Developed by: Merrick, Richards Updated: August 2003 U1-m4-s1 Aulacoseira sp. Autochthonous Energy Sources in Streams

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s2 Riverine Ecosystems Energy Sources  Autochthonous – instream  Allochthonous – out of stream /streamwatch/ swm10.html manual/6doing.htm veg/brfredmaple.html

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s3 Autochthonous?  Definition: generated from within  In this case, in-stream energy sources  Source of energy: sun  Who captures the energy? - Photoautotrophs - use the sun plus inorganic matter  Includes organisms in the following kingdoms: Eubacteria, Protista, Plantae

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s4 The sources of energy in streams: autochthonous, allochthonous, DOM

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s5 What is an Autotroph?

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s6 Autotrophs?  Acquire energy from sunlight  Acquire materials from non-living sources  Taxonomy?  Plantae - "macrophytes" : aquatic vascular & non- vascular (mosses)  Eubacteria: Cyanobacteria  Protista  Ochrophyta (mostly diatoms in streams)  Chlorophyta (greens)  Rhodophyta (reds, but only a few species)

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s7 Primary Production?  Definition: the capture of energy by photosynthesis.  NPP –vs- PP ??  Who does it? Autotrophs

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s8 How Might You Measure NPP??

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s9 How Do You Measure NPP?  Biomass accrual over time  preferred for macrophytes  Problems getting accurate values for microphytes  Turnover rates may be too fast  Measurement of open stream gas exchange  Entire stream as a unit  Difficult in low productivity/high turbulence streams  Assumptions about diel productivity flawed.. Who respires?  Light/Dark Bottle method modified for stream beds  uses 14 C uptake  Difficult: requires radioactive materials, community often very diverse

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s10 Primary production of periphyton measured by 14 C uptake using substrate placed in recirculating chambers, New River, VA Hill and Webster, 1982

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s11 What are the Autotrophs in a Stream?  Where might they live?

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s12 Benthic autotrophs  Benthic autotrophs grow on virtually all surfaces receiving light in flowing waters and are collectively referred to as the periphyton community.

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s13 Biofilm  Slippery film on rocks  Periphyton  Aufwuchs

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s14 Periphyton  Periphyton is a complex matrix of algae and heterotrophic microbes attached to submerged substrata in almost all aquatic ecosystems.

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s15 Periphyton  It serves as an important food source for invertebrates and some fish, and it can be an important sorber of contaminants.

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s16 Habitat Specialization  Allows for classification of benthic autotrophs into groups;  Species that grow on stones (epilithon)  Species that grow on soft sediments (epipelon)  Species that grow on other plants (epiphyton)

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s17 Hoffman Image Gallery Attached and benthic populations  Many blue-green algae grow attached on the surface of rocks and stones (epilithic forms), on submerged plants (epiphytic forms) or on the bottom sediments (epipelic forms, or the benthos) of rivers. blue-green algae (cyanobacteria)

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s18 University of Wisconsin Botanical Images Collection Hoffman Image Gallery Attached and benthic populations  The epiphytic flora of lotic communities is usually dominated by diatoms and green algae, and blue- greens are of less importance in this community. Diatoms Biodidac green algae (chlorophyta)

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s19 Periphyton taxa = mostly diatoms

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s20 What causes microscale patchiness?  Periphyton variation within a reach is very high.

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s21 What factors potentially influence periphyton?  Light  Temperature  Current  Substrate  Scouring effects of floods  Water chemistry  Grazing

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s22 Substrate:  Pringle (1990) - used artificial substrates with nutrient agar  Patchiness patterns:  Differences in type of substrate  Availability of nutrients in water

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s23 Epipelion: Periphyton on sandy substrates - variation by microhabitat 1. Bedload sandgrains 2. Upper story mat 3. Mucilaginous layers 4. Understory layer From: Pringle, 1990

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s24 Light  Green algae associated with high levels  Diatoms & cyanobacteria in lower light  Motile algae can pick their spot

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s25 Photosynthesis vs. Irradiance Curve: light adapted and shade adapted community responses Light adapted Shade adapted

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s26 Seasonality in periphyton Chl a PAR Peaks prior To leaf-out

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s27 Seasonal succession in periphyton communities  Diatoms dominate during the winter, spring, and early summer  Green algae and cyanobacteria populations increase during the summer  Benthic autotrophs tends to decrease during the summer as a result of increased shading, increasing again in fall

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s28 Shading and other factors  Not all studies show direct correlation with light  Lack of nutrients can prevent response  Grazing can keep increased light from increasing biomass

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s29 Nutrients  P, N, and Si most commonly limiting  Si is rarely in short supply in rivers  Few studies have looked at influence  Cyanobacteria, nitrogen fixation

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s30 Nutrient Addition Experiments  Protocol: troughs built beside or in stream, add nutrients to streamwater passing through troughs, measure periphyton accumulation over time.

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s31 Continuous flow periphyton bioassay system Nutrient addition Glass slides

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s32 Changes in dominant diatom species in nutrient addition experiments. # of diatoms X m -2

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s33 Nutrient Response  P seems most important  N alone has little affect  But, in specific cases N can be limiting

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s34 Changes in relative abundance of the major diatoms in response to nutrient manipulation. Note: decline in A. minutissima in PO 4 only.

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s35 Nutrient Response 2  N/P ratio can matter  Individual species respond differently

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s36 Diatom abundance on nutrient-releasing substrates in a nutrient poor stream.

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s37 Light and Nutrients Matter  What Else?

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s38 Current  Why?

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s39 Influence of Current  How well attached  Current influences substrate type  Flow renews gases & nutrients => diffusion rates, boundary layers  However, can “scour” the substrate  Growth forms within a species responds to current: Cladophora glomerata is plumose in slow water, long & rope-like in faster flows (Whitton, 1975)

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s40 Cladophora glomerata

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s41 Impact of Floods & Spates  What difference should this make?

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s42 Flow vs. periphyton accumulation Periphyton accumulation has inverse relationship To flood events.

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s43 Substrate effects?  Chemical composition of rocks (Parker, et al, 1973)  Monostroma quaternarium confined to iron-rich rocks  Hydrurus occurred mainly on lime and sandstone  Batrachospermum showed no specificity  Presence of crevices = allows some taxa to persist in high flow (Keithan & Lowe, 1985)

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s44 Stone surface coverage by the moss Hygrohypnum, as a function of stone size in a mountain stream.

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s45 Macrophytes  Taxa:  Flowering Plants  Bryophyta  Lichens  Charales  (complex green algae)

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s46 Macrophyte growth forms  Emergents: banks and shoals  Floating-leaved: stream margins  Free-floating: slow (tropical) rivers  Submerged: midstream (limited by light penetration, current speed, and substrate type) Emergent cce.cornell.edu/onondaga/watersheds/images/milfoil.jpg Floating-leaved Free-floating Submerged

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s47 What adaptations might help in streams?

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s48 Adaptations - Flowing water, current  Firm attachment by adventitious roots  Tough, flexible stems and leaves  Rhizomes  Vegetative reprodution  Hydrophillous pollination aquat1.ifas.ufl.edu/zizaqu2.jpg Stems and leaves Adventitious roots

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s49 High flow species  Almost all Bryophytes  Two families of flowering plant  Require free CO 2  Most macrophytes do better in backwaters

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s50 Patchy distribution of macrophytes  Macrophyte distribution and abundance changes seasonally (temporally)

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s51 Coverage varies within a system  How much of the bottom of streams is covered with macrophytic vegetation?  Variable  Appalachian rivers = %  Bavarian streams = 37% of the area had less than 10% cover

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s52 What might limit growth and distribution?

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s53 Macrophytes: Limitation to growth  What limits?  Temperature  temperate: dormancy via below sediment rhizomes during winter  Tropical: little seasonality  Nutrients: in oligotrophic areas, PO 4 most often limiting  Light often more important  Being rooted can reduce the affect  Free CO 2 availability  Bryophytes or Gymnosperms?  Light: most often limiting factor, along with current

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s54 Macrophyte Energy Flow  Even in streams with high macrophyte NPP, a small fraction of the streams energy comes from macrophytes.  Why?

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s55 Macrophyte productivity: Detrital  Macrophytes have high fiber content  Some have high tanin concentrations + other anti-herbivore compounds (phenolics)  Fiber + tannin = indigestible  animals must adapt to “harsh” diet  Most productivity enters a detrital cycle OR  Secretion of dissolved organic matter  Like Allocthanous input

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s56 So Who Eats the Stuff?  Mainly vertebrates  Waterfowl  Manatee  Grass carp  Muskrat  Moose.  And some invertebrates  Rusty Crayfish  Invasive

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s57 Hoffman Image Gallery Phytoplankton  Lotic phytoplankton include:  Algae  Protozoans  Cyanobacteria  These are small enough to remain suspended in the water column and be transported by currents.  Are there other sources for planktonic input? phytoflagellates (euglenophyta) Biodidac

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s58 Other Phytoplankton Sources?  Sloughing  Import from lentic systems

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s59 What Limits Phytoplankton Productivity?  Typical for any autotroph:  Light  Nutrients  Temperature  With regard to these factors what might make life harder for plankton?

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s60 Light, Turbidity, Turbulence and Depth  In Hudson River Algae 18-22h below 1% light level  But, source could be shallower water  Source-Sink & Plankton

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s61 Depth of mixing in Lakes vs. streams Lake River Thermocline

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s62 Nutrients  Rarely Limiting  Abundance several times lower than expected based upon nutrients  What Else Limits Phytoplankton Productivity in Lotic Systems?

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s63 Lotic Specific Phytoplankton Limiter  Discharge regime (flooding, current)

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s64 Discharge  Inverse relationship to plankton  Population Doubles once or twice per day  Requires slower flow  Flood may connect to standing water  Source of plankton

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s65 Grazing  Zooplankton not a major factor  Reproduce too slow  Mollusks matter!  Asiatic Clam 40-60% reduction in Potomac  Zebra Mussels Can filter entire volume of the Hudson in 1-4 days!  85% drop in phytoplankton biomass  Changes energy flow  Increases clarity

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s66 Algal primary productivity Photosynthesis -Light- Temperature -Nutrient- Chronic toxicity -Velocity Respiration/Excretion Grazing Mortality -Acute toxicity -High temperature Sinking - Velocity - Stress Algal biomass Washout -Velocity -Available substrate Loading Turbulent diffusion

Developed by: Merrick, Richards Updated: August 2003 U1-m4-s67 Water on the Web  This presentation includes material from Water on the Web (WoW) WOW Water on the Web - Monitoring Minnesota Lakes on the Internet and Training Water Science Technicians for the Future - A National On-line Curriculum using Advanced Technologies and Real-Time Data. University of Minnesota-Duluth, Duluth, MN Authors: Munson, BH, Axler, R, Hagley C, Host G, Merrick G, Richards C.  I would also like to thank Dr. Jewett-Smith for her contributions to this presentation