Metabolic Ecology Field Project
Metabolic ecology is a relatively new discipline that explains how ecological processes are regulated by metabolic rates, which unite at all hierarchical levels from the individual to the biosphere to set the rates at which resources are extracted from the environment and allocated to survival, growth, and reproduction. Three factors constrain metabolic rate, and these are body size, temperature, and the stoichiometry of elements distributed among organisms in the environment.
The research will be directed to the human-water system and the influences of climate change on this system. Our major aim is to investigate the ecological stoichiometry from the geosphere and biosphere of a small biome. The overall goal is to understand the distributions, amounts, flux and paths of any given element in the environment and to trace the paths of resources available that sustain the metabolism of the entire ecosystem.
Metabolic Research at Lake Chilwa in Southern Malawie, 2014.
project aims
Body size and temperature are known for most organisms and environments respectively, but stoichiometry, which refers to the distributions and concentrations of all elements of the periodic table in the environment has not been systematically or comprehensively examined for any environment. Thus, our main project objective will be to evaluate the ecological stoichiometry from a reasonably small and well defined biome. That done, we will take what we have learned and apply it to an early human fossil locality.
Atmosphere
lithosphere
hydrosphere
Horizontal distribution through individual life histories
The study aims to not only to establish distributions and amounts of elements as they are today within the biome (vertically), but also trace changes during time (horizontally). More precisely, vertical element distribution/pathways refer to the distribution of chemical elements within the environment, along food webs and chains from soil to primary and secondary producers to humans. Horizontal element distribution/pathways refer to the distribution of chemical elements within individuals during their life span, relating elemental data to growth rate, and incremental lines in hard tissue structures, and in annual rings of trees.
Vertical distribution through the bioshpere
The acquired data will provide a solid base to couple chemical elements and physical properties of the abiotic environment with metabolic rates and life history of organisms within the Lake Chilwa biome. For example, a first trail found that 66Zn/88Sr roughly correspond with rainfall, suggesting that the metabolic flux of materials is sensitive to environmental factors and is comparable to variation in trace elements expected by physiological ecologists.
Taking water samples at Lake Chilwa, October 2014
Geographical aspects
Lake Chilwa is located in the southern region of Malawi, in the eastern Zomba district at the border to Mozambique. The lake extends 60 km north-south and 40 km east-west and is the second largest lake in Malawi, next to Lake Malawi. Its size, however, can vary considerably: when David Livingston came across the lake in 1859, it extended about 32 km south of its boundaries today. Yet, Lake Chilwa is also know to occasionally dry out completely (1968, 1995). The catchment area features seven major rivers that contribute to the lake, and feed the extensive wetlands with which the lake is surrounded by. Lake Chilwa lacks an outlet river and, despite its large surface area, has a water depth of 1 to 2 meters only. The lake features two islands: Chisi Island, closely located to the western shore, and Thwonge Island in the middle of the lake.
The main research area is located in the south-western (catchment) area of Lake Chilwa. Sediment and lake water, as well as hard tissue samples originate from a 10 km radius around the Kuchulu village, including Chisi and Thwonge Islands. River and well water samples originate from the south-western catchment area, reaching from the towns of Domasi (nothernmost) to Chiradzulu (southwest) and Phalombe (southeast) to the Kuchulu village (at the lake) spanning over the districts of Zomba, Chiradzulu, northern Mulanje and Phalombe.
Dr. Timothy G. Bromage
Hard Tissue Research Unit
Department of Biomaterials & Biomimetics
New York University College of Dentistry
345 East 24th Street
New York, NY 10010-4086
USA
Dr. Friedemann Schrenk
Senckenberg Gesellschaft für Naturforschung
Sektion Paläoanthropologie
Senckenberganlage 25
60325 Frankfurt
Deutschland
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