A coupled modeling and empirical approach to the study of the life history and
physiological ecology of cold seep vestimentiferans and communities.
Seep vestimentiferans and their symbionts are primary producers that provide complex
habitat structure in a non-toxic setting for a diverse assortment of seep-endemic and non-endemic
heterotrophic species. As such, they are arguably the most important keystone species
in widespread areas of seepage on the continental slope. Recent work has demonstrated that one
species (at least) of seep vestimentiferan is extremely long-lived and can support its autotrophic
life style with the uptake of dissolved gasses across buried portions of its body. Thus, in many
ways, the seep vestimentiferans are analogous to long-lived, ecosystem-structuring, woody plant
species in a terrestrial environment.
We will develop models to address resource acquisition and allocation, life histories, and
community productivity of cold seep vestimentiferans that will guide and focus field and
laboratory studies of cold seep vestimentiferan communities. We propose to work on the upper
Louisiana Slope of the Gulf of Mexico at a depth range of 540 to 1,000m and will include
communities on both hard substrata and sediment that are exposed to a range of sulfide
concentrations. We will use empirical studies and comparative methods to develop, test the
predictions of, and refine, Dynamic Energy Budget models, while at the same time addressing
specific hypotheses concerning vestimentiferan aggregation physiology and ecology.
Our in situ work will be guided by these mathematical models and interfaced with very
efficient and quantitative collection methods that will maximize the information gleaned from
each collection and provide material for future studies, thereby minimizing our short and long-term
impact on the communities. Growth rates of thousands of individuals will be measured and
these data used to estimate the longevity and to calculate the resources allocated to growth by
each vestimentiferan species. We will determine whether 'roots' (posterior extensions that can
be used to mine sulfide from within sediments) are a general feature of seep vestimentiferans and
whether they are environmentally induced. The models will be used to explore the relative
importance of root sulfide uptake to the sustenance of aggregations in different situations and the
implications of vestimentiferan sulfide demand on biogeochemical models of sulfide production.
To facilitate this, environmental concentrations of sulfide and diffusion distances across root
tubes and tissues will be measured, and concentrations and sulfide binding properties of the
hemoglobins in the different species will be determined. The biomass, size frequency,
distribution, and reproductive state of the vestimentiferans will be determined for intact
aggregations and collections processed so that the species richness and biomass of all associated
fauna in each collection can also be determined. This will allow us to formulate life history
models, to scale up the models of individuals to the levels of aggregations, and to model excess
production and its use by associated fauna.
Fisher has extensive experience with the Gulf of Mexico seep communities and has visited
the sites. Shea is a theoretical ecologist with experience in life-history modeling of terrestrial
and aquatic autotrophic systems. The proposed approach will significantly increase our
understanding of these widespread and productive deep-sea communities and their impact on the
surrounding deep sea, and will provide a modeling framework to focus related and future
investigations. The proposed studies will yield basic insights on the ecology, physiology and
reproductive biology of deep-sea systems in general and chemoautotrophic systems in particular.
They will also provide new theory, and tests for existing theory on the evolution of life history
|Effective start/end date||10/1/01 → 9/30/06|
- National Science Foundation: $529,999.00