John W. Tunnell

An Overview of Marine Biodiversity in United States Waters

Marine biodiversity of the United States (U.S.) is extensively documented, but data assembled by the United States National Committee for the Census of Marine Life demonstrate that even the most complete taxonomic inventories are based on records scattered in space and time. The best-known taxa are those of commercial importance. Body size is directly correlated with knowledge of a species, and knowledge also diminishes with distance from shore and depth. Measures of biodiversity other than species diversity, such as ecosystem and genetic diversity, are poorly documented. Threats to marine biodiversity in the U.S. are the same as those for most of the world: overexploitation of living resources; reduced water quality; coastal development; shipping; invasive species; rising temperature and concentrations of carbon dioxide in the surface ocean, and other changes that may be consequences of global change, including shifting currents; increased number and size of hypoxic or anoxic areas; and increased number and duration of harmful algal blooms. More information must be obtained through field and laboratory research and monitoring that involve innovative sampling techniques (such as genetics and acoustics), but data that already exist must be made accessible. And all data must have a temporal component so trends can be identified. As data are compiled, techniques must be developed to make certain that scales are compatible, to combine and reconcile data collected for various purposes with disparate gear, and to automate taxonomic changes. Information on biotic and abiotic elements of the environment must be interactively linked. Impediments to assembling existing data and collecting new data on marine biodiversity include logistical problems as well as shortages in finances and taxonomic expertise.

Four Regional Marine Biodiversity Studies: Approaches and Contributions to Ecosystem-Based Management

We compare objectives and approaches of four regional studies of marine biodiversity: Gulf of Maine Area Census of Marine Life, Baltic Sea History of Marine Animal Populations, Great Barrier Reef Seabed Biodiversity Project, and Gulf of Mexico Biodiversity Project. Each program was designed as an “ecosystem” scale but was created independently and executed differently. Each lasted 8 to 10 years, including several years to refine program objectives, raise funding, and develop research networks. All resulted in improved baseline data and in new, or revised, data systems. Each contributed to the creation or evolution of interdisciplinary teams, and to regional, national, or international science-management linkages. To date, there have been differing extents of delivery and use of scientific information to and by management, with greatest integration by the program designed around specific management questions. We evaluate each research programs relative emphasis on three principal elements of biodiversity organization: composition, structure, and function. This approach is used to analyze existing ecosystem-wide biodiversity knowledge and to assess what is known and where gaps exist. In all four of these systems and studies, there is a relative paucity of investigation on functional elements of biodiversity, when compared with compositional and structural elements. This is symptomatic of the current state of the science. Substantial investment in understanding one or more biodiversity element(s) will allow issues to be addressed in a timely and more integrative fashion. Evaluating research needs and possible approaches across specific elements of biodiversity organization can facilitate planning of future studies and lead to more effective communication between scientists, managers, and stakeholders. Building a general approach that captures how various studies have focused on different biodiversity elements can also contribute to meta-analyses of worldwide experience in scientific research to support ecosystem-based management.

Surface oil footprint and trajectory of the Ixtoc-I oil spill determined from Landsat/MSS and CZCS observations.

The Ixtoc-I oil spill occurred in 1979 in shallow waters (50 m) of the Bay of Campeche, Mexico. Although it is known that a large portion of the released oil from this second largest accidental marine oil spill in history reached the surface, to date there has been no attempt to document the surface footprint and trajectory of the released oil. Our study attempts to fill this knowledge gap using remote sensing data collected by Landsat/MSS and CZCS. Both showed the same general patterns of oil trajectory to the northwest and north, nearly parallel to the coastline of the western Gulf of Mexico (GoM) with possible oil landing on Mexican and Texas beaches. Field observations at selected beaches and islands along the coast of the western and southern GoM during and after the spill confirmed these satellite-based findings, which were also used to help in planning a recent field campaign to collect sediment samples in the southern GoM.

ENVIRONMENTAL IMPACT AND RECOVERY OF A HIGH MARSH PIPELINE OIL SPILL AND BURN SITE, UPPER COPANO BAY, TEXAS

ABSTRACT On January 7, 1992, a rupture in an underground oil transfer pipeline resulted in a spill of about 2,950 bbl (469 m3) of crude oil into a high marsh community near Chiltipin Creek, San Pat...

Response of shoal grass, Halodule wrightii, to extreme winter conditions in the Lower Laguna Madre, Texas

Abstract Effects of a severe freeze on the shoal grass, Halodule wrightii, were documented through analysis of temporal and spatial trends in below-ground biomass. The coincidence of the second lowest temperature (−10.6°C) in 107 years of record, 56 consecutive hours below freezing, high winds and extremely low water levels exposed the Laguna Madre, TX, to the most severe cold stress in over a century. H. wrightii tolerated this extreme freeze event. Annual pre- and post-freeze surveys indicated that below-ground biomass estimated from volume was unaffected by the freeze event. Nor was there any post-freeze change in biomass among intertidal sites directly exposed to freezing air temperatures relative to subtidal sites which remained submerged during the freezing period.

Coastal High Marsh Oil Spill Cleanup By Burning: 5-Year Evaluation

ABSTRACT On 7 January 1992, rupture of an underground oil transfer pipeline spilled 2,950 barrels of South Texas light crude oil (API gravity 37) into a high salt-marsh environment along Chiltipin ...

Shellfish of the Gulf of Mexico

Four of the five top species in the Gulf of Mexico by value and poundage of landings are shellfish species. Gulf-wide, there are at least 49 officially recognized shellfish species: 28 are mollusks, 18 are crustaceans, and three are echinoderms. Of these, 16 shellfish species are taken within US waters, 46 from Mexico, and 6 from Cuba. The major focus is on the northern Gulf species of brown, pink, and white shrimp, Eastern oyster, and blue crab. All species are known to vary widely or fluctuate in population levels in accordance with varying environmental conditions from year to year. In addition, shrimp have also been affected by exogenous factors, such as rising fuel costs, market competition from imported shrimp, and fleet damage from hurricanes. Shrimp populations seem to be flourishing, while the shrimp fishery is in decline. The oyster fishery appears to be fairly stable overall, except for hurricane damage in some places and a decadal decline in stock assessment in Louisiana. Oyster reef habitat loss is a major concern. The blue crab fishery is quite variable from state to state with Louisiana showing continued growth and the largest fishery over the past two decades, while Texas shows a decrease. Gulf-wide, there is agreement that healthy bays and estuaries lead to more productive fisheries; thus, habitats need to be conserved or in some cases, restored.

Habitats and Biota of the Gulf of Mexico: An Overview

An overview of 13 chapters that assess baseline conditions and status of habitats and biota in the Gulf of Mexico before the Deepwater Horizon oil spill in 2010. Brief summaries of water and sediment quality, energy flow—including natural oil and gas seeps, coastal and offshore habitats, major groups of biota and their diseases and mortalities, and commercial and recreational fisheries are provided. Biodiversity in the Gulf is high, but environmental impacts are numerous and varied and most occur within the coastal zone.