Phytoplankton Entrainment and distribution in the Pelagic C

Phytoplankton Entrainment and distribution in the Pelagic C. Reynalds, Chapter 2 Ecology of Phytoplankton Paul Simonin John Bisgrove

Physical Properties of Water • • Higher density Higher viscosity Higher melting point Higher boiling point Lower compressibility Polar molecule Aquo polymers High specific heat • Density is greatest at 3. 98 Celsius • Rate of density change increases as heated above

Viscosity and Turbulence • Turbulent Intensity – Product of root mean squares of time averaged fluctuations (u*)2 – Turbulent velocity (u*)

Turbulent Dissipation • Environmental grain Wind – The size and velocities decrease with transfer Velocities must equal or create heat Total volumes must equal

Turbulent Embedding of Phytoplankton

Sinking and Floating

Regulation of Density • Densities of cellular components – Proteins – Carbohydrates (cellulose) – Nucleic acids – Si. O 2 – Lightest lipids ~1, 300 kg m-3 ~1, 500 kg m-3 ~1, 700 kg m-3 ~2, 600 kg m-3(diatom walls) ~860 kg m-3 – Average cell density is rarely less than ~1050 kg m-3

Form resistance

Sinking and Entrainment in Natural Turbulence • Tendency to sink or float (ws) • Propulsion (us) • Velocities of the water • Horizontal motion increases distance traveled during fall

Loss of Sinking Particles from Turbulent Layers • 95% elimination te/t’=3. 0 • 99% elimination te/t’=4. 6

Mixing Largest eddy size Resistance to mixing Robustness of gradient

Vertical Structure in the Pelagic • • • diurnal time-scale wind time-scale seasonal time-scale compare to euphotic zone mixed layer thermocline

Spatial Distribution of Phytoplankton - Vertical • non-motile, negatively buoyant planters • positively buoyant plankters • neutrally buoyant plankters • motile plankters

Spatial Distribution of Phytoplankton – Langmuir circulation

Horizontal Spatial Distribution of Phytoplankton - Patchiness • Sampling Issues • Ecological Reasons – In fisheries patchiness leads to very reduced zones of high growth potential (Hobbie, 2000) • Small scale patchiness – Langmuir circulation • Small lake basins – Drift interrupted by shallows, margins, islands – Basin scale conveyer current – Drift of buoyant organisms – Patchiness as inverse function to wind speed • Large scale patchiness – Horizontal mixing time – Diffusivity – Population change

Oceanic Circulation

Additional resources • General concepts: Inland waters and their ecology, by I. A. E. Bayly and W. D. Williams; Textbook of limnology, by Gerald A. Cole; Wetzel texts… • United States. Environmental Protection Agency. Ecological research series ; EPA-600/… • Ecology of harmful algae, by E. Graneli, J. T. Turner (eds. ) • The Algae and their life relations; fundamentals of phycology, by Tilden, Josephine E (1935) • Local resources: ESF theses such as: The distribution and density of phytoplankton of Jamesville Reservoir, by Pingel, Patricia A. • Estuarine Science: A Synthetic Approach to Research and Practice Edited by John E. Hobbie, Island Press, Washington, D. C. (2000)