Biological Oceanography (BO)

Biological Oceanography is concerned with the interactions of populations of marine organisms with one another and with their physical and chemical environment. Because these interactions are frequently complex, and because the concepts and techniques draw from many fields, biological oceanography is, of necessity, an interdisciplinary science. Training in physical oceanography, marine chemistry, marine geology, and several biological areas are therefore pertinent.

Biological oceanography research is conducted on space/time scales ranging from short-term interactions between individual organisms (mm., sec.) to interdecadal variation in widely dispersed populations. The techniques used are diverse, and even within one space/time domain can include field observation, experimentation in the laboratory, and mathematical modeling.

Research topics include:

  • Primary and secondary productivity and nutrient regeneration
  • Community ecology of benthic and pelagic organisms
  • Food web structure and trophic ecology
  • Population dynamics, habitat changes and disruptions
  • Nonequilibrium ecosystems
  • Microbial ecology and biogeochemical cycling
  • Fishery biology and management
  • Marine mammal ecology and communication
  • Systematics and biogeography
  • Population genetics and evolution
  • Behavior as it affects distributions and food web interactions
  • Climate change impacts including warming, ocean acidification and deoxygenation

California current ecosystems, deep sea biology, kelp forest and coral reef ecology, and polar biology are among the realms addressed. Development and testing of new tools (molecular, optical, acoustic), design of sampling programs, and statistical/mathematical analyses of data and modeling also are significant activities.

Requirements for Admission

In addition to the general requirements for admission to the PhD program listed here, two years of chemistry, including general and organic chemistry, and a year of general biology are required. Physical chemistry with calculus may be substituted for physics with calculus where a more elementary physics course was taken. Zoology or botany may be substituted for general biology.

Preparation should also include a course in general geology and at least one course in each of the following categories: systematics (e.g., invertebrate zoology), population biology (e.g., ecology), functional biology (e.g., physiology).

In special cases, other advanced courses in mathematics or natural sciences may be substituted. Applicants are encouraged, but not required, to submit scores from the biology subject test of the GRE.

Program of Study


Required course work:

  • SIO 210 Physical Oceanography (4 units)
  • SIO 260 Marine Chemistry (4 units)
  • SIO 280 Biological Oceanography (4 units)
  • Graduate-level course in statistics/quantitative analysis
  • One of the following:
    • SIO 270 Pelagic Ecology (4 units)
    • SIO 270A Fisheries Oceanography (4 units)


  • One of the following:
    • SIO 275A Benthic Ecology (4 units)
    • SIO 277 Deep-Sea Biology (4 units)


  • One of the following:
    • SIO 271 Marine Zooplankton (5 units)
    • SIO 282 Phytoplankton Diversity (4 units)
    • SIO 283 Phycology: Marine Plant Biology (5 units)
    • SIO 284 Marine Invertebrates (6 units)
    • SIO 294 Biology of Fishes (5 units)
    • SIO 296 Marine Tetrapods (4 units)


    Participatory (required)