Lecture 1 Flashcards

Question

What are examples of corers?

Answer 1

* Hand-held corers * Megacorer (multiple corer) ## Footnote Corers are used for quantitative sampling methods.

Answer 2

* Minimize sediment disturbance * Comparable efficiency to box corers ## Footnote They reduce the bow wave effect.

Answer 3

* Underwater video * Camera systems ## Footnote These techniques are used for surveys, identification, and behavior studies.

Answer 4

* Quantitative method * Wide spatial coverage * Suitable for epifauna on the sediment surface * Highly efficient in capturing visual data ## Footnote Useful for behavioral and biodiversity assessments.

Answer 5

* Yoyo camera systems * Manned submersibles (e.g., Alvin) * ROVs (e.g., ISIS) * Autosub6000 * SCUBA ## Footnote These platforms are used for deep-sea exploration.

Answer 6

* Deep-sea exploration * Capturing high-resolution images * Conducting ecological studies ## Footnote They operate across varying depths.

Answer 7

* Manipulating specific variables in a controlled setting ## Footnote They can be conducted in laboratory settings or controlled field experiments.

Answer 8

Performed in natural habitats with minimal manipulation ## Footnote They study the response of benthic fauna to disturbances like dredging.

Answer 9

Non-invasive surveys to understand natural variability ## Footnote They often precede hypothesis-driven experiments.

Answer 10

Ensures reproducibility and robust conclusions ## Footnote It allows for a deeper understanding of ecological processes.

Answer 11

An ecological benchmark representing minimal or no human disturbance ## Footnote Helps to evaluate habitat degradation or recovery through comparative analysis.

Answer 12

Based on physical, chemical, and biological characteristics of the ecosystem, including: * Sediment type * Organic content * Faunal community structure ## Footnote These attributes help in understanding the ecological status of a habitat.

Answer 13

Widely used in environmental impact assessments (EIAs) to determine the extent of human-induced changes ## Footnote They serve as benchmarks for assessing ecological health.

Answer 14

A framework for defining reference conditions emphasizing long-term monitoring and comparisons across multiple locations ## Footnote This approach helps in establishing reliable ecological benchmarks.

Answer 15

Replication ensures that results are not due to random chance or anomalies ## Footnote It strengthens the reliability of study findings.

Answer 16

1. Spatial Replication 2. Temporal Replication ## Footnote Each type addresses different sources of variability in ecological studies.

Answer 17

Accounts for habitat heterogeneity and spatial variability ## Footnote Example: Sampling benthic species across different sediment types (e.g., sand vs. mud).

Answer 18

Accounts for seasonal changes or disturbance events ## Footnote Example: Monitoring benthic communities before and after a dredging operation.

Answer 19

Occurs when samples are not truly independent but are treated as replicates ## Footnote It can lead to misleading conclusions about ecological data.

Answer 20

Ensure sampling units are separated by sufficient distance and use statistical designs that reflect true variability ## Footnote This improves the integrity of study results.

Answer 21

The size must align with the ecological scale of interest ## Footnote Larger units capture more species but may dilute fine-scale variability.

Answer 22

1. Habitat Type 2. Target Species 3. Processes ## Footnote Each factor influences the effectiveness of sampling efforts.

Answer 23

Using multiple sampling unit sizes in tandem to account for diverse species and habitat types ## Footnote This strategy enhances the comprehensiveness of ecological assessments.

Answer 24

Sampling locations are selected randomly, reducing bias but may miss small-scale features or important gradients ## Footnote This method is beneficial for general assessments.

Answer 25

Sampling at regular intervals or grid points, providing even spatial coverage ## Footnote Useful for detecting patterns such as pollution gradients.

Answer 26

Population is divided into strata based on a characteristic (e.g., depth, sediment type) ## Footnote More targeted and efficient compared to random or systematic sampling.

Answer 27

1. Stratified Random Sampling 2. Stratified Systematic Sampling ## Footnote Each type has specific methodologies for selecting samples within strata.

Answer 28

Study objectives, habitat characteristics, and resource availability ## Footnote These factors determine the most effective approach for ecological research.

Answer 29

Microfauna Size: < 63 µm Includes: Protozoans, nematodes Meiofauna Size: 63 µm – 500 µm Includes: Small worms, copepods, foraminifera Macrofauna Size: > 500 µm (up to ~1 cm) Includes: Polychaetes, mollusks, amphipods Megafauna Size: > 1 cm Includes: Sea stars, crabs, larger burrowers

Answer 30

* Elutriation is the process of gently agitating a sieved benthic sample using a continuous upward stream of water to wash away fine particles. * It helps separate fine sediments from coarser material, allowing clearer analysis of benthic organisms like worms and shells. * Typically done in a cone-shaped chamber and used in sedimentology, marine biology, and environmental studies.

Answer 31

Thixotropic — these sands exhibit thixotropy, meaning they behave like a solid when undisturbed but become fluid when agitated, as the grain structure breaks down and water suspends the particles.

Answer 32

The carbon compensation depth (CCD) is where carbonate input equals dissolution in deep waters. Calcium carbonate dissolves more with depth due to pressure, cold, and CO2 from decomposing organic matter. The CCD is deeper in the Atlantic and tropical regions because of higher CO2 levels and lower surface productivity, respectively. Below the CCD, no carbonate sediment remains.

Answer 33

Calcareous ooze: Calcium carbonate shells; common where CCD is deep (e.g., Atlantic). Siliceous ooze: Silica shells from diatoms/radiolarians; found in cold/high productivity areas (e.g., Pacific, Southern Ocean). Phosphatic ooze: Rich in phosphate; near continental margins with high productivity. Detrital sediment: Not biogenous; made of land-derived rock fragments.

Answer 34

Found above the Redox Potential Discontinuity (RPD) boundary. RPD marks the depth where sediment redox potential = 0 mV. Sediment with positive redox values is oxidised; with negative values is reduced. aRPD (apparent RPD) is a visual indicator using sediment color (lighter = oxidised, darker = reduced), without direct measurement.

Answer 35

10% water loss: Calcite and aragonite 50% water loss: Gypsum 90% water loss: Halite

Answer 36

The thickness of sediment is not uniform * little on mid-oceanic ridges * upto 10,000m thick on continental rises * average depth c. 500m * the Atlantic is about twice that of the Pacific - rivers flowing into the Atlantic cover more land and bring more sediment than those from the Pacific.

Lecture 1 Flashcards

(60 cards)