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Title: PHYCOLOGY Kelp Forest Ecology and Deep Water Algal Assemblages By Heather Spalding Moss Landing Mari


1
PHYCOLOGYKelp Forest Ecology and Deep Water
Algal AssemblagesBy Heather SpaldingMoss
Landing Marine Laboratories
Developed for the Marine Science Research summer
institute 2000 Dr. Simona Bartl, program
director
2
  • I know of few things more surprising than to
    see this plant growing and flourishing amidst
    those breakers of the western ocean, which no
    mass of rock, let it be ever so hard, can long
    resist.
  • -Darwin (1860)

3
Terminology
  • Phycology- study of algae
  • Algae
  • pond scum, frog spittle, water mosses, seaweed
  • convenient term for most nonvascular aquatic
    plants
  • capable of photosynthesis with oxygen evolution
  • distinguishing characteristic is their sexual
    reproduction

4
Morphological Terminology
  • Coralline ( G. korallion, coral) term frequently
    used to refer to calcareous (impregnated with
    calcium carbonate) Rhodophyta of the
    Corallinaceae which resemble coral
  • Geniculate (L. geniculum, a little knee) bent in
    the manner of a knee geniculum is an uncalcified
    joint between segments of coralline algae
  • Nongeniculate encrusting coralline algae, does
    not bend
  • Foliose (L. folium, leaf) leaf-like a flat or
    curled, expanded thallus
  • Stipitate (L. stipes, stalk) stalked

5
3 Main Phyla
  • Phaeophyta brown algae, i.e. kelps
  • kelps large brown algae in the Order
    Laminariales
  • Giant Kelp Macrocystis pyrifera, a type of
    large brown algae that can grow up to 60m and
    form canopy-like forests in the water column
  • Rhodophyta red algae, i.e. foliose reds and
    coralline algae
  • Chlorophyta green algae, i.e. sea lettuce

6
Chlorophyta Codium sp.
Phaeophyta Macrocystis pyrifera
Rhodophyta Chondrus crispus
7
Overview of talk
  • Human interest in algae
  • history
  • biodiversity
  • invasive and nuisance species
  • human uses
  • scientific research
  • Local research
  • kelp forest ecology
  • deep water algal assemblages

8
Human interest in algae
  • Seaweed collected for food
  • China 2500 years ago
  • Europe 1500 years ago
  • Ireland over 800 years ago
  • Seaweed mariculture
  • Japan and China for over 300 years

9
Porphyra (Nori) Mariculture
10
Human interest in algae
  • 1600s European mariners used Macrocystis as a
    navigational aid
  • floating canopy of attached plants indicated
    shallow reefs
  • floating bundles of drift plants indicated that
    the coast was not far off

11
First ecological research
  • 1860 (Darwin) published some of the first
    insights made the first analogy between this
    giant kelp and terrestrial forests

12
Research continued
  • 1945 Andrew pioneered research on the fauna of
    giant kelp holdfasts
  • included some underwater observations, but
    hampered by the lack of simple diving equipment

13
Research continued
  • 1950s
  • With the advent of SCUBA, direct observations of
    kelp forests became relatively simple

14
  • Also in the 1950s
  • A large tract of Macrocystis disappeared off the
    Palos Verde Peninsula (Los Angelos County) and
    from other areas of southern California
  • Lead to the idea that stands of Macrocystis may
    be ephemeral
  • May be disturbed by pollution associated with
    large centers of population
  • This spawned a number of research programs to
    study life history features of giant kelp and its
    associated organisms
  • These found that many factors were responsible
    for the variation in kelp abundance

15
For example
  • 1967, 1969 Dayton estimated the size of
    Macrocystis beds by assessing the percent cover
    of surface canopy at several locations
  • found variation over time
  • To present.these studies continue, with hundreds
    to thousands of published papers on Macrocystis
  • Seaweed research in the U.S. has been ongoing for
    about 60 years

16
Algae researchWhy do we care?
  • Positive effects in nature
  • Important primary producers (base of the food
    chain)
  • Oxygenate the water during the day by
    photosynthesis
  • Some algae form symbiotic relationships with
    other organisms
  • Coral, certain protozoa, sponges, and marine worms

17
Symbiotic relationship Algae living the gut
tissues of this anemone (Anthopleura
xanthogrammica) give it a green hue. The anemone
gets extra nourishment from the by-products of
the algal photosynthesis, and the algae are
protected from grazers.
18
Create environment for biodiversity
  • North(1971) listed 130 species of plants almost
    800 species of animals associated with giant kelp
    in So. CA and Baja, Mexico
  • Defined 5 zonal associations occurring along a
    depth gradient in a giant kelp community

19
Inhabitants of a generalized kelp forest
Association 1 On surface of algae
Bryozoan on kelp blade
Association 2 Plankton
Crab larvae
Sea star larvae
Copepod
20
Inhabitants of a generalized kelp forest
Association 3 Fauna in giant kelp holdfast
Association 4 Flora and fauna on horizontal
surfaces
21
Inhabitants of a generalized kelp forest
Association 5 Organisms on Vertical Faces
22
Create environment for Biodiversity cont.
  • A variety of birds and mammals forage in the kelp
    forest community
  • Cormorants, harbor seals, sea otters

23
Create environment for Biodiversity cont.
  • Drift kelp is an important source of energy to
    other communities, from the deep sea to the beach

24
Negative effects in nature
  • Some algae form macroalgal blooms
  • Create an unpleasant smell and taste to water
  • Create an anoxic environment in the water
  • Nuisance algae and introduced species
  • Can foul boats and smother a native marine
    environment (Example Caulerpa taxifolia in the
    Mediterranean)
  • Some algae (dinophlagellates) secrete toxins
  • red tides and the fish-killing algae
    Pfiesteria

25
Invasive species Caulerpa taxifolia
Caulerpa taxifolia completely covering a coral
reef system in the Mediterranean. Photo credit
Alexander Meinesz, Univ. Nice-Sophia Antipolis
26
Nuisance algae Pfiesteria
27
Human Uses
  • Pharmaceuticals
  • Some algae (Cryptosiphonia) secrete compounds
    that are used to treat herpes virus infections
  • In China,
  • Laminaria and Sargassum species have been used in
    China to treat cancer (anti-tumor activity
    documented in animals and thought to be due to
    long-chained polysaccharides)
  • Dry Laminaria stipes, which slowly take up water
    and expand, have long been used in obstetrics to
    dilate the cervix prior to the insertion of
    intrauterine devices

28
Human Uses Food!
Yum !!!
29
Human Uses Food
  • Over 493 species eaten in Asian countries
  • Seaweeds account for 10 of the Japanese diet
  • Examples
  • Nori (Porphyra sp.) wrapped in sushi
  • Kombu (Laminaria sp.) cut into strips or
    powdered
  • Wakame (Undaria sp.) additive to soups
  • Kelps, such as Kombu and Wakame, are often used
    as a source of iodine as well as flavor

30
Human Uses Food
  • -In Ireland and Scotland
  • Dulse (Palmaria palmata) used as a sea
    vegetable sliced, diced, dried, etc. also in CA
  • Irish Moss (Chondrus crispus) used in soups,
    puddings, etc. also on the East Coast of USA

Palmaria palmata
Chondrus crispus
31
Human Uses Food
  • Native Americans have been harvesting seaweed on
    the Northern California Coast for many thousands
    of years

The Kashaya call the seaweed they harvest mei
bil, sea leaf (Porphyra sp.)
32
Additives for Human Consumption
  • Industrial Gums products used to achieve
    various levels of viscosity
  • Carrageenan (red algae, Chondrus crispus)
  • For thickening and stabilizing ice cream and
    other prepared foods
  • Agar (red algae, Gelidium sp.)
  • For packing canned food, treating constipation,
    and microbiological culture substrate
  • Alginates (brown algae, Macrocystis)
  • As emulsifiers and binding agents in food and
    pharmaceuticals
  • For medical dressings on burns and extensive
    wounds

33
Other Human Uses
Fucus used for fertilizer and fodder
  • Waste Management
  • Some algae are used as biological scrubbers to
    remove excess nutrients and oxygen from effluents
  • Manufacture
  • Macrocystis harvested for potash for making
    gunpowder in World War I
  • Some intertidal algae used as fertilizer in soil
  • Feed
  • Some intertidal algae used as fodder (food) for
    cattle and sheep Macrocystis harvested for
    abalone farming

34
Macrocystis Harvesting in CA
Kelco Kelp Harvesting Boat
Giant Kelp (Macrocystis pyrifera) Forest
35
Other Human Uses
  • Tourism
  • Recreational SCUBA diving
  • Sport Fishing
  • abalone, lobsters, crabs, scallops, fish
  • North (1971) lists over 40 species of fish
    associated with kelp forests that occur in the
    commercial and party boat catch in California
  • Maintenance of Fisheries
  • Kelp Forests serve as refuges for early life
    stages of commercially valuable fish

36
Whats known from research
  • Algal life history
  • Large variation in number of life stages across
    taxa
  • Simplest
  • Fucus sp. animal-like life history
  • Possibly most complex
  • Pfiesteria over 23 life stages documented thus
    far
  • In contrast to terrestrial plants

37
Typical terrestrial plant life history
  • Pollen transported to Pistil
  • Pollen fertilizes Ova (N) to produce a seed (2N)
  • Seed which grows into the sporophyte (plant2N)

Sporophyte
Pistil Ovary enclosed
Stamen pollen -bearing
38
Macrocystis Life History
  • Macrocystis pyrifera
  • Sori on sporophylls produce microscopic haploid
    (1N) spores
  • Spores settle and become male and female
    gametophytes (tiny stages we dont see)
  • Male gametes (sperm) fertilize eggs on female
    gametophyte
  • Resulting zygote develops into the macroscopic
    diploid sporophyte (2N the big plant we see)

Sporophyte (2N) with sporophylls at base of plant
39
Macrocystis Life History
Gametophytes (N)
Spores (N)
Male- releases sperm
Female
Sori
Developing Sporophyte (2N)
Sporophyte (2N)
Juvenile Sporophyte (2N)
40
Geographic Distribution
  • Subtidal forests of Macrocystis occur in many
    areas of the world, but are most widely
    distributed in the southern hemisphere

41
What makes central CA so ideal for kelp and other
seaweeds?
  • The primary requirement for seaweed is hard
    substrate (rock) for attachment, but many other
    factors affect its probability for survival

42
Factors affecting algae in CA
  • Substrate
  • Need rock for attachment, hardness of rock
    affects mortality due to water motion
  • Sedimentation and Sand movement
  • Can bury, scour, or prevent attachment of plants
    (especially microscopic stages)
  • Light
  • Need certain quality (kelp gametophytes need blue
    light to reproduce) and quantity (at least 1 of
    surface levels)

43
Factors affecting algae cont.
  • Water Motion
  • Can cause plant and animal loss in surge and
    current
  • Distributes nutrients and increases nutrient
    uptake
  • Temperature
  • Needs water lt16º C (related to nutrients)
  • Nutrients
  • Needs certain quantities of Nitrates, Phosphates
    and trace minerals and metals

44
Factors affecting seaweed cont.
  • Toxic Substances (heavy metals, pesticides)
  • Copper reduced algal growth and fertility at 30
    ppb
  • DDT possible alternation of community
  • Grazing (fish, sea urchins, snails, isopods,
    etc.)
  • Can destroy Macrocystis if plants at low density
  • Create small areas nearly devoid of foliose red
    algae
  • May destroy canopy and sub-canopy
  • May consume small life stages

45
Grazing Urchins
Urchin
Urchins grazing kelp holdfast
Giant kelp forest
Urchin barrens All vegetation grazed
46
Factors affecting seaweed cont.
  • Predation on grazers
  • Sea stars, sheephead, sea otters, and other
    predators (including humans) may affect the
    distribution and abundance of grazers
  • Competition
  • Canopy shading inhibits understory algal
    recruitment and growth within and among species
  • Pre-emption of space
  • Whiplash effects of algal fronds

47
Predation on Grazers
Sunflower Star
California Sheephead
Pycnopodia (Sunflower star)
Sea otter preying on urchin
48
Kelp forest ecology
  • The complex interaction of all these factors
    makes modeling and prediction very difficult
  • For example
  • Is an El Nino event beneficial or detrimental for
    kelp forests?

49
Overview of an El Nino
50
El Nino-Southern Oscillation Event
  • Causes
  • higher water temperatures
  • a lapse in upwelling
  • strong storms with large swell
  • increased terrestrial water run-off from rivers,
    streams, etc.

51
El Nino effects on a giant kelp
forest(Bluenegative Whitepositive)
  • Higher Water Temp
  • increased algal growth
  • less nutrients
  • increased growth of bacteria and epiphytes
  • Lapse in Upwelling
  • Higher water temp (see above)
  • Less nutrients upwelled from deep water

52
El Nino effects on a giant kelp forest
(Bluenegative Whitepositive)
  • Strong Storms with Swell
  • Increased water motion tears out vegetation
  • Increased sand scour abrades vegetation
  • More space and light made available!
  • Increased terrestrial water run-off
  • Increased turbidity, so less light
  • Increased nutrients, so more algal growth, but
    may stimulate phytoplankton blooms, so less light
  • Increased sedimentation with possible burial
  • Increased pollutants

53
El Nino effects on a giant kelp forest
(Bluenegative Whitepositive)
  • Also, an El Nino is usually followed by a La Nina
    (cold water, lots of upwelling), which greatly
    stimulates algal growth!

54
Local research
  • Two preliminary studies on human effects on kelp
    forests
  • One comprehensive study of deep water algal
    assemblages

55
Local Research on Kelp Forest Ecology
  • Diver Disturbance in Kelp Forests (Schaeffer and
    Foster, 1998)
  • The Effects of Small-scale Kelp Harvesting of
    Giant Kelp Surface Canopy Dynamics in the Ed
    Ricketts Underwater Park Region (Donnellan and
    Foster, 1999)

56
Diver Disturbance in Kelp Forests
  • Recreational SCUBA diving activity has greatly
    increased in the past 20 years, with the
    potential for causing important disturbance to
    subtidal reefs.
  • While diver disturbance on coral reefs has been
    assessed and negative impacts have been
    documented, effects on temperate kelp forests
    have not been previously examined.

57
Diver Disturbance in Kelp Forests Hypotheses
  • Ho Divers are having no effect on giant kelp
    forest communities
  • Ha Divers are causing permanent disturbance in
    giant kelp forest communities
  • Ha Divers are having an effect, but no permanent
    disturbances

58
Diver Disturbance in Kelp Forests Methods
  • 42 divers followed underwater
  • first group divers making a shore entry
    concurrently with investigators
  • divers told investigators were observing
    environments that divers like to explore, so
    normal diving behavior would not be altered
  • Disturbances documented
  • Observations started when divers were completely
    submerged, recorded for 20-30 min., and
    standardized to 30 min.

59
Diver Disturbance in Kelp Forests Results
  • During a 0.5 hr dive, the average diver
  • contacted the bottom 43 times
  • touched 4 animals
  • detached 2 algal blades
  • An estimated 60,000 divers use the studied kelp
    forests every year

60
Diver Disturbance in Kelp Forests Conclusions
  • Investigators concluded that the large
    concentration divers in local, usually
    wave-protected kelp forests could lead to
    permanent alterations in community structure
  • Diver impacts might be mitigated through
  • More environmentally aware diving programs
  • Designation of ecologically resilient shore
    entry, exit points, and underwater training areas

61
Diver Disturbance in Kelp Forests Future
Directions
  • A more comprehensive analysis, would
  • compare different locations
  • assess diver experience
  • compare heavily utilized diving locations to
    areas not used by divers
  • monitor the long-term impacts or ecological
    effects

62
The Effects of Small-scale Kelp Harvesting
  • This study assessed the effects of
    hand-harvesting of giant kelp on the surface
    canopy of local kelp forests
  • These harvesting activities are concentrated
    within a small local area during the winter
  • Hand-harvesting may negatively impact the giant
    kelp, rockfish, and sea otter populations

63
Methods
  • Data from two sources was compared
  • aerial photographs dating to 1976
  • kelp forest harvest records
  • Kelp harvesting intensity divided into 3 periods
  • Moderate 1972-1985 (n8)
  • Low 1986-1995 (n8)
  • High 1996-1998 (n2)
  • Assessed kelp canopy surface area, kelp forest
    spatial extent, and kelp canopy blade intensity
  • Used a BACI (Before-After-Control-Impact) study
    design and ANOVA (Analysis of Variance) to
    compare above variables between 3 harvested areas
    and one non-harvested control area.

64
Results Conclusions
  • No statistically significant differences were
    found, but statistical power to detect an effect
    was low given the small sample size of the
    high-intensity period (n 2) and inherent
    natural variability of kelp canopies
  • Conclusion Continued yearly aerial surveys
    during the period of fall maximum kelp canopy are
    needed to substantiate results

65
What lies beyond the giant kelp forest?
  • Because of its size and commercial importance,
    most research on seaweed ecology has focused on
    Macrocystis communities
  • Other communities are less studied
  • Even fewer studies have gone beyond 30m (100ft)
    due to the time and depth limitations of
    conventional SCUBA diving

66
New technologies allow for deep water studies
  • Recent technological advances
  • SCUBA with enriched air Nitrox diving
  • access to submersibles and Remotely Operated
    Vehicles (ROVs)
  • Scientists can now study deep water (gt30m) algal
    communities

67
Deep Water Algae
  • Have same requirements as other algae
  • rock substrate
  • nutrients
  • temp. lt16 C
  • light
  • the limiting factor controlling the lower depth
    limits

Maripelta rotata
68
Why study Deep Water Algal Assemblages (DWAAS)?
  • To understand a new ecosystem
  • To assess algal biogeography
  • knowing what is found where allows us to
    monitor long-term changes in the ocean
  • A gradual warming of the water over a long period
    of time would affect an algas distribution
  • DWAAS may form habitat for commercially important
    fish

69
Why study DWAAS cont.
  • Water quality bio-indicators
  • As water quality decreases, turbidity increases,
    and so the lower depth limits and possibly
    species composition changes..
  • It has been suggested that the deep water
    environment is less variable over time
  • .But first we have to know how variable the
    algae are at different locations and in bodies of
    water with different water clarities!

70
In order to test the variability of deep water
algal communities, we have to find out.
  • What are the species composition and abundances
    of deep water algae?
  • What are the lower depth limits of deep water
    algae? What are the light levels?
  • What is the temporal (year to year) and spatial
    (among and within locations) variation?
  • How does the zonation of DWAAS in central CA
    compare with worldwide zonation observations and
    lower depth limits?

71
  • Methods
  • SCUBA sampling (30m)
  • Counts of algae in 5x1m area
  • cover based on 20 random point contacts in a
    5x2m area
  • Qualitative collections made for algae
    identification

72
Methods The ROV Ventana
  • Video surveys of algae from 100m-30m depth
  • At each 5m depth increment, 5 1m2 areas were
    sampled
  • Representative species were collected for
    verification

73
Method of determining cover from ROV Ventana
digital video with Optimas imaging software
74
Beers Law
75
DWAAS Preliminary Results
  • The lower limits of different algal groups are

78m Nongeniculate (encrusting)
59m Foliose reds
50m Unknown green algal film
42m Kelps
76
Nongeniculate coralline
Foliose red algae
Brown algae
Depth (m)
cover
77
Pleurophycus gardneri
Desmarestia tabacoides
Maripelta rotata
10 SE
4 SE
Depth (m)
Individuals
78
Results
  • Profiles (K)
  • Offshore of East Pinnacle
  • 10/5/99 ------------0.1101
  • 10/17/99 -----------0.117
  • 1/27/00 ------------0.113
  • 3/11/00 ------------0.123
  • 5/4/00 --------------0.1246
  • 5/18/00-------------0.0921
  • Other sites
  • 9/29/99 Diablo Pinnacle ------0.1077
  • 9/29/99 Yankee Point ---------0.085
  • Average K (SE) 0.109 (0.005)

79
Comparison of K values
from Kirk (1994)
80
Comparison of SI
81
Conclusions
  • Deep water kelps are abundant to 40m in central
    CA, forming previously undescribed kelp beds
    below the giant kelp forests
  • Pleurophycus gardneri, a kelp previously
    described as rare in California, is the most
    abundant alga at 30m with up to 10/m2.
  • The SI at the extinction depths of different
    algal groups is similar to that described by
    Hiscock (1986)
  • Central California water is exceptionally clear
    with an average K value of 0.109

82
Summary
  • Algae have a number of human uses
  • Algae create an environment for biodiversity
  • Kelp forests are the most studied algal system in
    the US
  • Complex system with inherent natural variability
  • Local preliminary studies have addressed impacts
    of divers and hand harvesters

83
Summary
  • Deep water algae in central CA are present to at
    least 78 m
  • Form previously undescribed algal assemblages

84
Acknowledgements
  • Local Research Studies by Tim Schaeffer, Mike
    Donnellan, and Mike Foster
  • Deep Water Algal Assemblage work by Heather
    Spalding, Mike Foster, and John Heine through
    NOAAs National Undersea Research Program,
    Monterey Bay Initiative
  • Monterey Bay Aquarium Research Institute provided
    video lab time
  • Website images by Monterey Bay Aquarium, National
    Univ. Ireland, Catalina Island website by Dr.
    Bushing, UCSC Biology Dept. Macrocystis homepage,
    Sonoma State Univ. Dept. Biology, Maine Coast Sea
    Vegetables, Berkeley Dept. Biology
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