Lecture 14 - Nitrogen Sulfur Phosphorus and Other Nutrients

studied byStudied by 0 people
0.0(0)
learn
LearnA personalized and smart learning plan
exam
Practice TestTake a test on your terms and definitions
spaced repetition
Spaced RepetitionScientifically backed study method
heart puzzle
Matching GameHow quick can you match all your cards?
flashcards
FlashcardsStudy terms and definitions

1 / 10

encourage image

There's no tags or description

Looks like no one added any tags here yet for you.

11 Terms

1

Nitrogen

N2 gas is most common form of N (78% of atmosphere) • Not easily used by organisms

• In aquatic ecosystems N can be in inorganic and organic forms

• Most important inorganic forms of N in aquatic ecosystems are:

• Nitrate (NO3 −) & Ammonium (NH4 +)

• Nitrite (NO2 −) and Nitrous Oxide (N2O) can also be present in significant quantities

• Many organic forms • Amino acids, Nucleic Acids, Proteins and Urea • Organic forms can be dissolved or particulate

New cards
2

Nitrogen Fluxes

• Nitrogen is required for life • Component of many essential biological molecules • Amino acids, DNA, etc •

Many consumers can only assimilate organic nitrogen • Fish, insects, mammals • Use enzymes to break down complex organic molecules • Important source of organic and inorganic nitrogen to system → excretion

• Primary producers and bacteria can take dissolved inorganic nitrogen from the water

• Nitrate, Nitrite and Ammonium • Ammonium is preferred (mostly) because requires less energy to use

New cards
3

Nitrogen Fixation


Many bacteria and some archaea can assimilate (“Fix”) N2 gas

• Includes some cyanobacteria (often associated with algal blooms)

• Enzyme nitrogenase → Energetically costly

• Inactivated by oxygen →use specialized cells (heterocysts) to protect enzyme from oxygen

• Fixation also occurs from lightning

New cards
4

Nitrification/Denitrification

Denitrification is process of reducing nitrate to nitrogen gas

• Process is used to convert organic carbon to energy

• Only occurs in anoxic waters

• Results in removal of inorganic N from aquatic systems

<p><span>Denitrification is process of reducing nitrate to nitrogen gas</span></p><p><span>• Process is used to convert organic carbon to energy</span></p><p><span> • Only occurs in anoxic waters </span></p><p><span>• Results in removal of inorganic N from aquatic systems</span></p>
New cards
5

Presence of N in the Environment

Inorganic N is most abundant as ammonium or nitrate • Balance depends on presence of oxygen

New cards
6

Phosphorus

• Limiting nutrient in many aquatic ecosystems

• One dominant inorganic form → Phosphate (𝑃𝑂4 3−)

• Concentrations often below detection in pristine waters (< 1 ug P/l)

• Many organic phosphorus forms • Lipids, nucleic acids, etc.

• P is often bound to particles such as sediments • Not bioavailable

New cards
7

Phosphorus Transformations

• Availability of phosphate determined by interactions with iron

• In oxic conditions, phosphate precipitates with 𝐹𝑒3+ and other metals • Leads to deposition of particulate phosphorus in the sediments

• In anoxic conditions (e.g., hypolimnion), phosphates dissociates from metals and is released to water column

<p><span>• Availability of phosphate determined  by interactions with iron </span></p><p><span> • In oxic conditions, phosphate  precipitates with 𝐹𝑒3+ and other metals • Leads to deposition of particulate  phosphorus in the sediments</span></p><p></p><p><span> • In anoxic conditions (e.g., hypolimnion),  phosphates dissociates from metals and  is released to water column</span></p>
New cards
8

Sulfur


Complex cycle driven by numerous redox states in which sulfur can occur

• Many bacteria and archaea involved in cycle

• Important as is tightly linked to inorganic metal cycles (e.g., iron) and thus indirectly to phosphorus cycle

New cards
9

Silicon


Highly abundant element on Earth, but…

• Limited solubility so not a major dissolved ion in water

• Abundance in water dependent on geology/weathering

• Most in volcanic areas, least in limestone areas

•Critically important to diatoms

• Make frustules (specialized cell wall) from silicon

• Can deplete silicon in lakes in summer → replenished by weather and erosion

New cards
10

Iron

• Key element in many biological elements

• But generally low demand compared to C, N, and P

• Present in several dissolved forms – often dependent on O2

• For example, 𝐹𝑒3+ (oxic conditions), 𝐹𝑒2+ (anoxic conditions)

• Recall: Important to P availability

New cards
11

Other important nutrients

• Manganese, Copper, Selenium, Zinc, Molybdenum

• Sodium, Potassium, chloride and boron

• Needed in trace amounts and most are not naturally abundant

• Many are toxic when abundan

New cards

Explore top notes

note Note
studied byStudied by 18 people
899 days ago
5.0(1)
note Note
studied byStudied by 32 people
794 days ago
5.0(1)
note Note
studied byStudied by 1 person
28 days ago
5.0(1)
note Note
studied byStudied by 103 people
856 days ago
5.0(1)
note Note
studied byStudied by 3 people
761 days ago
5.0(1)
note Note
studied byStudied by 10 people
693 days ago
4.5(2)
note Note
studied byStudied by 39 people
953 days ago
5.0(1)
note Note
studied byStudied by 11 people
776 days ago
5.0(1)

Explore top flashcards

flashcards Flashcard (33)
studied byStudied by 3 people
792 days ago
5.0(1)
flashcards Flashcard (62)
studied byStudied by 5 people
765 days ago
5.0(1)
flashcards Flashcard (82)
studied byStudied by 10 people
56 days ago
5.0(1)
flashcards Flashcard (40)
studied byStudied by 5 people
171 days ago
5.0(1)
flashcards Flashcard (20)
studied byStudied by 115 people
507 days ago
5.0(1)
flashcards Flashcard (25)
studied byStudied by 12 people
468 days ago
5.0(1)
flashcards Flashcard (25)
studied byStudied by 2 people
661 days ago
5.0(1)
flashcards Flashcard (38)
studied byStudied by 38 people
8 days ago
5.0(1)
robot