Estuaries and Coasts (2010) 33:182-194 DOI 10.1007/S12237-009-9235-Z Macrozooplankton Community Dynamics in Relation to Environmental Variables in Willapa Bay, Washington, USA Eileen S. Graham • Stephen M. Bollens Received: 16 July 2008 /Revised: 1 October 2009 /Accepted: 6 November 2009 /Published online: 8 December 2009 © Coastal and Estuarine Research Federation 2009 Abstract Willapa Bay is a large, economically and ecolog- Introduction ically important estuary on the Washington coast, USA for which the zooplankton community has not previously Estuaries been are complex ecosystems characterized by rapidly studied. Thus, in 2006 and 2007, six stations within Willapa fluctuating conditions where inputs from both river freshwater Bay were sampled biweekly for macrozooplankton, chloro-and oceanic coastal water can alter the environment as often as phyll, and various abiotic variables to elucidate the processes every tidal cycle. Although the environment of estuaries can underlying community composition and dynamics. Non-be stressful to organisms due to the large fluctuations in water metric multidimensional scaling identified water temperature conditions, organisms that can tolerate such changes thrive and upwelling values as major factors defining two distinct because of high productivity levels created by enriched temporal communities. High densities and a community nutrient concentrations (Correli 1978; Cole and Cloern dominated by oceanic species (Calanus pacificas, Centro- 1987; Howarth 1988). Macrozooplankton, classified in this pages abdominalis) marked the winter season, while summer study by a size larger than 500 'xm, are intermediate (or the upwelling season) was dominated by estuarine consumers found in most productive aquatic ecosystems. This species (Palaemonidae, Clevelandia ios). Smaller scale group consists of both holoplanktonic and meroplanktonic changes in the community were characterized by variation taxa that consume a large proportion of primary productivity in chlorophyll a concentration and salinity and were markedand act as intermediaries between primary producers and by the presence of other taxa (Neotrypaea calif orniensis, higher trophic levels (Gewant and Bollens 2005). This Mysidae). These results point to the importance of physical productivity is an important resource for many fish species processes, including the import of marine organisms that and utilize these rich systems during larval and juvenile stages retention of estuarine organisms, in the structuring whenof the food availability is paramount to survival (Gunderson et macrozooplankton community in Willapa Bay. al. 1990; Houde and Rutherford 1993; Beck et al. 2001). In estuaries around the world plankton communities Keywords Macrozooplankton • Community structure •have been found to correlate with various abiotic factors. In Multivariate community analysis • Ordination • Estuary a• study of several estuaries on the coast of Texas (USA), Washington coast Holt and Strawn (1983) found that significant differences in macrozooplankton community composition between warm E. S. Graham (M) and cool seasons were distinguished by salinity, due to river Applied Science Associates, Ine, flow, and temperature. Soetaert and Van Rijswijk (1993) 55 Village Square Drive, observed that salinity explained most of the variance within South Kingstown, RI 02879, USA e-mail: [email protected] a mesozooplankton community, while temperature played a much lesser role in the estuarine reaches of the Scheide S. M. Bollens River (Belgium and the Netherlands). The macrozooplank- School of Earth and Environmental Sciences, ton and micronekton community composition in San Washington State University Vancouver, 14204 NE Salmon Creek Ave, Francisco Bay (USA) was correlated with season and Vancouver, WA 98686, USA proximity to the mouth of the estuary (Gewant and Bollens Ô Springer This content downloaded from 130.95.106.69 on Sat, 03 Jun 2017 09:45:05 UTC All use subject to http://about.jstor.org/terms Estuaries and Coasts (2010) 33:182-194 183 2005). Season, as defined Because by Willapatemperature, Bay plays also playeda major a role in both the major role in describing economic two and distinct ecologie mesozooplankton health of the region, it is imperative communities in a Southernto document California its current estuary biological (USA) status. Due to biological (Elliott and Kaufmann invasions 2007). (Bollens et al. 2002; Wonham and Carlton 2005; Willapa Bay, an estuary Ruesink on et the al. 2006),southern aquaculture coast of activity (Simenstad and Washington state (USA), Fresh is part1995; of Ruesink a network et of al. estuaries 2006), and pesticide use along the west coast (Dumbauldof North America and Wyllie-Echeverria connected through 2003; Pulkkinen 2003), coastal hydrographie the processes estuary is (Emmett changing. et Macrozooplankton al. 2000). In are sensitive to Willapa Bay, where more changes than in half many of abioticthe surface factors, area naturaland or anthropogenic volume of the estuary (Holt are anddrained Strawn at low 1983; tide Soetaert (Hickey and Van Rijswijk 1993; Banas 2003), conditions Gewant may and be Bollens highly 2005), influenced and therefore by the community is coastal processes due a to good the candidate large exchange to analyze of water in conjunction with with variation in the coastal ocean. Other environmental inputs to Willapa conditions. Bay include Currently, the no studies have Willapa and Naselle rivers examined which the drain macrozooplankton largely undeveloped community in Willapa watersheds, a rarity Bay. in coastal For these systems reasons, (Secord the currentand Cohen status of Willapa Bay, its 2001). Although the planktonrelatively community, small drainage and may the providemechanisms affecting their some input into the system,dynamics the are effect important of this to input understand. may be superceded by the large This tidal study influence examined (Banas the macrozooplanktonet al. 2004). community The California Current of Willapa System Baydrives with the twocoastal objectives. oceans The first was to of the eastern Pacific; measure during the the composition, spring and distribution,summer it is and concentration of dominated by the southward macrozooplankton California Current, in Willapa while Bay the over two consecutive northward Davidson years.Current The prevails second during objective the wasfall andto correlate community winter (reviewed in variationsEmmett et to al. biotic 2000; andHickey abiotic and factors, Banas including chloro- 2003). Coastal upwelling phyll anda (chl-a) downwelling concentration, events other occur community members, annually prevailing duringsalinity, the temperature, summer and upwellingwinter, respec- indices, and tidal fluctua- tively (Hickey 1989). tions.In the Thesummer, larger northerly goal was winds to elucidate favor the relationships upwelling which brings between colder, species more and saline, their and environment nutrient- within Willapa Bay enriched water as close as well as aas few to providekilometers insights from into shore; estuarine zooplankton during the winter, winds dynamics from more the south generally. generate downwel- ling conditions that force warmer, less saline, and nutrient- reduced water onshore (Hickey and Banas 2003; Banas et al. 2004). In Oregon andMaterials andWashington, Methods these southerly winds also force the Columbia River plume back onshore at which point it can enter Willapa Study Site Bay (Roegner et al. 2002; Hickey and Banas 2003; Banas et al. 2004). Willapa Bay supports Willapa Bay commercialis a shallow estuary located between thefisheries for Dung- eness crab (Cancer mouth magister), of the Columbia River to the southEnglish and Grays sole (Parophrys vetulus), and the Pacific Harbor to the north (Fig.oyster 1). The drowned river(Crassostrea valley gigas). The oyster fishery is a large drains a relatively source small watershed of 2,900of km2 income (Emmett et to the region and produces between al.10% 2000; Hickey andand Banas 2003) and25% has an area ofof nearly the commercially harvested oysters in 350 the km2, half ofUSA which is intertidal (Emmett (Roegner et al. 2002). et al. 2000; Feldman et al. 2000; Ruesink et The estuaryal. is aligned2006). along a north-south The axis oyster and is fishery is facing major changes in its connected pest to the ocean management by a relatively small opening in the procedures as new regulations are forcing northwest corner. the One major fishery channel runs south from to the phase out the use of carbaryl (1-napthol n-methylcarbamate) mouth connecting with the Naselle River, while another runs in its management of burrowing shrimp (Pulkkinen east from the mouth to the Willapa River2003). (Banas et al. 2004). These endemic pests, the ghost shrimp Neotrypaea Tidal speed and influence vary over californiens the length and width of is and the mud shrimp Upogebia pugettensis, the estuary and over the tidal cycle burrow (Banas et al. 2004). into the substrate, compromise the sediment stability, and allow oysters to sink and suffocate (Feldman Field Sampling et al. 2000; Dumbauld et al. 2001). Without a viable alternative for pest control, the oyster fishery may suffer, Wecausing selected six sampling regionalstations within Willapa Bayeconomic problems and decreasing national oyster (Fig. 1) to cover the spatialsupply. extent of the bay and both major Ô Springer This content downloaded from 130.95.106.69 on Sat, 03 Jun 2017 09:45:05 UTC All use subject to http://about.jstor.org/terms