Zooplankton of tidal marsh channels in relation to environmental variables in the upper San Francisco Estuary

Abstract

Zooplankton are important trophic intermediaries between aquatic primary producers and higher level consumers such as fish, but to date they have been little studied in intertidal marshes. This is particularly true in the San Francisco Estuary (SFE), which is heavily impacted by human activities and is being targeted for restoration of its native wetland communities. As part of a multi-year field study investigating wetland dynamics in the upper SFE, we conducted approximately quarterly sampling of the mesozooplankton (> 73 µm) at 3 channels in each of 6 marshes. Here, we describe seasonal and regional variation in the composition and abundance of zooplankton, and relate these to variations in environmental conditions. Cluster analysis identified 6 different marsh zooplankton communities. The 66 taxa identified included both native and non-indigenous species (NIS), with NIS being particularly dominant in the summer and autumn. Ordination analyses indicated that salinity, temperature, and other freshwater-related variables such as freshwater flow and distance to the coastal ocean were the strongest environmental drivers of marsh zooplankton community composition and individual abundance. Zooplankton communities in intertidal marshes were similar to those of open water habitats of the SFE in many regards, although differences in some taxa were observed, e.g. higher abundances of the copepod Eury temora affinis and lower abundances of tintinnid ciliates in the marshes. Apparent differences in zooplankton between intertidal marsh and open water habitats, and between different regions of the estuary, could have important implications for young fish and other consumers.

Zooplankton invasion on a grand scale: insights from a 20‐yr time series across 38 Northeast Pacific estuaries

“…, Graham and Bollens , Bollens et al. , , Breckenridge et al. ), with water column stratification, eutrophication, and other anthropogenic disturbances exerting further influence (Laprise and Dodson , Marques et al.…”

The trouble with stress: A flexible method for the evaluation of nonmetric multidimensional scaling

“…This latter point is especially critical given that datasets appear to be increasing in size over time—as one might expect given the ongoing maturation of long‐term studies and the growing prevalence of multi‐investigator projects. Indeed, our research group has published many papers ( n = 13) using NMDS, but only in relatively recent years have our sample sizes grown to n > 100 (Bollens et al ; Dexter et al ; Lee et al ; Hassett et al ).…”

“…Each panel plots this relationship for ordination in (k 5 2,3,4) dimensions, showing a clear decrease in ordination stress with increasing values of k. Each of the six data series are comprised of 10 independently generated samples at each value of n, with the resulting mean (1/2 SE) shown as a loess smoothed line with span set to 0.5. expect given the ongoing maturation of long-term studies and the growing prevalence of multi-investigator projects. Indeed, our research group has published many papers (n 5 13) using NMDS, but only in relatively recent years have our sample sizes grown to n > 100 (Bollens et al 2014;Dexter et al 2015;Lee et al 2015;Hassett et al 2017).…”

Factors Controlling Calanoid Copepod Biomass and Distribution in the Upper San Francisco Estuary and Implications for Managing the Imperiled Delta Smelt (Hypomesus transpacificus)

“…A wide diversity of factors has been implicated in regulating copepod species composition and numbers. This includes phytoplankton availability, competition for resources and predation on all life stages, toxic blue-green algae occurrences, floodplain inundation, water temperature, and salinity (Cryer and Townsend 1988;Orsi and Mecum 1996;Mauchline 1998;Sobczak et al 2002;Mueller-Solger et al 2006;Grosholz and Gallo 2005;Ger et al 2009;Brucet et al 2010;Greene et al 2011;Kimmel 2011;Bollens et al 2014;Durand 2015;O'Rear and Moyle 2018).…”