MACRQFAUNA DISTRIBUTIONS in the SWASH ZONE of NOURISHED and PROTECTED BARRIER ISLAND BEACHES

Ph.D. Dissertation Proposal

Cinde Donoghue

Department of Environmental Science

University of Virginia

5/10/94

V

In troduction:

With the increase in development on the nation’s beaches and barrier

islands has come a need to mitigate coastal erosion. Earlier forms of

erosion control consisted of “hard” engineering structures, such as groins,

sea walls and breakwaters. The hard structure method to stabilize

beaches is now avoided by most state agencies and the Army Corps of

Engineers. Today, the widely accepted approach to beach restoration is to

use “soft” engineering or sand replenishment. All of these engineering

practices have raised questions concerning how alterations to the

physical environment impact biological processes. Strong links between

beach characteristics and biology, such as the direct relationship between

beach morphology and sea turtle nesting (Ryder, 1991) or the tidal cycle

and spawning of the grunion on sandy beaches of California (Thompson and

Thompson, 1919) demonstrate the need for a thorough understanding of

both biotic and abiotic factors when managing the coast. The research

described in this proposal is designed to answer some of the fundamental

questions concerning the nature of the physical-biological link between

sandy beaches and swash zone macrofauna.

In comparison to other coastal regions, such as mud flats and rockyx

shores, exposed beaches have received less attention in terms of their

physical and biological interactions (McLachlan, 1983). The difficulty in

carrying out field work in this dynamic environment is at least partially

responsible for this neglect. Beach topography can vary daily, and

sediment transport can reverse direction within an hour (Inman et al.,

1980). The distribution of intertidal organisms changes with tidal, storm,

and seasonal cycles. Winds and waves alter the shore during storms,

sometimes changing the beach-face considerably within a few hours.

Because exposed beach ecosystems are subjected to such high physical

1

stress, it is expected that the distribution of organisms will have a

strong physical basis. For these reasons certain beach-face organisms,

such as Emerita taipoida, Donax variabilis and Scolelepis squamata,

have been used as indicators of the biological health of beaches. However,

recent studies suggest that many of these organisms have considerable

mobility and can migrate voluntarily with the aid of the beach-face wave

and current system (Perry, 1980; Wenner pers. comm.). These results may

cast some doubt on the degree of dependence by the organisms on the

physical processes, and thus bring into question their use or limit as

indicator species.

The spatial distributions of Emerita, Donax and S co le lep is are

examples of how some organisms are not totally dependent on the physical

processes. Although there are specific sand sizes, beach slope and wave

states that the organisms “prefer,” there is high variability in the

available field data (Bowman,1981; Bally,1983; Alexander et a l., 1993;

Fleishack and de Freitas, 1989). Alongshore aggregations of all three

species suggest some independence to the beach-face morphology (Wenner,

pers. communication), and there is a vertical component to the cross­

shore distribution of Em erita that occurs in response to beach cut and

fill during storms that may contribute to complexities in theirA

distributions which has not been investigated (Hayden, pers. comm.).

The several such discrepancies between physical processes and

macrofauna distribution have puzzled investigators since they first began

observing them in the 1970s. Either the organisms have more independent

mobility than previously assumed, or the sampling designs used have not

revealed the processes responsible for their distributions. To what extent

the distributions of Emerita, Donax and S co le lep is are dictated by

physical processes is the question this proposed study will attempt to

2

answer.

I have an excellent opportunity to address this question through

comparison of processes on two barrier island beaches: Pea Island, a

coarse grained beach on the Outer Banks of North Carolina that has been

modified and replenished with sand several times in the last three years,

and Hog Island, a fine grained, protected island on the eastern shore of

Virginia. I have been involved in monitoring the health of the Pea Island

beach following replenishment for the past three years. This monitoring

has resulted in the most extensive compilation of regional scale data on

Em erita densities and beach-face characteristics in existence, providing

valuable information on the long-term, large-scale distributions.

Although my focus will continue to be on Pea Island, data collected this

summer on Hog Island will provide valuable information for comparison

purposes (figs. 1 and 2). To date there has been no work on Emerita,

Donax or Scole lep is distributions on Virginia barrier islands other than

an investigation of the spawning season and larval life of Em erita at

nearby Virginia Beach (Hunter, 1973). Comparison of same season

sampling results of macrofauna distributions collected from two beaches

which have similar wave climates and species diversity, yet possess

different sand grain and beach-face characteristics has not, to myA

knowledge, been done before.

Background:

Several investigators have studied the relationship among abiotic

parameters and the distribution of beach face organisms (Salvat, 1964;

Eleftheriou and Nicholson, 1975; McLachlan et al., 1981; Fleischack and de

Freitas, 1989), however, their sampling was generally conducted during

the daylight hours, over a single day, at best repeated monthly, and usually

3

T L A N T I C

n r E a X

PEA I S L A N D

3000 '500

SCALE iN FEET3000 6(

T

\O

oO

Figure 1. Sampling site on Pea Island, North Carolina.

Shrub Thicket

Dense Grass

Sparse Grass

Fresh I Salt

| High Marsh

| Sait Flat

WaterMay. 1991 VCRLTER

Figure 2 Sampling site on Hog Island, Virginia.

along one transect across the coast. These sampling designs disregard the

temporal and particularly the alongshore spatial variability typical of an

exposed beach and are therefore of limited value.

In my research, I propose to examine relationships between physical

parameters and swash zone macrofauna distributions over several spatial

and temporal scales, both across and alongshore. I am convinced that the

impact of storms on the vertical component of cross-shore distribution,

and alongshore distribution due to the formation of cusps, will provide

important new insight to the links between physical and biological

processes on the beach. Comparisons between nourished and natural

portions of the beaches will also be made. This sampling scheme will

permit examination of the temporal and spatial scales of interest in this

ecosystem.

Although an investigation treating all aspects of these complex

beach ecosystems is admittedly ambitious and labor intensive, at this

initial stage I believe it is necessary in order to avoid the possibility of

missing key causal elements. After my preliminary work is completed it

will be possible to narrow the focus to those aspects that appear to be the

dominant factors influencing macrofaunal distributions.A

As stated earlier, the organisms I will investigate, Donax

variabilis, Emerita talpoida and Scolelepis squamata, are assumed by

most coastal scientists and engineers to be excellent indicator species

because they are the dominant beach-face organisms on the east coast,

they are large enough to be easily identified and inventoried in the field,

and their lifespans are long enough to permit observation of seasonal

variation in population densities. Species of Donax form the most

abundant group in exposed sandy beach environments around the world

(Ansell, 1983). This genus is followed closely in abundance by

crustaceans, such as Emerita. Polychaetes are ubiquitous to coastal

ecosystems, and in tropical and warm temperate areas rival Donax in

abundance. Scolelepis squamata is the most common polychaete on the

eastern coastal barrier islands of the U.S. (Day et al., 1971). All three

species are important food for birds, fish and larger crustacea. Therefore,

one may assume that engineering measures, such as beach nourishment

will have consequences beyond the beach-face.

Because these organisms live in and on the beach-face they are

adapted to high stress conditions. Em erita and Donax are both quite

mobile, “surfing" the beach with each wave uprush. As the tides change

these organisms migrate up and down the beach, maintaining their

position in the active swash zone where optimal feeding conditions exist

(Turner and Belding, 1957; MacGinitie, 1938). Emerita are capable of

moving into wetted sand by vibrating their lower appendages and creating

a “quicksand” in their immediate area (Matta, 1977). Donax burrow

rapidly into wet sand between each wave backrush to avoid being

stranded on dry sand above the uprush zone (Trueman, 1971; Leber, 1982).

S co le lep is ’ ability to burrow is crucial to its survival as it must remain

in moist sand to avoid dehydration. Anything that alters the beach-face,

including sand grain size, percentage of heavy minerals, wave energy, or

beach slope, has the potential to impact Donax, Emerita and S co le lep is

densities and distributions. However, this assumption of a complete

dependency between the range of physical processes and the distribution

of macrofauna across and along the beach may be presumptuous. Although

distribution of Em erita has been identified with sediment grain size in a

spectrum of 0.5-0.6 mm (Bowman, 1981), covariables have not been

factored out. Sco le lep is has been associated with areas of finer sand yet

this correlation is not very strong either (Bally, 1983). Donax variabilis

5

burrow successfully in fine-grained sand, yet they inhabit the spectrum of

gravely to fine sandy areas (Alexander et al., 1993). A comparison of the

sediment transport processes and beach attributes is fundamental to this

research and will make a valuable contribution to the existing literature.

Previous investigators have found that both the west coast species

Emerita analoga and the east coast Emerita talpoida are sensitive to air

and water temperatures (Barnes and Wenner 1968; Bowman and Dolan,

1981). These findings are supported by my preliminary data which

indicate positive correlations between temperature and abundance of

Emerita talpoida on Pea Island, North Carolina (fig. 3). Emerita talpoida

has been observed moving into deeper water in the winter at Cape Cod,

Massachusetts (Edwards and Irving, 1943). Investigators studying beaches

along the south eastern coast, however, have found no Emerita talpoida in

winter at stations of 2 to 3 meters in water depth (Matta 1977, Salomon

1976, Spring 1981). Overwintering females on these beaches probably

remain in swash zone (Nelson, 1985).

Samples I have collected from Pea Island reveal seasonal trends in

Emerita talpoida abundance with decreasing numbers occurring during the

winter months (fig 4 and 5). The possibility of Emerita talpoida moving

deeper into the sediment on the beach as temperatures drop has not been

thoroughly investigated. Low temperatures are also known to impact the

burrowing rates of Donax (McLachlan and Young, 1982). It is likely that

seasonal changes in population abundance in the three swashzone species

of interest may be at least partially explained by temperature changes.

Emerita talpoida can survive sea water concentrations of 14-62°/°o

up to six hours (Bursey and Bonner, 1977). This tolerance is especially

important to a surf zone filter feeder which is subject to daily

fluctuations in salinity due to evaporation of interstitial water and

avg

wat

er t

emp

average water temperature vs. total emerita

to <0 (J> CM tf)

total emerita

average air temperature vs. total emerita

to ® C\itotal emerita T_

Figure 3. Regressions of air and water temperatures with total monthly emerita population.

1500

800

600

400H

200 ̂

Annual Emerita Population Trend:Large, Medium and Small Crabs Along Pea Island

1 1 1eg C\| CMCT» o> CDco CO COCM -'»• ▼*“r-'

GO00

OCM

00

1— " I----"1----~ i— “ 1— “ 1-----1 ---- 1 1 1CM CM CM CM CM CM CM CM CO CO COa> O) a> o> o> a> CD o> a> cn o>*»•*

v— o> CO CM o* o> h- CMr— *■*"* ▼— CM CM ■*— T— T— CMO o V”C7) o O o y— CM T- CM coT“ ▼— T—

OCO

N.eg

date

Figure 4. Annual trend in Emerita population from 7/92 to 6/93

6/22

/93

EMERITA POPULATION TREND FROM OCTOBER 31, 1990 to JUNE 22 1993

O O r- r* f f- t*S S a g a o tA o iK > C E f r > * > > Z

a CM to g 52

58$»S>SS>SiS»§»SiS»8l8{8S8f8l&S{S»&8{8HMIS§S8MI(i^333Mkk§g§g§S8DATE

Figure 5. Two year trend in Emerita population density on Pea Island, N.C.

flooding with each tidal cycle. Survival beyond twenty-four hours

requires salinity within the range of 23-407 °o (Bursey, 1978). This may

account for the depression in Em erita density I have found within 1.5 km

along the open coast adjacent to Oregon Inlet where salinity has been

measured at 15°/oo(fig 6) The salinity tolerance of the other swash zone

species of interest are not known. In any case, tolerance does not

necessarily indicate “preference” and changes in salinity may impact

population distribution.

Donax, Scolelepis, and Em erita have demonstrated patchy long­

shore distribution, the cause of which has yet to be fully explained ( Bally;

1983; Bally, 1986; Perry, 1980). Some preliminary work with Em erita

analogs on the west coast indicates that patchiness tends to vary

diumally, decreasing at nights and increasing during daytime and the full

moon (Wenner, pers. comm). This phenomena has not yet been studied on

the east coast. By sampling intensively through tidal cycles, and different

tidal phases, the presence or absence of this diurnal variability may be

found to occur on the east coast. Less ephemeral aggregations of Em erita

analogs have also been observed, some remaining intact over several

months (Efford, 1965). Aggregations appear to occur according to age

class as well as gender (Wenner, 1987; Perry, 1980). Along Santa Barbara,4

California beaches, populations changed on a daily basis and from beach to

beach implying that aggregations are not maintained by individuals but are

in response to changing physical factors (Perry, 1980). Physical

characteristics which indicate high energy transfer and the movement of

large volumes of sand, such as cusps or bars, may also affect their

distribution (Ansell, 1983; Wenner, pers comm.). Because the alongshore

distribution of E m erita has not been found to correspond as expected

with these beach features, research focusing on this is especially

necessary.

7

Inlet

Emerita population along Pea Island 7/28/92

Figure 6. Emerita population along Pea Island showing depression on the north end near the inlet.

Effects of tidal stage, height of water table, and water filtration

rate on macrofauna! abundance and distribution have been observed in

several Southern Australian and African Beaches (Fleischack and de

Freitas, 1989; McLachlan et al., 1985). The correlation of these

parameters with Emerita taipoida, Donax variabilis and S co le lep is

squamata on the east coast barrier islands has yet to be investigated.

Numerous researchers have investigated the impact of beach

nourishment on macrobenthos (Reilly and Beilis, 1983; Gorzelany and

Nelson, 1987; Marsh et al., 1980; Hayden and Dolan, 1974), however, my

proposed dissertation project extends the scope of these previous

investigations. By combining previous data collected from The Fish and

Wildlife Service Pea Island beach monitoring projects with my

dissertation field work, data from this research will span four years. It

will cover four major hydraulic nourishment projects and one smaller

truck hauled nourishment. Monthly sampling for the first year of the study

included sediment grain size and sorting, wave height, swash width, water

temperature, beach slope and Em erita population density in both

nourished and control areas on the beach of Pea Island. During the second

and third year, percentage heavy minerals and mineral content analysis

were included as part of the monitoring. The proposed sampling regime

for the fourth year* will expand the data base to include Donax and

S co le iep is population densities, and more intensive sampling both

spatially and temporally on Pea Island as well as a comparison study on

Hog Island.

Specific Objectives:

1) To determine the impact of abiotic factors on the distribution of three

representative swash zone macrofauna species; the bivalve Donax

8

va ria b ilis , the hippid crab Emerita talpoida and the common polychaete

Scolelepis squamata.

2) To compare the distributions of Donax variabilis, Em erita talpoida

and Scolelepis squamata as well as physical parameters on two beach

types; a nourished, coarse grained, steep, beach on Pea Island, North

Carolina and a protected, fine grained, flat, beach on Hog Island, Virginia.

3) To investigate the relationship between post-storm beach morphology

(i.e. beach cusps) and the distribution of swash zone organisms.

4) And to develop a process-response biophysical model of the swash zone

of exposed sandy beaches.

Experimental Design:

Addressing the objectives listed above requires that my field

sampling encompass the alongshore, cross-shore, and vertical d istribution

patterns of Emerita, Donax and S co le lep is over seasonal, tidal and

diurnal time cycles. The Pea Island monitoring project mentioned

previously was designed to answer questions about large-scale, long-term

impacts of sand replenishment on the health of the beach. Sediment and

Em erita samples were collected monthly up the beach-face at transects

spaced 1/10 and 2/10 mile (160 and 320 meters respectively) along the

beach in both nourished and non nourished portions. From this monitoring,

seasonal variability in Em erita population densities and distributions

were determined in the cross-shore and regional longshore dimensions. I

have, however, observed aggregations of Emerita, Donax and S co le lep is

9

at a scale less than 1/10 mile (100-300 m). Beach cusps and sand bars

which may play a role in their distribution also occur within this scale. I

have found Em erita vertically distributed beyond the top 20 cm of

sampled sediment. Aggregations have been observed changing over tidal

cycles within a day (Wenner, pers. comm ). The field sampling proposed

for my dissertation work must therefore be designed to examine

macrofauna distribution at these observed scales of variability.

Field sampling

Sampling sites and times:

The field component of the study will consist of sampling on two

mid-Atlantic barrier islands. Sampling will continue on Pea Island, North

Carolina, in the nourished and non-nourished areas, however, I will sample

on a finer spatial and temporal scale. Sampling sites on an open sandy

beach similar to that found on Pea Island will be established on Hog Island

at the Virginia Coastal Reserve. The sampling sites will consist of a 200

meter area along the shore (fig 7). This along the coast length is long

enough to incorporate beach features such as cusps which range from 10

to 100 meters, and is small enough to sample aggregations of Emerita,

Donax and Scolelepis. I will establish five transects within the 200

meter area across the beach (fig 8) and sample for physical

characteristics such as upwash distance and time, swash period, wave

period, number of effluent line crossings, height of saturation zone,

salinity, water temperature, beach slope and sediment grain size (a

description detailing the sampling techniques is included in the appendix

of this document).

Samples from these transects will provide the data necessary to

create a contour map of the area. This contour map will provide physical

data at each randomly selected point where I will sample organism

1 0

Schematic of Alongshore Sampling Design:

200 m sampling area

nourished area(diagram not to scale)

Figure 7. Alongshore sampling design indicating 200 m areas in both nourished and non nourished portions of the beach.

tideefffuertt

hi9h tideeffbent iine

®Ure 8. Cm. "O^WfanCross section of

effluent /,„ **ach faro .

6S’ and m a n d ,^one mw:. d /ow fw QW ca te c . W e slvas/) ^

population densities. Twenty such random samples will be collected

during each sampling session. This is the maximum number of samples

that it is possible to analyze at the height of the biological season given

the amount of field assistance available. A grid of 1 m x 1 m cells will be

overlayed on the 200 m sampling area (fig 9). Prior to each sampling

session a random number generator will be used to select sites for

organism sampling. These sites will be mapped on the grid so each

location will be known and can be efficiently sampled. Two sampling

areas will occur outside the nourished region and two will occur within

the nourished region on Pea Island Two sampling areas will be

established on Hog Island. Sampling will occur over six 12.5-hour tidal

cycles. At least two tidal cycles will be sampled consecutively. During

each tidal cycle, samples will be taken at five intervals, at low tide,

rising mid-tide, high tide, falling mid-tide and low tide (fig. 10). It would

be desirable to repeat the sampling regime each month through the field

season (May through September).

Sampling will also be carried out immediately following any storm

which erodes at least 1.0 m of sediment from the beach face. These would

rate as class 2 to 3 on the Dolan/Davis storm scale (Dolan and Davis

1993). During these post storm periods, beach cusps are generally most

apparent. I will employ a similar grid scheme as described above that

will be overlain on cusps. Length and width of the grid will be determined

by the cusp size. Transects will be established through the horns and

embayments of the cusps. I will sample at least three cusps in this

manner. Post storm sampling will occur from May through September

when the population densities are at their highest.

Alongshore distribution:Alongshore distribution of E m erita will be investigated by tracking

11

Transect and Grid Design for sampling Along Beach

200 meters

Figure 9. Schematic of transect and sampling grid design indicating well sites along transect.

sites

high tide

A

Figure 10. Tidal cycle with sampling periods indicated.

aggregations and following the movement of groups over time. Groups can

easily be distinguished by the roughened beach surface within their

boundaries. When feeding, “v” marks from their antennae can be seen

protruding into the swash waters (Efford, 1965; Perry, 1980; and Diaz,

1980). The diameter of the aggregation will be measured and the

aggregation will be sampled to obtain an estimate of the density. Groups

can be dyed with a non-toxic long lasting dye that will aid in determining

group lifetime and the extent of intermingling among groups (Efford,

1966). Other methods of marking include cutting notches into the side of

the carapace with cuticle clippers (Dillery and Knapp 1970), or attaching a

cork to the posterior portion of the carapace with lightweight fishing line

(Diaz, 1980; Hayden, personal comm ). The corks can be color coded for

each aggregation. These last two methods have an inherent lim itation in

that only large individuals can be marked. Along shore distribution of

Donax and Scole lep is can also be observed using dye however

aggregations are not surficially obvious as are Emerita and will require

sieving to locate.

Across-shore distribution:

Samples will be collected from within the active swash zone. TheA

width of this zone will vary with the tide and beach slope. The vertical

component of the across-shore distribution will be examined by digging

below the top 20 cm of sediment within and above the swash zone and

recording populations of Em erita or Donax. I have found live E m erita in

field sand samples that have been stored for eight months and live Donax

that have been stored for two months. Groups of E m erita have been

observed below the top 20 cm sand (Hayden pers. comm), and I have found

large Em erita (>20 mm) up to a meter below the surface. This strongly

suggests that some of these organisms are able to survive beneath the

1 2

beach surface for long periods without feeding, perhaps from one season

to the next. It is well established that Em erita are capable of rapidly

burrowing downwards in wet sand, but cannot dig down more than a few

centimeters (Efford, 1966; Trueman, 1970 and others). In fact, their

anatomy has been described as specifically designed for burrowing

(Snodgrass, 1952; Pearse et al., 1942), however, their ability to dig

upwards remains unexamined. It is assumed that with each wave

backwash the sand above the crabs is loosened and washed away. Em erita

must quickly dig downwards again to maintain their position in the

shifting sand. When very high energy waves are hitting the beach the

velocity of the backwash may be so high that the Em erita must burrow

below the actively shifting sediment. Large volumes of sand are moved

onto and off of the beach during storms. The Em erita are perhaps trapped

after a storm and then released later during another storm that erodes or

cuts sand from the beach face.

Data AnalysisThe field data collected from the two beaches will be compared and

differences evaluated. Analyses of variance will be performed to compare

variances among and between the data from the sampling areas on each*

beach and over the diurnal, tidal and seasonal cycles. Multiple regression

will be used to test the hypothesis concerning the relationship between

physical parameters and macrofaunal distribution. Through statistical

analyses, the combined impact of abiotic parameters on macrofaunal

distribution at various temporal and spatial scales will be assessed. The

results will be interpreted and used to develop a process-response model

which will characterize the dynamics of abiotic parameters in the swash

zone.

1 3

Process-Response Model

The results of my analyses will provide the framework for a more

detailed explanation of the biophysical processes in the swash zone. A

qualitative model will be developed from this framework that will

integrate knowledge of the physical processes of wave dynamics and

sediment transport with information obtained from field sampling. Field

data of population densities and distributions of Emerita talpoida, Donax

v a r ia b ilis and Scolelepis squamata will be interpreted in the context of

what is currently understood of each organisms lifecycle, migration

patterns and reproductive behavior.

APPENDIX.

Sampling Techniques:

Grain size and sorting:

Cored samples will be collected using a 20 cm diameter, 20 cm deep

pvc plastic pipe. The sample will be poured through a 70 nm sieve to

remove the water. Mean grain size of the sand particles and percentage

gravel/shell fraction will be estimated using a rapid visual assessment

method. This method uses visual comparison of the field sample with

vials containing sand samples of predetermined mean grain sizes.

Accuracy of this method has been verified through comparison with

results from settling tube analysis of sediments and the difference

between the two was not statistically significant (Dolan, et al. 1993).

Every tenth sediment sample will be retained and brought back to the

laboratory for washing, drying, weighing, and grain size analysis for

verification of the field estimates.

Density counts:

As much of the sample processing as possible will be performed in

the field, including estimates of sediment size and sorting, as well as*

Donax, Emerita and Scolelepis density counts. The organisms will be

sampled using the same corer described above. Following extraction of

the core, the sample will be poured through a 1 mm sieve. Organisms will

be counted and classed for size and gender. Every tenth faunal sample will

also be retained for examination of biomass.

Wave and uprush measurements:

Velocity of wave uprush across the beach has been measured by a

variety of methods. Some more technical ones include videotaping the

1 5

uprush and viewing the tape through a computer video processor (Guza and

Thornton, 1982) or placing wires across the surf zone that are tripped as

water rushes up the beach face (Waddell, 1976). The spatial scale of this

study precludes the application of these methods, so I will use a method

that is more portable and less complicated. It involves placing stakes up

the beach at measured increments along the distance of runup, from the

point where the bore collapses to the point of maximum runup, and timing

the movement of the swash as it moves up past the stakes with a

stopwatch (Dolan and Ferm, 1966; McArdle and McLachlan, 1992). Wave

height and direction will be estimated by sight. These estimates can be

verified with wave gauge data available from an Corps of Engineers buoy

in Oregon Inlet for Pea Island and a NOAA buoy near Fishermans Island for

Hog Island. Wave and swash period will be measured by timing the

intervals between waves and swashes with a stopwatch.

Beach Slope:

Beach slope will be measured within the upper and lower limits of

the swash for each sampling session in a tidal cycle using a standard

compass (McArdle and McLachlan, 1992).

Ground Water Level and Number of Effluent Line Crossings:

Wells will be placed in transects across the beach-face so water

level and salinity can be sampled. Measurements will be relative rather

than absolute to determine changes after storms and over tidal cycles.

The number of times wave runup crosses the effluent line will be

recorded. The effluent line is the point where the beach face and water

table intersect. The beach face below the effluent line is saturated and

has a “glassy" appearance on sandy beaches (McLachlan et al., 1985). The

number of times this line is crossed by runup may be important in

saturated sand beyond the swash zone.

1 6

Salinity, Water and Air Temperature:

Salinity will be measured using a refractometer which can be

calibrated for accuracy using a conductivity meter. Water and air

temperatures will be measured with a standard thermometer several

times within each sampling area.

Preliminary Scheduling:

Spr ‘94 - Reconnaissance field sampling, review literature, write and

defend proposal

Sum ‘94- Continue literature review, begin field sampling, sample

processing, data analysis

Fall ‘94- Class work, continue field sampling, sample processing, data

analysis.

Spr '95- Class work, data analysis, dissertation writing

Sum ‘95- Complete comprehensive exams.

Fall ‘95- Dissertation writing and defense.

Alexander, R.R., R.J. Stanton Jr., and J R. Dodd, 1993, Influence of Sediment

Grain Size on the Burrowing of Bivalves.Correlation with Distribution and

Statigraphic Persistence of Selected Neogene Clams. Palaios, 8(3):289-

303.

Ansell", A.D. 1983, The Biology of the Genus Donax. In: McLachlan, A and T

Erasmus (eds ),Sandy Beaches as Ecosystems. The Hague:Junk pp. 607-

635.

Bally, R. 1983, Factors Affecting the Distribution of Organisms in the

Intertidal Zones of Sandy Beaches. In: McLachlan, A and T Erasmus

(eds.),Sandy Beaches as Ecosystems. The Hague:Junk pp. 391-403.

Bally, R., 1986 The Biogeography of Donax (Mullusca:Bivalvia). In: Donn,

T.E. (ed.) Biology of the Genus Donax in Southern Africa 1-6 Institute for

Coastal Research, University of Port Elizabeth, Report no. 5

Barnes, N. B., and A. M. Wenner, 1968, Seasonal Variation in the sand crab

E. analoga in the Santa Barbara area of California. Limnology andA

Oceanography, 13:465-475.

Bowman, M.L., 1981, The relationship of Em erita ta lpo ida to beach

characteristics. Master Thesis, University of Virginia, Charlottesville,

Virginia. 106 pp.

Bursey, C. R., and E. E. Bonner, 1977, Osmotic regulation and Salinity

Tolerance of the mole crab E. talpoida. Comp. Biochem Physiol.,

57A.207-21 0.

References:

1 8

Day, J.H., J.G. Field, and M.P. Montgomery, 1971, The Use of Numerical

Methods to Determine the Distribution of the Benthic Fauna Across the

Continental Shelf of North Carolina. J. Animal Ecology, 40:93-125.

Dolan, R., and Davis, R., 1993, Nor’easters. American Scientist, 81:428-

439,

Dolan, R., C. Donoghue, and A. Elmore, 1993, Monitoring and Analysis of

1992 Beach Nourishment Placed on Pea Island, North Carolina; Final

Report. Fish and Wildlife, Alligator River National Wildlife Refuge,

Manteo North Carolina Unpublished Report.

Dolan, R., and J. Ferm, 1966, Swash Processes and Beach Characteristics.

The Professional Geographer, 18(4) 210-213.

Edwards, G.A., and L. Irving, 1943, The Influence of Temperature and

Season Upon the Oxygen Consumption of the Sand Crab Em erita talpoida.

J. Cell Comp. Physiol., 21 (2): 169-1 82.

Efford, I. A., 1966, Feeding in the Sand Crab, Emerita Analoga.A

Crustaceana, 10:167-182.

Eleftheriou, A., and M.D. Nicholson, 1975, The Effects of Exposure on Beach

Fauna. Cahiers de Biologie Marine, 16:695-710.

Fleischack, P C , and A.J. de Freitas, 1989, Physical Parameters

Influencing the Zonation of Surf Zone Benthos. Estuarine, Coastal and

Shelf Science, 28:517-530.

1 9

Gorzelany, J.F., and W.G. Nelson, 1987, The Effects of Beach Replenishment

on the Benthos of a Sub-tropical Florida Beach. Marine Envi. Rsch., 21 :75 -

94.

Guza, R.T., and E. B. Thornton, 1982, Swash Oscillations on a Natural Beach.

Journa l of Geophysical Research, 87:483-491.

Hayden, B., and R. Dolan, 1974, Impact of Beach Nourishment on

Distribution of Emerita Talpoida, the Common Mole Crab. J. Waterways,

Harbors and Coastal Engineering Division ASCE, 100:WW2, 123-32.

Inman, D.L., J.A. Zampol, T.E. White, D.M. Hanes, B.W. Waldorf, and K.A.

Kastens, 1980, Field Measurements of Sand Motion in the Surf Zone.

Proc. 17th In. Coastal Eng. Congr., 1215-1234.

Leber, K.M, 1982, Bivalves (Tellinacea:Donacidae) on a North Carolina

Beach Contrasting Population Size Structures and Tidal ^Migrations Mar.

Ecol. Prog. Ser., 7:297-301.

MacGinitie, G.E., 1938, Movements and Mating Habits of the Sand Crab

Emerita analoga. Amer. Midi. Nat., 19:471 -481.A

Marsh, G.A., P R. Bowen, D R. Deis, D.B. Turbeville, and W.R. Courtenay Jr.,

1980, Ecological Evaluation of A Beach Nourishment Project at Hallandale

(Broward County), Florida, U.S. Army Corps of Engineers, CERC Misc. Rep.,

80-1(11)1-31.

McArdle, S B., and A. McLachlan, 1992, Sand Beach Ecology:Swash Features

Relevant to the Macrofauna. Jou. Coast. Rsch., 8(2):398-407.

20

McLachlan, A., 1983, Sandy Beach Ecology- A Review. In: McLachlan, A

and T Erasmus (eds.),Sandy Beaches as Ecosystems. The Hague.Junk pp.

321-380 .

McLachlan A., I.G. Eliot, and D.J. Clarke, 1985, Water Filtration through

Reflective Microtidal Beaches and Shallow Sublittoral Sands and its

Implications for an Inshore Ecosystem in Western Australia. Estuarine,

Coastal and Shelf Science, 21:91-104.

McLachlan, A, T. Wooldridge, T., and A H. Dye, 1981, The Ecology of Sandy

Beaches in Southern Africa. S. Afr. J. of Zooi, 16:219-231.

McLachlan A., and N. Young, 1982, Effects of Low Temperature on the

Burrowing Rates of Four Sandy Beach Molluscs. J. Exp. Mar. Biol. Ecoi,

65 :275-284.

Nelson, W.G., 1985, Physical and Biological Guidelines for Beach

Restoration Projects Part I, Biological Guidelines. Report No. 76 , Florida

Sea Grant College.

Reilly, F.J., and F.J. Beilis, 1983, The Ecological Impact of Beach

Nourishment with Dredged Materials on the Intertidal Zone at Bogue Banks,

North Carolina, University, Army Corps of Engineers, CERC Misc. Rep.,

83(3), 1-74.

Ryder, C.E., 1991, The Effect of Beach Renourishment on Sea Turtle

Nesting and Hatch Success. Sebastion Inlet State Recreation Area East-

Central Florida. Submitted to: Sebastion Inlet Tax District Commission,

29 pps.

21

Salvat, B., 1964, Les Conditions Hydrodynamiques Interstitielle des

Sediment Meubles Intertidaux et la Repartition Verticale de la Jenne

Endogee. C.R. Academie Sciences Paris, 259:1567-1579.

Thompson W.F., and J.B. Thompson, 1919, The Spawning of the Grunion

Fish Bull., 3:2-29

Trueman, E. R., 1971, The control of Burrowing and the Migratory

Behaviour of Donax denticulatus (Bivalvia Tellinacea). J. Zoo!., Lond.,

1655:453-469.

Turner, H.J., and D.L. Belding, 1957, The Tidal Migrations of Donax

variabilis. Limnol. Oceanogr., 2:120-124.

Waddell, E., 1976, Swash-Groundwater-Beach Profile Interactions In:

Davis, R.A. and R. E Ethington (eds.) Beach and Nearshore Sedimentation.

Society for Economic Paleontology and Mineralogy, Special Publication pp

115-125.

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