Ecological Process Fundamentals of Ecological Machinery

1
Ecological Process Fundamentals of Ecological
Machinery
Scott Wallace North American Wetland
Engineering, 20 North Lake Street, Forest Lake,
Minnesota  55025 www.nawe-pa.com David Austin
Dharma Living Systems, 8018 NDCBU, 125 La
Posta, Taos, New Mexico 87571
www.dharamlivingsystems.com

• INTRODUCTION
• All ecosystem receive energy inputs from natural
  sources.
• Engineered ecosystems receive energy from
  mechanical sources in construction, operation or
  both.
• Ecosystem self-organization is controlled by
  energy inputs.
• If operating design goals cannot be met by
  natural energy inputs then operational machinery
  must be employed.
• Here, we consider process fundamentals of
  operating ecological machinery.
• We offer two brief examples for this poster (this
  subject really needs a large textbook)
• Hydraulic machinery in temperate, shallow,
  eutrophic lakes to prevent formation of anoxic
  hypolimnia.
• Aeration machinery in treatment wetlands to
  manage effluent quality.

• MECHANICAL MIXING CAN WORK . . . BUT SUSTAINED
  SUCCESS REQUIRES CAREFUL ECOLOGICAL SOCIAL
  DESIGN
• Lake restoration is non-trivial.
• Mixing design requires coupled hydrodynamic and
  thermal modeling as a first-order determination
  of project feasibility.
• Light penetration is substantially a function of
  phytoplankton density.
• Mixing may increase light penetration, but only
  if it is coupled to appropriate ecosystem
  processes.
• Phytoplankton density is a function of nutrient
  availability and filter-feeding (pelagic
  benthic) communities.
• Filter-feeding community structure can be
  radically improved by elimination of hypoxic
  hypolimnia, but
• Biomanipulation may still be required to control
  planktivorous fish populations. Public
  acceptance / cooperation?
• Nutrient availability is a complex design /
  management problem that mixing may or may not
  address.
• Successful destratification may shift primary
  productivity from algae to submerged macrophytes.
  Culturally acceptable?
• Ecological machinery is just an energy subsidy,
  not a complete design.