Rob's lectures

Question 1

Distribution patters influenced by environmental gradients

Answer 1

1.Particle size (grain size gradient)
2.Salinity
3.Vertical (emersion, depth)
4.Wave exposure
5.Latitude + temperature
6.Anthropogenic disturbance

Question 2

1 particle size

Answer 2

-Muddy shores (mangroves)- terrestrial plants, halophyte (salt tolerant), anoxic sediments (adaptation), sediment accretion, coastal erosion and protection. Infaunal communities. Serve as sponges for refuge for other species, they also buffer and absorb storms for us.
-Sandy beaches- physical substrate shifts and is unstable. Burrow to avoid stress and predation, substrate disturbance from waves, fauna rely on imported food. Low primary production.
-Stones + boulders- intermediate disturbance hypothesis, disturbed habitats can have more diversity than undisturbed/pristine habitats.
-Rocky shore- hard and stable substrate, organisms are visible. Live on top of substrate as epifauna and epifloral. Tend to be abundant and small, or sessile and sedentary.

Question 3

2 salinity gradients

Answer 3

-catchment to coast. Fully marine = 35 psu/ppt. Can be fully stratified, moderately stratified (tide mixing or wind), vertically homogenous.
-estuaries- variable salinity regime with few true estuarine species (that complete the whole cycle. Many visitors; both anadromous, catadromous. Adaptations include Osmoconforming and osmoregulation.
-rivers- broader biogeographic impacts of freshwater input. Yangtze river plume has been going on for years and speciation is occurring now.

Question 4

3 Vertical- shallow subtidal to intertidal terrestrial

Answer 4

Ecotones = abrupt changes in vegetation or two adjacent and homogenous community types, producing a narrow ecological zone between them. Zonation also within coral reefs (also in forests).

Question 5

4 wave exposure gradients

Answer 5

Horizontal along shore line. If waves change the coastline, the coastline changes the biodiversity.

Question 6

6 anthropogenic disturbance gradient

Answer 6

There is normally a functional homogenization. Artificialisation of coastline.

Question 7

Upwelling

Answer 7

Driven by surface winds, either seasonal or constant. Normally drags water up from the bottom and pushes warm surface water down.

Question 8

Aragonite

Answer 8

A crystal form of calcium carbonate, which is the primary mineral used by corals to build their skeleton. It’s more soluble than calcite so it dissolves more in acidic waters. It forms coral reefs; they extract calcium and carbonate from seawater to make the aragonite.

Question 9

Aragonite saturation State (Ωₐ )

Answer 9

-Ωₐ > 3.3 → Favourable for coral growth.
-Ωₐ ~2.5 → Growth slows, dissolution increases.
-Ωₐ < 2.0 → Corals struggle to grow, reef erosion outpaces growth.

Question 10

Natural acidification in Bahía Culebra

Answer 10

-Seasonal upwelling bring carbon dioxide rich waters and low pH waters
-Non-upwelling seasons still see acidification events
-Daily or seasonal fluctuations are controlled by photosynthesis and offshore water input

Question 11

Aragonite saturation (Ωₐ): upwelling vs none

Answer 11

-Non-upwelling: Ωₐ > 3.3
-Upwelling: Ωₐ < 2.5 (reduced calcification & increased dissolution).

Question 12

Coral growth in low pH

Answer 12

Showed high coral extension rates despite natural acidification. When the conditions aren’t right their growth slows, but then when the conditions are right, they grow even faster. But reefs are really thin despite how they are spread out. This may be because there is high bio-erosion and dissolution, which prevents long-term reef accumulation since it’s hollowing out from the bottom.

Question 13

Red tides

Answer 13

Pollution when there is a lot of shit in the sea. Normally with heavy rains and strong upwelling.

Question 14

Succession

Answer 14

The non-seasonal, directional + continuous pattern of colonisation + extinction of species populations.

Question 15

Primary succession

Answer 15

Succession in an area where no organisms are present. For example, if artificial pontoons are introduced and algae starts growing on it.

Question 16

Secondary succession

Answer 16

Succession in an area where a biological community is partially intact. Like extreme wave exposure on a rocky shore.

Question 17

Degradative succession

Answer 17

Succession on or in dead or dying organic matter.

Question 18

1883 eruption of Krakatoa

Answer 18

70% of island was blown out, including jungle, animals, humans. It put so much ash in the atmosphere that the earth actually cooled. It was the first time Europeans started studying succession. However, nature came back over time.

Question 19

The climax state: differing hypothesis

Answer 19

An emergent stable community in a successional series is called the climax state, which is self-perpetuating and in equilibrium with the physical and biotic environment.

-Monoclimax hypothesis = only one climax community toward which all communities are developing
-Polyclimax hypothesis = many climax communities may be recognised in an area
-Climax-pattern hypothesis = natural communities are adapted to the environmental factors.

Question 20

Regime shifts

Answer 20

Or phase shifts
-When the ecosystem state shifts due to an environmental driver
-Also known as alternative stable states

Question 21

Coral reefs

Answer 21

-Non-reef building is called ahermatypic, globally distributed
-Reef-building is called hermatypic, but are mainly restricted to the tropics. They live in colonies, skeletons deposit CaCO3, polyps have zooxanthellae, and do photosynthesis by day and feed with nematocysts by night.

Question 22

Corals resource availability

Answer 22

coral have improved resource availability through the coral-polyp associations through obligate mutualism and trophic interactions. Zooxanthellae provide nutrition to the corals as photosynthate, and they get nitrogen as a coral waste product.

Question 23

Coral landscapes of fear

Answer 23

-There are grazing halos which are made by the predator-prey interactions. Sharks push all of the grazers into limited patches around the reefs.
-Without predators there are no halos.

Question 24

EU habitats directive definitions of a reef

Answer 24

Reefs can be either biogenic concretions or of geogenic origin. They are hard compact substrata on solid & soft bottoms, which arise from the sea floor in the sublittoral & littoral zone. Reefs may support a zonation of benthic communities of algae & animal species as well as concretions & corallogenic concretions.

Question 25

Ecosystem services

Answer 25

Disturbed reefs become colonised by invasive oysters from nearby farms in France. Gaps between reefs are taken over by invasive slipper limpets, and surrounding sediment is home to bivalves and polychaetes.

Question 26

How to help fish on degraded coral reef

Answer 26

-Acoustic enrichment can enhance fish community development on degraded coral reef habitats. -He played the sound of a healthy coral reef to the degraded ones, which attracted fish enough to come back and colonise it -By adding a sound landscape, more fish came in (particularly parrotfish) and reproduced as well.

Question 27

Refuge from physical stress on saltmarsh ecosystems

Answer 27

-Habitat modification by plant and animal -By reducing salinity there was a positive effect on sea grass, new interactions shifted it from positive to negative with marsh elevation.

Question 28

r-selected species

Answer 28

r = pr capita rate of increase (expanding populations, faster LH (more allocation to reproduction)) short-lived, rapid development, many offspring, disturbed environments

Question 29

k-selected species

Answer 29

k = carrying capacity of pop (stable populations, slower LH (more allocation to survival)) long-lived, slow development, few offspring, stable environment

Question 30

Coral holobionts

Answer 30

Zooxanthellae, viruses, bacteria. Healthy holobionts = healthy reefs.

Question 31

Coral ecosystem services

Answer 31

Worth between 6-10 trillion dollars per year, without reefs, that whole industry and local livelihoods are done. There has been a 30% loss of coral cover from 2016-2017 alone.

Question 32

Coral reef restoration

Answer 32

Increases coral abundance, carbon sink, but are no more tolerant than parent corals. There is a 65% success rate, and is estimated to cost 1.6 million dollars per hector.

Question 33

Tolerance + how to measure it

Answer 33

-Use immune systems as a measure of stress -The maintenance of homeostasis (being healthy) = immunity

Question 34

coral immunity

Answer 34

They do have diseases or disorders, a response to this could be coral fluorescence. Corals can, for example, produce darker spots (melanin) around affected areas. Levels of immunity parameters underpin bleaching and disease susceptibility of reef corals.

Question 35

Melanin synthesis in vertebrate community

Answer 35

Role = to defend mechanisms in innate human response, and its triggered by the detection of pathogens or wounds. Enzyme phenoloxidase (PO) initiates melanin production. Prophenoloxidase (proPO) is activated by pathogen recognition, it converts tyrosine to dopa + dopaquinone. This leads to melanin polymerization. Function = encapsulates parasites and pathogens, can form melanotic nodules, produce reactive oxygen species (ROS which have antimicrobial properties. Regulated = by serine protease cascades to prevent overactivation. In arthropods, and molluscs too.

Question 36

Coral bleaching

Answer 36

Different categories of bleaching. Those that bleach the quickest are those least able to process phenoloxidase. Fast growing corals get sick and die quickly, but if they survive, they also bounce back quickly.

Question 37

Healing in corals

Answer 37

There is cell filtration. If you plug a hole (injury) in coral and don’t allow anything else in, it begins to heal, like humans. They struggle to heal in dirty, murky waters. Warmer water affects the immunity of tolerant reef coral. In warmer water they are unable to have an immune response, they are helpless.

Question 38

Why are corals fluorescent?

Answer 38

Fluorescent proteins have antioxidant proteins, they all respond differently to different wave lengths. When corals have inflamed tissue, they have more fluorescent proteins. It’s a way for coral to build an immune system, but they also have to shut down the pathway for melanin, otherwise they could go into overdrive.

Question 39

Damage threshold hypothesis

Answer 39

the immune activity vs the damage burden

Question 40

coral immunity mechanisms

Answer 40

include melanin synthesis, antimicrobial peptides, and fluorescent proteins that contribute to disease resistance

Question 41

Coral conservation

Answer 41

Long-term success depends on integrating immune resilience into conservation strategies. We must prioritise immune monitoring and identifying tolerant coral species to enhance outcomes.

Question 42

mangrove facts

Answer 42

Some of most productive ecosystems in the world, nearly 30% of commercial fish in the world depend on the mangrove in some stage of their lifecycle. Areas with more than 1km of mangrove can leave infrastructure unaffected by hurricanes, even category 3. 67% of historical mangrove habitat has been lost or degraded worldwide, 35% has been lost globally over the last two decades.

Question 43

mangrove locations

Answer 43

Normally within 20 degrees isotherms, like corals (coral triangle). And are replaced by salt marshes at higher latitudes. Most mangroves are found in developing countries (Indonesia).

Question 44

Main mangrove genera

Answer 44

Avicennia (black mangroves)- roots emerge from the ground in tubes, leaves are opposite and opaque green. Rhizophora (red mangroves)- can be found in rainforests too, stilt-shaped roots that detach laterally from the trunk. There can also be hanging roots, leaves are opposite and arranged in groups.

Question 45

family combretaceae

Answer 45

Also a type of mangrove, don’t have particular roots, distinguished by two glandular structures on the petiole.

Question 46

Why do mangroves zonate?

Answer 46

Due to different abilities to deal with waterlogged sediment, salt levels or nutrient levels.

Question 46

Waterlogging + solutions

Answer 46

Waterlogged sediment- normally anoxic, tree roots need oxygen, so they have special aerating devices. Knee roots (in Bruguiera)- that periodically break at the surface and then submerge again to get oxygen. Aerial roots (in Rhizophora)- which leave the tree up to 2m from the group, provide aeration through lenticles which are pores. Pneumatophores (in Avicennia)- which are shallow roots which extend metres from the tree and have tubes that emerge from the water, also with lenticles.

Question 46

salt uptake in mangroves

Answer 46

Disrupts cellular mechanisms + is fatal for most plants. -Exclusion of salt by roots -Tolerance of salt in tissue -Secretion of excess salt via bark or they shed leaves

Question 47

Mangrove reproduction

Answer 47

-Pollination (wind, bees, moths, butterflies) -Propagule development and fecundity -Dispersal and settlement

Question 48

Propagules and fecundity

Answer 48

-Seeds need to tolerate inundation and high-salt levels -Following pollination, the growing embryo remains on the parent plant for up to three months (vivipary) -Leaves the parent plant as a fully developed seedling or propagule, can be up to 1m -Represents 10-40% net primary production

Question 49

Dispersal and settlement

Answer 49

-Rhizophora seedlings drop from parent plant into the water -Initially they float horizontally, turning vertically after about a month when roots develop -Roots drag on bottom and seedlings can get stranded horizontally or sink -Seedlings erect themselves after rooting in the mud -If not rooted within 30 days, they remain buoyant for more than a year

Question 50

mangroves + corals

Answer 50

-Mangroves act as sediment traps to keep coral reef water clear, protecting them from runoff -Act as a nursery ground for coral reef fish Mumby et al. 2004: individual fish are larger on reefs near mangroves, biomass of reef fish was higher closer to mangroves.