Corals and reef animals in captivity Flashcards
What are 2 benefits to studying corals in the field?
- Corals are found in their natural setting/habitat
- Exposed to natural conditions
What are some logistical challenges with studying corals in the field?
- Long travels
- Expensive
- Limitations to the equipment that can be used
- Limited duration possible (corals have slow responses so this can mean they are not captured)
- Guarding of equipment is required
- Limited amount of waterproof equipment available (can be lower tech than lab equivalents)
What is one advantage of experimenting in captivity?
- High tech (with proximity to infrastructure)
- Long term experiments can be carried out
- Ideal to study physiology of corals using advanced analytical techniques
What are four technical basics that must be controlled in lab settings?
- Lighting
- Temperature
- Filtration
- Water chemistry
What two types of lighting used to be used in lab settings? What were the benefits and disadvantages of them?
- Fluorescent tubes (good spectrum, good spread, low intensity, not controllable)
- Metal halides (good spectrum and spread (like solar light), high intensity, not controllable and often overheat (additional costs))
What is the main lighting source used now in lab environments?
LEDs
List advantages of using LEDs in lab settings.
- Fully controllable (e.g., apps to control light intensity, time, spectrum etc)
- Narrow banded spectrum
- Very energy efficient (all energy converted to light)
- Can allow simulation of complex light environments and cycles
What is a disadvantage of using LEDs in lab settings?
They have a very sharp localised light which can make getting uniform light distributions challenging.
What are some key features of temperature in a lab setting?
- Fully controllable
- Often use heaters inside the water (especially in the UK, where outside temps are often colder)
- Can have a controller unit (outside the water)
Why must the water chemistry in lab systems be carefully monitored?
Organisms living will interact with each other and the water, modifying the water chemistry and producing a dynamic system which must be monitored.
What biotic features can be used to equilibrate water chemistry conditions? When can corals be added?
- Macroalgae (often used with scleractinian corals, which require stable conditions, as they control/stabilise nutrients)
- Fishes
Corals are added after these in the system as they require more stable conditions.
What are the main sources of management required in lab settings in terms of a running system (water chemistry focused)?
- Weeding (removal of excess coral growth)
- Water chemistry in a closed system must be controlled and material removed that is not required (e.g., calcium, trace elements etc.)
How is water chemistry monitored by humans (manually)?
- Water changes (reduces accumulated materials, replenishes required materials)
- Filtration (removes large particles etc.)
What are five different methods of filtration in lab settings?
- Live rocks
- Algal refuge
- Deep-sand bed
- Direct removal
- Protein skimmers
How can live rocks be used for filtration in a lab setting?
They provide food, host bacterial communities, and promote both nitrification and denitrification.
Some also help buffer water chemistry e.g., some are made of limestone, which helps maintain stable pH and calcium levels.
What types of algae are commonly used in an algal refuge?
Chaetomorpha and Caulerpa
How does an algal refuge help control nutrient levels in a lab setting (filtration)?
It exports nutrients and some metals by constantly removing them from the water.
Why is a reverse light cycle used in algal refuges? Why does this help buffer water chemistry in lab settings?
It helps maintain pH by allowing algae to photosynthesize at night while corals photosynthesize during the day.
How does a deep sand bed support different microbial communities?
It produces varying oxygen profiles, allowing different bacteria to thrive
What role does a deep sand bed play in nutrient export?
It supports denitrification, helping remove nitrogen from the water.
How does a deep sand bed help buffer mineral levels?
It stabilizes calcium and other minerals in the water.
How can bacteria be cultured externally for filtration in a lab setting?
In a reactor outside the system, where water cycles through to remove excess nitrates.
How does a phosphate reactor remove phosphate in a lab setting?
It uses chemical removal, with a changeable matrix (e.g., ROWA phos) that binds phosphate for removal.
What is the function of a protein skimmer in filtrating in a lab setting?
It physically removes contaminants like phosphate and nitrate, mostly in the form of phytoplankton.
