Linking nearshore kelp dynamics to sandy beach ecosystems
This proposal is a resubmission that was encouraged by the Biological Oceanography Program. The
Program Comments stated, “the Program agrees with reviewers that the questions posed have strong
intellectual merit. There are relatively few examples from marine systems where carbon transport
across ecosystems has been quantified and in this sense the proposal is novel. We also recognize that
the team assembled is well qualified to pursue this project. There is considerable merit in this project
because it is strongly aligned with the overall research goals of the SBC LTER.” Nevertheless, the
reviewers raised concerns over two main issues: the feasibility of tracking drifting kelp and the
overall complexity and extent of the proposed project. Therefore we have sharpened the project’s
focus: field efforts are now concentrated on a single reef and more complex ecological function
experiments have been eliminated.. Despite a lengthy amount of fieldwork, one revieiwer raised
concerns about needing even more observational time to tease out interannual variations. We believe
three years of observations allows for meaningful discoveries regarding annual variations. To address
reviewer concerns about our ability to track kelp, we conducted a pilot experiment using highresolution drifters as proposed. The effort was a resounding success, and shows that this project, will
produce interesting and unprecedented knowledge of material and energy exchange between coastal
kelp forests and intertidal ecosystems. We were pleased with the constructive nature of the reviewer
comments, and have used them to guide this resubmission.
1. Motivation and Research Overview
1.1 Exchange of Material Between Ecosystems Exchanges of material and energy between
neighboring habitats and ecosystems influence the spatial and temporal structure and dynamics of
communities and food webs. Quantifying the magnitude of these exchanges has long been a central
focus of ecosystem ecology (Odum 1971), although the effects of material subsidies and their
variation on recipient ecosystems have only recently begun to be appreciated (Polis et al. 2004). One
issue has been the continuing focus on food webs as static constructions, without temporal variability
(Polis et al. 2004, Moore and De Ruiter 2012). In marine ecosystems, our understanding of crossecosystem material fluxes, the variation of these fluxes in time and space, and the ecosystem
consequences of this variation to recipient communities is severely lacking.
Nearshore forests of highly productive giant kelp, Macrocystis sp., are the raw material for one of
the best examples of such exchanges in the marine realm. Macrocystis is the world’s largest alga and
as a foundation species profoundly shapes the kelp forest ecosystem. Surprisingly, however, only a
small fraction (<5%) of kelp-derived net primary production (NPP) is consumed within the forest
where it grows (Gerard 1976; Newell et al. 1982). Most kelp NPP is exported outside the forest to
other ecosystems (Gerard 1976), including beaches and the deep-water benthos, where it provides a
source of energy, nutrients, and habitat to consumers and alters the entire recipient ecosystem.
However, little work has been done to quantify the fate and transport of exported kelp NPP,
variability in these processes, and the consequences for recipient non-kelp ecosystems.
Some fraction of NPP exported from kelp forests reaches the shoreline. On sandy beaches, which
largely lack autochthonous sources of primary production, this imported kelp subsidy, commonly
referred to as kelp wrack, supports a complex food web. Wrack is consumed by a diverse group of
intertidal macrofaunal invertebrates, particularly arthropods such as amphipods, isopods, and insects
(Griffiths and Stenton-Dozey 1981; Griffiths et al. 1983; Inglis 1989; Lastra et al. 2008; Spiller et al.
2010). They in turn are an important prey resource for predators, including predaceous arthropods as
well as vertebrates such as shorebirds, seabirds, marine mammals, and fishes (Dugan et al. 2003;
Hubbard and Dugan 2003) as well as terrestrial reptiles, birds and mammals (Spiller et al. 2010).
Despite the well-documented importance of kelp as resource to neighboring ecosystems, we
have little understanding of the connectivity from kelp forests to sandy beaches, and how
variation in kelp inputs shapes local sandy beach communities (Figure 1).
Resource supply and its variability strongly affect consumer population growth, species
interactions including competition and predation, and food web complexity (Sears et al. 2004).
Variation and stability of resource supply also shapes the evolution of species life history and other
characteristics, and influences the pool of species that can take advantage of a resource (Anderson et
al. 2008). Conversely, species diversity and identity can affect the fate of a resource and its eventual
decomposition and remineralization (Srivastava et al. 2009). Such interactions between communities
of consumers and their resources are complex when primary producers are members of the
community, with their abundance and phenotypic traits influenced by competition and grazing. On
sandy beaches, food resources are largely controlled by processes that control transport of material to
the beach and dynamics of the donor communities, in this case kelp forests. With its large NPP and
the connection of exported production to the shoreline, kelp provides an excellent system in which to
investigate consumer-resource interactions.
1.2 Kelp Forest Ecosystems The giant kelp, Macrocystis pyrifera, forms extensive forests on
rocky reefs in temperate waters worldwide. Their floating surface canopy exposes kelp plants to
enormous drag forces from surface waves, and makes the species uniquely vulnerable to this physical
disturbance. Loss of plants tends to
be greatest in fall and winter, when
waves are largest (Gerard 1976;
Reed et al. 2008; Reed et al. 2011).
Primary productivity of
Macrocystis forests rivals that of
tropical rainforests on land, but is
characterized by much higher
temporal variability than highproductivity terrestrial ecosystems
(Reed et al 2011). Variability in
giant kelp abundance and NPP may
be driven by dispersal, physical
disturbance, and nutrient dynamics
(Dayton et al. 1999; Reed et al.
2006; Graham et al. 2007). Kelp
forests are likely to undergo shifts
in abundance and growth rate
linked to climatic variations
including ENSO, the Pacific
Decadal Oscillation (PDO), and
Figure 1. Conceptual diagram of processes identified in the proposed project.
global climate change (Chavez et al. Kelp biomass (NPP) from the extraordinarily productive donor ecosystem, the
kelp forest, is exported into the offshore ocean and onto low-NPP beaches, the
2003; Otero and Siegel 2004). Such
recipient ecosystem. Kelp forests and the transport processes that deliver kelp
shifts have already been
NPP to beaches are influenced by wind and waves, and beach condition. Once
documented for phytoplankton, in
on the beaches, kelp wrack provides habitat for animals and fuels a productive
the form of declines in primary
food web, here simplified to include three major groups, primary consumers,
production in the California Current
small predators, and shorebirds, each of which contains many species. Climate
that may be linked to climate change change will influence kelp forests and beaches directly, as well as the physical
processes (waves and currents) controlling connectivity between these
(McGowan et al. 1998; Barth et al.
ecosystems.
2007). In the Eastern Pacific, the
frequency of years with large winter storm waves has increased over the last 60 years, likely due to
anthropogenic climate change (Graham and Diaz 2001; Ruggiero et al. 2010). Waves both reduce the
abundance of giant kelp and export kelp NPP to adjacent communities (Dayton et al. 1984; Dayton et
al. 1999; Gaylord et al. 2008). Presently, we have little quantitative understanding of how much
kelp NPP is transported to beaches and the spatial scales over which this transport occurs,
which limits our understanding of how these changes may affect beach ecosystems.
1.3 Kelp Loss and Transport Kelp is removed from the forest through a combination of natural
senescence and physical disturbances. Wave disturbance is responsible for most removal of kelp, and
this loss varies seasonally and interannually (Reed et al. 2008; Cavanaugh et al. 2011). Once kelp is
removed from the forest, the fate and transport of large kelp detritus (herafter “drift kelp”) is driven
by the ocean circulation. Although most drift kelp likely moves more or less directly to shore, some
aggregates into floating rafts that may drift large distances. These floating rafts of kelp are common
in California coastal waters, and their abundance, dispersal and associated communities have been
the subject of several studies (Harrold and Lisin 1989; Kingsford 1995; Harrold et al. 1998; Hobday
2000a, b, c; Hinojosa et al. 2010; Rothausler et al. 2011a, b). Three studies have investigated their
dispersal using drifter techniques. Harrold and Lisin (1989) tracked 39 natural and artificial kelp
rafts released from varying distances away from kelp beds in Monterey Bay and showed a seasonal
signal in transport direction. Most rafts were washed up on shore by the end of the 5-7 day tracking
period. Kingsford (1995) tracked parcels of kelp for short time periods off Catalina Island, California,
and concluded that drift was mainly in the direction of prevailing winds. Neither ocean currents nor
the ending distribution of drift kelp were considered in these studies. Hobday (2000a) inferred drift
kelp dispersal patterns in the Southern California Bight using data from Argos satellite-tracked
drifters released an average of 12 km offshore of kelp beds. Drifters coming within 5 km of the coast
were considered to have contacted the coastline. The circulation patterns captured in the Hobday
(2000a) study are not necessarily indicative of the currents near kelp forests, within a few kilometers
from the coast. These existing studies of kelp transport were motivated by the concept of kelp rafts as
a dispersal mechanism for kelp and associated organisms, rather than as a vector of materials
connecting kelp forests to other ecosystems, particularly beaches, where its role in food webs has
been most clearly established. No estimates have been made of the fraction of kelp NPP exported
from forest to beach. Kelp connectivity between forest and shoreline has not been explored.
1.4 Kelp-based Beach Communities Sandy beaches in southern California support some of the
most diverse and abundant macroinvertebrate communities in the world, with >80 species and
densities that can exceed 80,000 individuals per meter of shoreline (Dugan et al. 2003). On average
>40% of these highly mobile species are directly associated with wrack, either by feeding on it or by
feeding on wrack consumers and wrack-associated communities include primary consumers,
predators, and scavengers (Dugan et al. 2003). Wintering and migratory shorebirds, which fluctuate
in abundance seasonally, use wrack as a major foraging habitat (Hubbard and Dugan 2003),
particularly in California, where wetland foraging grounds have been reduced by >90%. Through
studies of mechanically groomed and armored beaches, and via wrack removal/addition experiments,
we know the absence of kelp wrack subsidies severely impacts California beach communities.
Reducing kelp wrack abundance can depress macrofaunal species richness by ~5X and abundance by
two orders of magnitude on sandy beaches (Dugan et al. 2003, 2008). These effects are propagated
through the food web, depressing diversity and abundance of shorebirds that feed on wrackassociated macrofauna, including the threatened western snowy plover (Charadrius nivosus nivosus;
Dugan et al. 2003). Despite the demonstrated importance of wrack subsidies from kelp forests to
sandy beach ecosystems, we lack an understanding of the effect of natural variation in kelp
supply on the ecology of beach communities, and the drivers of this variation. This knowledge
gap, however, is not confined to beach ecosystems – we know little about the ecological effects of
variation in cross-ecosystem material exchange overall (Moore and De Ruiter 2012), and this system
provides a unique opportunity to advance our general understanding of these processes.
2. Proposed research
Here we propose to examine the proportion of kelp biomass exported from forest to shore, the
spatial distribution of this exported kelp along the sandy shoreline, and relationships between
shoreline kelp distributions and sandy beach ecosystem community species and abundances.
We hypothesize that variability in kelp supply on sandy beaches drives spatial and temporal
patterns in species diversity and abundance, and thus ecosystem function. Complementary
physical, biological and ecological approaches will be combined to test this broad hypothesis
Complementary physical, biological and ecological approaches will be combined to test this broad
hypothesis as follows:

Surface current trajectories from high-resolution coastal ocean circulation model results will
be used to quantify the spatial distribution of exported kelp along the sandy shoreline.

Kelp tagging and recovery, similar to historical “drift card” studies of ocean circulation, will
be performed to quantify kelp export to the shoreline and to validate distributions of shoreline
biomass from model trajectories.

“Kelp-drifter” studies, in which kelp plants are tagged and tracked with GPS, will
corroborate shoreline distributions from the kelp tagging approach, and validate pathways
and advection time from forest to shore obtained with model trajectories.

Kelp wrack biomass, species diversity of macrofauna and shorebirds, and secondary
production of consumers will be measured on beaches to assess strength of the crossecosystem linkage between offshore kelp forest and sandy beach ecosystems.

Measurements of consumption rates and secondary production of consumers will be used to
assess the effects of variation in imported resources on ecosystem function of sandy beaches.
The fieldwork will be accomplished over 4 years, tracking kelp and sampling sandy beach
communities to determine the spatial and temporal dynamics of kelp export and sandy beach
community dynamics in a system in which the kelp resource varies dramatically over time in
abundance and production.
2.1 Scientific objectives and significance
GOAL 1. Understand the link between kelp forests and beached kelp wrack.
Objective 1: Characterize transport patterns of Macrocystis NPP exported from the kelp
forest as drift kelp.
Hypothesis 1: Most kelp wrack is transported to beaches in close proximity to the kelp forest
where it originated.
Hypothesis 2: Temporal variability in kelp removal is driven primarily by wave energy.
Primary test: Make direct observations of kelp fate and transport by tagging kelp plants with
drift cards and GPS drifters.
Objective 2. Develop a statistical model of trophic connectivity between kelp forests and
beaches.
Hypothesis 3: Trajectories computed from numerical model solutions can be used to
accurately model connectivity between kelp forest and shoreline.
Primary test: Compute reef-to-shore connectivity with modeled trajectories and evaluate model
results with kelp tagging and GPS drifter observations.
GOAL 2. Link wrack abundance and variability with ecological patterns and processes on
beaches.
Objective 3: Evaluate spatial and temporal patterns of sandy beach community structure.
Hypothesis 4: Abundance and diversity of organisms on beaches is positively correlated in time
and space with input of kelp wrack.
Hypothesis 5: Diversity of organisms on beaches will exhibit a parabolic relationship with
variability in kelp wrack supply, with highest diversity at intermediate levels of variability.
Primary test: Quantify abundance and species diversity of beach communities at 6 sites varying
in kelp input rates (chosen using modeling results), and link these data to kelp input via linear
and nonlinear regression analysis.
Objective 4: Evaluate how input of kelp wrack affects ecosystem function on sandy beaches.
Hypothesis 6: Consumption rate of kelp wrack on beaches is positively correlated with flux of
kelp wrack and consumer diversity.
Hypothesis 7: Secondary production on beaches is positively correlated with flux of kelp wrack
and consumer diversity.
Primary test: Quantify consumption rates of kelp wrack and secondary production at 6 beach
sites varying in wrack input rates, and link these data to kelp input and community structure via
regression analysis.
Below we describe the motivation for these hypotheses and outline our approach to address them.
2.2 Quantifying export and fate of drift kelp from coastal kelp forests
Biomass and productivity of Macrocystis, and hence its availability for export to adjacent
ecosystems, is highly variable both temporally and spatially. Seasonally, kelp biomass in California
typically peaks in summer and autumn, with declines in late autumn and winter due to wave
disturbance (Gerard 1976; Reed et al. 2008). Between years, kelp biomass fluctuates due to removal
of plants by wave disturbance, variable recruitment, and in some cases nutrient availability (Dayton
et al. 1984; Reed et al. 2008, 2011; Cavanaugh et al. 2011). On longer timescales, ENSO cycles can
strongly affect kelp growth and production, as well as standing biomass, and the response of kelp to
these interannual cycles depends largely on the oceanographic regime state (Parnell et al. 2010),
which cycles on decadal to multidecadal time scales; these longer-term cycles include the Pacific
Decadal Oscillation (PDO), and Victoria Mode or North Pacific Gyre Oscillation in the Pacific
(Mantua et al. 1997; Bond et al. 2003; Di Lorenzo et al. 2008). Wave energy drives most loss of
biomass and mortality of giant kelp: fronds are removed as they senesce and their stipes weaken, and
whole sporophytes (plants) are dislodged from the bottom particularly during large winter storms,
when the largest proportion of kelp biomass removal occurs (Gerard 1976; Dayton et al. 1984; Reed
et al. 2008; Figure 2). Thus, we might
expect that the largest influx of kelp
wrack to beaches would occur during
winter. In the Mediterranean climate of
California, however, Macrocystis
biomass accumulates in the forest during
the calm conditions of summer, often
making the first storms of the fall season
disproportionately effective in removing
large amounts of kelp (Zobell 1971;
Gerard 1976; Graham 1997).
Transport of passive propagules with Figure 2. Wrack abundance on beach inshore of Mohawk Reef
the ocean circulation controls
compared to loss rate of Macrocystis biomass from the kelp
connectivity between populations and
forest at Mohawk Reef. Peaks in loss generally occur in
winter/early spring, whereas peaks in wrack abundance on the
communities of many marine organisms
beach are often seen in autumn (Revell et al. 2011).
(e.g. Cowen et al. 2006 and references
therein). A predictive understanding of
how ocean currents advect drifting larvae from source to destination is therefore necessary to
understand population dynamics, genetics, and community interactions, and has been the focus of
considerable research effort (e.g. Parrish et al. 1981; Pineda 1991; Shanks et al. 2000; Siegel et al.
2003; Shanks and Brink 2005; Tang et al. 2006; Mitarai et al. 2008; Mitarai et al. 2009; Ohlmann and
Mitarai 2010). Other forms of ecological connectivity within the ocean have received scant attention.
An important example is trophic connectivity via transport of resources across ecosystem boundaries.
Giant kelp provides one of the best examples of such exchanges in the oceans. Macrocystis is
extremely productive, and generally <5% of kelp-derived net primary production (NPP) is consumed
locally within the kelp forest (Gerard 1976; Newell et al. 1982). Detached kelp plants are buoyant
and freely floating, facilitating their export from the kelp forest and advection by ocean currents.
Therefore, the vast majority of kelp forest NPP is exported as biomass from the local forest to other
ecosystems (Gerard 1976). An understanding of kelp biomass connectivity between forest and
shoreline is necessary to understand how drift kelp affects adjacent sandy beach ecosystems.
No studies targeting connectivity or fate and transport of kelp biomass in Southern California are
known to exist. This is likely due to the historic inability to accurately model ocean currents over the
inner continental shelf, and logistical difficulty of attaching large numbers of tags or tracking devices
to kelp plants and monitoring them as they move from the kelp forest. In an observational study,
Hobday (2000c) draws conclusions regarding kelp
connectivity from drifter trajectories that also begin
far offshore of kelp forests. Most trajectories
considered by Hobday (2000c) were released more
than 5-10 km from shore, and many were released as
far as 20 km away. These studies do not give
accurate representations of kelp connectivity because
trajectories considered do not connect to nearshore
kelp forests where exported kelp biomass originates.
Connectivity matrices for the Southern California
Bight have recently been developed from numerical
ocean circulation model results for larval transport
applications (Mitarai et al. 2009; Figure 3). The
proposed work considers trajectories that begin at
kelp forests and uses trajectories from a model with
Figure 3. Probability distribution (pdf; color
100 m spatial resolution, an order of magnitude finer contours) showing ending distribution of
than considered by Mitarai et al. (2009). Such model trajectories that begin within the black circle
resolution is necessary to resolve variability in flows located off the north shore of the Santa Barbara
that exist over the inner shelf (e.g. Lentz and Fewings Channel. The greatest number of trajectories reach
red regions and relatively few trajectories reach
2012), and has only recently become available.
blue regions. Figure from Mitarai et al. (2009). The
Wrack accumulation on beaches can be
proposed work will produce a similar product for
influenced by beach morphology in addition to
the ending distribution of kelp advected from a
delivery rates. In Barkley Sound, British Columbia,
specific forest.
cobble beaches accumulated more wrack than sand
beaches, likely due to interstitial trapping of the seaweed fragments (Orr et al 2005). Beach segments
with seawalls and reduced upper beach habitat due to coastal development accumulated significantly
lower wrack biomass (1 to 3 orders of magnitude) than adjacent unarmored segments of beach
(Dugan and Hubbard 2006). Intermediate morphodynamic beaches, however, dominate in Southern
California and beach morphology is relatively consistent away from armored shorelines and
prominent headlands. One simple measure, width of the dry sand area, explained ~40% of the
temporal variation in wrack biomass on two beaches (Revell et al. 2011), but in general there is little
correlation between wrack standing crop and measures of beach morphology (Dugan et al 2003). We
hypothesize that in this system, patterns in transport of kelp from nearby kelp forests is tightly
coupled to kelp supply to sandy beach communities, reducing complexity and creating an ideal
milieu in which to study the trophic linkage between these ecosystems.
Research approach.
Goal 1 of the proposed work, a quantitative understanding of the link between the kelp forest
and beached kelp wrack, will be accomplished through a combination of (1) trajectories from
numerical model results, (2) tagging living kelp plants with “drift cards” at their source location and
determining the distribution of the drift cards recovered on the shoreline, and (3) by monitoring
trajectories of kelp plants tagged at their source location with GPS devices (drifters). Objective 1 (an
observational characterization of drift kelp transport) will be met by tagging a large number (3000) of
individual kelp plants within a forest and recording the ending locations of drift cards, as is done in
drift card studies (e.g. Levin 1983; Ebbesmeyer et al. 2011). This approach provides information on
the shoreline distribution of kelp wrack, but does not inform on specific pathways or advection time
from forest to beach. GPS drifters will therefore be attached to naturally drifting kelp plants in the
forest to obtain 100’s of transport pathway and advection time observations. We have tested the latter
technique and it works well (see Methods below). Objective 2, a statistical model of trophic
connectivity between kelp forest and beaches, will be developed by first computing tens of
thousands of trajectories that emanate from a single kelp forest using Eulerian maps of modeled
surface current vectors, and then computing probability distribution functions (pdf) from the ending
positions of the model trajectories (modeling details in Methods Section; see also Mitarai et al. 2009).
2.3. Linking wrack abundance and variability with patterns and processes in beach ecosystems
Allochthonous resource subsidies can produce a variety of responses in recipient populations and
communities (Anderson and Polis 2004). Donor-controlled resources are predicted to stabilize
populations of consumers if allochthonous supply is steady, since consumers are not able to
overexploit the resource. Conversely, destabilization of consumer populations can result if
allochthonous resources subsidize predators or parasites to the extent that they can depress prey
towards extinction (Polis et al. 1997; Huxel et al. 2002). Seasonal or annual variability in resource
availability can lead to food webs with weak to moderate links between many interacting species;
such complexity may enhance the stability of food webs (Polis and Strong 1996; Huxel and McCann
1998; Huxel et al. 2002; Rooney and McCann 2012). Communities reliant on pulsed allochthonous
subsidies are therefore likely to be fundamentally structured by such variability in resource supply.
Resource limitation that varies in space and time may be a key factor influencing the persistence of
populations and the structure and dynamics of communities (Anderson et al. 2008). Inferior
competitors may be more likely to be excluded if resource supply to competitors is steady, whereas
in a pulsed system persistence can be achieved through more rapid response rates to resource inputs,
e.g. rapid immigration (Holt 2004). On sandy beaches receiving Macrocystis wrack, we predict that
the diversity and abundance of macroinvertebrates will vary positively with wrack abundance. Four
congeneric species of wrack-consuming talitrid amphipods can coexist on beaches in our study area,
as well as multiple species of predatory intertidal beetles. However, the relationship between
diversity and variability in wrack inputs may be nonlinear, with exclusion of some species at low
levels of variability due to competitive interactions, and also at high variability due to lack of
resources. Therefore we predict that diversity of wrack-associated invertebrate communities will be
highest at intermediate levels of variability in wrack inputs.
Macrophyte subsidies benefit consumers and higher trophic levels of the food web in a number of
coastal marine communities (Menge 1992; Bustamante et al. 1995; Vetter 1995; Bustamante and
Branch 1996) and islands, where marine subsidies, including macrophytes, carrion, and seabird
inputs greatly exceed terrestrial productivity (Polis and Hurd 1995; Anderson and Polis 1998; Stapp
and Polis 2003). For example, macrofaunal biomass has generally been shown to be higher on
beaches with larger amounts of macroalgal wrack (Stenton-Dozey and Griffiths 1983; McLachlan
1985; Bally 1987; Ince et al. 2007), but quantitative relationships between wrack abundance or flux
and sandy beach community structure are sparse. Most studies have been snapshots in space. On 15
beaches in southern California, species richness and abundance of macroinvertebrates were
positively correlated with standing crop of kelp wrack in an autumn survey (Dugan et al. 2003).
Abundance of two shorebird species that rely on macrofauna for food was positively correlated with
wrack biomass, and both macrofaunal and shorebird abundance, and macroinvertebrate species
richness, were severely depressed on beaches where wrack was regularly removed (Dugan et al.
2003). Information is lacking on temporal variability in animal abundance on sandy beaches and its
relationship with resource supply. Revell et al. (2011) found that wrack abundance declined during
an El Niño, and that long-lived macrofaunal species, e.g. clams, were still less abundant two years
afterward and shorebird populations had not recovered.
Few studies have quantified the influence of allochthonous subsidies on patterns of species
diversity (Vidal et al. 2000; Barrett et al. 2003; Anderson et al. 2008). The regularity and magnitude
of the subsidy is likely to be crucial in determining its impact on the recipient community,
underscoring the need to integrate studies of pulses and subsidies (Anderson et al. 2008). The effect
of resource variation is interrelated with the demography of species in the community; for example,
high variability may result in dominance of species with high population growth rates that track the
resource, while less frequent fluctuations can allow species with slower response rates and longer
lifespans to persist (Nisbet and Gurney 1982).
Ecologists are increasingly recognizing the importance of the relationship of diversity with
ecosystem function, and the fact that diversity of consumers, in addition to primary producers, can
influence diversity and abundance of prey (Duffy et al. 2007; Gross and Cardinale 2007; Byrnes and
Stachowicz 2009; Srivastava et al. 2009). Yet, most biodiversity and ecosystem function studies
have focused on primary producers in isolation from grazers. In theory, and to a lesser extent in
experimental results, ecosystem function (e.g. primary production) shows a positive relationship with
producer diversity as a result of both functional complementarity and selection of highly productive
species (Duffy et al. 2007). This result is predicted to change at higher trophic levels, and a major
reason for that is
thought to be the
donor-controlled
nature of plant
resources (nutrients,
light), compared to the
often densitydependent relationship
of consumers with
their food, which is
subject to
overexploitation (Ives
et al. 2005). In
subsidized
Figure 4. Trajectories of ~600 drifters deployed at 3 cross-shore locations (~0.5, 1.0, and 1.5 km
communities such as
from the coastline). A total of 12 drifters were deployed each week for an entire year (November
sandy beaches,
2007 to November 2008). Drifters were deployed in clusters of 3 to investigate relative dispersion.
resources are donorTracks are roughly 5-8 hrs in length. Red plus symbols indicate ending positions.
controlled similar to
the case for plant communities, and we predict that ecosystem function in these communities will
exhibit a positive relationship with consumer diversity. Therefore, we predict that ecosystem
function, in this case wrack consumption rate and secondary productivity, will mirror patterns in
diversity and peak at intermediate levels of variability in wrack inputs.
Research approach.
Goal 2, linking wrack abundance and variability with patterns and processes in beach
ecosystems, will be reached through an intensive biological sampling program focused on beaches
inshore of the focal kelp forest. To accomplish Objective 3 we will quantitatively measure wrackassociated macrofaunal and bird communities as well as wrack abundance across time and space,
distributing our sampling effort using information on beach kelp wrack distributions computed from
modeled trajectories determined as part of Goal 1.
To examine relationships between wrack distribution and species diversity and abundance
(Hypothesis 5), we will sample wrack-associated macrofaunal communities and birds, and physical
characteristics of the beach at 6 locations within a 10 km swath of shoreline directly inshore of the
kelp forest. This sampling will be done seasonally (four times per year) for three years. We will
begin this sampling after computing shoreline distributions of kelp wrack from model trajectories and
observations. In an attempt to encompass the entire gradient in wrack input rates, the 6 sites will be
chosen using estimated kelp beaching rates along the shore computed from ROMS model trajectories.
In subsequent years, the same 6 beaches will be sampled to allow evaluation of ecological effects of
interannual variation in wrack inputs within sites. Variability in wrack standing stock along the shore
within the sampled area is high (Figure 5), and any 6 sites will exhibit substantial variability even if
ROMS modeling is inadequate to capture most spatial variation in kelp transport patterns.
Objective 4 will be reached through a combination of process studies and population measurements.
First, the relationships between wrack input, consumer diversity and consumption rates will be
explored by measuring kelp consumption rates at our 6 study sites. To measure secondary production
of consumers, we will use the size distribution of populations at each study site and allometric
equations relating macrofaunal production to biomass and temperature. These measurements will
focus on the most abundant consumers, the talitrid amphipods Megalorchestia spp. and will be done
seasonally in conjunction with the ecological surveys. These consumption and production
measurements will then be linked back to site-specific wrack input calculated under Goal 1 to
explore the nature of their relationship with patterns of resource supply.
# fresh kelp plants
3. METHODS
35
Study sites. To capture temporal and
spatial variability in delivery of kelp
30
wrack to beaches, we will focus our
efforts on the well-studied kelp forest
25
at Mohawk Reef (Fig. 6) and the
nearby beaches. The Mohawk Reef
20
kelp forest is roughly 0.2 km2 and
contains roughly 10,000 kelp plants
15
(Reed et al 2008, Reed personal
communication). The location was
10
picked for its manageable size,
location in the region of targeted high5
resolution ocean circulation modeling,
and because biomass, production and
0
loss rates have been monitored
0
1000
2000
3000
4000
5000
monthly at the site since 2000 by the
Position (Meters)
Santa Barbara Coastal Long-Term
Ecological Research program (SBC LTER).
Kelp wrack transport observations. Kelp wrack transport will be observed by tagging/tracking live
kelp plants with drift cards and drifters with GPS positioning. At Mohawk Reef, 1000 mature kelp
plants (~10% of the population) will be tagged at the beginning of the study. Drift card tags will be
constructed of 4” x 6” x 0.5” wood and painted bright orange with non-toxic marine anti-fouling
paint. A steel washer will be bolted to each tag to achieve neutral buoyancy and facilitate detection
on the beach using metal detectors. Each tag will include a unique identification number (ID), a brief
explanation of its purpose, and instructions for contacting the research team with the tag’s ID and
location where it was found. The tags are to be similar in material and design to drift cards often used
to track ocean currents (Figure X; http://archive.orr.noaa.gov/faq_topic.php?faq_topic_id=4). Tags
will be attached to the base of kelp plants uniformly distributed within the forest. When plants are
tagged, their size (# of fronds) and location within the forest will be recorded on the drift card. The
kelp forest perimeter will be mapped with GPS coordinates,
enabling the starting position of each tagged plant (via its
attached drift card) to be precisely known. This will allow
analysis of how plant biomass, which is strongly correlated
with frond number (Reed et al. 2009), and relative location
within the forest affect the fate of detached kelp plants, and
vulnerability to detachment. Monthly diver surveys will be
done to record which plants are lost when and correlate loss
with significant storm events (see below).
Fate of tagged kelp plants will be determined as tags are
found during our beach surveys (described below), and by
Figure 6. Detached kelp plants were
tagged and released at the offshore edge of local beachcombers (as is typical in drift card studies) and
Mohawk Reef, a few hundred meters from during our beach surveys (described below). Over the past 8
years (2006-2013), yearly plant removal rates at Mohawk
the shoreline. The picture shows the large
Reef have averaged 86.5%, close to the 84% average across
amount of kelp between the tagged plant
and shoreline. Inset: Photograph of drifter
reefs in our area (Reed et al 2008). Therefore, we can expect
attached to freely floating kelp.
that approximately 860 of our tagged plants will be removed
from the forest during the first year. The recent NOAA
“Safe Seas” drift card study released cards ~15km offshore of the CA coast and achieved a >50%
card recovery rate (http://archive.orr.noaa.gov/dc_study.php?study_id=1). We expect a greater
recovery rate as the cards in our study are expected to be confined to limited stretch of beach inshore
of Mohawk Reef. Nevertheless, even if we assume a typical recovery rate of 50% for our cards, this
would still give an ending distribution with 425 data points after the first year, and 500 data points in
total. Thus, the number of tags proposed (1000) should ensure statistically meaningful results while
also being economically and logistically feasible. A small pilot effort showed that it takes a diver,
conservatively, 2 minutes to attach a tag; at this rate 1000 tags could be applied by a team of four
divers in ~8 diving hours, an effort that will be easily accomplished in one week. A set of ~600
drifter trajectories collected off the Santa Barbara coast over the course of a year indicate that ocean
surface currents primarily move nearshore drifters in the shoreward direction (Figure 3; Ohlmann et
al 2012b). These observations are the primary basis for hypothesis 2.
High resolution Microstar drifters, built by Pacific Gyre Corporation (Oceanside, CA), are
proposed for tracking drifting kelp plants originating at kelp forests (Figure 6). The Microstar records
its position with GPS and transmits the position data to a host computer through the Iridium satellite
network. Data transmission is near real-time allowing drifter positions to be monitored from any
computer with Internet access. Position data is accurate to within ~5 m. The spatial accuracy and
near real-time transmission enables drifters to be recovered and redeployed. The Microstar normally
uses a collapsible tri-star type drogue. In our application, we will attach the tracking buoy with
drifter electronics (hereafter “drifter”) to a detached kelp plant that would act as a drogue. To avoid
the direct influence of wind on the buoy, the in water drag area of kelp should be roughly 40 times
larger than the drag area of the surface float, and this is the case for whole plants with even a small
number of fronds (approximately ≥5). The Microstar has high resolution (required to resolve the
small scales of motion that characterize coastal flows) and is extremely economical (recoverable
rather than expendable) making it appropriate for the proposed work. Drifters for the project will be
borrowed from Ohlmann’s laboratory at UCSB, and made available to this project at minimal cost. A
more detailed description of the Microstar drifter is given in Ohlmann et al. (2005).
To address concerns raised in the previous submittal of this proposal (August 2012) about our
ability to tag and track kelp, we conducted a pilot experiment with the goal of demonstrating the
feasibility of tracking whole kelp plants with drifters. Four kelp plants (16-26 fronds) at the offshore
edge of Mohawk reef were detached and tagged with drifters on 23 April 2013. Initially, all four
plants moved mostly alongshore in the poleward direction (Figure 7). Three of the plants were
quickly caught up in the kelp forest canopy. One plant moved alongshore for nearly an hour before
becoming entangled in kelp canopy about 1km poleward of the release location. During the next 12
hours, all tagged kelp plants moved slowly (< 1 cm/s) in the onshore direction through kelp forests
(Figure 6). One kelp plant moved through the kelp forest, made its way along the coast (between the
kelp beds and shoreline) in the equatorward direction, and beached shoreward of Mohawk reef
roughly 24 hours after deployment (blue track in Figure 7). Two kelp plants remained stuck in the
Mohawk kelp forest and showed very little movement during three days of tracking. A single kelp
plant twice moved away from the Mohawk reef kelp forest and then back to the Mohawk reef kelp
forest (green and yellow loops shown in Figure 7). This plant was eventually beached ~16 km from
its release location after 5 days of drifting.
The pilot experiment demonstrates three things. First, kelp plants are easily tagged with GPS
drifters, the drifters stay firmly attached to the kelp (up to 5 days in our experiment), and they do not
alter the drift characteristics of kelp either in or out of a forest. There was no sign of drifters
becoming separated from kelp, suggesting that kelp plants could be tracked for much longer times.
Second, detached kelp is highly likely to get caught up in attached kelp canopy and remain in the
coastal ocean kelp forests for at least days (as observed) and presumably weeks. This is consistent
with common observations of detached plants within the forest by divers (Miller, personal obs.).
Third, once detached kelp breaks away from the bottom and from the attached kelp plants, ocean
currents can move it great distances in relatively short periods of time..
To understand actual pathways and advection time from kelp forest to beach, we will tag
detached plants at Mohawk Reef with drifters and track them until they either reach shore, appear
they are exiting the Santa Barbara Channel, or up to 30 days. Naturally detached kelp plants, which
are common in the forest, will be used whenever possible; otherwise plants will be manually
removed. We will tag 10 kelp plants with drifters each month in year 1 of the study, and 6 plants
every two months in years 2 and 3 of the study. This sampling scheme will give 120 trajectories in
year 1 and 36 trajectories in years 2 and 3, which should provide statistically significant information
(e.g. Ohlmann and Mitarai 2010, Ohlmann et al. 2012). The monthly tagging in year 1 will allow
synoptic scale variability to be resolved. Tagging in all years is sufficient for resolving seasonal
variations in kelp transport.Plants will be tagged at randomly selected positions within the forest,
chosen by dividing the forest into 10 x 10 m plots on a map, assigning each plot a number, and
randomly picking numbers each month.
Physical modeling. The Regional Oceanic Modeling System (ROMS) is a three dimensional model
that solves the primitive equations of motion in a rotating coordinate system including the effects of
stratification (Shchepetkin and McWilliams 2005). Existing ROMS solutions for the Southern
California Bight will be used with a horizontal grid resolution of up to 75 m, including tidal forcing
(Buijsman et al. 2012) and realistic atmospheric surface fluxes provided by the Weather Research
and Forecasting model (WRF). The model configuration consists of a series of one-way nested grids
with the coarsest and outermost domain L0 for the U.S. West Coast having a horizontal resolution of
5 km (514x402 grid cells), followed sequentially by L1, L2, and L3 with horizontal resolutions of 1
km, 250 m, and 75 m, respectively. Each domain has 40 (L0, L1, and L2) or 32 (L3) topographyfollowing levels
vertically stretched such
that grid cell refinement
occurs most strongly
near the surface and the
bottom. The model
topography is based on
the 30-arc second
resolution global
topography/bathymetry
grid (SRTM30; Becker et
al. 2009) and when
available, the 3 arcsecond product from the Figure 7. Tracks of kelp tagged with drifters, color coded by time. Small dots
show position data recorded with GPS every 10 minutes. All tagged plants
National Oceanic and
emanate from the offshore edge of the Mohawk reef kelp forest at the same
Atmospheric
Administration/National time. The longest track extends well beyond the map, cropped so the shorter
Geophysical Data Center tracks that stayed near Mohawk Reef can be seen.
(NOAA/NGDC) coastal
relief dataset (http://www.ngdc.noaa.gov/mgg/coastal/crm.html) for the near-shore regions. The
minimum water depths are 50, 3, 3, and 1.5 m for the L0, L1, L2, and L3 domains, respectively.
Detailed model descriptions are given by Buijsman et al. (2012) for the L0-L2 domains and
Uchiyama et al. (in review) for the L3 domain.
Kelp pathways from the Mohawk Reef kelp forest will be simulated by computing trajectories
from existing ROMS Eulerian velocity fields at 1 m depth using fourth order Runge-Kutta
integration or Adams-Bashford-Moulton predictor-corrector scheme following Mitarai et al. (2009)
and Ohlmann and Mitarai (2010). Kelp forest boundaries will be located with GPS positioning data
from a small boat survey. The starting location of trajectories within the kelp forest will be randomly
distributed following a uniform distribution. If results of the drift card study show spatial weighting,
it will be incorporated into model trajectory calculations. A set of thousands of trajectories will begin
each day. Trajectories will be integrated until they beach or leave the model domain. Probability
distributions of beaching location as a function of initial condition from the model trajectories will
provide a comprehensive Lagrangian PDF of the ending distribution of kelp biomass exported from
Mohawk Reef under varying conditions. These ROMS trajectory results will be validated using our
in situ kelp tagging observations following methods used in Ohlmann and Mitarai (2010). The drift
card data will be used to assess the verity of the Lagrangian PDFs computed with modeled
trajectories and the drifter data will be used to assess the verity of the modeled trajectory pathways.
The ROMS model in its described configuration is being used by Dr. Leonel Romero (UCSB) to
investigate the fate of freshwater runoff (which can provide nutrients to kelp forests) in the vicinity
of Mohawk Reefas part of the SBC LTER project. Thus, we will have easy access to the necessary
model results. It should be reiterated that no new ROMS model simulations are required (or will be
performed) as part of this study. Rather, we will simply compute surface current trajectories through
Eulerian surface current fields that have already been produced with ROMS simulations (e.g.
Ohlmann et al. 2012b). Further, the proposed work is focused on material and energy exchange
between ecosystems, and the influence of exchange on beach ecosystems. This requires a statistical
understanding of transport (i.e. ending distribution of kelp wrack along the shoreline), not an
understanding of the physics that give rise to the ocean currents that cause the transport. The latter
will not be considered in the proposed work (though the data collected will be useful in other more
physically-oriented studies). However, variation in kelp export associated with specific wave events
will be investigated by isolating trajectories (both modeled and observed) during times of large
waves as observed at a local NOAA NDBC Buoy (see Ohlmann et al. 2010a)..
Beach ecosystem surveys. To investigate cross-shore variability in kelp wrack flux, we will sample
a 10-km stretch of shoreline inshore of Mohawk Reef, centered on the kelp forest offshore (Figure 6).
Within this 10 km area, we will sample 6 different beaches, measuring wrack composition, cover and
depth (which is strongly correlated to biomass), diversity and abundance of shorebirds and
macrofauna, and beach morphology. These sites will be chosen to represent a gradient in wrack input,
using probability distributions of kelp plant beaching location from ROMS model trajectories (see
Section 2.3). We will use a stratified (by tide height and cross-shore) random sampling design to
capture within-beach variability at each site. Ecological sampling will be done seasonally, four times
per year, at these 6 sites for 3 years.
Cover and composition of macrophyte wrack will be determined at each of the 6 study sites as in
Dugan et al. (2003). Wrack cover, composition and depth will be measured with a line intercept
method on each of the transects used for macrofauna surveys and physical measurements. Cover of
major macrophytes (e.g., Macrocystis pyrifera, Phyllospadix spp., Egregia menziesii, Zostera
marina) will be calculated for each transect, and means will be calculated for each macrophyte type
for the site. Currently we have percent cover/biomass relationships that allow us estimate the biomass
of Macrocystis and Phyllospadix wrack from cover and depth data collected on these transects, and
we will develop relationships for the other major wrack species as part of this project. Macrocystis
makes up the majority of wrack on the study beaches, and is the preferred food of beach consumers
(Lastra et al. 2008), but other wrack species will also be evaluated as possible complimentary
resources when kelp wrack is scarce. Macroinvertebrate communities will be sampled on each
transect with sticky traps, standard insect net sweeps and cores (10 cm diameter, 20 cm deep) in a
stratified design targeting the upper and lower zones of wrack (10 pooled cores per zone per transect),
since these zones harbor different assemblages. All samples of animals and sticky traps will be
placed in labeled ziplock bags, and frozen or preserved for later processing. Core and net samples
will be sorted microscopically and all macrofauna (>1mm) will be counted and identified to species.
Animals retained on sticky traps will be counted and identified to major taxa. A separate set of 10
cores will be collected and sieved at each site for measurement of secondary production (see below).
Because estimates of species richness are dependent on sample size, transect samples will be sorted
to the extent necessary to reach the asymptote of species accumulation curves at each site (~6
transects, Dugan unpublished data), and excess transect samples will be collected to ensure the
asymptote is reached. Both species richness [estimated as observed richness and using Chao2, an
estimator of true richness that takes rare species into account (Colwell and Coddington 1994)] and
diversity indices (Shannon, Simpson index) will be used to examine the effect of wrack input on
beach communities. Bird abundance and richness will also be measured on the shoreline of each of
the same 6 sites. During each survey, all shorebirds, gulls and other birds, including seabirds and
terrestrial birds on the beach, will be identified to species whenever possible and counted by a single
observer stationed in a portable blind on the upper beach. Bird counts will be conducted for standard
5 min periods at each site and replicated over 3 days during the sampling week. As they are counted,
birds will be assigned to intertidal zones (upper intertidal, mid-intertidal, below WTO, swash zone)
and habitats (rocks, pools, wrack) and their behavior (feeding mode, roosting) noted. Bird diversity
will be assessed as for macrofauna. Because anthropogenic disturbance can affect birds, the number
of people and dogs on the beach and their zones of occurrence will also be quantified. Two teams of
2 observers will sample 1-2 sites/day each; all sites will be surveyed within one week and scheduled
so that the condition of the tide is constrained (0.75 m (2.5 ft) or lower tides spanning the two hours
preceding and following low tide). Dugan’s laboratory has >15yrs of experience sampling and
identifying sandy beach organisms, including birds.
To assess the effect of beach morphology and characteristics on wrack standing stock and
beach community structure,
we will also measure
physical characteristics of
each of the 6 study sites
seasonally. We will
measure overall intertidal
width and widths and slopes
of key ecological beach
zones as indicated by the
locations of water table
outcrop and high tide strand
line relative to the seaward
edge of terrestrial/dune
vegetation or toe of the
bluff (Revell et al. 2011).
Commonly used sediment- Figure 8. Map showing proposed study area with the Mohawk Reef kelp forest just
offshore. The six ecological sandy beach survey sites, locations of intensive biological
wave parameters, e.g.
sampling, will be located within a 10 km stretch of beach inshore of Mohawk Reek. The
Dean’s parameter Ω, while actual sites will be defined by the along-shore distribution of kelp wrack determined in year
useful in distinguishing
1 of the project.
between the reflective and the dissipative extremes of beach morphology, are inadequate to
characterize variability across the reflective-to-dissipative beach morphodynamic continuum because
all beaches are intermediate type in the SB Channel. The foreshore (intertidal) beach slope has been
shown to be a more sensitive index with which to characterize spatial and temporal changes in
intermediate beaches (Anthony 1998). Grain size of rinsed and dried sand samples from the wrack
zones above will be measured (Wentworth scale) using standard testing sieves.
To link the data attained in Goal 1 with community structure, we will use linear and nonlinear
least-squares techniques to test the nature of the relationship between wrack delivery rate and
standing stock on abundance and diversity of macroinvertebrates and birds across the 6 sites.
Variability in wrack inputs at each site will be estimated using the yearly coefficient of variation of
monthly wrack input calculated using modeled and observed results from Goal 1. To link yearly
variability in wrack inputs (CVs) with species diversity of invertebrate communities, we will
estimate mean yearly diversity from seasonal measurements for each site. Three years of sampling
will enable us to evaluate whether sites are consistent in their levels of wrack input variability (and
patterns of diversity) across years due to consistent patterns of physical transport.
Ecological process measurements. Consumption rates of kelp wrack will be measured by setting
out 6 replicate pre-weighed parcels of fresh kelp (collected in the swash zone before it washes
ashore) on the beach at each of the 6 study sites, collecting them after overnight exposure to beach
consumers, and weighing each parcel immediately after collection. Because the wrack will dry out
and lose weight with exposure, we will measure consumption in terms of carbon rather than mass. A
sample of the kelp will be collected at the time the kelp is weighed, and analyzed using a CHN
elemental analyzer (Carlo-Erba Flash EA 1112 series, Thermo-Finnigan Italia) in the UCSB Marine
Science Institute Analytical Laboratory. We can then convert the initial wet weight of the fresh kelp
to its carbon content. Upon collection the kelp parcels will be reweighed and another sample will be
collected and analyzed to convert the dessicated weight to carbon and allowing total consumed C to
be estimated. All organisms inhabiting each kelp parcel will be counted, identified, and weighed to
estimate biomass. These measurements will be done seasonally in the same month as the surveys.
Secondary production of talitrid amphipods, the most abundant wrack consumers and a
primary food source for shorebirds (Dugan et al. 2003) will be measured seasonally at the 6 study
sites using methods that have been applied to many crustacean species, including other amphipods
(Taylor 1998). A general allometric equation (P = 0.0049 * B0.80 T0.89) which relates daily
macrobenthic production P (g day-1) to ash-free dry weight B (g) and temperature T (C) has been
calculated from the published production rates of 41 invertebrate species (Edgar 1990) and extended
to adult and juvenile animals. Production will be estimated using the mean ash-free dry weight of
animals retained by sieves of differing mesh size, the abundances of animals in different sieve size
classes, and the general equations described above. The mean biomass of animals in the various sieve
size classes used in production calculations will be measured using the empirically derived equation
log B = - 0.01 + 2.64 * logS, where B is faunal ash-free dry weight (mg) and S is sieve size (mm).
Samples will be rinsed through a nested series of sieves (8.0-0.50 mm) stacked in descending order
of size and the AFDW calculated as the difference between the dried (60 C) and ashed (500 C for 2
h) weights of animals retained by each sieve (Edgar 1990). To test hypotheses 6 and 7, the
relationship of consumption rates and secondary production with species richness and wrack input
estimates from Goal 1 will be evaluated using least-squares fitted models.
IV. BROADER IMPACTS
Project Significance.
This project addresses an issue of broad current interest in ecology: how connectivity among donor
and recipient ecosystems influences resource variability and affects recipient food webs and
communities (Polis et al. 2004; Holt 2008), and does so in a predictive way at relatively large spatial
and temporal scales. This task is made possible through a collaborative interdisciplinary effort that
merges physical oceanography with biology. It moves beyond the typical static food web studies and
will help us understand how these communities respond to the environmental changes and
disturbances that cause productivity in the ecosystem to vary (De Ruiter et al. 2005).
Climate change will strongly impact both sandy beaches and kelp forests, as well as the
physical processes controlling connectivity between these ecosystems. Anthropogenic climate
change is likely to impact kelp forests through at least two direct effects: (1) increased stratification
and resulting lower nutrient supplies due to warming (Parnell et al. 2010) and (2) increased
frequency and intensity of winter storms and resulting increases in wave disturbance to kelp
populations (Byrnes et al. 2011). Beaches will be directly inundated by rising sea levels and
profoundly affected by altered storm intensities and frequencies, and beach invertebrate and wildlife
communities will be reshaped in response to changes in ocean chemistry, temperature, and
circulation that cause shifts in larval distributions, dispersal, habitat fragmentation, species ranges,
and species interaction and trophic relationships (Harley et al. 2006; Schlacher et al. 2007; 2008). At
the same time, human populations are disproportionately rising along the coastal zone, as are human
demands, such as resource extraction, recreation, and coastal development (Schlacher et al. 2008;
Dugan and Hubbard 2010). Many of these impacts will be synergistic with other anthropogenic
impacts on sandy beaches, potentially reducing the resilience of these vulnerable coastal ecosystems.
A quantitative understanding of ecological patterns and processes on sandy beaches is needed if we
are to predict impacts of climate change, as well as more immediate and visible anthropogenic
impacts to beach ecosystems, such as beach grooming and shoreline armoring.
Education, Training, and Outreach.
Because of the strong field component of this project, which will be done at a site close to UCSB’s
campus, it will provide a wealth of opportunity for student involvement. Dugan’s lab has trained over
sixty undergraduates in sandy beach ecology and this project will continue this legacy. We engage
under-represented high school students in our research through the UCSB Summer Sessions program,
and we will continue doing so with this project. The graduate student will mentor undergraduates
throughout the year and high school students in the summers. Our past experience has shown that
high school students benefit greatly from mentoring by undergraduate as well as from graduate
students and post docs, and the mentoring is in itself an important aspect of training for students.
Results of the proposed research will be disseminated to the public at large by interface
directly with SBC-LTER’s extensive outreach program, which includes the SBC LTER Schoolyard
Program, a combination of school-based activities, field trips, and an on-campus residential
experience that immerses local at-risk middle school students (7th–9th grade from Santa Barbara
Junior High School and Goleta Valley Junior High School) in the environment of a college campus.
Ohlmann has set up a web site where real-time tracking data is shown from the active Microstar
drifters (http://www.drifterdata.com). This will be incorporated into a Schoolyard lesson on
oceanography, and the students will be able to track drifting kelp plants in real time and learn about
the processes moving them, including alongshore currents and waves.
The kelp tagging project will also offer a significant opportunity for public outreach. We
plan to publicize this effort to maximize involvement of the local citizenry and our tag return rate. In
addition, we will organize a group of enthusiastic lay people to search for our tags, in a model similar
to the enormously successful Grunion Greeters (http://grunion.pepperdine.edu/), a group that Dugan
is involved with that monitors the reproduction of a fish species, the grunion, on California beaches.
Large numbers of retirees and others already take daily beach walks, and our project will turn some
of this activity into an educational experience that broadens public awareness of intertidal ecosystems.
Results of this project will not only be communicated through the scientific literature, but to the
public and other stakeholders via public lectures through the Santa Barbara Natural History Museum
and the Channel Islands National Park, both of which host public lecture series and have shown
interest in our previous research. Dugan’s participation as a founding member of the Beach Ecology
Coalition, a group working to enhance ecosystem conservation and beach management to balance
natural resource protection and recreational use through research, training, expertise exchange, and
outreach will provide direct communication to beach managers and policy makers.
Results from prior support
Dugan: Dugan is a new investigator with NSF. She is an associated investigator with Santa Barbara
Coastal LTER, and has coordinated a wider variety of studies of beach ecosystems and their role in
coastal nutrient cycling. This research has resulted in several peer-reviewed publications, including
Hubbard et al (2013), Barnard et al (2012), Schooler et al. (2012; In Press), Viola et al (In Press), and
Dugan et al (2011; 2013). The Hubbard et al (2013) study, , received considerable press, including radio,
television and newspaper (LA Times) coverage.
Ohlmann: OCE-0352187, Collaborative Research: Stochastic Transport Models for the Coastal Ocean,
$459,874 for the period 02/01/2004 – 01/31/07 awarded to C. Ohlmann, L. Washburn, and A. Mariano. A
new surface drifter technology is combined with HF radar data to develop a Lagrangian stochastic model
(LSM) for predicting trajectories through Eulerian time-space average surface current maps for the
coastal ocean. The following peer-reviewed publications resulted: Ohlmann et al. (2005), Ohlmann et al.
(2007), Ohlmann and Mitarai (2010), and Ohlmann et al. (2012b). The Ohlmann et al. (2007) study was
identified by the AMS as noteworthy, and summarized in a BAMS article. OCE-1031893, Collaborative
Research: The Propagating Response of the Inner Shelf to Wind Relaxations in a Coastal Upwelling
System, $698,120 for the period 07/1/2010 – 06/30/2014. The project is a comprehensive observational
and analytical program to examine the dynamics and source waters of relaxation flows in a coastal
upwelling system on the central California coast. The novel use of gliders to collect “moored” ADCP data
was demonstrated in years 1 and 2 of the project. Year 3 fieldwork is in progress.
Miller: OISE-1318469, Sources of particulate organic matter to suspension feeders in New Zealand kelp
forests, $58, 354 for the period 07/01/2013-07/01/2014 awarded to R Miller and HM Page. This is a
Catalyzing New International Collaborations (CNIC) award to extend NSF-supported research on kelp
forest food webs by Miller and Page to New Zealand. Miller has worked extensively with Page on the
project funded by OCE-962306, Sources of particulate organic matter and their use by suspension-feeders
in the coastal California ecosystem (PI - HM Page). Miller is an associated investigator with Santa
Barbara Coastal LTER, with whom he has made significant progress in our understanding of patterns of
primary production in kelp forests and competitive relationships between different groups of primary
producers. A major finding of this research was that production by understory algae and phytoplankton
can equal that of giant kelp when kelp abundance is low, potentially acting as a source of
complementarity dampening variation in production over time and space. The above research resulted in
several peer-reviewed publications in the last 4 years including Harrer et al (2013), Miller et al (2011;
2012, 2013), Miller and Page (2012) and Yorke et al (in press). 4 additional manuscripts are currently in
preparation.