Freshwater Ecology (Algae, Nutrients, Zooplankton, Macroinvertebrates)

Algae

Simple non-flowering plants of a large group that includes seaweeds and many single-celled forms.

Cyanobacteria

Also known as blue-green algae, they are prokaryotic organisms capable of photosynthesis and play a crucial role in nitrogen fixation.

Chlorophyta

Green algae that are primarily freshwater organisms, known for their chlorophyll content and their relationship to land plants.

Bacillariophyta

Diatoms, unicellular algae with intricate silica cell walls, important in freshwater and marine ecosystems.

Pyrrophyta

Dinoflagellates, mostly marine plankton known for their two flagella and ability to bioluminesce.

Chrysophyta

Golden algae, characterized by golden-brown pigments, found in freshwater and known for forming cysts.

Intrinsic growth rate (r)

A critical factor influencing algae populations, indicating the growth potential of algal species.

Selective grazing

A behavior exhibited by zooplankton where they consume specific types of algae based on size, nutritional content, or toxicity.

Algal defenses

Strategies developed by algae to avoid grazing, including toxin production and forming difficult-to-consume structures.

P vs. I curve

The Photosynthesis vs. Irradiance (P vs. I) curve describes the relationship between light intensity and photosynthesis rates in algae. It illustrates how photosynthetic efficiency changes with varying light levels, showing saturation points and light compensation.

Michaelis-Menton model

A model that explains how algae uptake nutrients, indicating that uptake rate increases with nutrient concentration until saturation.

Spiraling length

The distance a nutrient travels downstream before being taken up by organisms, a measure of nutrient cycling efficiency.

Ephemeroptera

Commonly known as Mayflies, these are bioindicators that contribute to nutrient cycling in streams.

Plecoptera

Also known as Stoneflies, they are sensitive to pollution and important for organic matter breakdown in streams.

Decapoda

Crayfish, important detritivores and scavengers that contribute to nutrient cycling in freshwater systems.

Bivalvia

Class of mollusks that includes clams, known for filtering water and significantly affecting nutrient cycling.

Nutrient dynamics

The study of how nutrients are transported, transformed, and taken up across ecosystems.

Hydrology

The science concerning the properties and movement of water, essential for understanding nutrient cycling.

Detritivores

Organisms that feed on dead organic material, playing a crucial role in nutrient cycling and decomposition.

Dinoflagellates

A group of protists, mainly marine, responsible for bioluminescence and harmful algal blooms.

Zooplankton

Small aquatic organisms that feed on algae and are crucial in aquatic food webs.

Where do algae predominantly live?

Algae predominantly live in aquatic environments, including freshwater and marine ecosystems, where they can thrive in various light conditions.

What are the taxonomic units used to classify algae?

Algae are traditionally classified into divisions based on pigments, cellular structures, and biochemical characteristics, although the classifications can be ambiguous.These divisions include Chlorophyta (green algae), Rhodophyta (red algae), and Phaeophyta (brown algae), among others.

What are cyanobacteria?

Cyanobacteria, or blue-green algae, are prokaryotic organisms capable of photosynthesis, found in both freshwater and marine environments, and are known for their role in nitrogen fixation. They can form harmful algal blooms and are important in nutrient cycling.

What characterizes Chlorophyta?

Chlorophyta, or green algae, are primarily freshwater organisms that contain chlorophyll a and b, are related to land plants, and can form structures from unicellular to multicellular.

What are Bacillariophyta?

Bacillariophyta, or diatoms, are unicellular algae known for their intricate silica cell walls and are important in freshwater and marine food webs. They play a crucial role in primary production and are indicators of environmental conditions.

What defines Pyrrophyta?

Pyrrophyta, or dinoflagellates, are mostly marine plankton characterized by two flagella and bioluminescence; some produce toxins and are linked to harmful algal blooms. They are important in marine ecosystems and can exhibit mixotrophic behavior, utilizing both photosynthesis and heterotrophy.

What does the equation dN/dt = rN represent in algal growth?

This equation describes how algal growth is influenced by the intrinsic growth rate (r), indicating exponential growth under ideal conditions. It shows the rate of change in population size (dN/dt) over time, where N is the population size.

What insights did the Hubbard Brook experiment provide?

The Hubbard Brook experiment provided insights into ecosystem dynamics, particularly how nutrient cycling and hydrology are affected by forest cover and human activities. It highlighted the importance of forest ecosystems in regulating water quality and nutrient retention.

What role do Plecoptera play in freshwater ecosystems?

Plecoptera, or Stoneflies, are sensitive to pollution, found in clean streams, and play important roles in organic matter breakdown.