3. METHODS IN MICROBIAL ECOLOGY

HAPIT NANG EXAM, SIGE RAKAG TINAPULAN. SIPAON KO GYUD NAANG IMONG TILAOK!

-Number of organisms
-Biomass of population
-Rate of activity
-Cycling and transfer rates of materials

To understand the structure and functioning of ecosystems, it requires quantitative information about …

TRUE

TRUE OR FALSE: It is rarely feasible to subject the whole ecosystem to enumeration and measurement procedures.

-Sample collection
-Sample processing
-Actual measurements

Each determination consists of three phases.

TRUE

TRUE OR FALSE: All procedures must be taken into consideration when results are interpreted for measurements are profoundly influenced by the manner of sample collection and processing.

TRUE

TRUE OR FALSE: Different approaches are being used for sampling microorganisms from different environments.

-physical and chemical properties of the ecosystem
-the expected abundance of microorganisms
-the enumeration or measurement procedures to be performed

In sample collection, the methods to use is determined by:

ENVIRONMENT: Air
ACCESS: Direct
NUMBERS: Low
SAMPLING DEVICES: Filters, Andersen samplers

ENVIRONMENT: Air
ACCESS:
NUMBERS:
SAMPLING DEVICES:

ENVIRONMENT: Water
ACCESS: Direct or remote
NUMBERS: High or low
SAMPLING DEVICES: Nets, containers, filters

ENVIRONMENT: Water
ACCESS:
NUMBERS:
SAMPLING DEVICES:

ENVIRONMENT: Sediment
ACCESS: Remote
NUMBERS: High
SAMPLING DEVICES: Grabs corers

ENVIRONMENT: Sediment
ACCESS:
NUMBERS:
SAMPLING DEVICES:

ENVIRONMENT: Soil
ACCESS: Direct
NUMBERS: High
SAMPLING DEVICES: Shovels, corers

ENVIRONMENT: Soil
ACCESS:
NUMBERS:
SAMPLING DEVICES:

1. The number or activity of microorganisms are not altered in a non-quantifiable manner.

2. Samples collected are not contaminated with foreign microorganisms.

3. Samples collected are representatives of the whole ecosystem being sampled.

Sampling procedures to be used must ensure that:

not homogenous, but patchy

In many environments, the distribution of microorganisms is …

Through types of sampling

How can sampling error be minimized?

-Probability Sampling
-Non-probability Sampling

Types of Sampling

Probability Sampling

A mathematical approach and commonly used to get representative samples.

-Simple random sampling
-Systematic sampling
-Stratified sampling

Basic types of probability sampling

Non-probability sampling

A non-mathematical approach and contains sampling biases

-Judgment sampling
-Convenience sampling
-Quota sampling

Basic types of non-probability sampling

Simple random sampling

In this, every single sample has an equal chance of selection

Systematic sampling

Stipulations are made to further make the procedure highly selective.

Stratified sampling

Area to be sampled is further broken into smaller sub-areas.

Judgment sampling

Deliberately avoid areas not representative of the entire area.

Convenience sampling

Use samples which are available

Quota sampling

A given number of sample is obtained

Composite sampling

Individual samples are obtained, bulked together and then mixed.

-Equal number and amount of individual samples are used.
-No interactions exist among individual sampling units
-Only objective of the study is to obtain an unbiased estimate of the mean.

Composite sampling can be valid on certain conditions. What are these conditions?