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Steve Lonhart, PhD

Fall 2024

UCSC Kelp Forest Ecology

Invertebrate Lecture

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  • The Office of National Marine Sanctuaries encompasses over 600,000 square miles of marine and Great Lakes waters in the US.
  • The network includes 16 national marine sanctuaries and 2 marine national monuments.

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sanctuarysimon.org

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SeaPhoto now on Android and iOS

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sanctuarysimon.org

Sanctuary

Integrated

Monitoring

Network

Visit the web site!

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Invertebrates in Kelp Forests

  • Taxonomic diversity
  • Trophic interactions
  • Habitat engineers
  • Reproduction
  • Invertebrate ID

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1.5 M terrestrial plants and animals

described to date

~300,000 marine species. True global total likely >1 M

35 marine phyla (animals)

14 exclusively marine

Pearse & Buchsbaum 1987

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Table 1. Estimated number of species for the major phyla occurring along eastern Pacific, with known counts of species found within four of the west coast sanctuaries (as of fall 2020). These counts encompass all marine habitats, including kelp forests.

And you need to learn about 70 of the invertebrates!

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Oregonian and Californian biogeographic provinces

  • Central California, and Monterey in particular, is in a transition zone (yellow area)
  • Point Conception is a leaky southern barrier
  • Central California has a very rich biota, a mix of cold- and warm-temperate species

Large-scale benthic patterns of diversity and distribution are influenced from above by regional atmospheric and oceanic forcing, and from below by local geology

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Invertebrates in Kelp Forests

  • Taxonomic diversity
  • Trophic interactions
  • Habitat engineers
  • Reproduction
  • Invertebrate ID

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Graham et al. (2007)

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Graham et al. (2007)

Producers

Primary Consumers

Higher Order Consumers

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Trophic groups in a kelp forest

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1º producers: imported algae resident algae imported plankton

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1º consumers: grazers detritivores SSFs planktivores

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2º consumers: invert & vertebrate predators scavengers

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3º consumers: vert predators parasites scavengers

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Decomposers

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Grazers

  • Herbivores (selective)
    • Some turban snails (e.g., Tegula)
  • Incidental omnivores (non-selective)
    • Chitons and limpets (e.g., Tonicella)
    • And those that “switch”
      • Urchins (e.g., Strongylocentrotus purpuratus)

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Primary

Consumers

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Detritivores

  • Detritus = fragments of animals or algae
  • Kelp forests produce lots of drift kelp
  • Urchins and abalone “grab” drift algae
  • Bat stars extrude stomachs onto detritus

Primary

Consumers

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Deposit feeders

  • Feed on epibenthic detritus
  • Apostichopus uses tentacles to “pad” the surface of rocks and sediment

Primary

Consumers

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Sessile suspension feeding (SSF)

  • Passive
    • Extrude mucous nets--Thylacodes
    • Extend structures--Eudistylia, Urticina, Pachycerianthus, Primavalens
  • Active
    • Sweep with a structure--Balanus
    • Pump water--Tethya

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For many sessile suspension feeders, the same structure is used for feeding and respiration

Primary

Consumers

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Cucumaria miniata uses 10 highly branched tentacles

to capture plankton and particulate organic matter

Primary

Consumers

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Predators

  • Lethal: mortality due to consuming all or most of the prey
  • Sub-lethal: not lethal since only part of the prey is consumed (e.g., snipping of tentacles, eating a few sea star rays)

Higher Order Consumers

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Scavengers

  • Opportunistic
  • Mobile, often quick
  • Acute senses (esp. chemosensory)
  • Broad diet

Higher Order Consumers

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Parasites in kelp forests

  • Wentletraps parasitize anemones
  • Annelids on sea stars
  • Cancellaria cooperi is a “blood sucker” parasitizing both Pacific electric rays and gumboot chitons

Higher Order Consumers

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Invertebrates in Kelp Forests

  • Taxonomic diversity
  • Trophic interactions
  • Habitat engineers
  • Reproduction
  • Invertebrate ID

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Invertebrates as habitat engineers

  • Inverts can provide habitat
    • Externally (e.g., shell, crab carapace)
    • Internally (e.g., shell, sponge, tunicate)
  • Inverts can alter habitat/geology
    • Consolidate sand (Diopatra)
    • Destroy reef (pholad clams)
    • Build reef
      • Permanent (Dodecaceria)
      • Temporary (Phragmatopoma)

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Juvenile Loxorhynchus covered with Corynactis, tunicates, and hydroids

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Phragmatopoma is substrate for a bryozoan, tunicates, and hydroids

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Dodecaceria concharum

Colonial tubeworm, white tube with green-brown tentacles,

tube openings 2 mm diameter. This “chalk” reef as growing on top of granite, and while granite has a Mohs value of 6, the biogenic CaCO3 has a value of about 3.5.

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Invertebrates in Kelp Forests

  • Taxonomic diversity
  • Trophic interactions
  • Habitat engineers
  • Reproduction
  • Invertebrate ID

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Reproduction

  • Sexual (dioecious)
    • Internal fertilization
      • Internal development of eggs
      • External development of eggs (e.g., capsules)
      • Larvae released into water column
        • Feeding
        • Non-feeding (yolk stores)
      • Larvae crawl away from parent
    • External fertilization
      • Broadcast spawning
    • Monoecious (hermaphroditism)
      • Sequential (size advantage model)
      • Simultaneous (low density model)

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Reproduction

  • Asexual
    • No gametes involved
      • Budding (e.g., hydroids, bryozoans)
      • Fragmentation (e.g., sea stars)
      • Fission (e.g., anemones)
    • Gamete involved
      • Parthenogenesis

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Reproduction

  • Protogynous hermaphrodite
    • Begin female, then add male gonads
    • Young remain with parent for ~3 months

Brooding anemone Epiactis prolifera

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Reproduction

  • Asexual
    • Fission: rips self in two to form identical clones

Aggregating anemone Anthopleura elegantissima

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Invertebrate ID