marine biology

• ecosystem services → a function performed by an ecosystem that directly or indirectly benefits humans
• sessile → this refers to organisms that are fixed in one place and do not move, typically attached to substrates such as rocks, the ocean floor, or other surfaces.
• DOC → Dissolved organic carbon; it’s organic carbon that is present in water in dissolved form, originating from the decomposition of plant and animal materials and playing a crucial role in the carbon cycle
• POM → particulate organic matter; consists of small particles of organic material suspended in water, which are derived from dead and decaying organisms, fecal matter, and other organic debris
• trophic level → a trophic level is a specific position in a food chain or ecological pyramid, representing a group of organisms that share the same function in the ecosystem and obtain their energy in similar ways, such as primary producers, primary consumers, secondary consumers, and so on
• holoplankton → these are organisms that spend their entire life cycle as plankton, drifting in the water column, and include species such as certain types of algae, jellyfish, and copepods
• benthos → This refers to organisms that live on, in, or near the seabed, also known as the benthic zone, including species such as clams, crabs, sea stars, and various types of worms
• maerl → it is a type of calcareous algae, primarily composed of red algae, which forms loose unattached beds on the seabed and provides important habitat for marine life
• keystone species → These are species that have a disproportionately large effect on its ecosystem relative to their abundance, often playing a critical role in maintaining the structure and balance of the ecological community.
• critical depth → it is the depth in the ocean where the rate of photosynthesis by phytoplankton equals the rate of respiration, resulting in no net growth of the phytoplankton population
• What are some characteristics of diatoms?

  diatoms are phytoplankton with silicate cell walls, which offer protection from predators. They have no visible flagella, meaning they are non-motile. Diatoms can have two kinds of shapes: centric or pennate. Pennate shaped diatoms can have a frustule running down their length. Centric shaped diatoms are either cylindrical or disk / drum shaped. They are unicellular, which means that they are made of only one cell that provides all functions for the organisms. Most diatoms are photosynthetic, so they use sunlight to create energy.
• describe the function of zooxanthellae, their trophic type/ecological role, and their systematic classification?

  zooxanthellae are a type of phytoplankton. The nonmotile stages of zooxanthellae can form symbiotic relationships with reef building hermatypic corals. This process involves the coral sheltering the zooxanthellae and the zooxanthellae providing nutrients for the coral in return. There are also non-motile zooxanthellae that are ahermatypic. This means that they have no symbiotic relationship with corals. Some examples of non-motile zooxanthellae are sea anemones and molluscs.
• catches -> fish / organisms caught
• landings -> fish/ organisms brought to land
• by-catches -> not targeted fish / organisms caught
• discards -> fish / organisms caught but not landed
• MPA -> Marine protected area; a marine area where the exploitation (for example fishing) of that area is prohibited
• hermatypic corals -> “hard” coral which secrete calcium carbonate to form a hard structure / polyp
• ahermatypic corals -> “soft” corals, such as sea anemones, which do not secrete calcium carbonate, and do not have a symbiotic relationship with zooxanthellae
• autotroph -> an organism which fixes carbon from inorganic sources (such as carbon dioxide or sulphur)
• heterotroph -> an organism which fixes carbon from organic sources, such as eating other organisms
• passive fishing gear -> fishing gear left out, which catches fish by having them swim into it; includes gill nets, long lines, and fish traps
• active fishing gear -> fishing gear which is used to actively catch fish, includes harpoons and dynamite.
• discuss how recruitment can affect fish stocks and how this is used in fishery management?

  recruitment is how many individuals join a fish stock per year. It is used by fishery management to predict fish stock sizes, but this does not take into account the fish lost to catches. Positive recruitment will increase the size of the fish stock, while negative recruitment will decrease the size of the fish stock
• why are there fewer species inhabiting an estuary than those in adjacent freshwater or marine habitats?

  because of the unstable / inconsistent environment. Freshwater and marine habitats are less unstable than estuaries, making them more predictable environments to live in.
• how does the production to biomass ration (P/B) correlate with size and why?

  larger organisms have a low P/B ratio, because they have low growth and death rates. These organisms have a large amount of biomass already and grow slowly (production is low) This means that the ratio of biomass to production is low. Small organisms have a high P/B ratio because they have high growth and death rates. These organisms have a small amount of biomass, but grow quickly (production is high) This means that the ratio of biomass to production is high.
• name three key organisms in the oceanic microbial food webs:

  calanus, diatoms, and dinoflagellates
• describe the function of zooxanthellae, their trophic type/ecological role, and their systematic classification?

  zooxanthellae are a type of phytoplankton. The nonmotile stages of zooxanthellae can form symbiotic relationships with reef building hermatypic corals. This process involves the coral sheltering the zooxanthellae and the zooxanthellae providing nutrients for the coral in return. Some other examples of non-motile endosymbiotic zooxanthellae are sea anemones and molluscs