OCEAN 2002: Multiple Choice

Phaeocystis

• Major spring bloomers; compete with diatoms.

  • Phaeocystis are not able to move up the food chain (unlike diatoms), to combat this they form a colonial ‘goo’ where they are able to defend themselves

• When nutrients are depleted, they are able to prey on bacteria/small organisms

  • Naturally autotroph but can become heterotroph when environment not great. Known as mixotroph

• phytoplankton

Colonial Phaeocystis

• hundreds of cells are embedded in a polysaccharide gel matrix, which can increase massively in size during blooms

Ascophyllum

• Intertidal brown algae which goes from the temperate to sub-polar waters

• Foundational species: important non-trophic effects in ecosystems

  • Provides refuge for different species according to tide level

  • Productive intertidal species, most of the production goes to the detrital pathway

• Useful to human

  • Industry in harvesting Ascophyllum in NS

Eelgrass

• One of about 72 species of seagrasses

  • Only group of plants in the ocean which are not an algae

• Sexual and asexual reproduction

• Some of the oldest living organisms

• Very important for providing habitat for organisms (like Asophyllum), and also production goes to detrital pathway

• DR KRISTINA BOERESTER

C. dinmarchicus

• Zooplankton copepod species

• Live over areas with a deeper seafloor due to spring migration

• Spring bloom specialists, mature over the summer, finishes bloom and goes into diapause (stalled) phase in fall

  •   Need deep water to reach diapause phase → cold → “put themselves in the fridge”

• Diel vertical migrators

Homarus americanus

• benthic invertebrate

  • lobster

• Local to temperate western Atlantic (warmer water, not tolerant of cold water)

  • Distribution determined by habitat (right places to hide) and temperature (above 12 degrees)

• Active ambush predators

• Lifecycle tuned to “get big fast” to lessen predation

How have humans altered Lobster ecosystems?

• We have altered their ecosystem 2 ways

  • Fishing

    • we have removed their dominant predators; cod

    • we are feeding them in traps which they can easily escape from

  • Climate change

A. rostrata

• Eel

• Widely distributed along western edge of North Atlantic

• Catadromous

  • Spawn in sea water, spend lives in fresh water

  • Spawn in Sargasso Sea

• Fascinating life history stages

  • Aleptocephalus larval phase floating in currents for ~1 year, transform to glass eels, then closer to shore get colour and become elvers, then mature swim upstream to fresh water to live out their lives

Eel Life History Strategy

• Catadromous

  • Spawn in sea water, spend lives in fresh water

  • Spawn in Sargasso Sea

• Fascinating life history stages

  • Aleptocephalus larval phase floating in currents for ~1 year, transform to glass eels, then closer to shore get colour and become elvers, then mature swim upstream to fresh water to live out their lives

Eel Fisheries

• Targets of fisheries

  • Primarily in China, and primary interest in Elvers rather than mature Eels

  • Aquaculture poses new threats to species

D. coriacea

• Leatherback sea turtle

  • largest sea turtle

• Ectotherms and have adaptations which allow them to go to incredibly cold waters

  • Black body colour: absorb heat

  • Blood flow

  • Large body

• Long lived and slowly reproducing

  • Not good when these species face risks; hard to bounce back

  • Conservational efforts have been positive, specifically in the protection of nesting beaches

• FERRIS KERR

Leatherbacks Diving Behaviour

• Deep-diving behaviour

  • This is seen more in transit rather than when they are feeding. Perhaps they are deep diving to check if they should stay in the area? Paul likes this hypothesis

Morus bassanus

• seagull

  • largest North American sea bird

• fierce, plunge-diving predator

  • feeds on small fish (however, same fish humans catch, which present a challenge to conservation)

• colonial nester

Halichoerus grypus

• grey seal

  • most common seal in our waters

• demersal predator

• growing population which has led to a changing ecosystem

• semi-aquatic

  • can be seen ‘hauled out’

Importance of Phytoplankton

§  Food

·      Basis of food chain (make 95% of food for the ocean)

§  Carbon cycling

§  Oxygen

§  Toxins

·      Harmful toxins; algal blooms

Phytoplankton Size

o   Larger cells favoured by higher nutrient levels

§  Good reasons to be big, but makes less competitive for nutrient levels

§  Bigger types in the spring (for the bloom), and then disappear for rest of year

Phytoplankton Mixing/Stratification

o   Understanding mixing and stratification are key

• Stratification is what limits nutrients

• Mixing is what brings nutrients back up to the surface

o   Climate change may impact phytoplankton community structure

• As we get warmer, water becomes more stratified, smaller plankton favoured, which do not make it up the food chain as effectively

Harmful Algal Blooms

• Out-of-control algal growth

  • Generally caused by an increased in nutrient availability

  • Human-result often

• Some produce toxins

  • Toxins enter the human food chain through filter-feeding shellfish

  • Major economic, public health impacts

• HABs are increasing globally

  • We’re putting too many nutrients in costal waters

  • No solutions are perfect

Blue Sharks

• Generalist feeders

• One of the most reproductively prolific elasmobranchs

  • Faster producers; recover from overfishing better

• Pupping grounds in the Azores

• Segregate by sex, and life history stage

• Most common shark in Atlantic Canada

  • Stay/leave based on temperature differences

Cetacean Sanctuary

• Proposed 100 acre pen whale sanctuary on Eastern Shore of NS (Port Hilford, NS)

  • Aid to whales kept in captivity (practice seen since 1862)

• Issues, delays due to environmental concerns, among other things

  • Questionable finances

  • This has been going on for a long time, and moves ahead very very slowly

  • Historical goldmining along the shores; bad sediments

Canadian Sea Turtle Network

• tasked in aiding the conservation of sea turtles

• impressive outcomes

Mutualism Between Dolphins and Orcas

• Dolphins are excellent at locating salmon

  • Orcas are excellent too, but why not get a little help?

• Orcas capture and kill large salmon, and dolphins feed on the scraps

Life Surroundings Vents

o   “background” fauna

o   Sessile suspension feeders

o   Mobile scavengers

o   Higher diversity leads to decrease in abundance

• Try to put this in a framework of zonation or succession?

MONICA NEUFELD

Deep Sea Mining

o   Polymetallic sulphides, manganese nodules, cobalt crusts

• Items of interest

o   Concerns include sediment plumes, habitat recovery time, lack of knowledge

• Most of deep-sea life is dependent upon bioluminescence, so even the smallest kick up of sediments throws deep sea ecosystems out of loop

o   Increasing pressure to mine, and increasing pressure to conserve

Deep Sea Mining Regulations

o   The ISA regulates mining in the deep sea

• International Seabed Authority both regulates and promotes; makes it open to corruption

o   Difficulties developing an international mining code (been working on since 1994)

• The USA is forging ahead without the ISA, causing concerns about international law

Nova Scotia Fisheries

o   NS has a variety of wild-caught fisheries

• Lobster is significantly more valuable than the other 4:

·      Scallops

·      Snow crabs

·      Halibut

·      Northern shrimp

o   Lobster, scallops, and halibut in good/OK shape

o   Snow crab and shrimp under pressure from increasing temperatures

LSSHN (tony soprano saying “lesson”)

Fisheries Closures

o   Cod stocks collapsed due to better tech. and unsustainable fishing

o  Total allowable catch of cod increasing year-over-year despite concerns

o   Elver worth lots of money

• Closed because the DFO ‘threw hands up’

• Illegal market

o   Closures can be used to protect whales and humans

Ocean Cleanup

o   Bold initiative to remove microplastic waste from the ocean

o   An impact assessment indicates that positive effects of cleanup outweigh negative effects, but result is not statistically significant

• Is it worth it to keep trying? Paul Hill thinks so, but who’s to say!

o   Accusations of “greenwashing”

Dr. Kristina Borester

• Eelgrass lecture

• 1 of 72 species of seagrasses

  • only plants which grow in ocean and are not algae

• crucial for providing habitats to organisms, production goes to detrital pathway

• asexual and sexual reproduction possible

Monica Neufeld

• life surrounding vents lecture

• main groups:

  • background fauna

  • sessile suspension feeders

  • mobile scavengers

Ferris Kerr

• Leatherback turtle; D. coracea lecture

• ecto/poikilotherms which have adaptations to allow them to go into cold waters

  • black body colour which absorbs heat

  • blood flow

  • large body

• slow lifestyle;

  • long lived

  • slow to reproduce

  • challenge when species is at risk; hard to bounce back