Lecture 10

Lecture 10 - 2nd Reminder: Midterm 1 is this Friday...

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Unformatted text preview: 2nd Reminder: Midterm 1 is this Friday February 1st 2nd • • • Midterm 1 is 15% of your final grade Midterm It covers all lectures through Monday January 28th It Extended office hours today Wednesday 10AM-NOON It covers ALL reading assigned for weeks 1-4 , including topics not covered in class reading Lecture related material is emphasized but general reading is covered generally (optional study aids are Lecture but available on website for early reading assignments) available • It will be short answer comprehensive based upon understanding of content, not problem solving. It • a) a) b) c) d) e) Expect you to know Expect Fundamental properties of seawater, major currents, light Chemotaxonomic pigments General properties of different phytoplankton groups Photosynthesis Primary production methods, formula and nomenclature e. g. Spectral estimates of PP, P-I curves and names/symbols of parts e. g. Qpar, Qpar (λ ), Pmax, Ik, aph(λ ),, alpha, beta, etc. ),, f) Generalities about major case studies discussed in readings: spring blooms in lakes, along coasts, and over the N. Atlantic the General Current patterns of the Southern California Bight SBC resides in northern portion of the Southern California Bight (not Bite) below Pt. Conception California California Current (CC): cool (15C), nutrient rich, flows south along the outer edge of the Continental Shelf (1000 m). south Southern California CounterCurrent (SCCC): warmer, lower nutrient waters that turns from a southerly flow off shore to a northerly flow over the Continental Shelf until encountering the SBC which block much of the flow and divert it seward to mix again with the CC. Episodic upwelling north of Pt. Conception brings very cold (13C<), nutrient rich water from deep waters to surface, which mixes with the CC water forming sharp surface, sharp frontal boundaries as it encounters the SCCC. Upwelling is frontal the primary source of nutrients derived from the ocean near the coast of central California the Subtropical oligotrophic waters flow north along the coast in summer months, more so in El Nino years. Very El warm(>20 C), oligotrophic waters in relatively shallow surface current. SST The current dynamics of the SBC region generate marked gradients in the physical, chemical, biological and optical properties of the upper water column (0 to 160 m) are observed across the SBC coastal region. observed West-East Transect Line, showing 12 stations where vertical profiling of physical, optical, chemical and biological properties were made. optical, Working between dawn and dusk of a single day, transect stations can sampled across the cold-front-warm boundaries along the outer side of the SBC. boundaries Hydrographic conditions change between repeated transects at weekly intervals, e.g. During strong upwelling No upwelling The abundance, composition and photosynthetic capabilities of phytoplankton communities vary widely across the frontal boundaries in SBC region communities SST = sea surface temperature Surface Pmax/vol FRONTAL BOUNDARY cold Surface Chl /vol SeaWifs Chl map Surface water temperature, SST warm cold warm Highly variable waters of the SBC region create a diverse spatial gradients in hydrographic properties TEMP Nutrient-limitation downwelling Uniform mixing Subtropical oligotrophic MIXED LAYER DEPTH DEPTH OF EUPHOTIC ZONE HIGH BIOMASS BIOMASS DOMINATED DOMINATED BY LARGE DIATOMS FOLLOWING UPWELLING UPWELLING MODERATE MODERATE BIOMASS BIOMASS DOMINATED DOMINATED BY MIXED COMMUNITY OF DIATOMS AND MICROFLAGEL MICROFLAGEL LATES LOW BIOMASS;FEW LOW SMALL DIATOMS; COMMUNITY DOMINATED BY SMALL SMALL MICROFLAGELLAT ES & PICO SIZE ES ‘RED’ CYANOBACTERIA CYANOBACTERIA Note differences in pigment concentration range for cold, front, warm waters c P w Chl-specific Pmax = photosynthetic potential f QPAR Chl-specific alpha ~ relative quantum yield Chl-specific P = (Pmax )(tanh I/Ik) f c w Chl biomass upwelling California Current Cold, nutrient rich Diatom-dominated microplankton Frontal baundary Upwelling event at west end of SBC before upwelling at west end of SBC Comment on phytoplankton size and food chain dynamics Net phytoplankton feed the linear food via larger zooplankton via Nano- and pico-phytoplankton feed the microbial loop ...
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