff Turner (UMass.-Dartmouth) and Gordon Wallace (UMass.-Boston).

To include a biological component in the Rapid Environmental Assessment that will enable testing of hypotheses that link the physical and biological event scales in the coastal ocean and provide the basis for coupled forecasting.

• obtain a companion suite of data for biological state variables, and fully embed these in the real-time forecast experiment
• using forecasts for the evolution of physical processes and events, and for the biological responses to them, strategically assess these biological reaction rates for the further refinement of models.

Certain aspects of the ecological systems of Massachusetts Bay have been investigated in both specifically focused and time-series studies to serve a variety of purposes. The commercial and recreational importance of Massachusetts Bay fisheries and their ecological links to offshore populations have driven much of this research.

Regionally, the unique characteristics of Stellwagen Bank result in this topographic feature having extraordinary significance in the life histories of large cetaceans and numerous birds and fishes. The singularity of ecosystem conditions on Stellwagen Bank was acknowledged in the decision to accord it national sanctuary status. Intense biological activity on banks is not unusual, and can usually be attributed to physical features that either enrich via advection or enable retention of nutritive materials of several trophic levels. In the case of Stellwagen Bank, which rises from surrounding depths of 80 meters to less than 20 meters over the Bank, tidal currents and wave action are thought to play important roles in nutrient delivery.

Anthropogenic activities, in addition to fishing, and particularly those related to marine commerce, watershed drainage, and domestic and industrial waste discharge have also resulted in Massachusetts Bay research programs. Some of these have had a considerable temporal continuity and spatial extent - MWRA studies associated with the new sewage outfall, for example - but most have not. However, very little of this work has been executed in the context of dynamic physical processes. In fact, important details of the circulation of Massachusetts Bay that have biological relevance have only emerged in recent years.

The LOOPS study in 1998 (Robinson et al., 1999; Besiktepe et al., 1999) revealed new scales of near-surface physical processes that are of great biological importance. The profoundly different circulation that arises with different wind conditions, and especially the emergence of highly localized upwelling features, have unquestionable implications for biological processes in Massachusetts Bay, yet these have not been examined.

The proposed system of models and adaptive sampling for assessment of physical fields and dynamics provides a context in which to pose hypotheses regarding the relative importance of different physical processes for sustaining some unique and important biological features of Massachusetts Bay. In addition to the survey mode of sampling for physical, biological and chemical properties, strategic sampling will enable real-time assessment of the rates of processes that transform materials from one trophic level to another. Data such as these can have immense value in testing the realism of model functions that represent causal linkages among physical and biological processes, such as the biological response to upwelling and tidal mixing events. The models, protocols and procedures to be used initially in the nested and coupled physical/biological modeling context will be the same as those used in the LOOPS Massachusetts Bay Sea Trial 1998 experiment (Besiktepe et al., 1999).

Figure 1 - Schematic of the biogeochemical/ecosystem model module of the Harvard Ocean Prediction System (HOPS) (click to enlarge)

5. Ship Requirements and Instrumentation

Careful consideration needs to be given to the development of a sampling capability that has two fundamental features. First, the survey mode will quantify key components of the biogeochemical-ecological system, principally nutrients and biomass of different trophic levels. In addition the determination of rate measurements of basic processes, such as primary production, new production, and zooplankton grazing is required at key localities. Second, and of equal importance, however, is a nimble streamlined sampling and experimental capability that can be deployed rapidly in one area after another where forecasts indicate the emergence of a localized physical process that can be hypothesized to influence biological production and biomass retention processes.

Plans are underway to have the R/V Lucky Lady (UMass.-Dartmouth) and the R/V Neritic (UMass.-Boston) collaborate with the NRV Alliance to maintain an interdisciplinary synoptic picture of Massachusetts Bay throughout the course of the experiment. Collaboration with MWRA Research and Monitoring, including the use of the R/V Aquamonitor (Battelle Lab) is regarded as mutually desirable and beneficial. Involvement of the EPA research vessel OSV Anderson is a possibility.

• Vertical profiles
• Niskin bottle samples for nutrients, pigments for biomass and floristic analyses, and primary production
• Light attenuation
• Net tows for zooplankton
• Towed instruments

• Chlorophyll fluorescence

• Vertical Profiles
• Large volume Niskin bottles for Nitrogen assimilation measurements of new and recycled production

Initialization and verification surveys of Massachusetts Bay with the NRV Alliance - As per ASCOT-01 document.

Adaptive sampling will continue with one or more coastal vessels - This is required to maintain the bay-wide scale synoptic assessment. It will also facilitate the siting of the subsequent strategic sampling observations in dynamically interesting places.

Strategic sampling from one or more coastal vessels - In concert with the adaptive sampling schedule, stations will be identified for more intensive sampling of biological properties and processes. Depending upon the location and time of day some work with these samples may be done aboard ship or on shore.

While many of the biological samples can be frozen or otherwise preserved for subsequent analyses, the production rate measurements can only be made with freshly collected samples.

Besiktepe, S., A.R. Robinson, D. Kroujiline and J.A. Dusenberry (1999). Modeling of the lower trophic levels of Massachusetts Bay and Cape Cod Bay. Harvard University Reports in Physical/Interdisciplinary Ocean Science #63, Harvard University.

Robinson, A.R. and the LOOPS Group (1999). Realtime forecasting of the multidisciplinary coastal ocean with the Littoral Ocean Observing and Predicting System (LOOPS). Third Conference on Coastal Atmospheric and Oceanic Prediction and Processes, 3-5 Nov. 1999, New Orleans, LA, American Meteorological Society.