BULLETIN OF MARINE SCIENCE. 54(3): 1059-1071. 1994 A LONG-TERM INTERDISCIPLINARY STUDY OF THE FLORIDA KEYS SEASCAPE John C. Ogden, James W. Porter, Ned P. Smith, Alina M. Szmant, Walter C. Jaap and David Forcucci ABSTRACT The SEAKEYS (Sustained Ecological Research Related to Management of the Florida Keys Seascape) program is a research framework which encompasses the large geographic scale and long time scale of natural marine processes and ecosystem variation upon which human impact is superimposed. The need for interdisciplinary long-term research in coastal ecosystems is critical as we anticipate extraordinary resource management obligations and scientific opportunities in the next decade. The core of the program is six instrumented, satellite-linked monitoring stations which span the 220 mile-long coral reef tract and Florida Bay and which, since 1991, have documented the potential impact of summer heating, winter cold fronts, storms, and distant floods. Meso-scale physical oceanographic studies have doc- umented the net flow of water from Florida Bay to Hawk Channel which provides a potential mechanism to link water quality in Florida Bay with the waters of Sanctuary. Water column and sediment nutrient studies have shown elevated nutrient levels in nearshore waters de- creasing sharply to low levels near the offshore coral reef tract. There is a potential link of nearshore and offshore via a seaward deflection in the near-bottom flow. Regional nutrient dynamics are complicated by periodic upwelling driven by the Florida Current. A series of long-term photomosaic stations have tracked coral community dynamics for more than 5 years and have indicated a loss of over 40% in coral cover at some sites. This loss may be linked to declining water quality in Florida Bay. As a large marine ecosystem, the new Florida Keys National Marine Sanctuary and adjoining parks and reserves must be studied and man- aged holistically if human use of the region is to be sustained. A major problem with marine ecosystem research related to resource manage- ment is the difficulty in discriminating natural variation in ecosystems from changes or declines caused by human impacts that may be managed, such as waste disposal, human visitation, boat groundings, and over-fishing. As natural processes vary on a time scale different from research funding cycles, only rarely have studies encompassed the time course of: (1) natural phenomena such as population explosions and declines, diseases, storms, and periodic oceanographic- atmospheric events such as the ENSO; or (2) natural processes, such as produc- tivity, larval dispersal, recruitment, global warming trends, and sea level rise. We now have enough experience to know that long-term data sets are essential to the understanding of the functioning of marine ecosystems and fundamental to their management (D'Elia et aI., 1991; Franklin, 1989; Ludwig et aI., 1993; Primack, 1992). A second problem is that management-oriented marine ecosystem research is too often confined to single sites which may be the best-developed or the easiest to get to, but which are not representative of the range of development of the ecosystems being studied. Sites should be selected over the full range of devel- opment of the ecosystem and research should be of sufficient length to encompass the natural variation of those systems (Duarte et aI., 1992; Kenchington, 1990; Ogden, 1987). Declines in environmental quality, while imperceptible on a day-to-day basis, are dramatic on a decade scale and involve large geographic regions. To document and understand these changes, we must integrate research across the appropriate 1059 1060 BULLETIN OF MARINE SCIENCE, VOL. 54, NO.3, 1994 81' BISCAYNE FLORIDA KEYS NATIONAL MARINE SANCTUARY 25' FT. JEFFERSON • ~ - • ~ / NAT'L. MONIJMENT ..-- .:::::::. ~- - - \ "" ~ /' ;...- ---..••• - -- - - -, • ~ - I ' /' ./ • - - - -- - .J • ••• /' ,,// .. ; J--=-~.. ~- •......../' KEYLARGONAT'L. I I DRY TORTUGAS I '~. .)"" MARINE SANCTUARY It"'il .1" ",,--". J- I.J --:::"-1'-ro''-:: -- / " ~ _ _ - - - - - LOOE KEY NAT'L. KEY WEST NAT'L. MARINE SANCTUARY _____ • WILDLIFE REFUGE Figure I. The South Florida seascape including the Florida Keys National Marine Sanctuary (FKNMS), Everglade:; National Park (including Florida Bay), Biscayne National Park, and other parks, sanctuaries and refuges encompassed by FKNMS, Black dots mark locations of automated monitoring stations (north to south): Fowey Rocks (Biscayne National Park); Molasses Reef; Florida Bay; Som- brero Reef; Sand Key; Dry Tortugas. Arrows indicate major patterns of water circulation discussed in the text. disciplines and direct this effort over the geographic and temporal scales of natural ocean processes upon which human impact, which we seek to manage, is super- imposed. Florida Keys Seascape.-Southeast of the Florida Peninsula, stretching for 220 miles from Soldier Key to the Dry Tortugas, lies the only stretch of tropical coastline in the continental United States. The Florida Keys "seascape," a mosaic of interacting ecosystems including the coral reef tract, seagrass beds, mangrove forests, the expanse of Florida Bay, and the adjoining Everglades, is a unique national resource (Fig. 1). The region, now encompassed in the new Florida Keys National Marine Sanctuary, will be an increasingly significant element in tourism in Florida and is critical to regional economic sustainability. The coastal ecosystems (coral reefs, seagrasses, and mangroves) of south Flor- ida south of approximately 26°N latitude typify those of the Caribbean Sea, but they are at the edge of the zoogeographic northern boundary of the tropics. For example, coral reefs in Florida regularly experience winter temperatures well be- low those associated with vigorous coral reef development. Similarly, while thriv- ing coral reefs grew in the central keys 5,000 years ago, the formation of Florida Bay by steady sea level rise has created conditions on the central reef tract that no longer favor coral reef development. To the north and south where the reef tract is sheltered from the waters of Florida Bay by the keys, vigorous coral reef growth can be found (Lidz and Shinn, 1991; Shinn et aI., 1989). This recent geological history of the keys coral reefs and the pivotal influence of Florida Bay is instructive as we attempt to grapple with management of human impact in a context of dynamic, long-term environmental change. There is a clear scientific and public consensus that the Florida Keys seascape is suffering a precipitous decline in environmental health. Any research program addressing the decline must involve long-term integrated, interdisciplinary studies OGDEN ET AL.: LONG-TERM STUDY OF THE KEYS SEASCAPE 1061 of the seascape, particularly the interplay between the land and the sea (Boesch et aI., 1993). Upstream, decades of water management have severely affected the quality, quantity, timing, and distribution of freshwater flow from the Everglades into Florida Bay (Bancroft, 1993; McIvor et aI., 1994; Van Lent et aI., 1993). Periodically, the salinity of the bay increases in the late summer to as high as 70%0, and has been implicated in fish kills (McIvor et aI., 1994). In 1987, the seagrass Thalassia began to die in central Florida Bay and the die-back continues (Robblee et aI., 1991; J. C. Zieman, pers. comm.). Blooms of microscopic algae have increased in frequency and intensity. The human population of the keys has had an increasing impact on nearshore water quality and Lapointe et aI. (1990) and Lapointe and Clark (1992) have speculated that nutrient-rich water may pen- etrate as far offshore as the coral reef tract. The reef tract has suffered dramatic and unexplained decrease in live coral coverage at certain sites in the last 10 years (Porter and Meier, 1992; Porter et aI., in press a, in press b). The reasons for this decline are speculative, but de- pending upon the geographic position of the reef there are likely numerous factors involved including nutrients, direct human impact (fishing, diving, collecting), and the accelerating decline of water quality in Florida Bay through water manage- ment (Porter et aI., in press c). A FRAMEWORK FOR REGIONAL RESEARCH The SEAKEYS (Sustained Ecological Research Related to Management of the Florida Keys Seascape) program grew out of a consensus developed at a meeting of regional scientists and resource managers (Miller, 1988). The consensus was achieved by addressing the question: "What are the critical data that we must have about this region over the next 10 years to take advantage of scient!fic opportunities and to serve resource management obligations?" It was agreed that a framework for research should be established that encompassed the geographic and time scales of the natural processes, often disturbed by human impact, that influence the keys region. The elements of the research framework were: (1) detailed knowledge of the distribution of habitats in the region; (2) understanding of the hydrodynamics; and, (3) automated environmental monitoring. As a major concern was the potential impact of nutrients from human impact on the coral reef tract, two additional elements were nutrient dynamics and coral community dynamics at a series of sites encompassing the coral reef tract. Phase I of the SEAKEYS program ran from 1989 to 1991 and Phase II will run through 1994. As the geographic scale of the program anticipated the 2,500 sq. mi. Florida Keys National Marine Sanctuary (FKNMS), established in 1990, the SEAKEYS research