Marine Biodiversity Flashcards

Question

What is a density dependant factor?

Answer 1

A density-dependent factor is one where the effect of the factor on the size of the population depends upon the original density or size of the population Disease is a good example Intra-specific competition (same species compete for limited resources) Environmentally dependent

Answer 2

Density-independent limiting factors are those such as climate extremes. These factors are considered to be density-independent due to the fact that they are not related to the size of the populations of organisms that are in the ecosystem

Answer 3

inverse density dependence’:- population birth rate decreases as population density drops The phenomenon where at the point when population density is too low for individuals to find mates, reproductive success sharply declines.

Answer 4

YES: The nature of resource utilisation and partitioning influences the number of species that can occupy same areas YES: An ability of a species to alter resource usage patterns enable coexistence YES: Plasticity enables higher species richness YES: Restrictive resource use stems from high competition and can lead to speciation (in the very long term) e.g. Galapagos Finches

Answer 5

An ecological resource is anything required by an organism for normal maintenance, growth, and reproduction. e.g. light, nutrients, food, territory, shelter). For individuals of the same species, can also include mates.

Answer 6

ecologically similar species sharing the same habitat exploit different resources, or the same resources but in different ways, thereby avoiding competition.

Answer 7

Resource differentiation and utilisation patterns, within a community may greatly influence the number of species a system can sustain So a wide variety of resources utilised restrictively and stably enables coexistence & high biodiversity through reduced competition The way in which a species utilises the resources (and environment) defines its ecological niche Therefore Niche theory, explains how species are able to coexist

Answer 8

ways in which species interact (including competition, resource partitioning, exclusion or coexistence) why some species are rare or abundant what determines geographical distribution of a given species what determines structure and stability of multi-species communities

Answer 9

Fundamental = all possible conditions under which population reproduces (maximum inhabitable hypervolume in the absence of competition, predation & parasitism)

Answer 10

Realized = the actual niche exhibited in particular time & space (smaller hypervolume occupied when the species is under biotic constraints) Realized niche will almost always be smaller portion of the fundamental niche due to biological interactions / competition & niche overlap

Answer 11

Competitive exclusion is commonly observed when a species colonizes a habitat and out-competes indigenous species - key issues of invasive species Coexistence through niche partitioning (dynamic) is rarely observed directly, but can often be inferred from traces left by "the ghost of competition past” Competitive release: resource use expands when a species is no longer influenced by a competitor and therefore expands its realized niche When niche shift involves an evolutionary change in attributes ("characters") of competing populations, it is termed character displacement.

Answer 12

Temperate, tropical, Antarctic and boreal species in broad, latitudinal bands across the oceans Width of latitudinal belt differs in species. Specific hydrographic regimes may lead to biantitropicality The three major oceans are not the same, share some but not all species

Answer 13

Cline: Gradation in one or more characteristics within a species or other taxon, especially between different populations. Ecocline: cline from one ecosystem to another, showing a continuous gradient between the two extremes.

Answer 14

Increased range of production in tropics More different food resources, more niches  Niche separation  speciation Greater evolutionary age of tropics  stability, competition  speciation Specialisation, e.g. gastropods ALSO: Solubility of CO2 high in cold waters! “Natural” Ocean Acidification low calcification potential

Answer 15

Diversity of shallow tropical environments preferentially generated in reefs --> probably because of their habitat complexity Reefs are prolific at exporting diversity to other environments --> low-diversity habitats more susceptible to invasions

Answer 16

Loss of shallow, circumglobal water circulation around the tropics When Tethys was open circulation allowed wide distribution of corals as larvae were dispersed through warm shallow water Interconnecting, warm shallow seas now absent.

Answer 17

In allopatric speciation, groups from an ancestral population evolve into separate species due to a period of geographical separation. In sympatric speciation, groups from the same ancestral population evolve into separate species without any geographical separation.

Answer 18

Gradient between sandy and muddy shores dependent on grain size (energy) Low energy sites small particles deposited = muddy shores Few meters wide to several kilometres e.g. Wash, Humber, Severn Are flat, high organic content = large biochemical oxygen demand (BOD): Low water and O2 exchange = anaerobic Transition zone = Redox Potential Discontinuity Layer (RPD) Burrows conspicuous feature - due to sediment stability Biological factors affect stability i.e. bioturbation = decrease and biostabilisation = increase Although tidal flats comprise only about 7% of total coastal shelf areas (Stutz and Pikey 2002), they are highly productive components of shelf ecosystems responsible for recycling organic matter and nutrients from both terrestrial and marine sources and are also areas of high primary productivity. Tidal flats are highly productive areas - often form the buffer zone between deeper protecting intertidal habitats by dissipating wave energy, thus reducing erosion of mangroves and salt marshes. When oxygen is depleted in a basin, bacteria first turn to the second-best electron acceptor, which in sea water, is nitrate. Denitrification occurs, and the nitrate will be consumed rather rapidly. After reducing some other minor elements, the bacteria will turn to reducing sulfate. This results in the byproduct of hydrogen sulfide (H2S), a chemical toxic to most biota and responsible for the characteristic "rotten egg" smell and dark black sediment color. Sulphate reduction  iron sulphides = BLACK (H2S = SMELLY) Iron reducers and iron oxidisors. Methane produced by methanogenesis by archaea. Ammonia all oxidized at surface for E production (aerobic process – i.e. only at surface). Decay of organic matter produces ammonia (NH4). Essex muds go anoxic within about 2 mins because so fine. Underneath respiring sulphate (obligate anaerobes, some facultative) Sulphate abundant in SW. Oxygen = terminal electron receptor in respiration.

Answer 19

Major primary producers :- 1. Diatoms (Bacillariophyceace) 2. Cyanobacteria (Cyanophyceace) 3. Euglenoids e.g. Euglena 4. Macroalgae e.g. Ulva, Enteromorpha 5. Angiosperms e.g. Zostera (eel grass) 6. Chemoautotrophs e.g. sulphur oxidising bacteria

Answer 20

Epipelic = Mud dwelling species, motile biraphid genera Episammic = Sandier environments attached to sand particles generally monoraphid genera LIVING ON MUD VS. SAND. LOW TIDE SEE BROWN BIOFILM. LIGHT BLOCKED BY WATER (OR NIGHT) Motile (via EPS) diatoms of intertidal muddy sediments – generally referred to as epipelic diatoms – exhibit migratory rhythms synchronized with diurnal and tidal cycles. These microalgae accumulate at the sediment surface during diurnal low tides and migrate down into the sediment before tidal inundation or darkness. Upward migration during diurnal low tide periods allows cells to reach the photic zone  photosynthesis. It has been suggested that downward migration reduces the exposure of cells to predation or physical disturbance and facilitates nutrient and carbon uptake and/or cell division. Microphytobenthos represents microscopic primary producers, primarily diatoms that often form heterogeneous biofilms on sediment surface. Microphytobenthos assemblages have been documented and reported to be closely linked with the biostabilisation of the sediment surface in the intertidal flat of Europe. Flood and ebb tides cause vertical movement of the benthic diatoms in the surface of the top sediment, which contributes to stabilizing the sediment. Light, salinity and other environmental stressors further initiate microphytobenthos to move up and down vertically in the surface of the top sediment. Diatoms produce and secrete extracellular polymeric substances in response to their locomotion, which favorably stabilize the sediment surface during high tide immersion.

Answer 21

Definition: Areas of alluvial deposits colonised by herbaceous plants and small shrubs, are almost permanently wet and frequently inundated by saline water Distinct from mudflats, eel grass beds, mangrove Several types: lagoon marshes beach plains barrier island marshes artificial marshes estuarine marshes

Answer 22

Spring tides have higher high tides and lower low tides whereas neap tides have lower high tides and higher low tides. Hence, the range (difference in water level between high and low tide) is much larger in a spring tide than in a low tide.

Answer 23

Salinity – Water-logging (anaerobic) Submergence (reduce gaseous exchange) Erosion

Answer 24

Muddy shores are formed along the seashores where there is no or little wave action. These intertidal areas are formed by the deposition of silt from the water flowing into the sea.

Answer 25

Avoidance of water-logging :- -live next to well drained creek e.g. Pemphigus trehernei living on Aster tripolium Avoidance of flooding :- -live within halophytes - 60 % of saltmarsh Lepidopterans -climb to top of emergent plants -migrate out of tidal limits -synchronise activity with tides e.g. Dicheirotrichus gustavi and Anurida maritima (springtail - circadian rhythm) Respiratory adaptations :- -small body size -reduction of metabolic activity during immersion -anaerobic respiration and excretion e.g. Arenicola marina -reverse Bohr effect e.g. Limulus (King crab) Adaptations to fluctuating salinities :- -Osmoconformers e.g. Mytilus edulis and A. marina -Osmoregulators e.g. e.g. Gammarus duebeni

Answer 26

Predation is key to sustainable biodiversity (TOP-DOWN CONTROL) Real-life application: protection of a predatory species (e.g. by fishing limits) may influence biological diversity Trophic cascades Disproportionate impact due to trophic position (particularly if a keystone predator) Top predators are often more vulnerable to depletion (e.g. slow to reproduce; need large ranges; vulnerable to habitat loss; dependent on availability of prey) Can alter entire ecosystems – examples? -Tiger sharks (remember Lecture 7!) -Baltic cod (coming up!) -Killer whales (coming up!)

Answer 27

Predation influences -Biodiversity and community structure -Biomass of prey and primary producers, and thus system productivity -Ecosystem function and stability Therefore their protection or exploitation can affect all of these factors too. Predators perform multiple roles. Predator diversity  redundancy i.e. the “insurance hypothesis”

Answer 28

A disease is an abnormal condition of an organism that impairs bodily functions, associated with specific symptoms (human) or signs (any other biota) It may be caused by:- -external factors e.g. infectious disease -internal dysfunctions e.g. autoimmune/genetic diseases -extrinsic factors e.g. environmental change

Answer 29

Species fitness Growth Fecundity Resilience Tolerance Population size Role in the community How? Metabolic impairment Photosynthetic impacts Intra-colonial translocation Host immune system Cell death mechanisms Reproductive dysfunction

Answer 30

Disease dynamics in the marine environment are influenced by climate change‐driven alterations of the physical, chemical and biological properties of ecosystems The impacts of climate change upon marine diseases have significant socio‐economic implications (food, health, GDP). Yet there is a general lack of awareness and research

Answer 31

Disease – a natural component of any ecosystem (density dependent factor) Can influence ecological community structure at different trophic levels Disease consequences depends on position and functional importance of diseased species Impact of disease also depends on composition of community e.g. dominance can enhance pathogenic loading & spread of disease

Answer 32

Coral reefs good example of how disease can impact ecosystems Increasing acceptance that increased disease is a consequence of human activity New knowledge suggests climate change will increase disease prevalence through -direct pathogenic physiological change (e.g. generation time) -impacting host physiology and stress responses -change in distribution of pathogens Marine life may be harbouring diverse pathogens that may be subjected to human waste and antibiotics, increasing resistance

Answer 33

A species restricted to a small geographical area because of the presence of a competitively superior species, is found to expand its distributional range when the competing species is experimentally removed. This is called competitive release.

Answer 34

An intimate, prolonged interaction between different species One species benefits… ..the second may be unaffected, harmed or helped There is a fourth, less ‘intimate’ category of symbiosis known as Mimicry, which involves one species imitating another to gain the benefits enjoyed by that species. How can Symbiosis be beneficial – give examples? -Genetic fitness -Competition -Reduced resource and niche overlap Increase richness per unit area -Enhance functionality of key ecosystem architects -Enable habitation of otherwise inhospitable environments extreme niche production.

Answer 35

A high number of negative consequences does not only influence the fish itself but is assumed to also have a larger impact on whole ecosystems Neither disease or parasite loading is considered in fish stock assessments. Parasitic loading can have same ecological impacts as described for disease.

Answer 36

Within fisheries biology, fish parasites can be used to separate different fish stocks Long-living species such as endoparasitic helminths can give information on the seasonal migrations of their hosts Short-living species, such as protozoan ectoparasites and monogenean trematodes can give information on environmental conditions Extinction of a single reef fish may result in co-extinction of around ten parasitic species

Answer 37

Parasites can disrupt ecological stability by impacting single species behaviour, physiology, and the dynamics of a community as well as its structure Parasitism has led to speciation in some cases and examples exist of specific evolved roles for parasitic cleaners Parasites themselves can add significantly to biodiversity Parasite loading appears to correlate with other community structural variables

Answer 38

Relationship between two organisms that benefits both, but mutualisms usually carry both costs and benefits to each partner. Evolutionary Selective forces: mutualism = when the benefits are greater than the costs May be Facultative (not essential for survival) or Obligatory (cannot survive in the absence of partner)

Answer 39

Coevolved mutualisms have become more specialized through time because a change in one partner may lead to a change in the other Coevolution is the process of evolutionary change in two species in which each changes in response to change in the other species Coadaptation is a feature which helps enable the mutualism by interacting with some feature of the other partner. Coadaptations usually are the result of coevolution, but not always! Can be due to chance - can also bring together two organisms that already have features that make their mutualism possible Conflict within Mutualisms Stable mutualisms must prevent cheating by a partner (cheaters receive the benefit at the cost of other organism)

Answer 40

Dispersal Mutualisms (e.g. bees dispersing pollen… Less common in marine. Why?) Cleaning Mutualisms (e.g. Cleaner wrasse) Defence Mutualisms (e.g. Anemone fish) Nutritional Mutualism (e.g. Vent worms)

Answer 41

Amensalism = one organism inflicts harm to another without any costs or benefits to itself Neutralism = two species interact but do not affect each other Mutualism: If we were in the warm waters of the Pacific or Indian Oceans, we'd likely spot an excellent example of mutualism: the relationship between clownfish and sea anemones. In a mutualistic relationship, both species benefit. Sea anemones live attached to the surface of coral reefs. predation/parasitism: Examples of common parasites found in the ocean include nematodes, leeches, and barnacles. That's right—though barnacles exist commensally with whales, they are parasites for swimming crabs. A barnacle may root itself within a crab's reproductive system. commensalism: Commensalism usually occurs between a species that is either vulnerable to predation or with an inefficient means of locomotion, and another species with a relatively effective system of defence. competition obligate mutualism : the relationship between the siboglinid tube worms and symbiotic bacteria that live at hydrothermal vents and cold seeps. The worm has no digestive tract and is wholly reliant on its internal symbionts for nutrition. The bacteria oxidize either hydrogen sulfide or methane, which the host supplies to them. The tube worm provides the perfect place for bacteria to get both oxygen and hydogen sulfide which are often difficult to find in one place.

Answer 42

‘Ecological succession’ is the observed process of change in the species structure of an ecological community over time. Within any community some species may become less abundant over some time interval, or they may even vanish from the ecosystem altogether. Similarly, over some time interval, other species within the community may become more abundant, or new species may even invade into the community from adjacent ecosystems.

Answer 43

Every species has a set of environmental conditions under which it will grow and reproduce most optimally. In a given ecosystem, and under that ecosystem's set of environmental conditions, those species that can grow the most efficiently and produce the most viable offspring will become the most abundant organisms. As long as the ecosystem's set of environmental conditions remains constant, those species optimally adapted to those conditions will flourish. The ‘engine’ of succession, the cause of ecosystem change, is the impact that established species have upon their own environments. Ecological succession may also occur when the conditions of an environment suddenly and drastically change.

Answer 44

Sedimentation and accretion Stage 1: Migration - seeds and spores land & germinate and develop. Pioneer plants colonise the surface of the mud. Stage 2: Colonisation - filamentous cyanobacteria colonise the mud – biostabilisation -fast growing algae e.g. Enteromorpha), Ulva Ulva grow attached to small stones - conditions still harsh - lots of open space Stage 3: Establishment - salt tolerant pioneers develop (e.g. Salicornia spp.) and cord grass (Spartina spp.) Roots help consolidate the mud - stems and leaves trap more sediment. plants = food and refuge for animals. Decomposition = organic matter, nutrients and minerals Stage 4: Competition -less stressful for plants,; time that the mud is out of the water increases. vegetation becomes 'closed' -conditions become suitable for additional species e.g. s sea purslane , sea lavender , sea aster who will take over from the pioneer species. -lots of species all wanting the same resources (water, light, carbon dioxide, oxygen, nutrients) = Competitive exclusion Stage 5: Stabilisation - species that have survived the competition will occupy different niches. Few new species appear at this stage. Stage 6: Climax - Shading by taller vegetation - woody species outcompete earlier species diversity. - climax community = deciduous woodland. No new species are added – long-term stability

Answer 45

Secondary succession: return of species following a disturbance -Gaps in communities are rapidly filled; species with strong powers of dispersal are usually intolerant of competition from other species -Race between good colonizers (bryozoans and polychaetes) and strong competitors (tunicates and sponges) -Intertidal rocky shore: limpet grazing depresses most species of algae but favours three species of rare and inferior competitors

Answer 46

Position of a species in a series depends on its rate of invasion and its responses to changes Facilitation: Early species improve habitat: mudflats (biostabilisation) Inhibition: Competition for space, nutrients, and light; allelopathic chemicals First arrivals take precedence Tolerance: Early establishment depends on dispersal abilities and physical conditions Later stages depend on relative competitive ability

Answer 47

This is the classic succession model theory suggests that the recently disturbed situation is first exploited by certain pioneer species that are most capable of reaching and establishing on the site. These initial species modify the site, making it more suitable for invasion by other species

Answer 48

Climax community Ecological communities are open systems whose composition varies continuously over environmental gradients Establishment of long lasting stable community

Answer 49

Species can prevent colonization of another Course of succession is dependent on which species arrive first and the next several stages will only occur following the death of those individuals and the successful colonization of the next set of species Consider zonation, competitive exclusion and gap formation

Answer 50

Whatever can live there will, and the best competitor for resources will win Little inhibition or facilitation Progress of succession dependent upon the lifespans of the individuals and the competitive abilities of the colonists.

Answer 51

Ecological Disturbance: a temporary change in average environmental conditions that causes a pronounced change in an ecosystem Could be: Droughts Floods Deforestation Marine harvesting Fire Disease Severe weather e.g. cyclones Volcanic eruptions Tsunamis Ocean temperature changes - El Niño Global warming Pollution Land-use / marine-use Humans

Answer 52

A density Independent Driver of population and community structure: Can have large and unpredictable effects that can reduce biomass and diversity or... Can be integral components of an ecosystem that can bring about increased biodiversity

Answer 53

Alteration of environmental conditions: change in dominance and long-term shifts in community structure! Outcome dependent on supply-side ecology (The role of juvenile dispersal in dictating adult distribution) and succession processes After a period conditions may return to pre-disturbed state = resilience Biodiversity is dependent on natural disturbance SYSTEM DEPENDENCE Many species are dependent on disturbance particularly in otherwise stable systems SPECIES DEPENDENCE

Answer 54

Dependent on the intensity, frequency and range of disturbance events Some events can cause dramatic loss of biodiversity e.g. Climate change shifts Multiple disturbances unfortunately common – Marine Major Ecological Disturbances Events (MMED’s) Some events regulate populations and enhance biodiversity

Answer 55

Intermediate disturbance hypothesis Intermediate level of disturbance yields highest biodiversity Relative effect on a population:- intervals between events, intensity of events

Answer 56

Systems generally respond to some level of stress Impacted systems may, because of resistance to disturbance, initially show little response Pushed beyond a point & change becomes rapid Highly altered state –slow recovery Level of disturbance or stress that can be tolerated is community dependent Due to ecological feedbacks, ecosystems display resistance to state shifts and therefore tend to remain in one state unless perturbations are large enough. Multiple states may persist under equal environmental conditions, a phenomenon known as hysteresis. (alternative stable states)

Answer 57

Disturbance is not a sole driver of community structure Impacts of disturbance can be regulated by species and also environments Can we enhance resilience to disturbance events? Habitat heterogeneity maybe key e.g. refuge environments, different species assemblages

Answer 58

Majority of systems are in some way disturbed It can moderate competition & enhance diversity (IDH) Impact depends on characteristics of the event and species impacts Many systems impacted by multiple disturbance events Disturbance impacting key species or functional groups can have dramatic cascade effects Understanding implications of disturbance on species and ecosystem functionality key to successful mitigation and management

Answer 59

Protozoa: single celled eukaryotes Polyphyletic (‘agglomeration of forms variously related’) Often FUNCTIONALLY defined, for example: type of food… Bacterivores -> eat bacteria Herbivores -> eat plants Carnivores -> eat animals (plankton) Mixotrophs -> combine the use of heterotrophy and autotrophy Osmotrophs -> take up dissolved organic nutrients

Answer 60

Heterotrophic nanoflagellates (HNAN) – eat bacteria, 2-20µm -Most HNAN heterokont: 2 functionally different flagella 25,000 +species! -Most nanoflagellates are actually autotrophic algae (some mixotrophs) Microzooplankton protists (MZP) – eat phytoplankton and HNAN, 20-200 µm  flagellates and ciliates -Tintinnids -Naked ciliates -Flagellates (auto- hetero- & mixotrophic dinoflagellates) Larval zooplankton -copepod nauplii

Answer 61

Phylum Sarcomastigophora Class Zoomastigophorea Ecologically important group HNAN: filter 12-67% of water column per day  e.g. choanoflagellates (Choanoflagellida) Resemble choanocytes of sponges

Answer 62

Phylum Sarcomastigophora Class Zoomastigophorea Ecologically important group HNAN: filter 12-67% of water column per day  e.g. choanoflagellates (Choanoflagellida) Resemble choanocytes of sponges

Answer 63

Engulfment/ phagocytosis Peduncle feeding (tube structure to suck nutrients from prey) Pallium feeding (shaped like veil or net that wraps prey) Feeding consists of 6 steps: Searching Contact Capture Processing Ingestion Digestion

Answer 64

Generally few species of Phaeophyceae [ Note! Kelp are not plants, they are brown algae and represent the largest protists in the world ] KELP FOREST = surface canopy – e.g. Macrocystis pyrifia, Nereocystis spp. KELP BED = no canopy – e.g. Laminaria hyperborea, Pterygophora spp., Ecklonia spp. Exists on hard substrate, cold temperate (< 20°C) - extension of rocky shores Wide distribution e.g. N & S America, N China, Japan, UK Depths: 5 - 15m in v. clear water up to 50 m

Answer 65

The morphology of a typical kelp is simple. Visually it resembles a plant. A rootlike holdfast attaches to a rock. A stipe resembles a stem and blades resemble leaves. You also have the main body of the plant called the frond and gas bladders to provide buoyancy.

Answer 66

Harvested for :- Fertilisers Iodine salts Chemicals Alginates Kelp and other types of algae are used for a range of products, including cosmetics like shampoo and toothpaste, and food like salad dressing and ice cream. Agar, carrageenan, and alginate are some of the compounds extracted from different types of algae, and mostly used as thickeners.

Answer 67

The bull kelps and fucalean algae have 'direct' life cycles and reproduce via eggs and sperm. BUT the true kelps (laminarian algae) that we are focusing on, exhibit ‘alternation of generations’ and heteromorphic life cycles (hetero = different, morph = shape/appearance). Alternate between two very different forms:1) ‘sporophyte' (spore-bearing) phase (large kelps that you see on the shoreline) vs. 2) 'gametophyte' phase. Gametophytes are microscopic and so small they have rarely been found in the wild; it is presumed they live in cracks and crevices in rocky reefs. Most are perennial (live for multiple years) Asexual reproduction = produce new individuals without the fusion of gametes (genetically identical to the parent) Perennial = living for several years Sporophyte = asexual diploid phase, producing spores from which the gametophyte arises. Sporangium = receptacle in which asexual spores form Gametophyte = sexual phase in the life cycle Diploid cells = contain two complete sets (2n) of chromosomes; Haploid cells have half the number of chromosomes (n) as diploid Archegonium= female sex organ in non-flowering plants/algae Antheridium = male sex organ in non-flowering plants/algae

Answer 68

Approx. 50 species e.g. Zostera marina (eel grass - temperate) Thalassia testudinum (turtle grass - tropical) Can exist at low (flat-uniform) or high (diverse - hummocks etc.) energy sites but water motion needs to be consistent Can reproduce sexually by pollination - dull flowers Generally asexual reproduction by network of subterranean rhyzome system

Answer 69

Can form dense beds (4000 leaves m-2) in distinct patches Large standing biomass e.g. 2 kg m-2 Long strap-like leaves & developed root/rhizome system Root systems stabilise sediments: leaves reduce water velocity -> decreased erosion, increased accretion & increased larval settlement. epiphyte =organism that grows on the surface of a plant/algae. As with any surface in the marine environment, seagrass leaves provide a place for planktonic organisms to settle. When they settle on seagrass leaves, they are called epiphytes (sessile organisms that grow on plants).

Answer 70

Bioturbation is defined as the reworking of soils and sediments by animals or plants. It includes burrowing, ingestion, and defecation of sediment grains. Bioturbating activities have a profound effect on the environment and are thought to be a primary driver of biodiversity.

Answer 71

Variety of trees and shrubs - tropical, intertidal soft sediments Mangrove swamps: 60 - 75 % tropical coastlines Common features / adaptations: Euryhaline - salt tolerant Aerial roots = Pneumatophores Prevention of salt uptake and / or salt secretion glands e.g. Avicennia - White mangrove Many are viviparous - seeds germinate on tree before detaching

Answer 72

Fine sediments with high organic loading High Bacterial respiration = anoxic sediments Adaptations e.g. shallow roots and Pneumatophores Positive feedback - root systems = deposition = accretion deposition - further development Salinity variations - adaptations - salt excretion glands of Avicennia

Answer 73

1. Avicennia - salt tolerant, not tolerant of shade; Sonneratia maybe at seaward edge) 2. Rhizophora - typical mangrove tree - cover large areas 3. Bruguiera - characteristics of heavy compact clays e.g. high water springs 4. Ceriops - nearly terrestrial - not always present

Answer 74

Roots = hard substrate, sediment = soft substrate, vertical structure = diverse habitat Above water forest terrestrial insects, snakes, lizards, spiders, bats majority are insectivores or piscivore Much of biomass exported as detritus Intertidal Swamp (roots and sediment): Molluscs - Litorinids on roots (graze epiphytes), Potamiidae crabs in sediment (detritus), Pelecypoda (Bivalvia) e.g. Oysters attached to roots. Crustacea e.g. Decapoda Semi-terrestrial crabs e.g. Uca - fiddler crab, Ocypodia - Ghost crabs Adaptations to terrestrial existence = vascularised gill compartment for air breathing Fish - mud skipper Periophthalamus - walk on pectoral fin rays eye adapted for focusing in air, gills reduced and chamber vascularised (also mouth cavity)

Answer 75

Biostabilisation - decreased coastal erosion Wood resource - firewood, timber for boats, leaves for thatching Food species - mullet, shrimps, crabs and molluscs Nursery grounds - fish, shrimps, lobsters, crabs

Answer 76

Hematypic = reef building Ahermatypic = non-reef building Differences between hematypic and ahermatypic corals: 1. Have symbiotic zooxanthellae(adapted dinoflagellates) 2. Limited distribution - shallow (light) tropical (temperature) seas 3. Produce large calcium carbonate deposits - reef producers

Answer 77

Heterotrophic Feeding: stick out tentacles (often retracted in day) to capture plankton. tiny stinging cells (nematocysts) that harpoon plankton (sticks to tentacle; then deposited in polyp's mouth. ------------------ Some corals are able to catch plankton and small fish using stinging cells on their tentacles…. But most corals obtain the majority of their energy and nutrients from photosynthetic unicellular dinoflagellates of the genus Symbiodinium that live within their tissues. These are commonly known as zooxanthellae and gives the coral color.

Answer 78

Photosynthetic endosymbiotic algae (zooxanthellae) Symbiodinium (dinoflagellate) Mutualism:- coral provides protected environment & compounds they need for photosynthesis; zooxanthellae provide O2, glucose, amino acids & waste removal (e.g. CO2, N)

Answer 79

Majority of coral dependent on zooxanthellae. Some large polyp species are more heterotrophic ---------------------- Zooxanthellae - gain protection and nutrition Zooxanthellae situated in the gastrodermis and: 1. Manufacture carbohydrates 2. Aid lipid synthesis 3. Provide 02 - stimulate metabolism 4. Enhance calcification 5. Remove waste products

Answer 80

Evidence for the role of zooxanthellae in coral nutrition Photosynthesis carried out by unicellular algae (zooxanthellae) adapted dinoflagellates (Symbiodinum = ‘Taxonomically diverse species complex’) Approximately 200 symbiotic clades- little known – subcladal – different physiology (Some more adapted to warming ?) Muscatine and Cernichiari (1969) - used radioactive isotopes = photosynthesates fixed by zooxanthellae translocated to polyp host ________________ There are 2 types of transmission: Vertical: from parent to eggs (offspring) Horizontal: acquired directly from the environment (planulae)

Answer 81

Coral Reef Ecosystems: -800 species of coral -5000 species of fish -25% of all marine species -complex food webs -oligotrophic but tight coupling and highly productive -Diversity driven by topographic diversity and intense --competition.

Answer 82

The Arctic and Antarctic are dominated by: -presence of snow and ice - pack Ice can cover up to 13% of Earths surface -year round cold temperatures -Extreme seasonal photoperiod Ice plays important role in global thermohaline circulation Research Expensive – limited research expeditions (need ice breaking ships) Hostile environments but support much life and diversity

Answer 83

Smallest ocean (14 million km2) 3rd is continental shelf and there are 4 deep basins (maximum 5450m) Two outlets: Bering Strait (Pacific, sill depth 55m) Fram Strait (Atlantic; sill depth 400m) Much thick multi-year sea ice (can be 10y old) ------------------------ Two major currents: Anticyclonic Beaufort Gyre over the Canadian Basin Transpolar Drift over Eurasian basin - exports to N. Atlantic -------------------------- Significant river inputs (e.g. Mackenzie River (N. America) and The River Ob (Russia): -Low-salinity stratified surface level (20-50m) -Lots of soft substrate due to sediment deposit -High nutrient and trace metal inputs

Answer 84

Southern Ocean is well-connected to major ocean basins 36 million km2 (~10% of the world’s oceans) Narrow, deep continental shelf and very deep oceanic region Highly seasonal annual sea ice coverage 50% of the marine area, reduced to <10% 1-2m thick (vs 3-4m in Arctic) ________________________________ Isolated by the Antarctic Circumpolar Current (ACC) Various frontal zones Cold Antarctic bottom water (AABW) sinks to ~4000m deep and is distributed around the world’s oceans (-0.8 to 2 °C; salinity = 34.6 to 34.7) Nutrient and O2 rich deep water rises as it moves towards the equator. _______________________________ 14 Million m2 – ice covered average 2km thick (mostly permanent) Freshwater inputs solely from melting ice sheets far less sedimentation and salinity stratification than Arctic

Answer 85

Spring phytoplankton bloom at ice-edge stimulated when ice retreats Huge increase in zooplankton grazers (“feeding frenzy”) No secondary bloom as seen in temperate waters NOTE: decline in phytoplankton biomass linked to the critical depth, rather than zooplankton grazing (no net photosynthesis below critical depth). Sea ice cover reduces the critical depth and limits algal growth __________________________________ MIXING DEPTH (DEPTH OF WIND MIXED LAYER VARIES WITH WIND & WEATHER PATTERNS) ICE AFFECTS CRITICAL DEPTH IF MIXING DEPTH > CRITICAL DEPTH = NO BLOOM IF MIXING DEPTH < CRITICAL DEPTH = BLOOM

Answer 86

Short photoperiods, but production can be high ( 1 g C m-2 d-1) due to the riverine/terrestrial nutrient inputs (Arctic) & convergence upwelling (Antarctic) Southern Ocean is nutrient-rich all year Arctic waters become nutrient limited --------------------------------------------- Dense diatom blooms (e.g. Thalassiosira antarctica) supports huge populations of krill Euphausia suberba (Antarctic) or copepods (Arctic) Nutrient recycling is slow due to the cold temperatures and decomposition and mineralisation rates are therefore slow

Answer 87

Sea ice consists of fauna and flora living within it show patterns of depth zonation High salinity network of brine channels form (a few thousandths of a millimeter to more than an 3cm in diameter) Some organisms are trapped, others may exist in the ice permanently (many of the 200+ species found in adjacent water) ----------------------------------------------- A well-developed algal/microbial food web exists in the ice Diatoms, flagellates , dinoflagellates , bacteria, fungi, viruses, ciliates, small metazoans (sympagic community “ice-associated.” ) ----------------------------------------------- Ice algae gives ice brown colour [1000 ug Chla l-1 vs. surface waters = 0-5 ug l-1] >50 % of PP can be within ice in some regions Low-light, low-temp, high salinity adaptations

Answer 88

Most polar benthic inverts long-lived & slow reproducing Suspension feeders dominate shelf & deep sea benthos Few major benthic predators Up to 6 × more benthic species in Antarctic & higher degree of endemism -Habitat heterogeneity Complex community structure: -Canopy: - suspension feeders reaching highest above surface of substrata e.g. anemones Edwarsia spp. -Understory: epifauna typically 0-1cm above surface, mobile crustacean deposit feeders and predators e.g. Cumacean crustaceans e.g. Eudorella spp. -Subsurface: - infauna e.g. tube dwelling polychaetes and deposit feeders. Antarctic soft sediment communities: dominated by burrowing and tube building polychaete worms and small crustacea (Density > 100,000 m-2)

Answer 89

Nutrient sources: -Phytodetritus & Krill faecal pellets in summer -Resuspension & lateral advection of organic material in winter --------------------------------------- Community relatively stable – generally lack of competitive dominance Antarctic: Iceberg scour is primary source of disturbance (in coastal areas): -0-15m depth: low diversity due to scouring by sea ice and almost universal coverage of anchor ice (submerged ice attached to bottom) -15-30m mobile fauna such as echinoderms - >30m many sessile species (e.g. sponges), and a rich and diverse group of other invertebrates The starfish prey on the sponges and keep them in check (e.g. The fast growing sponge Mycale acerata).

Answer 90

Many benthic organisms much greater in size than temperate or tropical water relatives Cold water = slow metabolic rates & longer lifespan -Some sponges over 1500 years old Oxygen availability: abundant O2 in water

Answer 91

Greater diversity in the Antarctic than the Arctic (for some groups, e.g. sponges, bryozoans, amphipods) -more diverse substratum: epifauna (on bottom) & endofauna (buried) Antarctic has much higher endemism (95% of fish and 90% of amphipod species). Arctic fauna = mainly Atlantic species. Generally at any given depth the Antarctic has a biomass of one to two orders of magnitude above the Arctic Polar larval strategy is often planktotrophic and the larvae take a longer time than temperate species to reach metamorphosis

Answer 92

Copepods & Amphipods often dominate the Arctic waters whilst Euphausids (e.g. Euphausia superba) dominate Antarctic waters (densities up to 60,000 m-3) Dense lipid-rich populations support a variety of fauna including baleen whales (e.g. Meganoptera novaeanliae and Balaenoptera musculus, which can eat 8 tonnes a day), penguins, seals and fish.

Answer 93

Climate change Invasive Species and range shifts: -Changes to community structure Direct human activity: -Oil exploration (Arctic) -Pollution, bioaccumulation -Overfishing / illegal fishing -Tourism

Answer 94

It will draw the the species out into new areas where they will have to compete with other species. This may make them develop more niches which will then improve overall diversity.

Answer 95

CZCS (Coastal zone colour scanner) measured reflected solar energy. Sunlight backscattered by the atmosphere contributes 80-90% (at key wavelngths used for Chl a) of the radiance measured by a satellite sensor. Such scattering arises from dust particles and other aerosols, and from molecular (Rayleigh) scattering. However, the atmospheric contribution can be calculated and removed if additional measurements are made.

Answer 96

Using a bongo net to zooplankton. Rosette sampler for discrete water samples Equipped with a “CTD” (conductivity, temperature, depth) Also can include salinity, pressure (depth) Chl fluorescence, water clarity (transmission), PAR , Coloured DOC, Nitrate etc. You can then use these in depth measurements to create good analysis.

Answer 97

For one, the most rapid periods of diversity increase occur immediately after mass extinctions. But perhaps more striking, recovery isn't only driven by an increase in species numbers. In a recovery, animals innovate – finding new ways of making a living. They exploit new habitats, new foods, new means of locomotion.

Answer 98

In evolutionary ecology, an ecotype, sometimes called ecospecies, describes a genetically distinct geographic variety, population, or race within a species, which is genotypically adapted to specific environmental conditions.

Answer 99

In ecology, Connectivity refers to how the movement of living organisms and the flow of nutrients and materials are facilitated (or not) by the landscape. This broad ecological concept includes two, intertwined components: Structural Connectivity, a notion purely related to the physical characteristics of the landscape, measuring its heterogeneity and structuring (e.g. ice cover, marine currents, chemical barriers), Functional Connectivity, which represents all the movements of organisms that result in the exchange of genes, biomass or energy between heterogeneous habitat patches. These are either caused, facilitated or hampered by Structural Connectivity patterns.

Answer 100

Interplay of mixing, nutrients and light affect phytoplankton growth -> not one single parameter responsible for productivity! Thermal stratification greatly affects these parameters -> thermocline! The thermocline is the boundary between dense cooler water and warmer less dense surface water Stratification leads to phytoplankton ‘blooms’

Answer 101

most vent organisms lecithorophic – so colonise other vents nearby (pacific vents 10km apart, fields >100km so problems of dispersal) -Two models of gene flow ‘Stepping-stone‘ model -Dispersal limited so most gene exchange with neighbouring populations -Gene flow declining with distance - Riftia tubeworm ‘Island‘ model -Migration rate appears unrelated to distance -Long distance dispersal -Mixing of larvae within a migrant pool -Wide sispersal might be related to ability to colonize range of seep/vent types? - Bathymodiolus mussel.

Answer 102

In an ideal environment, one that has no limiting factors, populations grow at an exponential rate Unlimited resources are very rare! Population regulation results in populations achieving (or returning to) a size at equilibrium with the surrounding environment (carrying capacity, or K) Competition for resources Two Types of Regulation: Density Dependent factors Density Independent factors

Answer 103

Niche Theory is used to describe and analyze ways in which species interact (including competition, resource partitioning, exclusion or coexistence) why some species are rare or abundant what determines geographical distribution of a given species what determines structure and stability of multi-species communities

Answer 104

The Tethys Ocean, also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean during much of the Mesozoic Era and early Cenozoic Era, located between the ancient continents of Gondwana and Laurasia, before the opening of the Indian and Atlantic oceans during the Cretaceous Period. Consequences: Loss of shallow, circumglobal water circulation around the tropics When Tethys was open circulation allowed wide distribution of corals as larvae were dispersed through warm shallow water Interconnecting, warm shallow seas now absent

Answer 105

one of the most interesting aspects of vent ecology is how organisms disperse between vents and how new vents become colonized. If dispersal, and thus gene flow, is limited then there would be extensive genetic differentiation between vent fields. Two different models of gene flow are apparent in vent taxa. Riftia fits a ‘stepping-stone’ model with most gene exchange occurring between neighbouring populations and gene flow declining with distance

Answer 106

Allopatric speciation (1) occurs when a species separates into two separate groups which are isolated from one another. A physical barrier, such as a mountain range or a waterway, makes it impossible for them to breed with one another. Each species develops differently based on the demands of their unique habitat or the genetic characteristics of the group that are passed on to offspring. In parapatric speciation (3), a species is spread out over a large geographic area. Although it is possible for any member of the species to mate with another member, individuals only mate with those in their own geographic region. Like allopatric and peripatric speciation, different habitats influence the development of different species in parapatric speciation. Instead of being separated by a physical barrier, the species are separated by differences in the same environment. Sympatric speciation (4) is controversial. Some scientists don’t believe it exists. Sympatric speciation occurs when there are no physical barriers preventing any members of a species from mating with another, and all members are in close proximity to one another. A new species, perhaps based on a different food source or characteristic, seems to develop spontaneously. The theory is that some individuals become dependent on certain aspects of an environment—such as shelter or food sources—while others do not.

Answer 107

Although tidal flats comprise only about 7% of total coastal shelf areas (Stutz and Pikey 2002), they are highly productive components of shelf ecosystems responsible for recycling organic matter and nutrients from both terrestrial and marine sources and are also areas of high primary productivity. Tidal flats are highly productive areas - often form the buffer zone between deeper protecting intertidal habitats by dissipating wave energy, thus reducing erosion of mangroves and salt marshes. When oxygen is depleted in a basin, bacteria first turn to the second-best electron acceptor, which in sea water, is nitrate. Denitrification occurs, and the nitrate will be consumed rather rapidly. After reducing some other minor elements, the bacteria will turn to reducing sulfate. This results in the byproduct of hydrogen sulfide (H2S), a chemical toxic to most biota and responsible for the characteristic "rotten egg" smell and dark black sediment color. Sulphate reduction  iron sulphides = BLACK (H2S = SMELLY) Iron reducers and iron oxidisors. Methane produced by methanogenesis by archaea. Ammonia all oxidized at surface for E production (aerobic process – i.e. only at surface). Decay of organic matter produces ammonia (NH4). Essex muds go anoxic within about 2 mins because so fine. Underneath respiring sulphate (obligate anaerobes, some facultative) Sulphate abundant in SW. Oxygen = terminal electron receptor in respiration.

Answer 108

Predation is key to sustainable biodiversity (TOP-DOWN CONTROL) Real-life application: protection of a predatory species (e.g. by fishing limits) may influence biological diversity Trophic cascades Disproportionate impact due to trophic position (particularly if a keystone predator) Top predators are often more vulnerable to depletion (e.g. slow to reproduce; need large ranges; vulnerable to habitat loss; dependent on availability of prey) Can alter entire ecosystems – examples? -Tiger sharks (remember Lecture 7!) -Baltic cod (coming up!) -Killer whales (coming up!)

Answer 109

Fine sediments with high organic loading High Bacterial respiration = anoxic sediments Adaptations e.g. shallow roots and Pneumatophores Positive feedback - root systems = deposition = accretion deposition - further development Salinity variations - adaptations - salt excretion glands of Avicennia

Answer 110

Avicennia - salt tolerant, not tolerant of shade; Sonneratia maybe at seaward edge) 2. Rhizophora - typical mangrove tree - cover large areas 3. Bruguiera - characteristics of heavy compact clays e.g. high water springs 4. Ceriops - nearly terrestrial - not always present

Answer 111

Symbiosis is the interaction between two dissimilar organisms living in close physical association. Mutualism, communalisms and parasitism.

Answer 112

Bacteria provide giant tube worms with food in exchange for shelter. The bacteria (the “symbiont”) use a process known as chemosynthesis to reap energy from hydrogen sulfide to make organic compounds that the giant worm (the “host”) can eat.

Answer 113

The warmer the ocean surface, the shallower the mixed layer. Therefore ocean heat rises will affect this. Winds and storms, such as hurricanes and typhoons, are the mechanisms by which the surface ocean is mixed with the deep ocean.

Answer 114

What is the critical depth theory? The Critical Depth Hypothesis formalized by Sverdrup in 1953 posits that vernal phytoplankton blooms occur when surface mixing shoals to a depth shallower than a critical depth horizon defining the point where phytoplankton growth exceeds losses. Mixed layer deepening and decreased sunlight reduce phytoplankton growth, causing biomass to decrease through winter and early spring. Increasing mixed layer light drives phytoplankton growth past a critical threshold and initiates a bloom. Mixed layer deepening impacts zooplankton grazing more than phytoplankton growth, causing bloom initiation in early winter. Increasing mixed layer light sustains predator-prey imbalance and perpetuates bloom.

Answer 115

Greater biodiversity in ecosystems, species, and individuals leads to greater stability. For example, species with high genetic diversity and many populations that are adapted to a wide variety of conditions are more likely to be able to weather disturbances, disease, and climate change. According to the hypothesis of top-down control, the abundance of marine fish populations is controlled by predation from top predators. Predation is easier to demonstrate than competition because evidence of it can be found in the predators' stomachs. Predators also taking longer to recharge in numbers making them more vulnerable. What is the definition of top down control? In its simplest form, 'top-down' control refers to directional regulation within an ecosystem, where species occupying higher trophic levels exert controlling influences on species at the next lower trophic level (Terborgh et al., Reference Terborgh, Estes, Paquet, Soulé and Terborgh1999).

Answer 116

Within the field of ecology, disturbance can be defined as a physical force, agent, or process, either abiotic or biotic, causing a perturbation or stress, to an ecological component or system, relative to a specified reference state and/or system. Disturbances act to disrupt stable ecosystems and clear species' habitat. As a result, disturbances lead to species movement into the newly cleared area (secondary succession). Once an area is cleared there is a progressive increase in species richness and competition between species takes place. The intermediate disturbance hypothesis predicts high richness in communities subject to a moderate degree of disturbance or stress; according to this model, high stress leads to mortality in all but fast-growing individuals, and under low stress, inter- and intraspecific interactions such as competition and predation determine community structure.

Marine Biodiversity Flashcards

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