| What does stream metabolism tell us | Carbon cycling an stream metabolism tells us about what is produced in the stream and outside the stream
It can also inform us about the efficiency of the ecosystem in converting organic mattr back to co2 compared to how much is transported down stream.
Its basicly the balance between consumption and export. |
| Snak om denne mange gange den er super vigtig | Rearation is highest in top - fast flowing shallow water. Reaeration is when oxygen used is replaced with oxygen from atmosphere. |
| GPP
ER
NEP | GPP = Gross primary production
ER = Ecosystem respiration
NEP = Net ecosystem production
GPP - ER = NEP
NEP > 0 - autotrophic
NEP < 0 - heterotrophic
NEP = 0 - equilibrium |
| Snak lidt om denne | We can use oxygen to meassure oxygen but we also have to meassure rearation between water and atmosphere - thats the plus minus E. it the water is oversatursated difussion will go out and it will go in if its not satturated. |
| Are streams often heterotrophic or autotrophic? | Huge contribution from alloctonus material. Most respiration happens on alloctonus material
On an anual basis streams are heterotrophic. But there can be few days where the streams are autotrophic.
Days with a lot of sun with high temp then they can be autotrophic. In mid summer basicly.
Could also be streams with very little riparian imput - sourced with groundwater for instance. |
| What is transient storage? | Transient storage
Transient storage is the part of the water that is moving slower than the most of the water. Things are then stored in the water for some time - in a transient state.
It is imporrtant. The more time the water stays in the reach the longer processes like decomposition can occur. So more is decomposed in trannsient storage areas.
Can be in pools, backwaters, hyporheric zone and mycrophyte beds |
| What is shown on this graph? | It shows transient storage.
X-axis: Time after tracer release (in minutes).
Y-axis: Concentration of the tracer (RWT, or Rhodamine WT dye) in parts per billion (ppb).
The shape of the curve shows how the tracer moves through the system:
Initial rise (blue arrow): The tracer enters the main channel and begins dispersing downstream.
Prolonged tail (pink arrow): Tracer is slowly released back from storage zones, creating a delayed decline in concentration over time.
Left side figure.
Its a model showing the fow in a channel.
The water that is flowing some of it is moving into storage stays there for a while and moves out again into the channel. The storage area/capacity
You can get how much water goes into the transient area by putting salt into the system. If there was no transient storage it would follow the black line. K1 is the blue pil and the purple arrow tells something about k2. something about how fast (dont think we have to know this. Just if its a hsort tail or long tail. |
| Which types of organic matter can be found in a stream? | Autochtonus sources: algee and macrophytes basicly.
Allochtochtonus sources: coming from outside (leaves (CPOM), any big course particulate organic matter. Can alsoo be fine (FPOM) or dissolved (DOC).
FPOM can also be FBOM (fine benthic organic matter) seston is suspended in the water. We seperate them cause they are food source for different organisms.
DOM is the largest pool of organic carbon in the stream. A lot of it is very hard for microbes to decompose - they often have very complex organic molecules which is hard to use for microbes. Although its a very big pool its not the most important when we talk about food web.
CPOM. - leaves, macrophytes and animal parts within and outside the stream.
FPOM - breakdown of CPOM and also feeces of smaller organisms - the difference is just size.
DOM - groundwater for instance. |
| What happens to CPOM when it enters the stream? | It is broken down eventually to FPOM over a series of steps through invertebrates and microbes.
All steps present a food source for some invertebrates. |
| Practice these functional feeding groups many times! MANY TIMES
Hvad er de, hvad er deres feeding mechanisms og størrelsen på deres mad.
Shredders
Collectors
Scrapers
Macrophyte piecers
Predators | Øv øv øv |
| Diskuter denne | FPOM |
| What are some pollution sources in streams? | This is organic matter pollution sources. All above can be altered by human activity.
Aquaculture are still a huge source of organic matter.
They dont also increase nutrients but also organic matter (and then more nitrogen) |
| How will global warming, land use change and flow regulation affect streams in regards to light regime, thermal regime and flow regime? | 1. Light Regime
Global Warming:
Longer ice-free periods, earlier leaf-out, and later leaf-fall extend the period of photosynthetically active radiation.
Land-Use Change:
Increased sediment load and reduced riparian shading decrease light penetration into streams.
Flow Regulation:
Reduced sediment load, altered water depth, and changes to riparian vegetation can increase or decrease light availability.
2. Thermal Regime
Global Warming:
Increases in mean annual temperatures directly raise water temperatures, affecting metabolic rates in aquatic organisms.
Land-Use Change:
Loss of riparian shading and channel incision amplify temperature fluctuations in streams.
Flow Regulation:
Releases of cold or warm water from reservoirs (e.g., hypolimnetic releases) and shallow basin retention alter the natural thermal regime.
Har ikke plads til at skrive mere se billedet for flow regime |
| How do the functional groups change in abundance through the stream orders? | Shredders:
High abundance in forested headwaters (low order) where CPOM (like leaves) is the main food source.
Collectors:
Large-particle collectors dominate in mid-order streams.
Fine-particle collectors become more important in high-order streams due to FPOM abundance.
Grazers:
Peak in mid-order streams where periphyton production is high (e.g., more light and less canopy cover).
Filter Feeders:
Increase downstream as FPOM becomes abundant and flow dynamics support suspension feeding.
Sediment Burrowers:
More common in low-gradient, large rivers with soft sediments. |
